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Controversy and Debate: Memory based Methods Paper 2
... Given the fictional discourse on diet-disease relations and the escalating debate over the validity of M-BMs (16,17,(61)(62)(63)(64), the purpose of this critical analysis is to present evidence that the current controversies regarding diet-disease relations are not driven by legitimate differences in scientific inference on the physiologic effects of dietary intake (i.e., consumed foods and beverages). Rather, we contend that current confusion on the putative health effects of dietary sugar, salt, fat, and cholesterol were engendered by a fictional discourse on diet-disease relations created by deeply flawed, demonstrably misleading, and pseudoscientific nutrition epidemiologic reports (9, 15-17, 20, 21, 23, 55). ...
... Most recently, the Journal of Clinical Epidemiology published a series of "Controversy and Debate" articles on the "Fatal Flaws of Food Frequency Questionnaires. . . " (16,17,63,64). In our target paper (17), we presented a number of very specific challenges to the status quo in nutrition epidemiology. ...
... In our target paper (17), we presented a number of very specific challenges to the status quo in nutrition epidemiology. Nevertheless, our esteemed opponents in the debate failed to address the issues and chose to offer mere ipse dixit statements and fallacious arguments (e.g., ignoratio elenchi, ad hominems, ad populum) (63,64). Thus, in our closing statement we wrote that improving nutrition science and public health policy will be achieved only if the epidemiologic research community acknowledges and addresses contrary evidence and empirical refutations (16). ...
Controversies regarding the putative health effects of dietary sugar, salt, fat, and cholesterol are not driven by legitimate differences in scientific inference from valid evidence, but by a fictional discourse on diet-disease relations driven by decades of deeply flawed and demonstrably misleading epidemiologic research. Over the past 60 years, epidemiologists published tens of thousands of reports asserting that dietary intake was a major contributing factor to chronic non-communicable diseases despite the fact that epidemiologic methods do not measure dietary intake. In lieu of measuring actual dietary intake, epidemiologists collected millions of unverified verbal and textual reports of memories of perceptions of dietary intake. Given that actual dietary intake and reported memories of perceptions of intake are not in the same ontological category, epidemiologists committed the logical fallacy of “Misplaced Concreteness.” This error was exacerbated when the anecdotal (self-reported) data were impermissibly transformed (i.e., pseudo-quantified) into proxy-estimates of nutrient and caloric consumption via the assignment of “reference” values from databases of questionable validity and comprehensiveness. These errors were further compounded when statistical analyses of diet-disease relations were performed using the pseudo-quantified anecdotal data. These fatal measurement, analytic, and inferential flaws were obscured when epidemiologists failed to cite decades of research demonstrating that the proxy-estimates they created were often physiologically implausible (i.e., meaningless) and had no verifiable quantitative relation to the actual nutrient or caloric consumption of participants. In this critical analysis, we present substantial evidence to support our contention that current controversies and public confusion regarding diet-disease relations were generated by tens of thousands of deeply flawed, demonstrably misleading, and pseudoscientific epidemiologic reports. We challenge the field of nutrition to regain lost credibility by acknowledging the empirical and theoretical refutations of their memory-based methods and ensure that rigorous (objective) scientific methods are used to study the role of diet in chronic disease.
... At a group level, people may be asked to report their consumption to inform nutritional guidelines and public policy; this information is also used to understand the association between diet and disease (e.g., Afshin et al., 2017;Forouzanfar et al., 2015). These reports of dietary consumption rely on people's memories, which has led to criticisms about the validity of the information reported because they are not direct measures of intake and there is no way to determine whether the reported consumption matches people's actual consumption (e.g., Archer et al., 2018; although see Martin-Calvo & Martinez-González, 2018). In the current study, we considered dietary consumption to be a repeated event because meals are similar types of experiences that involve the same actions, and often occur in the same locations with the same people (Dilevski, Paterson, Walker, & van Golde, 2021). ...
Self‐reported dietary intake is commonly used to inform policy; however, memory‐based reports are subject to error. Our aim was to examine dietary reporting errors using a repeated‐events framework. Participants ( N = 102) completed a 3‐day food diary and 10 days later recalled what they had consumed on one self‐nominated day and one experimenter‐nominated day from the diary period. Self‐nominated day reports were more accurate than experimenter‐nominated day reports. Across both days, participants made more errors by reporting a food from the wrong day than by reporting foods not recorded in the diary at all. Unexpectedly, participants who completed their food‐diary across Sunday–Monday–Tuesday were more accurate than those who completed across Thursday–Friday–Saturday, and participants who completed the study in 2020 were more accurate than those who completed it in 2021/2. Overall, results are consistent with the repeated events literature and outline a new approach to better understand dietary self‐reporting.
... Although controversy exists in the literature relating to the accuracy and validity of self-reported dietary intake as estimated by Food Frequency Questionnaires, 24-h dietary interviews, and dietary records [46,47], the first limitation of our study is the lack of reports the athletes' dietary data. Further, we did not measured stool metabolites and therefore were unable to confirm the effects of any significant increase of intestinal SCFA producers at the end of the training period. ...
Background
Physical exercise has favorable effects on the structure of gut microbiota and metabolite production in sedentary subjects. However, little is known whether adjustments in an athletic program impact overall changes of gut microbiome in high-level athletes. We therefore characterized fecal microbiota and serum metabolites in response to a 7-week, high-intensity training program and consumption of probiotic Bryndza cheese.
Methods
Fecal and blood samples and training logs were collected from young competitive male ( n = 17) and female ( n = 7) swimmers. Fecal microbiota were categorized using specific primers targeting the V1–V3 region of 16S rDNA, and serum metabolites were characterized by NMR-spectroscopic analysis and by multivariate statistical analysis, Spearman rank correlations, and Random Forest models.
Results
We found higher α-diversity, represented by the Shannon index value (HITB-pre 5.9 [± 0.4]; HITB-post 6.4 [± 0.4], p = 0.007), (HIT-pre 5.5 [± 0.6]; HIT-post 5.9 [± 0.6], p = 0.015), after the end of the training program in both groups independently of Bryndza cheese consumption. However, Lactococcus spp . increased in both groups, with a higher effect in the Bryndza cheese consumers (HITB-pre 0.0021 [± 0.0055]; HITB-post 0.0268 [± 0.0542], p = 0.008), (HIT-pre 0.0014 [± 0.0036]; HIT-post 0.0068 [± 0.0095], p = 0.046). Concomitant with the increase of high-intensity exercise and the resulting increase of anaerobic metabolism proportion, pyruvate ( p [HITB] = 0.003; p [HIT] = 0.000) and lactate ( p [HITB] = 0.000; p [HIT] = 0.030) increased, whereas acetate ( p [HITB] = 0.000; p [HIT] = 0.002) and butyrate ( p [HITB] = 0.091; p [HIT] = 0.019) significantly decreased.
Conclusions
Together, these data demonstrate a significant effect of high-intensity training (HIT) on both gut microbiota composition and serum energy metabolites. Thus, the combination of intensive athletic training with the use of natural probiotics is beneficial because of the increase in the relative abundance of lactic acid bacteria.
... Second, we used self-reported information, which Fig. 1 Directed acyclic graph (DAG) of the hypothesized association between parental underestimation of their offspring's weight status, parental healthy dietary attitudes and offspring's risk of overweight or obesity is susceptible to misclassification bias. Nevertheless, a validation study of the anthropometric measures reported by parents of participants in the SENDO project showed high correlation coefficients between the measured and the reported data [37]. Third, our sample was not representative of the pediatric population. ...
Background
The association between parental perception of child’s weight and their attitudes towards his/her dietary habits has not been reported yet. This study aimed to assess the association between parental underestimation of child’s weight and parental attitudes towards child’s dietary habits.
Methods
We conducted a cross-sectional analysis of SENDO cohort participants recruited between January 2015 and June 2020. All information was collected through online questionnaires completed by parents. We calculated crude and multivariable-adjusted odds ratio (OR) and 95% confidence intervals (CI) for unhealthy attitudes towards child’s dietary habits associated with parental underestimation of child’s weight.
Results
Sixteen percent of children in the SENDO project had parents who underestimated their weight. Parents who underestimated their child’s weight status were more likely to have unhealthy attitudes toward his/her dietary habits [OR 3.35; 95% CI (1.71–6.53)].
Conclusions
Parental underestimation of child's weight was associated with unhealthy attitudes towards child’s dietary habits. Pediatricians and public health practitioners should pay attention to the parental perception of child’s weight to identify parents who underestimate it as an at-risk group in which to inquire about lifestyle and dietary habits.
... Dietary assessment methods, including food frequency questionnaires, are useful and valid to assess diet-disease relationships in epidemiological studies and have contributed to science for decades through studies investigating the association between dietary intake and the occurrence of clinical outcomes, in general related to chronic non-communicable diseases [5,6]. It is a culturally specific instrument; this is why it is important to assess whether each new FFQ presents reproducible and valid results for the target population of the study [7]. ...
Objective This study evaluated reproducibility, relative validity, using a 24-hour recall questionnaire as a reference standard, and estimated calibration factors for a food frequency questionnaire adapted for use with German descendants living in Brazil. Methods The target population consisted of 50 volunteers, of both genders, aged over 20 years, living in a German colonization city in southern Brazil. The food frequency questionnaire was applied twice, in the first and third months of the investigation. During this period, three 24-hour recalls were applied, with an interval of one month between them. Reproducibility was estimated by the intraclass correlation coefficient. Validity was tested by the intraclass correlation coefficient, weighted kappa test and Bland-Altman method. Calibration factors were estimated using linear regression. Results Among the food frequency questionnaires, there was a strong correlation for energy and most of the nutrients corrected for energy. There was a weak correlation between a food frequency questionnaire and a 24-hour dietary recall. However, the exact concordance in the categorization in tertiles among the instruments ranged from 28% (vitamin A) to 52% (fiber and potassium). Gross values of the food frequency questionnaire were reduced with the calibration and approached the consumption data estimated by the 24-hour dietary recall. Conclusions The food frequency questionnaire showed good reproducibility, however, weak correlation with the 24-hour dietary recall. The calibration of the data obtained by the food frequency questionnaire brought them closer to the reference method.
... Self-report methods of dietary intake assessment, such as food diaries, 24-hour recalls, and FFQs, have been a longstanding topic of debate in nutritional research (17,38), while remaining the most prevalent techniques to assess diet-disease relationships (4,39). Critics state that the reliance on memory and the influence of researcher/social-approval biases can incur random and systematic measurement errors, such as the over-reporting of FV intake (12)(13)(14)17). ...
Background
Dietary assessments in research and clinical settings are largely reliant on self-reported questionnaires. It is acknowledged that these are subject to measurement error and biases and that objective approaches would be beneficial. Dietary biomarkers have been purported as a complementary approach to improve the accuracy of dietary assessments. Tentative biomarkers have been identified for many individual fruits and vegetables (FVs), but an objective total FV intake assessment tool has not been established.
Objectives
To derive and validate a prediction model of total FV intake (TFVpred) to inform future biomarker studies.
Methods
Data from the National Diet and Nutrition Survey (NDNS) were used for this analysis. A modeling group (MG) consisting of participants aged >11 years from the NDNS years 5–6 was created (n = 1746). Intake data for 96 FVs were analyzed by stepwise regression to derive a model that satisfied 3 selection criteria: SEE ≤80, R2 >0.7, and ≤10 predictors. The TFVpred model was validated using comparative data from a validation group (VG) created from the NDNS years 7–8 (n = 1865). Pearson's correlation coefficients were assessed between observed and predicted values in the MG and VG. Bland-Altman plots were used to assess agreement between TFVpred estimates and total FV intake.
Results
A TFVpred model, comprised of tomatoes, apples, carrots, bananas, pears, strawberries, and onions, satisfied the selection criteria (R2 = 0.761; SEE = 78.81). Observed and predicted total FV intake values were positively correlated in the MG (r = 0.872; P < 0.001; R2 = 0.761) and the VG (r = 0.838; P < 0.001; R2 = 0.702). In the MG and VG, 95.0% and 94.9%, respectively, of TFVpred model residuals were within the limits of agreement.
