Association between dietary glycemic index, glycemic load, and body mass index in the Inter99 study: is underreporting a problem?
ABSTRACT The few studies examining the potential associations between glycemic index (GI), glycemic load (GL), and body mass index (BMI) have provided no clear pictures. Underreporting of energy intake may be one explanation for this.
We examined the associations between GI, GL, and BMI by focusing on the confounding factor of total energy intake and the effect of exclusion of low energy reporters (LERs).
This was a cross-sectional study of 6334 subjects aged 30-60 y. Dietary intake was estimated from a food-frequency questionnaire. GI and GL were estimated by using white bread as the reference food. Underreporting of energy intake was assessed as reported energy intake divided by basal metabolic rate (EI/BMR); LERs were defined as those having an EI/BMR < 1.14. Univariate and multiple linear regression models were used to test for associations between GI, GL, and BMI. The confounders were sex, age, smoking, physical activity, alcohol intake, and energy intake. All analyses were conducted on 1) the entire population and 2) a subsample excluding LERs.
In the univariate analyses of the entire population, GL was inversely associated with BMI. No association was observed for GI. After full adjustment (including energy intake), both GI and GL were positively associated with BMI. When LERs were excluded, GL was positively associated with BMI in all analyses, and GI was positively associated with BMI in the multiple analyses.
We showed a positive association between GI, GL, and BMI. Energy adjustment and the exclusion of LERs significantly affected the results of the analysis; thus, we stress the importance of energy adjustment.
- [Show abstract] [Hide abstract]
ABSTRACT: The increased prevalence of overweight and obesity in the United States since approximately 1980 is temporally associated with an increase in carbohydrate intake, with no appreciable change in absolute intake of fat. Despite speculation that both carbohydrate quantity and quality have contributed significantly to excess weight gain, the relationship between carbohydrate intake and body mass index (BMI) is controversial. A review of relevant literature indicates that most epidemiologic studies show an inverse relationship between carbohydrate intake and BMI, even when controlling for potential confounders. These observational studies are supported by results from a number of dietary intervention studies wherein modest reductions in body weight were observed with an ad libitum, low-fat, high-carbohydrate diet without emphasis on energy restriction or weight loss. With few exceptions, high glycemic load is associated with lower BMI, even when adjusted for total energy intake. Data on the association between glycemic index and BMI are not as consistent, with more studies showing either no association or an inverse relationship, rather than a positive relationship. Whole-grain intake is generally inversely associated with BMI; refined grain intake is not. Because overall dietary quality tends to be higher for high-carbohydrate diets, a low-fat dietary strategy with emphasis on fiber-rich carbohydrates, particularly cereal fiber, may be beneficial for health and weight control.Journal of the American Dietetic Association 11/2007; 107(10):1768-80. DOI:10.1016/j.jada.2007.07.011 · 3.92 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The TUB gene, encoding an evolutionary conserved protein, is highly expressed in the hypothalamus and might act as a transcription factor. Mutations in TUB cause late-onset obesity, insulin-resistance and neurosensory deficits in mice. An association of common variants in the TUB gene with body weight in humans has been reported. The aim was to investigate the relationship of single nucleotide polymorphisms (SNPs) of the TUB gene (rs2272382, rs2272383 and rs1528133) with both anthropometry and self-reported macronutrient intake from a validated food frequency questionnaire. These associations were studied in a population-based, cross-sectional study of 1680 middle-aged Dutch women, using linear regression analysis. The minor allele C of the rs1528133 SNP was significantly associated with increased weight (+1.88 kg, P = 0.022) and BMI (+0.56 units, P = 0.05). Compared with non-carriers, both AG heterozygotes and AA homozygotes of the rs2272382 SNP derived less energy from fat (AG: -0.55+/-0.28%, P = 0.05, AA: -0.95+/-0.48%, P = 0.047). However, both genotypes were associated with an increased energy intake from carbohydrates (0.69+/-0.33%, P = 0.04 and 1.68+/-0.56%, P = 0.003, respectively), mainly because of a higher consumption of mono- and disaccharides. Both these SNPs, rs2272382 and rs1528133, were also associated with a higher glycemic load in the diet. The glycemic load was higher among those with AG and AA genotypes for the variant rs2272382 than among the wild types (+1.49 (95% CI: -0.27-3.24) and +3.89 (95% CI: 0.94-6.85) units, respectively). Carriers of the minor allele C of rs1528133 were associated with an increased glycemic load of 1.85 units compared with non-carriers. Genetic variation of the TUB gene was associated with both body composition and macronutrient intake, suggesting that TUB might influence eating behavior.PLoS ONE 02/2008; 3(1):e1405. DOI:10.1371/journal.pone.0001405 · 3.53 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Most pregnant women gain more weight than the ranges recommended. Excessive weight gain is linked to pregnancy complications and to long-term maternal and child health outcomes. The objective was to examine the impact of dietary glycemic load and energy density on total gestational weight gain and the weight gain ratio (observed weight gain/expected weight gain). Data are from 1231 women with singleton pregnancies who participated in the Pregnancy, Infection, and Nutrition Cohort Study. Dietary information was collected at 26-29 wk of gestation with the use of a semiquantified food-frequency questionnaire. Linear regression models were used to estimate the associations between quartiles of glycemic load and energy density with total gestational weight gain and weight gain ratio. Dietary patterns of pregnant women significantly differed across many sociodemographic and behavioral characteristics, with the greatest contrasts seen for glycemic load. After adjustment for covariates, compared with women in the first quartile consuming a mean dietary energy density of 0.71 kcal/g (reference), women in the third quartile consuming a mean energy density of 0.98 kcal/g gained an excess of 1.13 kg (95% CI: 0.24, 2.01), and women in the fourth quartile consuming a mean energy density of 1.21 kcal/g gained an excess of 1.08 kg (95% CI: 0.20, 1.97) and had an increase of 0.13 (95% CI: 0.006, 0.24) units in the weight gain ratio. All other comparisons of energy intakes were not statistically significant. Glycemic load was not associated with total gestational weight gain or weight gain ratio. Dietary energy density is a modifiable factor that may assist pregnant women in managing gestational weight gains.American Journal of Clinical Nutrition 10/2008; 88(3):693-9. · 6.92 Impact Factor