ArticlePDF AvailableLiterature Review

Can adults adequately convert ??-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)?

Authors:
Helga Gerster at Roche
Helga Gerster
Download full-text PDFDownload full-text PDF
Read full-text
Download citation

Abstract

A diet including 2-3 portions of fatty fish per week, which corresponds to the intake of 1.25 g EPA (20:5n-3) + DHA (22:6n-3) per day, has been officially recommended on the basis of epidemiological findings showing a beneficial role of these n-3 long-chain PUFA in the prevention of cardiovascular and inflammatory diseases. The parent fatty acid ALA (18:3n-3), found in vegetable oils such as flaxseed or rapeseed oil, is used by the human organism partly as a source of energy, partly as a precursor of the metabolites, but the degree of conversion appears to be unreliable and restricted. More specifically, most studies in humans have shown that whereas a certain, though restricted, conversion of high doses of ALA to EPA occurs, conversion to DHA is severely restricted. The use of ALA labelled with radioisotopes suggested that with a background diet high in saturated fat conversion to long-chain metabolites is approximately 6% for EPA and 3.8% for DHA. With a diet rich in n-6 PUFA, conversion is reduced by 40 to 50%. It is thus reasonable to observe an n-6/n-3 PUFA ratio not exceeding 4-6. Restricted conversion to DHA may be critical since evidence has been increasing that this long-chain metabolite has an autonomous function, e.g. in the brain, retina and spermatozoa where it is the most prominent fatty acid. In neonates deficiency is associated with visual impairment, abnormalities in the electroretinogram and delayed cognitive development. In adults the potential role of DHA in neurological function still needs to be investigated in depth. Regarding cardiovascular risk factors DHA has been shown to reduce triglyceride concentrations. These findings indicate that future attention will have to focus on the adequate provision of DHA which can reliably be achieved only with the supply of the preformed long-chain metabolite.
Can adults adequately convert alpha linoleic acid to eicosapentaenoic acid and docosahexaenoic ac
id.pdf
Content uploaded by Helga Gerster
Author content
All content in this area was uploaded by Helga Gerster on Mar 25, 2016
Content may be subject to copyright.
Can adults adequately convert alpha linoleic acid to eicosapentaenoic acid and docosahexaenoic ac
id.pdf
Content uploaded by Helga Gerster
Author content
All content in this area was uploaded by Helga Gerster on Mar 25, 2016
Content may be subject to copyright.
... Additionally, the body has enzymes called delta-desaturases and elongases that convert short-chain omega-3 fatty acids-such as ALA, which is typically found in plants (e.g., chia seeds, flax seeds, and walnuts)-to long-chain fatty acids (e.g., DHA and EPA) [73]. The human body converts short-chain omega-3 fatty acids from plant-based sources to long-chain fatty acids with an average efficiency of approximately 5% [74]. ...
Linoleic Acid: A Narrative Review of the Effects of Increased Intake in the Standard American Diet and Associations with Chronic Disease
Article
Full-text available
  • Jul 2023
The intake of linoleic acid (LA) has increased dramatically in the standard American diet. LA is generally promoted as supporting human health, but there exists controversy regarding whether the amount of LA currently consumed in the standard American diet supports human health. The goal of this narrative review is to explore the mechanisms that underlie the hypothesis that excessive LA intake may harm human health. While LA is considered to be an essential fatty acid and support health when consumed in modest amounts, an excessive intake of LA leads to the formation of oxidized linoleic acid metabolites (OXLAMs), impairments in mitochondrial function through suboptimal cardiolipin composition, and likely contributes to many chronic diseases that became an epidemic in the 20th century, and whose prevalence continues to increase. The standard American diet comprises 14 to 25 times more omega-6 fatty acids than omega-3 fatty acids, with the majority of omega-6 intake coming from LA. As LA consumption increases, the potential for OXLAM formation also increases. OXLAMs have been associated with various illnesses, including cardiovascular disease, cancer, and Alzheimer's disease, among others. Lowering dietary LA intake can help reduce the production and accumulation of OXLAMs implicated in chronic diseases. While there are other problematic components in the standard American diet, the half-life of LA is approximately two years, which means the damage can be far more persistent than other dietary factors, and the impact of reducing excessive LA intake takes time. Therefore, additional research-evaluating approaches to reduce OXLAM formation and cardiolipin derangements following LA consumption are warranted.