Conclusions
Intakes of a concise FV list can be used to predict total FV intakes in a UK population. The individual FVs included in the TFVpred model present targets for biomarker discovery aimed at objectively assessing total FV intake.
... However, recall-based assessment methods remain reasonable representations for health behaviors with alternative biases and problems inherent in observed assessment methods. 43,44 Some self-reported exposures and covariates captured by UK Biobank at baseline will have changed during follow-up (eg, average TV time may have reduced for some individuals), and our results do not account for these changes. ...
Objective
To inform potential guideline development, we investigated nonlinear associations between television viewing time (TV time) and adverse health outcomes.
Methods
From 2006 to 2010, 490,966 UK Biobank participants, aged 37 to 73 years, were recruited. They were followed from 2006 to 2018. Nonlinear associations between self-reported TV time (hours per day) and outcomes explored using penalized cubic splines in Cox proportional hazards adjusted for demographics and lifestyle. Population-attributable and potential impact fractions were calculated to contextualize population-level health outcomes associated with different TV time levels. Nonlinear isotemporal substitution analyses were used to investigate substituting TV time with alternative activities. Primary outcomes were mortality: all-cause, cardiovascular disease (CVD) and cancer; incidence: CVD and cancer; secondary outcomes were incident myocardial infarction, stroke, and heart failure and colon, lung, breast, and prostate cancer.
Results
Those with noncommunicable disease (109,867 [22.4%]), CVD (32,243 [6.6%]), and cancer (37,81 [7.7%]) at baseline were excluded from all-cause mortality, CVD, and cancer analyses, respectively. After 7.0 years (mortality) and 6.2 years (disease incidence) mean follow-up, there were 10,306 (2.7%) deaths, 24,388 (5.3%) CVD events, and 39,121 (8.7%) cancer events. Associations between TV time and all-cause and CVD mortality were curvilinear (Pnon-linear ≤.003), with lowest risk observed <2 hours per day. Theoretically, 8.64% (95% confidence interval [CI], 6.60-10.73) of CVD mortality is attributable to TV time. Limiting TV time to 2 hours per day might have prevented, or at least delayed, 7.97% (95% CI, 5.54-10.70) of CVD deaths. Substituting TV time with sleeping, walking, or moderate or vigorous physical activity was associated with reduced risk for all outcomes when baseline levels of substitute activities were low.
Conclusion
TV time is associated with numerous adverse health outcomes. Future guidelines could suggest limiting TV time to less than 2 hours per day to reduce most of the associated adverse health events.
... However arguments against self-reported information sometimes show a lack of understanding of basic principles in epidemiology. 23, 24 We observed a high response rate on birth information (over 99% for birth weight and gestational age). The differences observed between the participants in the validation sample and the rest of the children in the SENDO project do not affect the interpretation and validity of the results, as they are not related to parents' capacity of reporting birth information data. ...
Objective:
To test the validity of parent-reported birth information obtained through an online, self-administered questionnaire.
Method:
The SENDO project is a prospective and dynamic paediatric cohort of Spanish children aged 4 to 6 years old at recruitment. Objective data from medical birth records were compared to parent-reported data getting intra-class correlation coefficients (ICC) for quantitative variables and weighted Kappa Index for qualitative ones. Percentage of responders and of total agreement was also evaluated.
Results:
Parental response rate was over 99% for birth weight and gestational age and 76% for birth length. ICC for birth weight was 0.95 (95% confidence interval [95%CI]: 0.94-0.96) and 0.78 (95%CI: 0.73-0.83) for birth length, both showing very high correlations. The total agreement percentage for gestational age was 97%, and Kappa weighted index was 0.90 (95%CI: 0.89-0.90), showing a very high agreement as well.
Conclusions:
We found high correlations and excellent agreement in parent-reported birth data 4 to 6 years after delivery. Our results show parent-reported birth data, especially birth weight, are valid for use in epidemiological research.
... However, other investigators strongly disagree with the assertions made by those authors regarding the validity and usefulness of FFQs and other M-BM in assessing diet-disease relationships in epidemiologic studies. Indeed, Martin Calvo and Martinez-Gonzalez [40] emphasized that the growing evidence regarding diet-disease relationships found in observational studies based on M-BM is sufficiently reliable to be used for public health policies. In addition, well-controlled prospective studies using objective biomarkers of intake have confirmed the results of previous studies using self-reported dietary assessment methods. ...
Diet is one of the key modifiable behaviors that can help to control and prevent non-communicable chronic diseases. Therefore, it is important to evaluate the overall diet composition of the population through non-invasive and independent indexes or scores as diet quality indexes (DQIs). The primary aim of the present work was to estimate the adequacy of the intake of critical nutrients in the Spanish “Anthropometry, Intake, and Energy Balance Study” (ANIBES) (n = 2285; 9–75 years), considering, as a reference, the European Food Scientific Authority (EFSA) values for nutrients for the European Union. We also assessed the quality of the diet for adults and older adults using four internationally accepted DQIs, namely the Healthy Diet Indicator (HDI), the Mediterranean Diet Score (MDS), the Mediterranean Diet Score-modified (MDS-mod), and the Mediterranean-Diet Quality Index (MED-DQI), as well as the ANIBES-DQI, stratified by education and income. The ANIBES-DQI was based on compliance with EFSA and Food and Agriculture Organization recommendations for a selected group of nutrients (i.e., total fat, saturated fatty acids (SFAs), simple sugars, fiber, calcium, vitamin C, and vitamin A), with a total range of 0–7. Misreporting was assessed according to the EFSA protocol, which allowed us to assess the DQIs for both the general population and plausible reporters. The majority of the Spanish population had high intakes of SFAs and sugars and low intakes of fiber, folate, and vitamins A and C. In addition, about half of the population had low DQI scores and exhibited low adherence to the Mediterranean diet pattern. Overall, older adults (>65–75 years) showed better DQIs than adults (18–64 years), without major differences between men and women. Moreover, primary education and low income were associated with low MDS and ANIBES-DQI scores. For the ANIBES-DQI, the percentage of the population with low scores was higher in the whole population (69.5%) compared with the plausible energy reporters (49.0%), whereas for medium and high scores the percentages were higher in plausible reporters (41.2% vs. 26.2% and 9.8% vs. 4.3%, respectively). In conclusion, the present study adds support to marked changes in the Mediterranean pattern in Spain, and low education and income levels seem to be associated with a low-quality diet. Additionally, the misreported evaluation in the ANIBES population suggests that this analysis should be routinely included in nutrition surveys to give more precise and accurate data related to nutrient intake and diet quality.
... Indeed, well-designed and -conducted RCTs are useful to determine the potential effects of the consumption of food products and disease risk. However, when intervention studies are not feasible, longitudinal cohorts with an appropriate control of confounding and based on the use of memory-based dietary assessment methods become an important tool (92). Anyhow, FFQs are prone to measurement error: 1) cognitively, the usual frequency of intake questions are difficult to answer; 2) the number of foods one can ask about is limited and extensive detail about food preparation is not collected; 3) FFQs generally query usual portion size, which may not be so problematic for discrete foods like pieces of fruit or packaged foods, but can be quite difficult and highly variable for foods like cheese, pasta, vegetables, beverages, fish, and meats (93). ...
Milk and dairy products containing milk fat are major food sources of saturated fatty acids, which have been linked to increased risk of cardiovascular-related clinical outcomes such as cardiovascular disease (CVD), coronary heart disease (CHD), and stroke. Therefore, current recommendations by health authorities advise consumption of low-fat or fat-free milk. Today, these recommendations are seriously questioned by meta-analyses of both prospective cohort studies and randomized controlled trials (RCTs) reporting inconsistent results. The present study includes an overview of systematic reviews and meta-analyses of follow-up studies, an overview of meta-analyses involving RCTs, and an update on meta-analyses of RCTs (2013-2018) aiming to synthesize the evidence regarding the influence of dairy product consumption on the risk of major cardiovascular-related outcomes and how various doses of different dairy products affect the responses, as well as on selected biomarkers of cardiovascular disease risk, i.e., blood pressure and blood lipids. The search strategies for both designs were conducted in the MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Web of Science databases from their inception to April 2018. From the 31 full-text articles retrieved for cohort studies, 17 met the eligibility criteria. The pooled risk ratio estimated for the association between the consumption of different dairy products at different dose-responses and cardiovascular outcomes (CVD, CHD, and stroke) showed a statistically significant negative association with RR values <1, or did not find evidence of significant association. The overview of 12 meta-analyses involving RCTs as well as the updated meta-analyses of RCTs did not result in significant changes on risk biomarkers such as systolic and diastolic blood pressure and total cholesterol and LDL cholesterol. Therefore, the present study states that the consumption of total dairy products, with either regular or low fat content, does not adversely affect the risk of CVD.
... However, the validity of self-reported data obtained via such memory-based dietary assessment methods, and hence the whole value of nutrition epidemiology, is being challenged based on their purported inability to correctly reflect true food and nutrient consumption [4][5][6][7]. However, others have argued that despite recognized limitations, relying on self-reported dietary intake data in epidemiological studies has been instrumental in developing impactful dietary guidelines and recommendations over the years [1,2,[7][8][9][10]. One of the fundamental issues in this heated debate relates to whether 24HRs and FFQs can measure true energy intake, due among other factors to significant random and systematic errors [1,[11][12][13][14]. ...
Traditional food frequency questionnaires (FFQs) are influenced by systematic error, but web-based FFQ (WEB-FFQs) may mitigate this source of error. The objective of this study was to compare the accuracy of interview-based and web-based FFQs to assess energy requirements (mERs). The mER was measured in a series of controlled feeding trials in which participants daily received all foods and caloric drinks to maintain stable body weight over 4 to 6 weeks. FFQs assessing dietary intakes and hence mean energy intake were either interviewer-administered by a registered dietitian (IA-FFQ, n = 127; control method) or self-administered using a web-based platform (WEB-FFQ, n = 200; test method), on a single occasion. Comparison between self-reported energy intake and mER revealed significant under-reporting with the IA-FFQ (−9.5%; 95% CI, −12.7 to −6.1) and with the WEB-FFQ (−11.0%; 95% CI, −15.4 to −6.4), but to a similar extent between FFQs (p = 0.62). However, a greater proportion of individuals were considered as accurate reporters of energy intake using the IA-FFQ compared with the WEB-FFQ (67.7% vs. 48.0%, respectively), while the prevalence of over-reporting was lower with the IA-FFQ than with the WEB-FFQ (6.3% vs. 17.5%, respectively). These results suggest less accurate prediction of true energy intake by a self-administered WEB-FFQ than with an IA-FFQ.
Background
An essential component of systematic reviews is the assessment of risk of bias. To date, there has been no investigation of how reviews of non-randomised studies of nutritional exposures (called ‘nutritional epidemiologic studies’) assess risk of bias.
Objective
To describe methods for the assessment of risk of bias in reviews of nutritional epidemiologic studies.
Methods
We searched MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews (Jan 2018–Aug 2019) and sampled 150 systematic reviews of nutritional epidemiologic studies.
Results
Most reviews (n=131/150; 87.3%) attempted to assess risk of bias. Commonly used tools neglected to address all important sources of bias, such as selective reporting (n=25/28; 89.3%), and frequently included constructs unrelated to risk of bias, such as reporting (n=14/28; 50.0%). Most reviews (n=66/101; 65.3%) did not incorporate risk of bias in the synthesis. While more than half of reviews considered biases due to confounding and misclassification of the exposure in their interpretation of findings, other biases, such as selective reporting, were rarely considered (n=1/150; 0.7%).
Conclusion
Reviews of nutritional epidemiologic studies have important limitations in their assessment of risk of bias.
Objective:
to analyze the validity of self-reported somatometry data through a self-reported online questionnaire.
Method:
the SENDO project (Follow-up of Children for Optimal Development) is a prospective, dynamic pediatric cohort. Participants are recruited when they are between 4 and 6 years old, and followed annually through an online questionnaire. In a subsample of 82 participants, we compared the anthropometric information reported in the baseline questionnaire with the direct measurements collected by the investigating staff. To do this, we calculated the intraclass correlation index (ICC) and the Bland-Altman coefficient.
Results:
the ICC was 0.96 (95 % confidence interval [CI]: 0.94-0.98 for weight; 0.95 (95 % CI: 0.92-0.96) for height; 0.75 (95 % CI: 0.64-0.86) for waist circumference; and 0.84 (95 % CI: 0.76-0.89) for hip circumference. In relation to the indices calculated from these measurements, we found an ICC of 0.84 (95 % CI: 0.77-0.90) for body mass index; 0.46 (95 % CI: 0.27-0.62) for waist-hip ratio; and 0.59 (95 % CI: 0.43-0.72) for waist-height index. The Bland-Altman index ranged from 3.7 % for weight to 8.5 % for body mass index.
Conclusions:
we found a high correlation and concordance between the data collected in the physical exam and those reported by the parents. Our results indicate that the anthropometric measures provided by parents, especially those with which they are most familiar, are valid and can be used in epidemiological research.
Healthy Nordic diet has been beneficially associated with coronary heart disease (CHD) risk factors, but few studies have investigated risk of developing CHD. We investigated the associations of healthy Nordic diet with major CHD risk factors, carotid atherosclerosis, and incident CHD in middle-aged and older men from eastern Finland. A total of 1981 men aged 42-60 years and free of CHD at baseline in 1984-1989 were investigated. Diet was assessed with 4-d food recording and the healthy Nordic diet score was calculated based on the Baltic Sea Diet Score. Carotid atherosclerosis was assessed by ultrasonography of the common carotid artery intima-media thickness in 1053 men. Analysis of covariance and Cox proportional hazards regression analyses were used for analyses. Healthy Nordic diet score associated with lower serum C-reactive protein concentrations (multivariable-adjusted extreme-quartile difference 0.69 mg/L, 95% confidence interval 0.15-1.22 mg/L), but not with serum lipid concentrations, blood pressure, or carotid atherosclerosis. During the average follow-up of 21.6 years (SD 8.3 years), 407 men had a CHD event, of which 277 were fatal. The multivariable-adjusted hazard ratios (95% confidence interval) in the lowest vs. the highest quartile of the healthy Nordic diet score were 1.10 (0.85-1.45) for any CHD event ( P -trend 0.429) and 1.38 (0.95-2.00) ( P -trend 0.119) for fatal CHD event. We did not find evidence that adherence to a healthy Nordic diet would be associated with a lower risk of CHD or with carotid atherosclerosis or major CHD risk factors, except for an inverse association with serum C-reactive protein concentrations.
Introduction:
currently, it is important to determine whether food frequency questionnaires (FFQ) are valid tools to collect information on usual diet in children.
Objective:
we evaluated the reproducibility and validity of the semi-quantitative FFQ used in a Spanish cohort of children aged 4-7 years.
Methods:
to explore its reproducibility, parents filled a 138-item FFQ at baseline (FFQ-0) and then one year later (FFQ-1). To explore its validity, the FFQ-1 was compared with four weighed 3-day dietary records (DRs) that were used as standard of reference. To estimate associations we calculated deattenuated Pearson's correlation coefficients to correct for season-to-season variability, and the Bland-Altman index. We also calculated the weighted kappa index and assessed participant's gross misclassification across quintiles. We analyzed data from 67 (for reproducibility) and 37 (for validity) children aged 4-7 years old, recruited by the pilot study of the SENDO project.
Results:
regarding reproducibility, we found mean Bland-Altman indexes of 0-10.45 % for nutrients and 1.49 %-10.45 % for foods. The adjusted r ranged between 0.29 and 0.71, and between 0.27 and 0.74 for nutrients and foods, respectively. Regarding validity, we found mean Bland-Altman indexes of 0 %-16.22 % and 0 %-10.81 % for nutrients and for food groups, respectively. The deattenuated r ranged between 0.38 and 0.81 for nutrients, and between 0.53 and 0.68 for foods. The weighted kappa index for agreement across quintiles ranged from 54.1 to 85.1 for nutrients, and from 55.4 to 78.4 for food groups.
Conclusions:
our results showed acceptable levels of both reproducibility and validity, and that the ad-hoc developed FFQ is a valid tool for assessing usual diet in Spanish preschoolers.
Objective: To examine the relation between the consumption or avoidance of meat and psychological health and well-being.
Methods: A systematic search of online databases (PubMed, PsycINFO, CINAHL Plus, Medline, and Cochrane Library) was conducted for primary research examining psychological health in meat-consumers and meat-abstainers. Inclusion criteria were the provision of a clear distinction between meat-consumers and meat-abstainers, and data on factors related to psychological health. Studies examining meat consumption as a continuous or multi-level variable were excluded. Summary data were compiled, and qualitative analyses of methodologic rigor were conducted. The main outcome was the disparity in the prevalence of depression, anxiety, and related conditions in meat-consumers versus meat-abstainers. Secondary outcomes included mood and self-harm behaviors.
Results: Eighteen studies met the inclusion/exclusion criteria; representing 160,257 participants (85,843 females and 73,232 males) with 149,559 meat-consumers and 8584 meat-abstainers (11 to 96 years) from multiple geographic regions. Analysis of methodologic rigor revealed that the studies ranged from low to severe risk of bias with high to very low confidence in results. Eleven of the 18 studies demonstrated that meat-abstention was associated with poorer psychological health, four studies were equivocal, and three showed that meat-abstainers had better outcomes. The most rigorous studies demonstrated that the prevalence or risk of depression and/or anxiety were significantly greater in participants who avoided meat consumption.
Conclusion: Studies examining the relation between the consumption or avoidance of meat and psychological health varied substantially in methodologic rigor, validity of interpretation, and confidence in results. The majority of studies, and especially the higher quality studies, showed that those who avoided meat consumption had significantly higher rates or risk of depression, anxiety, and/or self-harm behaviors. There was mixed evidence for temporal relations, but study designs and a lack of rigor precluded inferences of causal relations. Our study does not support meat avoidance as a strategy to benefit psychological health.
Two recent commentaries published in this journal argued against the usefulness of memory-based dietary assessment methods (M-BMs). A pair of responding commentaries disputed those negative claims regarding M-BMs and defended the usefulness of M-BMs. This article is intended to clarify the claims made in the four commentaries cited previously, identify the manner in which those claims have been supported, and suggest possible ways forward. In service of the goals of this article, I have identified the main arguments found in each of the four commentaries cited previously. I then partitioned each argument into two principle components: data and claim. I then identified the type of data used to support each claim. Finally, I have identified some of the potential reasons for the disagreements between the two parties and have suggested potential opportunities for progress on the issues at the heart of the controversy.
The authors evaluated the performance of a semi-quantitative food frequency questionnaire (SFFQ), web-based 24-hour recalls (ASA24s), and 7-day dietary records (7DDRs) compared to biomarkers among 627 women in Women's Lifestyle Validation Study (US, 2010-2012). Two paper SFFQs, one web-based SFFQ, four ASA24s (beta version), two 7DDRs, four 24-hour urine samples, one doubly-labeled water (repeated among 76 participants), and two fasting blood samples were collected over a 15-months-period. Dietary variables evaluated were energy, energy-adjusted intakes of protein, sodium, potassium, and specific fatty acids, carotenoids, α-tocopherol, retinol and folate. In general, relative to biomarkers, averaged ASA24s had lower validity than SFFQ2; SFFQ2 had slightly lower validity than one 7DDR; the averaged SFFQs had similar validity to one 7DDR; and the averaged 7DDRs had the highest validity. The de-attenuated correlation of energy-adjusted protein intake assessed by SFFQ2 with its biomarker was 0.46, similar to its correlation with 7DDRs (de-attenuated r = 0.54). These data indicate that the SFFQ2 provides reasonably valid measurements for most energy-adjusted nutrients assessed in our study, consistent with earlier conclusions using 7DDRs as the comparison. The ASA24 needs further evaluation for use in large population studies, but an average of 3 days will not be sufficient for some important nutrients.
Background and purpose:
The associations of individual long-chain n-3 polyunsaturated fatty acids with incident ischemic stroke and its main subtypes are not well established. We aimed to investigate prospectively the relationship of circulating eicosapentaenoic acid, docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) with risk of total ischemic, atherothrombotic, and cardioembolic stroke.
Methods:
We measured circulating phospholipid fatty acids at baseline in 3 separate US cohorts: CHS (Cardiovascular Health Study), NHS (Nurses' Health Study), and HPFS (Health Professionals Follow-Up Study). Ischemic strokes were prospectively adjudicated and classified into atherothrombotic (large- and small-vessel infarctions) or cardioembolic by imaging studies and medical records. Risk according to fatty acid levels was assessed using Cox proportional hazards (CHS) or conditional logistic regression (NHS, HPFS) according to study design. Cohort findings were pooled using fixed-effects meta-analysis.
Results:
A total of 953 incident ischemic strokes were identified (408 atherothrombotic, 256 cardioembolic, and 289 undetermined subtypes) during median follow-up of 11.2 years (CHS) and 8.3 years (pooled, NHS and HPFS). After multivariable adjustment, lower risk of total ischemic stroke was seen with higher DPA (highest versus lowest quartiles; pooled hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.58-0.92) and DHA (HR, 0.80; 95% CI, 0.64-1.00) but not eicosapentaenoic acid (HR, 0.94; 95% CI, 0.77-1.19). DHA was associated with lower risk of atherothrombotic stroke (HR, 0.53; 95% CI, 0.34-0.83) and DPA with lower risk of cardioembolic stroke (HR, 0.58; 95% CI, 0.37-0.92). Findings in each individual cohort were consistent with pooled results.
Conclusions:
In 3 large US cohorts, higher circulating levels of DHA were inversely associated with incident atherothrombotic stroke and DPA with cardioembolic stroke. These novel findings suggest differential pathways of benefit for DHA, DPA, and eicosapentaenoic acid.
Research has shown that a greater adherence to the Mediterranean diet is associated with a reduced risk of major chronic disease. However, the existing literature leads to debate for different issues, such as the measurement of the adherence to the Mediterranean diet, the use of a wide variety of dietary indices with various food components and the large heterogeneity across the studies. In order to summarise the evidence and evaluate the validity of the association between the adherence to the Mediterranean diet and multiple health outcomes, an umbrella review of the evidence across meta-analyses of observational studies and randomised clinical trials (RCTs) was performed. Thirteen meta-analyses of observational studies and 16 meta-analyses of RCTs investigating the association between the adherence to the Mediterranean diet and 37 different health outcomes, for a total population of over than 12 800 000 subjects, were identified. A robust evidence, supported by a P-value<0.001, a large simple size, and not a considerable heterogeneity between studies, for a greater adherence to the Mediterranean diet and a reduced the risk of overall mortality, cardiovascular diseases, coronary heart disease, myocardial infarction, overall cancer incidence, neurodegenerative diseases and diabetes was found. For most of the site-specific cancers, as well as for inflammatory and metabolic parameters, the evidence was only suggestive or weak and further studies are needed to draw firmer conclusions. No evidence, on the other hand, was reported for bladder, endometrial and ovarian cancers, as well as for LDL (low density lipoprotein)-cholesterol levels.European Journal of Clinical Nutrition advance online publication, 10 May 2017; doi:10.1038/ejcn.2017.58.
Background: Hydroxytyrosol is a phenolic compound that is present in virgin olive oil (VOO) and wine. Hydroxytyrosol-related foods have been shown to protect against cardiovascular disease (CVD).
Objective: We investigated the associations between hydroxytyrosol and its biological metabolite, 3-O-methyl-hydroxytyrosol, also known as homovanillyl alcohol (HVAL), with CVD and total mortality.
Design: We included 1851 men and women with a mean ± SD age of 66.8 ± 6 y at high risk of CVD from prospective cohort data. The primary endpoint was a composite of myocardial infarction, stroke, and death from cardiovascular causes; the secondary endpoint was all-cause mortality. Twenty-four-hour urinary hydroxytyrosol and HVAL and catechol-O-methyltransferase (COMT) rs4680 genotypes were measured.