View
... The parent fatty acid ALA (18:3 n-3), found in vegetable oils such as linseed or rapeseed oil, is used by the human body partly as an energy source and partly as a precursor of metabolites. However, the degree of endogenous conversion appears to be unreliable and limited [54]. Most human studies have shown that the conversion of high doses of ALA to EPA occurs, but to a limited extent, whereas the conversion to DHA is severely limited. ...
A Targeted Mass Spectrometry Approach to Identify Peripheral Changes in Metabolic Pathways of Patients with Alzheimer’s Disease
Article
Full-text available
Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common cause of dementia in the elderly population. Since its original description, there has been intense debate regarding the factors that trigger its pathology. It is becoming apparent that AD is more than a brain disease and harms the whole-body metabolism. We analyzed 630 polar and apolar metabolites in the blood of 20 patients with AD and 20 healthy individuals, to determine whether the composition of plasma metabolites could offer additional indicators to evaluate any alterations in the metabolic pathways related to the illness. Multivariate statistical analysis showed that there were at least 25 significantly dysregulated metabolites in patients with AD compared with the controls. Two membrane lipid components, glycerophospholipids and ceramide, were upregulated, whereas glutamic acid, other phospholipids, and sphingolipids were downregulated. The data were analyzed using metabolite set enrichment analysis and pathway analysis using the KEGG library. The results showed that at least five pathways involved in the metabolism of polar compounds were dysregulated in patients with AD. Conversely, the lipid pathways did not show significant alterations. These results support the possibility of using metabolome analysis to understand alterations in the metabolic pathways related to AD pathophysiology.
View
... Studies have shown that testicular function appears to be positively correlated with omega-3 PUFAs intake and negatively correlated with omega-6 PUFAs intake (90). Gerster found that the conversion of ALA to EPA and DHA was reduced by 40-50% when the ratio of omega-6/omega-3 PUFAs in the diet was elevated (91). Due to lack of research data, the appropriate ratio of omega-6/omega-3 PUFAs requires further research. ...
Regulation of semen quality by fatty acids in diets, extender, and semen
Article
Full-text available
  • Apr 2023
Fatty acids (FAs) are classified into different types according to the degree of hydrocarbon chain saturation, including saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), omega-3 polyunsaturated fatty acids (omega-3 PUFAs) and omega-6 polyunsaturated fatty acids (omega-6 PUFAs), which play an important role in maintaining semen quality. This review focuses on the regulation of FAs in semen, diet and extender on semen quality, and expounds its effects on sperm motility, plasma membrane integrity, DNA integrity, hormone content, and antioxidant capacity. It can be concluded that there are species differences in the FAs profile and requirements in sperm, and their ability to regulate semen quality is also affected by the addition methods or dosages. Future research directions should focus on analyzing the FAs profiles of different species or different periods of the same species and exploring suitable addition methods, doses and mechanism of regulating semen quality.
View
... This is not altogether unsurprising, as ALA is a known precursor for longer chain PUFAs, is also utilised for β-oxidation, and is, therefore, not commonly stored [44,45]. However, the metabolism of ALA to EPA or DHA is considered to be poor [46]. This can be mediated by the amount consumed, with Goyens et al. [47] reporting that a low intake of LA increased ALA metabolism to EPA, while a high intake of ALA increased DHA production. ...