Results: After multivariable adjustment, all biomarkers were associated, as a continuous variable, with lower CVD risk, but only HVAL showed a strong inverse association (HR: 0.44; 95% CI: 0.25, 0.80) for the comparison between quintiles. Only HVAL, as a continuous variable, was associated with total mortality (HR: 0.81; 95% CI: 0.70, 0.95). Individuals in the highest quintile of HVAL compared with the lowest had 9.2 (95% CI: 3.5, 20.8) and 6.3 (95% CI: 2.3, 12.1) additional years of life or years free of CVD, respectively, after 65 y. Individuals with the rs4680GG genotype had the highest HVAL concentrations (P = 0.05). There was no association between COMT genotypes and events or interaction between COMT genotypes and HVAL concentrations.
Conclusions: We report, for the first time to our knowledge, an independent association between high urinary HVAL concentrations and a lower risk of CVD and total mortality in elderly individuals. VOO and wine consumption and a high metabolic COMT capacity for methylation are key factors for high HVAL concentrations. The association that stems from our results reinforces the benefits of 2 key components of the Mediterranean diet (wine and VOO). This trial was registered at www.predimed.es as ISRCTN35739639.
The authors evaluated the validity of a 152-item semiquantitative food frequency questionnaire (SFFQ) by comparing it with two 7-day dietary records (7DDRs) or up to 4 automated self-administered 24-hour recalls (ASA24s) over a 1-year period in the women's Lifestyle Validation Study (2010-2012), conducted among subgroups of the Nurses' Health Studies. Intakes of energy and 44 nutrients were assessed using the 3 methods among 632 US women. Compared with the 7DDRs, SFFQ responses tended to underestimate sodium intake but overestimate intakes of energy, macronutrients, and several nutrients in fruits and vegetables, such as carotenoids. Spearman correlation coefficients between energy-adjusted intakes from 7DDRs and the SFFQ completed at the end of the data-collection period ranged from 0.36 for lauric acid to 0.77 for alcohol (mean r = 0.53). Correlations of the end-period SFFQ were weaker when ASA24s were used as the comparison method (mean r = 0.43). After adjustment for within-person variation in the comparison method, the correlations of the final SFFQ were similar with 7DDRs (mean r = 0.63) and ASA24s (mean r = 0.62). These data indicate that this SFFQ provided reasonably valid estimates for intakes of a wide variety of dietary variables and that use of multiple 24-hour recalls or 7DDRs as a comparison method provided similar conclusions if day-to-day variation was taken into account.
NHANES is the cornerstone for national nutrition monitoring to inform nutrition and health policy. Nutritional assessment in NHANES is described with a focus on dietary data collection, analysis, and uses in nutrition monitoring. NHANES has been collecting thorough data on diet, nutritional status, and chronic disease in cross-sectional surveys with nationally representative samples since the early 1970s. Continuous data collection began in 1999 with public data release in 2-y cycles on ∼10,000 participants. In 2002, the Continuing Survey of Food Intakes by Individuals and the NHANES dietary component were merged, forming a consolidated dietary data collection known as What We Eat in America; since then, 24-h recalls have been collected on 2 d using the USDA's Automated Multiple-Pass Method. Detailed and targeted food-frequency questionnaires have been collected in some NHANES cycles. Dietary supplement use data have been collected (in detail since 2007) so that total nutrient intakes can be described for the population. The continuous NHANES can adapt its content to address emerging public health needs and reflect federal priorities. Changes in data collection methods are made after expert input and validation/crossover studies. NHANES dietary data are used to describe intake of foods, nutrients, food groups, and dietary patterns by the US population and large sociodemographic groups to plan and evaluate nutrition programs and policies. Usual dietary intake distributions can be estimated after adjusting for day-to-day variation. NHANES remains open and flexible to incorporate improvements while maintaining data quality and providing timely data to track the nation's nutrition and health status. In summary, NHANES collects dietary data in the context of its broad, multipurpose goals; the strengths and limitations of these data are also discussed in this review.
Recent reports have asserted that, because of energy underreporting, dietary self-report data suffer from measurement error so great that findings that rely on them are of no value. This commentary considers the amassed evidence that shows that self-report dietary intake data can successfully be used to inform dietary guidance and public health policy. Topics discussed include what is known and what can be done about the measurement error inherent in data collected by using self-report dietary assessment instruments and the extent and magnitude of underreporting energy vs. other nutrients and food groups. Also discussed is the overall impact of energy underreporting on dietary surveillance and nutritional epidemiology. In conclusion, 7 specific recommendations for collecting, analyzing, and interpreting self-report dietary data are provided: 1) continue to collect self-report dietary intake data because they contain valuable, rich, and critical information about foods and beverages consumed by populations that can be used to inform nutrition policy and assess diet-disease associations; 2) do not use self-reported energy intake as a measure of true energy intake; 3) do use self-reported energy intake for energy adjustment of other self-reported dietary constituents to improve risk estimation in studies of diet-health associations; 4) acknowledge the limitations of self-report dietary data and analyze and interpret them appropriately; 5) design studies and conduct analyses that allow adjustment for measurement error; 6) design new epidemiologic studies to collect dietary data from both short-term (recalls or food records) and long-term (food-frequency questionnaires) instruments on the entire study population to allow for maximizing the strengths of each instrument; and 7) continue to develop, evaluate, and further expand methods of dietary assessment, including dietary biomarkers and methods using new technologies.
Objectives To examine the prospective associations between consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice with type 2 diabetes before and after adjustment for adiposity, and to estimate the population attributable fraction for type 2 diabetes from consumption of sugar sweetened beverages in the United States and United Kingdom.
Design Systematic review and meta-analysis.
Data sources and eligibility PubMed, Embase, Ovid, and Web of Knowledge for prospective studies of adults without diabetes, published until February 2014. The population attributable fraction was estimated in national surveys in the USA, 2009-10 (n=4729 representing 189.1 million adults without diabetes) and the UK, 2008-12 (n=1932 representing 44.7 million).
Synthesis methods Random effects meta-analysis and survey analysis for population attributable fraction associated with consumption of sugar sweetened beverages.
Results Prespecified information was extracted from 17 cohorts (38 253 cases/10 126 754 person years). Higher consumption of sugar sweetened beverages was associated with a greater incidence of type 2 diabetes, by 18% per one serving/day (95% confidence interval 9% to 28%, I2 for heterogeneity=89%) and 13% (6% to 21%, I2=79%) before and after adjustment for adiposity; for artificially sweetened beverages, 25% (18% to 33%, I2=70%) and 8% (2% to 15%, I2=64%); and for fruit juice, 5% (−1% to 11%, I2=58%) and 7% (1% to 14%, I2=51%). Potential sources of heterogeneity or bias were not evident for sugar sweetened beverages. For artificially sweetened beverages, publication bias and residual confounding were indicated. For fruit juice the finding was non-significant in studies ascertaining type 2 diabetes objectively (P for heterogeneity=0.008). Under specified assumptions for population attributable fraction, of 20.9 million events of type 2 diabetes predicted to occur over 10 years in the USA (absolute event rate 11.0%), 1.8 million would be attributable to consumption of sugar sweetened beverages (population attributable fraction 8.7%, 95% confidence interval 3.9% to 12.9%); and of 2.6 million events in the UK (absolute event rate 5.8%), 79 000 would be attributable to consumption of sugar sweetened beverages (population attributable fraction 3.6%, 1.7% to 5.6%).
Conclusions Habitual consumption of sugar sweetened beverages was associated with a greater incidence of type 2 diabetes, independently of adiposity. Although artificially sweetened beverages and fruit juice also showd positive associations with incidence of type 2 diabetes, the findings were likely to involve bias. None the less, both artificially sweetened beverages and fruit juice were unlikely to be healthy alternatives to sugar sweetened beverages for the prevention of type 2 diabetes. Under assumption of causality, consumption of sugar sweetened beverages over years may be related to a substantial number of cases of new onset diabetes.
Dear Editor,
We write in response to a recent letter to the Editor entitled “Implausible Data, False Memories, and the Status Quo in Dietary Assessment” by Archer and Blair (1). Although we disagree with some other aspects of their letter, we confine ourselves here to the portion of the letter in which the authors cite data from our recently published article (2). The authors claim that our data “demonstrate the futility” of self-report dietary data methods. They cite estimates of squared average correlation between true usual energy intake and self-reported energy intake of between 0.04 and 0.10, stating that these values “provide unequivocal evidence that self-report dietary data offer an inadequate basis from which to draw scientific conclusions.”
We strongly disagree with their conclusions. It does not follow logically that because energy intake is poorly estimated by self-reporting methods, self-report dietary data can never be used to establish scientifically valid conclusions. Archer and Blair ignore 2 of our findings. First, FFQ-reported protein density (protein intake divided by energy intake) has a far higher correlation with true usual intake than does protein itself. This same finding was also evident for potassium and sodium, as well as for the sodium-potassium ratio (3). Increased correlations are also seen with 24-h recall reported intake after forming densities. These findings indicate that self-report instruments are more suited to the elicitation of a person’s dietary composition than his or her absolute intake. This has long been recognized within the nutritional epidemiology community, and it has led to the common practice of energy adjustment (4) when analyzing self-reported intake of nutrients and food groups. In a similar vein, recent versions of the Healthy Eating Index (5) have been based on energy-adjusted intake. Second, we found that the averages of 2 and 3 24-h recall protein reports had substantially higher correlations with true usual intake than a single recall. This also was evident for potassium (3). Thus, the use of repeated 24-h recalls is another device that can be used to improve the quality of self-report dietary data.
Throughout their letter, Archer and Blair claim that their arguments are logical and empirically supported. In fact, their conclusions are far too sweeping.
The Scientific Report of the 2015 Dietary Guidelines Advisory Committee was primarily informed by memory-based dietary assessment methods (M-BMs) (eg, interviews and surveys). The reliance on M-BMs to inform dietary policy continues despite decades of unequivocal evidence that M-BM data bear little relation to actual energy and nutrient consumption. Data from M-BMs are defended as valid and valuable despite no empirical support and no examination of the foundational assumptions regarding the validity of human memory and retrospective recall in dietary assessment. We assert that uncritical faith in the validity and value of M-BMs has wasted substantial resources and constitutes the greatest impediment to scientific progress in obesity and nutrition research. Herein, we present evidence that M-BMs are fundamentally and fatally flawed owing to well-established scientific facts and analytic truths. First, the assumption that human memory can provide accurate or precise reproductions of past ingestive behavior is indisputably false. Second, M-BMs require participants to submit to protocols that mimic procedures known to induce false recall. Third, the subjective (ie, not publicly accessible) mental phenomena (ie, memories) from which M-BM data are derived cannot be independently observed, quantified, or falsified; as such, these data are pseudoscientific and inadmissible in scientific research. Fourth, the failure to objectively measure physical activity in analyses renders inferences regarding diet-health relationships equivocal. Given the overwhelming evidence in support of our position, we conclude that M-BM data cannot be used to inform national dietary guidelines and that the continued funding of M-BMs constitutes an unscientific and major misuse of research resources.
Copyright © 2015 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.
We pooled data from 5 large validation studies (1999-2009) of dietary self-report instruments that used recovery biomarkers as referents, to assess food frequency questionnaires (FFQs) and 24-hour recalls (24HRs). Here we report on total potassium and sodium intakes, their densities, and their ratio. Results were similar by sex but were heterogeneous across studies. For potassium, potassium density, sodium, sodium density, and sodium:potassium ratio, average correlation coefficients for the correlation of reported intake with true intake on the FFQs were 0.37, 0.47, 0.16, 0.32, and 0.49, respectively. For the same nutrients measured with a single 24HR, they were 0.47, 0.46, 0.32, 0.31, and 0.46, respectively, rising to 0.56, 0.53, 0.41, 0.38, and 0.60 for the average of three 24HRs. Average underreporting was 5%-6% with an FFQ and 0%-4% with a single 24HR for potassium but was 28%-39% and 4%-13%, respectively, for sodium. Higher body mass index was related to underreporting of sodium. Calibration equations for true intake that included personal characteristics provided improved prediction, except for sodium density. In summary, self-reports capture potassium intake quite well but sodium intake less well. Using densities improves the measurement of potassium and sodium on an FFQ. Sodium:potassium ratio is measured much better than sodium itself on both FFQs and 24HRs.
Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.
Nutritional epidemiology has recently been criticized on several fronts, including the inability to measure diet accurately, and for its reliance on observational studies to address etiologic questions. In addition, several recent meta-analyses with serious methodologic flaws have arrived at erroneous or misleading conclusions, reigniting controversy over formerly settled debates. All of this has raised questions regarding the ability of nutritional epidemiologic studies to inform policy. These criticisms, to a large degree, stem from a misunderstanding of the methodologic issues of the field and the inappropriate use of the drug trial paradigm in nutrition research. The exposure of interest in nutritional epidemiology is human diet, which is a complex system of interacting components that cumulatively affect health. Consequently, nutritional epidemiology constantly faces a unique set of challenges and continually develops specific methodologies to address these. Misunderstanding these issues can lead to the nonconstructive and sometimes naive criticisms we see today. This article aims to clarify common misunderstandings of nutritional epidemiology, address challenges to the field, and discuss the utility of nutritional science in guiding policy by focusing on 5 broad questions commonly asked of the field.
© 2015 American Society for Nutrition.
Dietary assessment has long been known to be challenged by measurement error. A substantial amount of literature on methods for determining the effects of error on causal inference has accumulated over the past decades. These methods have unrealized potential for improving the validity of data collected for research studies and national nutritional surveillance, primarily through the NHANES. Recently, the validity of dietary data has been called into question. Arguments against using dietary data to assess diet–health relations or to inform the nutrition policy debate are subject to flaws that fall into 2 broad areas: 1) ignorance or isunderstanding of methodologic issues; and 2) faulty logic in drawing inferences. Nine specific issues are identified in these arguments, indicating insufficient grasp of themethods used for assessing diet and designing nutritional epidemiologic studies. These include a narrow operationalization of validity, failure to properly account for sources of error, and large, unsubstantiated jumps to policy implications. Recent
attacks on the inadequacy of 24-h recall–derived data from the NHANES are uninformative regarding effects on estimating risk of health outcomes and on inferences to inform the diet-related health policy debate. Despite errors, for many purposes and inmany contexts, these dietary data have proven to be useful in addressing important research and policy questions. Similarly, structured instruments, such as the food frequency questionnaire, which is the mainstay of epidemiologic literature, can provide useful data when errors are measured and considered in analyses. Adv. Nutr. 5: 447–455, 2014.
We pooled data from 5 large validation studies of dietary self-report instruments that used recovery biomarkers as references to clarify the measurement properties of food frequency questionnaires (FFQs) and 24-hour recalls. The studies were conducted in widely differing US adult populations from 1999 to 2009. We report on total energy, protein, and protein density intakes. Results were similar across sexes, but there was heterogeneity across studies. Using a FFQ, the average correlation coefficients for reported versus true intakes for energy, protein, and protein density were 0.21, 0.29, and 0.41, respectively. Using a single 24-hour recall, the coefficients were 0.26, 0.40, and 0.36, respectively, for the same nutrients and rose to 0.31, 0.49, and 0.46 when three 24-hour recalls were averaged. The average rate of under-reporting of energy intake was 28% with a FFQ and 15% with a single 24-hour recall, but the percentages were lower for protein. Personal characteristics related to under-reporting were body mass index, educational level, and age. Calibration equations for true intake that included personal characteristics provided improved prediction. This project establishes that FFQs have stronger correlations with truth for protein density than for absolute protein intake, that the use of multiple 24-hour recalls substantially increases the correlations when compared with a single 24-hour recall, and that body mass index strongly predicts under-reporting of energy and protein intakes.
Abstract
Background: It is unknown whether individuals at high cardiovascular risk sustain a benefit in cardiovascular
disease from increased olive oil consumption. The aim was to assess the association between total olive oil intake, its varieties (extra virgin and common olive oil) and the risk of cardiovascular disease and mortality in a Mediterranean population at high cardiovascular risk.
Methods: We included 7,216 men and women at high cardiovascular risk, aged 55 to 80 years, from the
PREvención con DIeta MEDiterránea (PREDIMED) study, a multicenter, randomized, controlled, clinical trial.
Participants were randomized to one of three interventions: Mediterranean Diets supplemented with nuts or
extra-virgin olive oil, or a control low-fat diet. The present analysis was conducted as an observational prospective cohort study. The median follow-up was 4.8 years. Cardiovascular disease (stroke, myocardial infarction and cardiovascular death) and mortality were ascertained by medical records and National Death Index. Olive oil consumption was evaluated with validated food frequency questionnaires. Multivariate Cox proportional hazards and generalized estimating equations were used to assess the association between baseline and yearly repeated measurements of olive oil intake, cardiovascular disease and mortality.
Results: During follow-up, 277 cardiovascular events and 323 deaths occurred. Participants in the highest
energy-adjusted tertile of baseline total olive oil and extra-virgin olive oil consumption had 35% (HR: 0.65; 95% CI: 0.47 to 0.89) and 39% (HR: 0.61; 95% CI: 0.44 to 0.85) cardiovascular disease risk reduction, respectively, compared to the reference. Higher baseline total olive oil consumption was associated with 48% (HR: 0.52; 95% CI: 0.29 to 0.93) reduced risk of cardiovascular mortality. For each 10 g/d increase in extra-virgin olive oil consumption, cardiovascular disease and mortality risk decreased by 10% and 7%, respectively. No significant associations were found for cancer and all-cause mortality. The associations between cardiovascular events and extra virgin olive oil intake were significant in the Mediterranean diet intervention groups and not in the control group.
Conclusions: Olive oil consumption, specifically the extra-virgin variety, is associated with reduced risks of cardiovascular disease and mortality in individuals at high cardiovascular risk.
Metabolomics is an emerging field with the potential to advance nutritional epidemiology; however, it has not yet been applied to large cohort studies.
Our first aim was to identify metabolites that are biomarkers of usual dietary intake. Second, among serum metabolites correlated with diet, we evaluated metabolite reproducibility and required sample sizes to determine the potential for metabolomics in epidemiologic studies.
Baseline serum from 502 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was analyzed by using ultra-high-performance liquid-phase chromatography with tandem mass spectrometry and gas chromatography-mass spectrometry. Usual intakes of 36 dietary groups were estimated by using a food-frequency questionnaire. Dietary biomarkers were identified by using partial Pearson's correlations with Bonferroni correction for multiple comparisons. Intraclass correlation coefficients (ICCs) between samples collected 1 y apart in a subset of 30 individuals were calculated to evaluate intraindividual metabolite variability.
We detected 412 known metabolites. Citrus, green vegetables, red meat, shellfish, fish, peanuts, rice, butter, coffee, beer, liquor, total alcohol, and multivitamins were each correlated with at least one metabolite (P < 1.093 × 10(-6); r = -0.312 to 0.398); in total, 39 dietary biomarkers were identified. Some correlations (citrus intake with stachydrine) replicated previous studies; others, such as peanuts and tryptophan betaine, were novel findings. Other strong associations included coffee (with trigonelline-N-methylnicotinate and quinate) and alcohol (with ethyl glucuronide). Intraindividual variability in metabolite levels (1-y ICCs) ranged from 0.27 to 0.89. Large, but attainable, sample sizes are required to detect associations between metabolites and disease in epidemiologic studies, further emphasizing the usefulness of metabolomics in nutritional epidemiology.
We identified dietary biomarkers by using metabolomics in an epidemiologic data set. Given the strength of the associations observed, we expect that some of these metabolites will be validated in future studies and later used as biomarkers in large cohorts to study diet-disease associations. The PLCO trial was registered at clinicaltrials.gov as NCT00002540.
Scientific knowledge changes rapidly, but the concepts and methods of the conduct of research change more slowly. To stimulate discussion of outmoded thinking regarding the conduct of research, I list six misconceptions about research that persist long after their flaws have become apparent. The misconceptions are: 1) There is a hierarchy of study designs; randomized trials provide the greatest validity, followed by cohort studies, with case-control studies being least reliable. 2) An essential element for valid generalization is that the study subjects constitute a representative sample of a target population. 3) If a term that denotes the product of two factors in a regression model is not statistically significant, then there is no biologic interaction between those factors. 4) When categorizing a continuous variable, a reasonable scheme for choosing category cut-points is to use percentile-defined boundaries, such as quartiles or quintiles of the distribution. 5) One should always report P values or confidence intervals that have been adjusted for multiple comparisons. 6) Significance testing is useful and important for the interpretation of data. These misconceptions have been perpetuated in journals, classrooms and textbooks. They persist because they represent intellectual shortcuts that avoid more thoughtful approaches to research problems. I hope that calling attention to these misconceptions will spark the debates needed to shelve these outmoded ideas for good.
Background Observational cohort studies and a secondary prevention trial have shown an inverse association between adherence to the Mediterranean diet and cardiovascular risk. We conducted a randomized trial of this diet pattern for the primary prevention of cardiovascular events. Methods In a multicenter trial in Spain, we randomly assigned participants who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly individual and group educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was the rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes). On the basis of the results of an interim analysis, the trial was stopped after a median follow-up of 4.8 years. Results A total of 7447 persons were enrolled (age range, 55 to 80 years); 57% were women. The two Mediterranean-diet groups had good adherence to the intervention, according to self-reported intake and biomarker analyses. A primary end-point event occurred in 288 participants. The multivariable-adjusted hazard ratios were 0.70 (95% confidence interval [CI], 0.54 to 0.92) and 0.72 (95% CI, 0.54 to 0.96) for the group assigned to a Mediterranean diet with extra-virgin olive oil (96 events) and the group assigned to a Mediterranean diet with nuts (83 events), respectively, versus the control group (109 events). No diet-related adverse effects were reported. Conclusions Among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events. (Funded by the Spanish government's Instituto de Salud Carlos III and others; Controlled-Trials.com number, ISRCTN35739639 .).
BACKGROUND: Observational cohort studies and a secondary prevention trial have shown an inverse association between adherence to the Mediterranean diet and cardiovascular risk. We conducted a randomized trial of this diet pattern for the primary prevention of cardiovascular events.
METHODS: In a multicenter trial in Spain, we randomly assigned participants who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly individual and group educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was the rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes). On the basis of the results of an interim analysis, the trial was stopped after a median follow-up of 4.8 years.
RESULTS: A total of 7447 persons were enrolled (age range, 55 to 80 years); 57% were women. The two Mediterranean-diet groups had good adherence to the intervention, according to self-reported intake and biomarker analyses. A primary end-point event occurred in 288 participants. The multivariable-adjusted hazard ratios were 0.70 (95% confidence interval [CI], 0.54 to 0.92) and 0.72 (95% CI, 0.54 to 0.96) for the group assigned to a Mediterranean diet with extra-virgin olive oil (96 events) and the group assigned to a Mediterranean diet with nuts (83 events), respectively, versus the control group (109 events). No diet-related adverse effects were reported.
CONCLUSIONS: Among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events. (Funded by the Spanish government's Instituto de Salud Carlos III and others; Controlled-Trials.com number, ISRCTN35739639.).
Background:
The consumption of beverages that contain sugar is associated with overweight, possibly because liquid sugars do not lead to a sense of satiety, so the consumption of other foods is not reduced. However, data are lacking to show that the replacement of sugar-containing beverages with noncaloric beverages diminishes weight gain.
Methods:
We conducted an 18-month trial involving 641 primarily normal-weight children from 4 years 10 months to 11 years 11 months of age. Participants were randomly assigned to receive 250 ml (8 oz) per day of a sugar-free, artificially sweetened beverage (sugar-free group) or a similar sugar-containing beverage that provided 104 kcal (sugar group). Beverages were distributed through schools. At 18 months, 26% of the children had stopped consuming the beverages; the data from children who did not complete the study were imputed.
Results:
The z score for the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) increased on average by 0.02 SD units in the sugar-free group and by 0.15 SD units in the sugar group; the 95% confidence interval (CI) of the difference was -0.21 to -0.05. Weight increased by 6.35 kg in the sugar-free group as compared with 7.37 kg in the sugar group (95% CI for the difference, -1.54 to -0.48). The skinfold-thickness measurements, waist-to-height ratio, and fat mass also increased significantly less in the sugar-free group. Adverse events were minor. When we combined measurements at 18 months in 136 children who had discontinued the study with those in 477 children who completed the study, the BMI z score increased by 0.06 SD units in the sugar-free group and by 0.12 SD units in the sugar group (P=0.06).