Omega-3 Fatty Acids during Pregnancy in Indigenous Australian Women of the Gomeroi Gaaynggal Cohort
Article
Full-text available
  • Apr 2023
Higher dietary intakes of Omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) have been linked to lower rates of preterm birth and preeclampsia. The aim of this analysis was to describe dietary intake and fractions of red blood cell (RBC) membrane LC-PUFAs during pregnancy in a cohort of Indigenous Australian women. Maternal dietary intake was assessed using two validated dietary assessment tools and quantified using the AUSNUT (Australian Food and Nutrient) 2011–2013 database. Analysis from a 3-month food frequency questionnaire indicated that 83% of this cohort met national n-3 LC-PUFA recommendations, with 59% meeting alpha-linolenic acid (ALA) recommendations. No nutritional supplements used by the women contained n-3 LC-PUFAs. Over 90% of women had no detectable level of ALA in their RBC membranes, and the median Omega-3 Index was 5.5%. This analysis appears to illustrate a decline in concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) across gestation in women who had preterm birth. However, there was no visible trend in LC-PUFA fractions in women who experienced hypertension during pregnancy. Further research is needed to better understand the link between dietary intake of n-3 LC-PUFA-rich foods and the role of fatty acids in preterm birth and preeclampsia.
View
... Moreover, the presence of higher levels of these fatty acids elevated the proportion of n-3 PUFA and n-6 PUFA in colostrum and n-3 PUFA in milk. Higher ratio of n-6:n-3 may limit the production of anti-inflammatory eicosanoids derived from eicosapentaenoic acid [37]. Maternal diets with varying n-6:n-3 PUFA ratios affected the antioxidant status, immune cell eicosanoid responses, immunoglobulins, fatty acids composition, and growth performance [38,39]. ...
Supplementation with alpha-glycerol monolaurate during late gestation and lactation enhances sow performance, ameliorates milk composition, and improves growth of suckling piglets
Article
Full-text available
  • Apr 2023
Background: Physiological changes during lactation cause oxidative stress in sows, reduce immunity, and hamper the growth capacity of piglets. Alpha-glycerol monolaurate (α-GML) has potential for enhancing the antimicrobial activity of sows and the growth of suckling piglets. Methods: Eighty sows were allocated randomly to four groups: basal diet and basal diets supplemented with 500, 1000, or 2000 mg/kg α-GML. The experiment started on d 85 of gestation and lasted until piglets were weaned on d 21 of lactation. The number of live-born piglets was standardized to 12 ± 1 per sow on day of parturition. On d 0 and 21 of lactation, body weight of piglets was measured and milk samples were obtained from sows, and serum samples and feces from piglets were obtained on d 21. Results: Feed intake, backfat loss, and weaning estrus interval did not differ among the four groups of sows. Maternal α-GML supplementation increased (P < 0.05) the body weight of piglets at weaning and the apparent total tract digestibility of crude fat of sows. The immunoglobulin A and immunoglobulin G levels were greater (P < 0.05) in a quadratic manner in the milk of sows as dietary α-GML increased. Concerning fatty acid profile, C12:0, C15:0, C17:0, C18:2n6c, C18:3n3, C24:0, and C22:6n3 were higher (P < 0.05) in linear and quadratic manners in colostrum of sows-fed α-GML diets compared with the control sows. There was lower (P < 0.05) n-6:n-3 polyunsaturated fatty acid ratio in milk than in the control sows. Maternal α-GML increased the abundance of Firmicutes (P < 0.05) and decreased the abundance of Proteobacteria (P < 0.05) of piglet fecal microbiota. Conclusions: Dietary supplementation with α-GML improved milk immunoglobulins and altered fatty acids of sows, thereby improving the health of piglets.
View
... Essential fatty acids are the ones that cannot be synthesized by the body. The long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be synthesized from LNA (Spector & Kim, 2019), but due to low conversion efficiency, they must be supplied from foods rich in EPA and DHA (Gerster, 1998). ...
Essential fatty acids in farmed tambaqui (Colossoma macropomum) from the Brazilian Amazon Area
Article
Full-text available
  • Sep 2022
The goal of this study was to determine the essential fatty acids of the total lipids of the fillet, head and orbital cavity tissue from farmed tambaqui (Colossoma macropomum) fish from a Brazilian Amazon area. The tambaqui were acquired from different fish farms in the Roraima state, located at Western Brazilian Amazon. The meat, the head and the fatty tissue from orbital cavity were dissected for lipid extraction and analysis of fatty acids by gas chromatography. The fatty acids were quantified in mg g-1 of total lipids using C23:0 as an internal standard. The nutritional quality of the lipids was determined by using the atherogenicity and thrombogenicity indices, and also by the ratio between hypocholesterolemic / hypercholesterolemic fatty acids. The orbital cavity tissue had the higher concentration amount of linoleic and α-linolenic acid, whereas the fillet had higher docosahexaenoic acid (DHA). The eicosapentaenoic acid (EPA) concentration was: 1.28, 0.97, 1.71 mg g-1 of total lipids, in the filet, in head, and in orbital cavity tissue, respectively. All essential fatty acids were detected in the three parts analyzed. The nutritional quality of the total lipids from the head and from the orbital cavity tissue was similar to the fillet.