Conclusions:
Masked replacement of sugar-containing beverages with noncaloric beverages reduced weight gain and fat accumulation in normal-weight children. (Funded by the Netherlands Organization for Health Research and Development and others; DRINK ClinicalTrials.gov number, NCT00893529.).
The authors aimed to evaluate the association of the traditional Mediterranean diet and major food groups with incidence of and mortality from cerebrovascular disease (CBVD) in a Mediterranean population. The study population was a cohort of 23,601 participants from the Greek segment of the EPIC Study (European Prospective Investigation into Cancer and Nutrition) who were free of cardiovascular diseases and cancer at baseline (1994-1999). Diet was assessed by means of a validated food frequency questionnaire. A 10-point scale integrating key Mediterranean diet characteristics was used to assess the participants' degree of adherence to this diet. During a median follow-up period of 10.6 years (1994-2009), 395 confirmed incident cases and 196 deaths from CBVD were recorded. Using Cox proportional hazards regression and adjusting for potential confounders, increased adherence to the Mediterranean diet, as measured by 2-point increments in score, was inversely associated with CBVD incidence (adjusted hazard ratio = 0.85, 95% confidence interval: 0.74, 0.96) and mortality (adjusted hazard ratio = 0.88, 95% CI: 0.73, 1.06). These inverse trends were mostly evident among women and with respect to ischemic rather than hemorrhagic CBVD and were largely driven by consumption of vegetables, legumes, and olive oil. These data provide support for an inverse association of adherence to the Mediterranean diet with CBVD incidence and mortality.
Background:
A limited number of studies have evaluated self-reported dietary intakes against objective recovery biomarkers.
Objective:
The aim was to compare dietary intakes of multiple Automated Self-Administered 24-h recalls (ASA24s), 4-d food records (4DFRs), and food-frequency questionnaires (FFQs) against recovery biomarkers and to estimate the prevalence of under- and overreporting.
Design:
Over 12 mo, 530 men and 545 women, aged 50-74 y, were asked to complete 6 ASA24s (2011 version), 2 unweighed 4DFRs, 2 FFQs, two 24-h urine collections (biomarkers for protein, potassium, and sodium intakes), and 1 administration of doubly labeled water (biomarker for energy intake). Absolute and density-based energy-adjusted nutrient intakes were calculated. The prevalence of under- and overreporting of self-report against biomarkers was estimated.
Results:
Ninety-two percent of men and 87% of women completed ≥3 ASA24s (mean ASA24s completed: 5.4 and 5.1 for men and women, respectively). Absolute intakes of energy, protein, potassium, and sodium assessed by all self-reported instruments were systematically lower than those from recovery biomarkers, with underreporting greater for energy than for other nutrients. On average, compared with the energy biomarker, intake was underestimated by 15-17% on ASA24s, 18-21% on 4DFRs, and 29-34% on FFQs. Underreporting was more prevalent on FFQs than on ASA24s and 4DFRs and among obese individuals. Mean protein and sodium densities on ASA24s, 4DFRs, and FFQs were similar to biomarker values, but potassium density on FFQs was 26-40% higher, leading to a substantial increase in the prevalence of overreporting compared with absolute potassium intake.
Conclusions:
Although misreporting is present in all self-report dietary assessment tools, multiple ASA24s and a 4DFR provided the best estimates of absolute dietary intakes for these few nutrients and outperformed FFQs. Energy adjustment improved estimates from FFQs for protein and sodium but not for potassium. The ASA24, which now can be used to collect both recalls and records, is a feasible means to collect dietary data for nutrition research.
OBJECTIVES: To examine the prospective associations between consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice with type 2 diabetes before and after adjustment for adiposity, and to estimate the population attributable fraction for type 2 diabetes from consumption of sugar sweetened beverages in the United States and United Kingdom. DESIGN: Systematic review and meta-analysis. DATA SOURCES AND ELIGIBILITY: PubMed, Embase, Ovid, and Web of Knowledge for prospective studies of adults without diabetes, published until February 2014. The population attributable fraction was estimated in national surveys in the USA, 2009-10 (n=4729 representing 189.1 million adults without diabetes) and the UK, 2008-12 (n=1932 representing 44.7 million). SYNTHESIS METHODS: Random effects meta-analysis and survey analysis for population attributable fraction associated with consumption of sugar sweetened beverages. RESULTS: Prespecified information was extracted from 17 cohorts (38,253 cases/10,126,754 person years). Higher consumption of sugar sweetened beverages was associated with a greater incidence of type 2 diabetes, by 18% per one serving/day (95% confidence interval 9% to 28%, I(2) for heterogeneity=89%) and 13% (6% to 21%, I(2)=79%) before and after adjustment for adiposity; for artificially sweetened beverages, 25% (18% to 33%, I(2)=70%) and 8% (2% to 15%, I(2)=64%); and for fruit juice, 5% (-1% to 11%, I(2)=58%) and 7% (1% to 14%, I(2)=51%). Potential sources of heterogeneity or bias were not evident for sugar sweetened beverages. For artificially sweetened beverages, publication bias and residual confounding were indicated. For fruit juice the finding was non-significant in studies ascertaining type 2 diabetes objectively (P for heterogeneity=0.008). Under specified assumptions for population attributable fraction, of 20.9 million events of type 2 diabetes predicted to occur over 10 years in the USA (absolute event rate 11.0%), 1.8 million would be attributable to consumption of sugar sweetened beverages (population attributable fraction 8.7%, 95% confidence interval 3.9% to 12.9%); and of 2.6 million events in the UK (absolute event rate 5.8%), 79,000 would be attributable to consumption of sugar sweetened beverages (population attributable fraction 3.6%, 1.7% to 5.6%). CONCLUSIONS: Habitual consumption of sugar sweetened beverages was associated with a greater incidence of type 2 diabetes, independently of adiposity. Although artificially sweetened beverages and fruit juice also showed positive associations with incidence of type 2 diabetes, the findings were likely to involve bias. None the less, both artificially sweetened beverages and fruit juice were unlikely to be healthy alternatives to sugar sweetened beverages for the prevention of type 2 diabetes. Under assumption of causality, consumption of sugar sweetened beverages over years may be related to a substantial number of cases of new onset diabetes.
Background:
Nutritional metabolomics is rapidly evolving to integrate nutrition with complex metabolomics data to discover new biomarkers of nutritional exposure and status.
Content:
The purpose of this review is to provide a broad overview of the measurement techniques, study designs, and statistical approaches used in nutrition metabolomics, as well as to describe the current knowledge from epidemiologic studies identifying metabolite profiles associated with the intake of individual nutrients, foods, and dietary patterns.
Summary:
A wide range of technologies, databases, and computational tools are available to integrate nutritional metabolomics with dietary and phenotypic information. Biomarkers identified with the use of high-throughput metabolomics techniques include amino acids, acylcarnitines, carbohydrates, bile acids, purine and pyrimidine metabolites, and lipid classes. The most extensively studied food groups include fruits, vegetables, meat, fish, bread, whole grain cereals, nuts, wine, coffee, tea, cocoa, and chocolate. We identified 16 studies that evaluated metabolite signatures associated with dietary patterns. Dietary patterns examined included vegetarian and lactovegetarian diets, omnivorous diet, Western dietary patterns, prudent dietary patterns, Nordic diet, and Mediterranean diet. Although many metabolite biomarkers of individual foods and dietary patterns have been identified, those biomarkers may not be sensitive or specific to dietary intakes. Some biomarkers represent short-term intakes rather than long-term dietary habits. Nonetheless, nutritional metabolomics holds promise for the development of a robust and unbiased strategy for measuring diet. Still, this technology is intended to be complementary, rather than a replacement, to traditional well-validated dietary assessment methods such as food frequency questionnaires that can measure usual diet, the most relevant exposure in nutritional epidemiologic studies.
Background:
The metabolic effects of omega-6 polyunsaturated fatty acids (PUFAs) remain contentious, and little evidence is available regarding their potential role in primary prevention of type 2 diabetes. We aimed to assess the associations of linoleic acid and arachidonic acid biomarkers with incident type 2 diabetes.
Methods:
We did a pooled analysis of new, harmonised, individual-level analyses for the biomarkers linoleic acid and its metabolite arachidonic acid and incident type 2 diabetes. We analysed data from 20 prospective cohort studies from ten countries (Iceland, the Netherlands, the USA, Taiwan, the UK, Germany, Finland, Australia, Sweden, and France), with biomarkers sampled between 1970 and 2010. Participants included in the analyses were aged 18 years or older and had data available for linoleic acid and arachidonic acid biomarkers at baseline. We excluded participants with type 2 diabetes at baseline. The main outcome was the association between omega-6 PUFA biomarkers and incident type 2 diabetes. We assessed the relative risk of type 2 diabetes prospectively for each cohort and lipid compartment separately using a prespecified analytic plan for exposures, covariates, effect modifiers, and analysis, and the findings were then pooled using inverse-variance weighted meta-analysis.
Findings:
Participants were 39 740 adults, aged (range of cohort means) 49-76 years with a BMI (range of cohort means) of 23·3-28·4 kg/m(2), who did not have type 2 diabetes at baseline. During a follow-up of 366 073 person-years, we identified 4347 cases of incident type 2 diabetes. In multivariable-adjusted pooled analyses, higher proportions of linoleic acid biomarkers as percentages of total fatty acid were associated with a lower risk of type 2 diabetes overall (risk ratio [RR] per interquintile range 0·65, 95% CI 0·60-0·72, p<0·0001; I(2)=53·9%, pheterogeneity=0·002). The associations between linoleic acid biomarkers and type 2 diabetes were generally similar in different lipid compartments, including phospholipids, plasma, cholesterol esters, and adipose tissue. Levels of arachidonic acid biomarker were not significantly associated with type 2 diabetes risk overall (RR per interquintile range 0·96, 95% CI 0·88-1·05; p=0·38; I(2)=63·0%, pheterogeneity<0·0001). The associations between linoleic acid and arachidonic acid biomarkers and the risk of type 2 diabetes were not significantly modified by any prespecified potential sources of heterogeneity (ie, age, BMI, sex, race, aspirin use, omega-3 PUFA levels, or variants of the FADS gene; all pheterogeneity≥0·13).
Interpretation:
Findings suggest that linoleic acid has long-term benefits for the prevention of type 2 diabetes and that arachidonic acid is not harmful.
Funding:
Funders are shown in the appendix.
Background
Few studies have evaluated the relationship between changes in diet quality over time and the risk of death.
Methods
We used Cox proportional-hazards models to calculate adjusted hazard ratios for total and cause-specific mortality among 47,994 women in the Nurses’ Health Study and 25,745 men in the Health Professionals Follow-up Study from 1998 through 2010. Changes in diet quality over the preceding 12 years (1986–1998) were assessed with the use of the Alternate Healthy Eating Index–2010 score, the Alternate Mediterranean Diet score, and the Dietary Approaches to Stop Hypertension (DASH) diet score.
Results
The pooled hazard ratios for all-cause mortality among participants who had the greatest improvement in diet quality (13 to 33% improvement), as compared with those who had a relatively stable diet quality (0 to 3% improvement), in the 12-year period were the following: 0.91 (95% confidence interval [CI], 0.85 to 0.97) according to changes in the Alternate Healthy Eating Index score, 0.84 (95 CI%, 0.78 to 0.91) according to changes in the Alternate Mediterranean Diet score, and 0.89 (95% CI, 0.84 to 0.95) according to changes in the DASH score. A 20-percentile increase in diet scores (indicating an improved quality of diet) was significantly associated with a reduction in total mortality of 8 to 17% with the use of the three diet indexes and a 7 to 15% reduction in the risk of death from cardiovascular disease with the use of the Alternate Healthy Eating Index and Alternate Mediterranean Diet. Among participants who maintained a high-quality diet over a 12-year period, the risk of death from any cause was significantly lower — by 14% (95% CI, 8 to 19) when assessed with the Alternate Healthy Eating Index score, 11% (95% CI, 5 to 18) when assessed with the Alternate Mediterranean Diet score, and 9% (95% CI, 2 to 15) when assessed with the DASH score — than the risk among participants with consistently low diet scores over time.
Conclusions
Improved diet quality over 12 years was consistently associated with a decreased risk of death. (Funded by the National Institutes of Health.)
Health effects of dietary fats have been extensively studied for decades. However, controversies exist on the effects of various types of fatty acids, especially saturated fatty acid (SFA), on cardiovascular disease (CVD). Current evidence supports that different types of dietary fatty acids have divergent effects on CVD risk, and the effects also depend strongly on the comparison or replacement macronutrient. A significant reduction in CVD risk can be achieved if SFAs are replaced by unsaturated fats, especially polyunsaturated fatty acids. Intake of industrially produced trans fat is consistently associated with higher CVD risk. Both n-6 and n-3 polyunsaturated fatty acids are associated with lower CVD risk, although the effects of fish oil supplementation remains inconsistent. The 2015-2020 Dietary Guidelines for Americans place greater emphasis on types of detary fat than total amount of dietary fat and recommend replacing SFAs with unsaturated fats, especially polyunsaturated fatty acides for CVD prevention. Expected final online publication date for the Annual Review of Nutrition Volume 37 is August 21, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Background:
The assessment of polyphenol intake in free-living subjects is challenging, mostly because of the difficulty in accurately measuring phenolic content and the wide presence of phenolics in foods.
Objective:
The aims of this study were to evaluate the validity of polyphenol intake estimated from food-frequency questionnaires (FFQs) by using the mean of 6 measurements of a 24-h dietary recall (24-HR) as a reference and to apply a unique method-of-triads approach to assess validity coefficients (VCs) between latent "true" dietary estimates, total urinary polyphenol (TUP) excretion, and a surrogate biomarker (plasma carotenoids).
Design:
Dietary intake data from 899 adults of the Adventist Health Study 2 (AHS-2; 43% blacks and 67% women) were obtained. Pearson correlation coefficients (r), corrected for attenuation from within-person variation in the recalls, were calculated between 24-HRs and FFQs and between 24-HRs and TUPs. VCs and 95% CIs between true intake and polyphenol intakes from FFQs, 24-HRs, and the biomarkers TUPs and plasma carotenoids were calculated.
Results:
Mean ± SD polyphenol intakes were 717 ± 646 mg/d from FFQs and 402 ± 345 mg/d from 24-HRs. The total polyphenol intake from 24-HRs was correlated with FFQs in crude (r = 0.51, P < 0.001) and deattenuated (r = 0.63; 95% CI: 0.61, 0.69) models. In the triad model, the VC between the FFQs and theoretical true intake was 0.46 (95% CI: 0.20, 0.93) and between 24-HRs and true intake was 0.61 (95% CI: 0.38, 1.00).
Conclusions:
The AHS-2 FFQ is a reasonable indicator of total polyphenol intake in the AHS-2 cohort. Urinary polyphenol excretion is limited by genetic variance, metabolism, and bioavailability and should be used in addition to rather than as a replacement for dietary intake assessment.
Background:
Diet plays an important role in chronic disease etiology, but some diet-disease associations remain inconclusive because of methodologic limitations in dietary assessment. Metabolomics is a novel method for identifying objective dietary biomarkers, although it is unclear what dietary information is captured from metabolites found in serum compared with urine.
Objective:
We compared metabolite profiles of habitual diet measured from serum with those measured from urine.
Design:
We first estimated correlations between consumption of 56 foods, beverages, and supplements assessed by a food-frequency questionnaire, with 676 serum and 848 urine metabolites identified by untargeted liquid chromatography mass spectrometry, ultra-high performance liquid chromatography tandem mass spectrometry, and gas chromatography mass spectrometry in a colon adenoma case-control study (n = 125 cases and 128 controls) while adjusting for age, sex, smoking, fasting, case-control status, body mass index, physical activity, education, and caloric intake. We controlled for multiple comparisons with the use of a false discovery rate of <0.1. Next, we created serum and urine multiple-metabolite models to predict food intake with the use of 10-fold crossvalidation least absolute shrinkage and selection operator regression for 80% of the data; predicted values were created in the remaining 20%. Finally, we compared predicted values with estimates obtained from self-reported intake for metabolites measured in serum and urine.
Results:
We identified metabolites associated with 46 of 56 dietary items; 417 urine and 105 serum metabolites were correlated with ≥1 food, beverage, or supplement. More metabolites in urine (n = 154) than in serum (n = 39) were associated uniquely with one food. We found previously unreported metabolite associations with leafy green vegetables, sugar-sweetened beverages, citrus, added sugar, red meat, shellfish, desserts, and wine. Prediction of dietary intake from multiple-metabolite profiles was similar between biofluids.
Conclusions:
Candidate metabolite biomarkers of habitual diet are identifiable in both serum and urine. Urine samples offer a valid alternative or complement to serum for metabolite biomarkers of diet in large-scale clinical or epidemiologic studies.
Objectives:
To review the contribution of the Nurses' Health Studies (NHSs) to diet assessment methods and evidence-based nutritional policies and guidelines.
Methods:
We performed a narrative review of the publications of the NHS and NHS II between 1976 and 2016.
Results:
Through periodic assessment of diet by validated dietary questionnaires over 40 years, the NHSs have identified dietary determinants of diseases such as breast and other cancers; obesity; type 2 diabetes; cardiovascular, respiratory, and eye diseases; and neurodegenerative and mental health disorders. Nutritional biomarkers were assessed using blood, urine, and toenail samples. Robust findings, together with evidence from other large cohorts and randomized dietary intervention trials, have contributed to the evidence base for developing dietary guidelines and nutritional policies to reduce intakes of trans fat, saturated fat, sugar-sweetened beverages, red and processed meats, and refined carbohydrates while promoting higher intake of healthy fats and carbohydrates and overall healthful dietary patterns.
Conclusions:
The long-term, periodically collected dietary data in the NHSs, with documented reliability and validity, have contributed extensively to our understanding of the dietary determinants of various diseases, informing dietary guidelines and shaping nutritional policy. (Am J Public Health. Published online ahead of print July 26, 2016: e1-e6. doi:10.2105/AJPH.2016.303348).
Importance:
Previous studies have shown distinct associations between specific dietary fat and cardiovascular disease. However, evidence on specific dietary fat and mortality remains limited and inconsistent.
Objective:
To examine the associations of specific dietary fats with total and cause-specific mortality in 2 large ongoing cohort studies.
Design, setting, and participants:
This cohort study investigated 83 349 women from the Nurses' Health Study (July 1, 1980, to June 30, 2012) and 42 884 men from the Health Professionals Follow-up Study (February 1, 1986, to January 31, 2012) who were free of cardiovascular disease, cancer, and types 1 and 2 diabetes at baseline. Dietary fat intake was assessed at baseline and updated every 2 to 4 years. Information on mortality was obtained from systematic searches of the vital records of states and the National Death Index, supplemented by reports from family members or postal authorities. Data were analyzed from September 18, 2014, to March 27, 2016.
Main outcomes and measures:
Total and cause-specific mortality.
Results:
During 3 439 954 person-years of follow-up, 33 304 deaths were documented. After adjustment for known and suspected risk factors, dietary total fat compared with total carbohydrates was inversely associated with total mortality (hazard ratio [HR] comparing extreme quintiles, 0.84; 95% CI, 0.81-0.88; P < .001 for trend). The HRs of total mortality comparing extreme quintiles of specific dietary fats were 1.08 (95% CI, 1.03-1.14) for saturated fat, 0.81 (95% CI, 0.78-0.84) for polyunsaturated fatty acid (PUFA), 0.89 (95% CI, 0.84-0.94) for monounsaturated fatty acid (MUFA), and 1.13 (95% CI, 1.07-1.18) for trans-fat (P < .001 for trend for all). Replacing 5% of energy from saturated fats with equivalent energy from PUFA and MUFA was associated with estimated reductions in total mortality of 27% (HR, 0.73; 95% CI, 0.70-0.77) and 13% (HR, 0.87; 95% CI, 0.82-0.93), respectively. The HR for total mortality comparing extreme quintiles of ω-6 PUFA intake was 0.85 (95% CI, 0.81-0.89; P < .001 for trend). Intake of ω-6 PUFA, especially linoleic acid, was inversely associated with mortality owing to most major causes, whereas marine ω-3 PUFA intake was associated with a modestly lower total mortality (HR comparing extreme quintiles, 0.96; 95% CI, 0.93-1.00; P = .002 for trend).
Conclusions and relevance:
Different types of dietary fats have divergent associations with total and cause-specific mortality. These findings support current dietary recommendations to replace saturated fat and trans-fat with unsaturated fats.
Objective: The purpose of this review is to provide guidance on the development, validation and use of food-frequency questionnaires (FFQs) for different study designs. It does not include any recommendations about the most appropriate method for dietary assessment (e.g. food-frequency questionnaire versus weighed record).
Methods: A comprehensive search of electronic databases was carried out for publications from 1980 to 1999. Findings from the review were then commented upon and added to by a group of international experts.
Results: Recommendations have been developed to aid in the design, validation and use of FFQs. Specific details of each of these areas are discussed in the text.
Conclusions: FFQs are being used in a variety of ways and different study designs. There is no gold standard for directly assessing the validity of FFQs. Nevertheless, the outcome of this review should help those wishing to develop or adapt an FFQ to validate it for its intended use.
International Journal of Obesity is a monthly, multi-disciplinary forum for papers describing basic, clinical and applied studies in biochemistry, genetics and nutrition, together with molecular, metabolic, psychological and epidemiological aspects of obesity and related disorders
Background:
Consumption of sugar-sweetened beverages may cause excessive weight gain. We aimed to assess the effect on weight gain of an intervention that included the provision of noncaloric beverages at home for overweight and obese adolescents.
Methods:
We randomly assigned 224 overweight and obese adolescents who regularly consumed sugar-sweetened beverages to experimental and control groups. The experimental group received a 1-year intervention designed to decrease consumption of sugar-sweetened beverages, with follow-up for an additional year without intervention. We hypothesized that the experimental group would gain weight at a slower rate than the control group.
Results:
Retention rates were 97% at 1 year and 93% at 2 years. Reported consumption of sugar-sweetened beverages was similar at baseline in the experimental and control groups (1.7 servings per day), declined to nearly 0 in the experimental group at 1 year, and remained lower in the experimental group than in the control group at 2 years. The primary outcome, the change in mean body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) at 2 years, did not differ significantly between the two groups (change in experimental group minus change in control group, -0.3; P=0.46). At 1 year, however, there were significant between-group differences for changes in BMI (-0.57, P=0.045) and weight (-1.9 kg, P=0.04). We found evidence of effect modification according to ethnic group at 1 year (P=0.04) and 2 years (P=0.01). In a prespecified analysis according to ethnic group, among Hispanic participants (27 in the experimental group and 19 in the control group), there was a significant between-group difference in the change in BMI at 1 year (-1.79, P=0.007) and 2 years (-2.35, P=0.01), but not among non-Hispanic participants (P>0.35 at years 1 and 2). The change in body fat as a percentage of total weight did not differ significantly between groups at 2 years (-0.5%, P=0.40). There were no adverse events related to study participation.
Conclusions:
Among overweight and obese adolescents, the increase in BMI was smaller in the experimental group than in the control group after a 1-year intervention designed to reduce consumption of sugar-sweetened beverages, but not at the 2-year follow-up (the prespecified primary outcome). (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; ClinicalTrials.gov number, NCT00381160.).
Importance:
Many changes in the economy, policies related to nutrition, and food processing have occurred within the United States since 2000, and the net effect on dietary quality is not clear. These changes may have affected various socioeconomic groups differentially.
Objective:
To investigate trends in dietary quality from 1999 to 2010 in the US adult population and within socioeconomic subgroups.
Design, setting, and participants:
Nationally representative sample of 29 124 adults aged 20 to 85 years from the US 1999 to 2010 National Health and Nutrition Examination Survey.
Main outcomes and measures:
The Alternate Healthy Eating Index 2010 (AHEI-2010), an 11-dimension score (range, 0-10 for each component score and 0-110 for the total score), was used to measure dietary quality. A higher AHEI-2010 score indicated a more healthful diet.