View
Genetic architecture and key regulatory genes of fatty acid composition in Gushi chicken breast muscle determined by GWAS and WGCNA
Article
Full-text available
Background Fatty acids composition in poultry muscle is directly related to its tenderness, flavour, and juiciness, whereas its genetic mechanisms have not been elucidated. In this study, the genetic structure and key regulatory genes of the breast muscle fatty acid composition of local Chinese chicken, Gushi-Anka F2 resource population by integrating genome-wide association study (GWAS) and weighted gene co-expression network analysis (WGCNA) strategies. GWAS was performed based on 323,306 single nucleotide polymorphisms (SNPs) obtained by genotyping by sequencing (GBS) method and 721 chickens from the Gushi-Anka F2 resource population with highly variable fatty acid composition traits in the breast muscle. And then, according to the transcriptome data of the candidate genes that were obtained and phenotypic data of fatty acid composition traits in breast muscle of Gushi chickens at 14, 22, and 30 weeks of age, we conducted a WGCNA. Results A total of 128 suggestive significantly associated SNPs for 11 fatty acid composition traits were identified and mapped on chromosomes (Chr) 2, 3, 4, 5, 13, 17, 21, and 27. Of these, the two most significant SNPs were Chr13:5,100,140 (P = 4.56423e-10) and Chr13:5,100,173 (P = 4.56423e-10), which explained 5.6% of the phenotypic variation in polyunsaturated fatty acids (PUFA). In addition, six fatty acid composition traits, including C20:1, C22:6, saturated fatty acid (SFA), unsaturated fatty acids (UFA), PUFA, and average chain length (ACL), were located in the same QTL intervals on Chr13. We obtained 505 genes by scanning the linkage disequilibrium (LD) regions of all significant SNPs and performed a WGCNA based on the transcriptome data of the above 505 genes. Combining two strategies, 9 hub genes (ENO1, ADH1, ASAH1, ADH1C, PIK3CD, WISP1, AKT1, PANK3, and C1QTNF2) were finally identified, which could be the potential candidate genes regulating fatty acid composition traits in chicken breast muscle. Conclusion The results of this study deepen our understanding of the genetic mechanisms underlying the regulation of fatty acid composition traits, which is helpful in the design of breeding strategies for the subsequent improvement of fatty acid composition in poultry muscle.
View
Air Pollution and Diet: Potential Interacting Exposures in Asthma
Article
Full-text available
Purpose of Review To provide a review of emerging literature describing the impact of diet on the respiratory response to air pollution in asthma. Recent Findings Asthma phenotyping (observable characteristics) and endotyping (mechanistic pathways) have increased the specificity of diagnostic and treatment pathways and opened the doors to the identification of subphenotypes with enhanced susceptibility to exposures and interventions. Mechanisms underlying the airway immune response to air pollution are still being defined but include oxidative stress, inflammation, and activation of adaptive and innate immune responses, with genetic susceptibility highlighted. Of these, neutrophil recruitment and activation appear prominent; however, understanding neutrophil function in response to pollutant exposures is a research gap. Diet may play a role in asthma pathogenesis and morbidity; therefore, diet modification is a potential target opportunity to protect against pollutant-induced lung injury. In particular, in vivo and in vitro data suggest the potential for diet to modify the inflammatory response in the airways, including impacts on neutrophil recruitment and function. Murine models provide compelling results in regard to the potential for dietary components (including fiber, antioxidants, and omega-3 fatty acids) to buffer against the inflammatory response to air pollution in the lung. Summary Precision lifestyle approaches to asthma management and respiratory protection in the context of air pollution exposures may evolve to include diet, pending the results of further epidemiologic and causal investigation and with neutrophil recruitment and activation as a candidate mechanism.
View
View
New alternative sources of omega-3 fish oil
Chapter
Long-chain omega-3 polyunsaturated fatty acids such as eicosapentaenoic and docosahexaenoic acids play an important role in brain growth and development, as well as in the health of the body. These fatty acids are traditionally found in seafood, such as fish, fish oils, and algae. They can also be added to food or consumed through dietary supplements. Due to a lack of supply to meet current demand and the potential for adverse effects from excessive consumption of fish and seafood, new alternatives are being sought to achieve the recommended levels in a safe and sustainable manner. New sources have been studied and new production mechanisms have been developed. These new proposals, as well as the importance of these fatty acids, are discussed in this paper.
View
The effect of dietary supplements of ??3 polyunsaturated fatty acids on the fatty acid composition of platelets and plasma choline phosphoglycerides
Article
Full-text available
  • Jun 1981
1. The effects of dietary supplements of ω 3 polyunsaturated fatty acids on the fatty acid composition of platelets and plasma choline phosphoglycerides were studied in vegans and in omnivores. 2. A supplement of 18:3ω3 led to an increase in 20:5 ω3 but was less effective than one of 20:5ω3+22:6ω3.
View
n-3 fatty acids in Indian diets — Comparison of the effects of precursor (alpha-linolenic acid) Vs product (long chain n-3 poly unsaturated fatty acids)
Article
Studies were conducted in human volunteers maintained on habitual Indian diets to determine (a) the effective dose of long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) needed for hypolipidemic and antithrombotic effects and (b) the efficacy of the use of alphalinolenic acid (ALNA), the precursor of LC n-3 PUFA, as a substitute for fish oils. Keeping the levels of linoleic acid constant, the levels of fatty acids were altered either in the form of LC n-3 PUFA or as ALNA. The results show that while 1.4g LC n-3 PUFA may be needed for hypotriglyceridemic effects, 0.6g appears to be sufficient for antithrombotic effects as judged by increase in LC n-3 PUFA levels in plasma and platelet phospholipids, and decrease in platelet aggregation. ALNA supplementation decreased plasma cholesterol levels but, had no effect on triglycerides. The increase in the levels of LC n-3 PUFA in plasma and platelet phospholipids was accompanied by a decrease in platelet aggregation, suggesting that ALNA rich vegetable oils used as a single source of visible fat in Indian diets, is beneficial. On the basis of the absolute increase in LC n-3 PUFA in plasma phospholipids with ALNA and LC n-3 PUFA supplementation, it was calculated that 3.7g ALNA may have biological effects similar to 0.3g LC n-3 PUFA. Therefore, it appears that replacement of part of the vegetable oil intake with mustard/rapeseed oil, so as to furnish n-6/n-3 ratio around 8, may be a feasible approach to ensure beneficial effects of n-3 fatty acids in vegetarians. Further, it also ensures a balanced intake of the other fatty acids.
View
Slow desaturation and elongation of linoleic and alpha-linolenic acids as a rationale of eicosapentaenoic acid-rich diet to lower blood pressure and serum lipids in normal, hypertensive and hyperlipemic subjects
Article
In normal, hypertensive and hyperlipemic subjects, diets supplemented with linoleic acid (LA) or alpha-linolenic acid (LNA) resulted in an increase of the corresponding fatty acids in serum lipids. However, their C20-derivatives, the prostaglandin precursors arachidonic acid (AA) and eicosapentaenoic acid (EPA), respectively, were not or only slightly augmented. On the other hand, an EPA-rich diet produced a marked increase of this fatty acid, especially in cholesterol esters. After this diet the decreases of blood pressure and serum lipids were more pronounced when compared with LA- and LNA-rich diets containing a 20-fold higher dose of the polyunsaturated fatty acids. The slow formation of AA and EPA from LA and LNA seems to be a characteristic finding in humans, being different from preferred laboratory animals, for instance, rats. This observation was independent of the presence of risk factors, like arterial hypertension or hyperlipoproteinemia (HLP).