Results:
The energy-adjusted mean of the AHEI-2010 increased from 39.9 in 1999 to 2000 to 46.8 in 2009 to 2010 (linear trend P < .001). Reduction in trans fat intake accounted for more than half of this improvement. The AHEI-2010 component score increased by 0.9 points for sugar-sweetened beverages and fruit juice (reflecting decreased consumption), 0.7 points for whole fruit, 0.5 points for whole grains, 0.5 points for polyunsaturated fatty acids, and 0.4 points for nuts and legumes over the 12-year period (all linear trend P < .001). Family income and education level were positively associated with total AHEI-2010, and the gap between low and high socioeconomic status widened over time, from 3.9 points in 1999 to 2000 to 7.8 points in 2009 to 2010 (interaction P = .01).
Conclusions and relevance:
Although a steady improvement in AHEI-2010 was observed across the 12-year period, the overall dietary quality remains poor. Better dietary quality was associated with higher socioeconomic status, and the gap widened with time. Future efforts to improve nutrition should address these disparities.
Background:
Previous studies on intake of linoleic acid (LA), the predominant n-6 fatty acid, and coronary heart disease (CHD) risk have generated inconsistent results. We performed a systematic review and meta-analysis of prospective cohort studies to summarize the evidence regarding the relation of dietary LA intake and CHD risk.
Methods and results:
We searched MEDLINE and EMBASE databases through June 2013 for prospective cohort studies that reported the association between dietary LA and CHD events. In addition, we used unpublished data from cohort studies in a previous pooling project. We pooled the multivariate-adjusted relative risk (RR) to compare the highest with the lowest categories of LA intake using fixed-effect meta-analysis. We identified 13 published and unpublished cohort studies with a total of 310 602 individuals and 12 479 total CHD events, including 5882 CHD deaths. When the highest category was compared with the lowest category, dietary LA was associated with a 15% lower risk of CHD events (pooled RR, 0.85; 95% confidence intervals, 0.78-0.92; I(2)=35.5%) and a 21% lower risk of CHD deaths (pooled RR, 0.79; 95% confidence intervals, 0.71-0.89; I(2)=0.0%). A 5% of energy increment in LA intake replacing energy from saturated fat intake was associated with a 9% lower risk of CHD events (RR, 0.91; 95% confidence intervals, 0.87-0.96) and a 13% lower risk of CHD deaths (RR, 0.87; 95% confidence intervals, 0.82-0.94).
Conclusions:
In prospective observational studies, dietary LA intake is inversely associated with CHD risk in a dose-response manner. These data provide support for current recommendations to replace saturated fat with polyunsaturated fat for primary prevention of CHD.
The beneficial impact of walnuts on human health has been attributed to their unique chemical composition. In order to characterize the dietary walnut fingerprinting, spot urine samples from two sets of 195 (training) and 186 (validation) individuals were analyzed by an HPLC-q-ToF-MS untargeted metabolomics approach, selecting the most discriminating metabolites by multivariate data analysis (VIP≥1.5). Logistic regression analysis was used to design a multi-metabolite prediction biomarker model. The global performance of the model and each included metabolite in it was evaluated by receiver operating characteristic curves, using the area under the curve (AUC) values. Dietary exposure to walnuts was characterized by 18 metabolites, including markers of fatty acid metabolism, ellagitannin-derived microbial compounds, and intermediate metabolites of the tryptophan/serotonin pathway. The predictive model of walnut exposure included at least one compound of each class. The AUC (95% CI) for the combined biomarker model was 93.5% (90.1%-96.8%) in the training set and 90.2% (85.9%-94.6%) in the validation set. The AUCs for individual metabolites were ≤85%. As far as we know, this is the first study proposing a combination of biomarkers of walnut exposure in a population under free-living conditions, as considered in epidemiological studies examining associations between diet and health outcomes.
Increasing evidence suggests that the Mediterranean diet can reduce the risk of CVD. Olive oil is the hallmark of this dietary pattern. We conducted a meta-analysis of case-control, prospective cohort studies and a randomised controlled trial investigating the specific association between olive oil consumption and the risk of CHD (101 460 participants) or stroke (38 673 participants). The results of all observational studies were adjusted for total energy intake. The random-effects model assessing CHD as an outcome showed a relative risk (RR) of 0·73 (95 % CI 0·44, 1·21) in case-control studies and 0·96 (95 % CI 0·78, 1·18) in cohort studies for a 25 g increase in olive oil consumption. In cohort studies, the random-effects model assessing stroke showed a RR of 0·74 (95 % CI 0·60, 0·92). The random-effects model combining all cardiovascular events (CHD and stroke) showed a RR of 0·82 (95 % CI 0·70, 0·96). Evidence of heterogeneity was apparent for CHD, but not for stroke. Both the Egger test (P= 0·06) and the funnel plot suggested small-study effects. Available studies support an inverse association of olive oil consumption with stroke (and with stroke and CHD combined), but no significant association with CHD. This finding is in agreement with the recent successful results of the PREDIMED randomised controlled trial.
The objective of this manuscript was to review the evidence on the association between adherence to a Mediterranean diet (MeDiet) and the risk of cardiovascular disease (CVD). We also updated the results of the last available meta-analysis.
In 2013, a landmark study in the field, the PREvención con DIeta MEDiterránea randomized trial, with 7447 high-risk participants, published its final results. They provided a strong support to the beneficial role of a traditional MeDiet for primary cardiovascular prevention. When these results were combined with those of the Lyon Diet Heart Study (a secondary prevention trial), we found that an intervention with a MeDiet was associated with a 38% relative reduction in the risk of CVD clinical events (pooled random-effects risk ratio: 0.62; 95% confidence interval, CI: 0.45-0.85). Regarding observational studies assessing clinical end-points as outcome, we identified seven new cohort studies published after the last meta-analysis. After removing studies that only assessed fatal outcomes, a two-point increase in adherence to the MeDiet (0-9 score) was associated with a significant reduction in cardiovascular events (pooled risk ratio: 0.87; 95% CI: 0.85-0.90) with no evidence of heterogeneity.
Consistent evidence suggests that the promotion of the Mediterranean dietary pattern is an effective and feasible tool for the prevention of CVD.
The essence of knowledge is generalisation. That rubbing wood in a certain way can produce fire is a knowledge derived by generalisation from individual experiences; the statement means that rubbing wood in this way will always produce fire. The art of discovery is therefore the art of correct generalisation. What is irrelevant, such as the particular shape or size of the piece of wood used, is to be excluded from the generalisation; what is relevant, for example, the dryness of the wood, is to be included in it. The meaning of the term relevant can thus be defined: that is relevant which must be mentioned for the generalisation to be valid. The separation of relevant from irrelevant factors is the beginning of knowledge.
The relation between sugar-sweetened beverages (SSBs) and body weight remains controversial.
We conducted a systematic review and meta-analysis to summarize the evidence in children and adults.
We searched PubMed, EMBASE, and Cochrane databases through March 2013 for prospective cohort studies and randomized controlled trials (RCTs) that evaluated the SSB-weight relation. Separate meta-analyses were conducted in children and adults and for cohorts and RCTs by using random- and fixed-effects models.
Thirty-two original articles were included in our meta-analyses: 20 in children (15 cohort studies, n = 25,745; 5 trials, n = 2772) and 12 in adults (7 cohort studies, n = 174,252; 5 trials, n = 292). In cohort studies, one daily serving increment of SSBs was associated with a 0.06 (95% CI: 0.02, 0.10) and 0.05 (95% CI: 0.03, 0.07)-unit increase in BMI in children and 0.22 kg (95% CI: 0.09, 0.34 kg) and 0.12 kg (95% CI: 0.10, 0.14 kg) weight gain in adults over 1 y in random- and fixed-effects models, respectively. RCTs in children showed reductions in BMI gain when SSBs were reduced [random- and fixed-effects: -0.17 (95% CI: -0.39, 0.05 kg) and -0.12 (95% CI: -0.22, -0.2 kg)], whereas RCTs in adults showed increases in body weight when SSBs were added (random- and fixed-effects: 0.85 kg; 95% CI: 0.50, 1.20 kg). Sensitivity analyses of RCTs in children showed more pronounced benefits in preventing weight gain in SSB substitution trials (compared with school-based educational programs) and among overweight children (compared with normal-weight children).
Our systematic review and meta-analysis of prospective cohort studies and RCTs provides evidence that SSB consumption promotes weight gain in children and adults.
Sugar-sweetened beverages (SSBs) are the single largest source of added sugar and the top source of energy intake in the U.S. diet. In this review, we evaluate whether there is sufficient scientific evidence that decreasing SSB consumption will reduce the prevalence of obesity and its related diseases. Because prospective cohort studies address dietary determinants of long-term weight gain and chronic diseases, whereas randomized clinical trials (RCTs) typically evaluate short-term effects of specific interventions on weight change, both types of evidence are critical in evaluating causality. Findings from well-powered prospective cohorts have consistently shown a significant association, established temporality and demonstrated a direct dose-response relationship between SSB consumption and long-term weight gain and risk of type 2 diabetes (T2D). A recently published meta-analysis of RCTs commissioned by the World Health Organization found that decreased intake of added sugars significantly reduced body weight (0.80 kg, 95% confidence interval [CI] 0.39-1.21; P < 0.001), whereas increased sugar intake led to a comparable weight increase (0.75 kg, 0.30-1.19; P = 0.001). A parallel meta-analysis of cohort studies also found that higher intake of SSBs among children was associated with 55% (95% CI 32-82%) higher risk of being overweight or obese compared with those with lower intake. Another meta-analysis of eight prospective cohort studies found that one to two servings per day of SSB intake was associated with a 26% (95% CI 12-41%) greater risk of developing T2D compared with occasional intake (less than one serving per month). Recently, two large RCTs with a high degree of compliance provided convincing data that reducing consumption of SSBs significantly decreases weight gain and adiposity in children and adolescents. Taken together, the evidence that decreasing SSBs will decrease the risk of obesity and related diseases such as T2D is compelling. Several additional issues warrant further discussion. First, prevention of long-term weight gain through dietary changes such as limiting consumption of SSBs is more important than short-term weight loss in reducing the prevalence of obesity in the population. This is due to the fact that once an individual becomes obese, it is difficult to lose weight and keep it off. Second, we should consider the totality of evidence rather than selective pieces of evidence (e.g. from short-term RCTs only). Finally, while recognizing that the evidence of harm on health against SSBs is strong, we should avoid the trap of waiting for absolute proof before allowing public health action to be taken.
The field of application of accelerometry is diverse and ever expanding. Because by definition all physical activities lead to energy expenditure, the doubly labelled water (DLW) method as gold standard to assess total energy expenditure over longer periods of time is the method of choice to validate accelerometers in their ability to assess daily physical activities. The aim of this paper was to provide a systematic overview of all recent (2007-2011) accelerometer validation studies using DLW as the reference. The PubMed Central database was searched using the following keywords: doubly or double labelled or labeled water in combination with accelerometer, accelerometry, motion sensor, or activity monitor. Limits were set to include articles from 2007 to 2011, as earlier publications were covered in a previous review. In total, 38 articles were identified, of which 25 were selected to contain sufficient new data. Eighteen different accelerometers were validated. There was a large variability in accelerometer output and their validity to assess daily physical activity. Activity type recognition has great potential to improve the assessment of physical activity-related health outcomes. So far, there is little evidence that adding other physiological measures such as heart rate significantly improves the estimation of energy expenditure.
Large nutritional epidemiology studies, with long-term follow-up to assess major clinical end points, coupled with advances in basic science and clinical trials, have led to important improvements in our understanding of nutrition in primary prevention of chronic disease. Although much work remains, sufficient evidence has accrued to provide solid advice on healthy eating. Good data now support the benefits of diets that are rich in plant sources of fats and protein, fish, nuts, whole grains, and fruits and vegetables; that avoid partially hydrogenated fats; and that limit red meat and refined carbohydrates. The simplistic advice to reduce all fat, or all carbohydrates, has not stood the test of science; strong evidence supports the need to consider fat and carbohydrate quality and different protein sources. This article briefly summarizes major findings from recent years bearing on these issues. Expected final online publication date for the Annual Review of Public Health Volume 34 is March 17, 2013. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.