View
The Inverse Relation between Fish Consumption and 20-Year Mortality from Coronary Heart Disease
Article
  • Jun 1985
The low death rate from coronary heart disease among the Greenland Eskimos has been ascribed to their high fish consumption. We therefore decided to investigate the relation between fish consumption and coronary heart disease in a group of men in the town of Zutphen, the Netherlands. Information about the fish consumption of 852 middle-aged men without coronary heart disease was collected in 1960 by a careful dietary history obtained from the participants and their wives. During 20 years of follow-up 78 men died from coronary heart disease. An inverse dose-response relation was observed between fish consumption in 1960 and death from coronary heart disease during 20 years of follow-up. This relation persisted after multiple logistic-regression analyses. Mortality from coronary heart disease was more than 50 per cent lower among those who consumed at least 30 g of fish per day than among those who did not eat fish. We conclude that the consumption of as little as one or two fish dishes per week may be of preventive value in relation to coronary heart disease.
View
View
Validation of a meta-analysis: The effects of fish oil in rheumatoid arthritis
Article
The purpose of this study was to validate the results of a meta-analysis showing the efficacy of fish oil in rheumatoid arthritis with the results of a re-analysis of the complete primary data set. A Medline search yielded seven published papers. Three additional trials were found by contacting authorities in the field. Inclusion criteria included (1) a double-blind, placebo-controlled study, (2) use of at least one of seven predetermined outcome measures, (3) results reported for both placebo and treatment groups at baseline and follow-up, (4) randomization, and (5) parallel or cross-over design. Papers were scored for quality. Demographic and outcomes variables were collected. For the re-analysis of the primary data, the same variables were abstracted for the 395 individual patients randomized. The meta-analysis demonstrated that dietary fish oil supplementation for 3 months significantly reduced tender joint count (rate difference [RD] [95% CI] = -2.9 [-3.8 to -2.1] [p = 0.001]) and morning stiffness (RD [95% CI] = -25.9 [-44.3 to -7.5] [p < 0.01]) as compared with heterogeneous dietary control oils. The re-analysis of the primary data confirmed a significant reduction in tender joint count (p = 0.001) and in morning stiffness (p < 0.02) in the parallel analysis that ignored interaction terms. The analyses that included an interaction term between site and treatment again confirmed a significant reduction in tender joint count. The results for morning stiffness were similar to the meta-analysis, but did not quite reach statistical significance (p = 0.052-0.083). The relative improvements in the other outcome variables did not reach statistical significance. Use of fish oil improved the number of tender joints and duration of morning stiffness at 3 months as analyzed by both meta- and mega-analysis. The fuller mega-analysis confirmed the results of the meta-analysis. The advantages of mega-analysis were as follows: (1) the ability to analyze the homogeneity of the patient populations, (2) the ability to make clinically sensible adjustments in the form of the comparison, and (3) the ability to examine subsets of the data.
View
Alpha-Linolenic Acid: A Preventive in Secondary Coronary Events?
Article
  • Aug 1995
In a 5-year study of survivors of a first myocardial infarction, the effect of an alpha-linolenic acid-enriched diet (experimental) was compared with the prudent diet of the American Heart Association (control) in prevention of secondary coronary events. After a mean follow-up of 27 months, there were 5 nonfatal myocardial infarctions and 3 cardiac deaths in the experimental group versus 17 nonfatal myocardial infarctions and 16 cardiac deaths in the control group. Overall mortality was 20 in the control and 8 in the experimental group. An alpha-linolenic acid-enriched diet appears to be effective in secondary prevention of coronary events, but a follow-up trial with a larger sample size is suggested.
View
Alpha-linolenic acid in the treatment of rheumatoid arthritis. A double-blind, placebo-controlled and randomized study: Flaxseed vs. Safflower seed
Article
  • Feb 1995
In rheumatoid arthritis various pro-inflammatory metabolites of arachidonic acid (AA), such as leukotriene B4 (LTB4) and prostaglandin E2 (PGE2), contribute to tissue destruction and pain. In contrast to AA, which is an omega-6 fatty acid, the omega-3 fatty acids, after having been liberated from the cell membrane phospholipids, are further converted into the non- or anti-inflammatory eicosanoids LTB5 and PGI3. AA concentration is an important regulatory step in the synthesis of both prostanoids and leukotriens. Dietary supplementation with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has therefore been used to decrease the ratio of AA to EPA or DHA to obtain beneficial clinical effects. EPA and DHA are found in animal fat and are quite expensive compared to their precursor alpha-linolenic acid (alpha-LNA) found in flaxseed oil. We, therefore, performed a placebo-controlled trial with alpha-LNA in 22 patients with rheumatoid arthritis, using a linoleic acid preparation as a placebo. After a 3-month follow-up, the treatment group showed an increased bleeding time, but the clinical, subjective (global assessment, classification of functional status, joint score index, visual analogue scale, pain tenderness score) and laboratory parameters (haemoglobin, erythrocyte sedimentation rate, C-reactive protein) did not show any statistical alterations. AA, EPA and DHA did not change either in spite of a significant increase in alpha-LNA in the treatment group. Thus, 3-month's supplementation with alpha-LNA did not prove to be beneficial in rheumatoid arthritis.
View
Fatty acid composition of erythrocyte, platelet, and serum lipids in strict vegans
Article
  • May 1995
The fatty acid composition of erythrocytes, platelets, and serum lipids was compared between subjects who had been eating a strict uncooked vegan diet ("living food") for years and omnivore controls. The vegan diet contains equal amounts of fat but more monounsaturated and polyunsaturated and less saturated fatty acids than the mixed diet of the control group. In vegans, the proportion of linoleic acid was greater in all lipid fractions studied. Also, the levels of other n-6 fatty acids were greater, with the exception of arachidonic acid levels, which were similar in most fractions. In erythrocytes, platelets and serum phospholipid fractions, this increase was mainly at the expense of the n-3 fatty acids. The proportions of eicosapentaenoic and docosahexaenoic acid were only 29-36% and 49-52% of those in controls, respectively. In vegans the ratio of n-3 to n-6 fatty acids was only about half that in omnivores. In addition to the lower levels of n-3 fatty acids, the proportions of palmitic and stearic acids were lower in serum cholesteryl esters, triglycerides and free fatty acids of vegans. The proportion of oleic acid was slightly lower only in serum cholesteryl esters and erythrocyte phosphatidylserine. The results show that, in the long term, the vegan diet has little effect on the proportions of oleic and arachidonic acids, whereas the levels of n-3 fatty acids are depressed to very low levels with prolonged consumption of the high linoleic and oleic acid components of this diet.
View
Dietary Intake of Marine n-3 Fatty Acids, Fish Intake, and the Risk of Coronary Disease among Men
Article
  • May 1995
It has been hypothesized that a diet containing n-3 fatty acids from fish reduces the risk of coronary heart disease, but few large epidemiologic studies have examined this question. In 1986, 44,895 male health professionals, 40 to 75 years of age, who were free of known cardiovascular disease completed detailed and validated dietary questionnaires as part of the Health Professionals Follow-up Study. During six years of follow-up, we documented 1543 coronary events in this group: 264 deaths from coronary disease, 547 nonfatal myocardial infarctions, and 732 coronary-artery bypass or angioplasty procedures. After controlling for age and several coronary risk factors, we observed no significant associations between dietary intake of n-3 fatty acids or fish intake and the risk of coronary disease. For men in the top fifth of the group in terms of intake of n-3 fatty acids (median, 0.58 g per day), the multivariate relative risk of coronary heart disease was 1.12 (95 percent confidence interval, 0.96 to 1.31), as compared with the men in the bottom fifth (median, 0.07 g per day). For men who consumed six or more servings of fish per week, as compared with those who consumed one serving per month or less, the multivariate relative risk of coronary disease was 1.14 (95 percent confidence interval, 0.86 to 1.51). The risk of death due to coronary disease among men who ate any amount of fish, as compared with those who ate no fish, was 0.74 (95 percent confidence interval, 0.44 to 1.23), but the risk did not decrease as fish consumption increased. Although the possibility of residual confounding by unmeasured factors cannot be entirely excluded, these data suggest that increasing fish intake from one to two servings per week to five to six servings per week does not substantially reduce the risk of coronary heart disease among men who are initially free of cardiovascular disease.
View