Omega 3

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Omega 3

Postby Acura » Thu Oct 28, 2010 9:17 am

I have seen quite few threads on this topic but could not find specific answer to my query.

Jeff and Dr M takes a simple approach where basically you eat anything that comes straight from the ground ad libitum and you should be fine which is true to the great extent.

Attached here is the article from renown vegan/vegetarian dietitian who pretty much agrees with what Jeff and Dr McDougall teaches but at the same time has clearly mentioned that we have to be aware of getting adequate Omega3s as the conversion is very poor and doubtful. She mentions some of the beans are high in omega6s.

Vegetarians enjoy many health advantages, and these benefits are related, at least in part, to a more favorable intake of fats and oils. Vegetarians eat less fat overall and consume less damaging saturated fats, cholesterol, and trans fatty acids. However, vegetarian diets appear to offer no advantages over omnivorous eating patterns regarding EFA balance and intake. Indeed, it has been suggested that vegetarians could be at a disadvantage, as plant sources of omega-3 fatty acids are limited and vegetarian diets are lacking in direct sources of long-chain omega-3 fatty acids (EPA and DHA). Dietitians can play a key role in helping vegetarians achieve optimal health by ensuring an adequate intake and balance of EFAs.
http://www.todaysdietitian.com/newarchi ... 0p22.shtml
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Re: Omega 3

Postby JeffN » Thu Oct 28, 2010 10:09 am

Chimichanga wrote:I have seen quite few threads on this topic but could not find specific answer to my query.

Jeff and Dr M takes a simple approach where basically you eat anything that comes straight from the ground ad libitum and you should be fine which is true to the great extent.

Attached here is the article from renown vegan/vegetarian dietitian who pretty much agrees with what Jeff and Dr McDougall teaches but at the same time has clearly mentioned that we have to be aware of getting adequate Omega3s as the conversion is very poor and doubtful. She mentions some of the beans are high in omega6s.

Vegetarians enjoy many health advantages, and these benefits are related, at least in part, to a more favorable intake of fats and oils. Vegetarians eat less fat overall and consume less damaging saturated fats, cholesterol, and trans fatty acids. However, vegetarian diets appear to offer no advantages over omnivorous eating patterns regarding EFA balance and intake. Indeed, it has been suggested that vegetarians could be at a disadvantage, as plant sources of omega-3 fatty acids are limited and vegetarian diets are lacking in direct sources of long-chain omega-3 fatty acids (EPA and DHA). Dietitians can play a key role in helping vegetarians achieve optimal health by ensuring an adequate intake and balance of EFAs.
http://www.todaysdietitian.com/newarchi ... 0p22.shtml


The only recommendations that really differs is to "consider" a direct source of DHA/EPA.

More recent evidence has shown that this is based on information that is not accurate, and that several false assumptions were made from that information, accurate or not.

This recent study showed that the conversion rate in Vegans is 2x that of a fish-eater.

Am J Clin Nutr. 2010 Sep 22.

Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the precursor-product ratio of {alpha}-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort.

“Comparison of the PLLC n23 PUFAs:DALA ratio between dietary-habit groups showed that it was 209% higher in vegan men and 184% higher in vegan women than in fish-eaters, was 14% higher in vegetarian men and 6% higher in vegetarian women than in fish-eaters, and was 17% and 18% higher in male and female meat-eaters, respectively, than in fish-eaters This suggests that the statistically estimated conversion may be higher in non-fish-eaters than in fish-eaters.

In addition, another study showed that despise this "theoretical" low conversion rate, there is no evidence of any harm so, the problem may not be in the conversion rate, but in the assumption that it is low.

Prostaglandins Leukot Essent Fatty Acids. 2009 Jun 3.

"There is no evidence of adverse effects on health or cognitive function with lower DHA intake in vegetarians.

In the absence of convincing evidence for the deleterious effects resulting from the lack of DHA from the diet of vegetarians, it must be concluded that needs for omega-3 fatty acids can be met by dietary ALA. "


They also noted the importance of limiting excess omega 6's, especially in vegans/vegetarians as they had higher intakes levels than the omnivores.

"Vegetarian and especially vegan diets supply more linoleic acid (18:2n-6) than omnivore diets."


In addition, this study showed a similar thing in regard to omega 6 and a low fat diet and fatty acid profile..

Total Fat Intake Modifies Plasma Fatty Acid Composition in Humans1
J. Nutr. February 1, 2001 vol. 131 no. 2 231-234

http://jn.nutrition.org/content/131/2/231.full

Abstract

Plasma fatty acid composition reflects dietary fatty acids. Whether the total fat content of the diet alters the fatty acid composition of plasma phospholipid, cholesteryl ester, triacylglycerol and free fatty acids is unknown. To evaluate the effects of low versus high fat diets on plasma fatty acids, a 12-wk, randomized, crossover, controlled feeding trial was conducted in healthy men and women with isoenergic low fat (20% energy) and high fat (45% energy) diets containing constant proportions of fatty acids. Ten subjects consumed one experimental diet for 28 d, their usual diet for 4 wk and the alternate experimental diet for 28 d. Endpoint measures of plasma fatty acids were determined at the end of each experimental period. The effects of the two diets were compared within subjects by analysis of variance. Plasma fatty acids (%) varied in response to total dietary fat with significantly greater total polyunsaturated fat, (n-6) and 18:2(n-6) levels in phospholipids and cholesteryl esters after high fat dietary consumption. The low fat diet was associated with significantly greater total (n-3) fatty acids, 20:5(n-3) and 22:6(n-3) levels in plasma phospholipid fatty acids and cholesteryl esters. Consumption of a low fat diet alters fatty acid patterns in a manner similar to that observed with feeding of (n-3) long-chain fatty acids. This change is likely related to decreased competition for the enzymes of elongation and desaturation, with reduced total intake of 18:2(n-6) favoring elongation and desaturation of available (n-3) fatty acids.


In regard to the issues of the conversion being low....

Due to privacy issues, I am posting these comments anonymously but the point is not who made them but their perspective and the points they make. If it matter, the person who made them is a highly respected lead researcher and writer in the longevity movement.

However, FYI, it is from one of the researchers and science writers in CR movement and happened recently as part of a discussion on whether or not humans can synthesize enough DHA and whether or not our ability is "Poor", "low", or 'Adequate".

Considering he is not a pro-veg person, I find his comments even more enlightening and I thought you would to.

The original statement..

Adding to the recent discussion of alpha linolenic acid (ALA), medium-chain omega-3 s, as found and consumed in walnuts, here is a
reminder that the conversion of ALA to the all important long-chain omega-3s, EPA and DHA, is *very poor* - according to the papers below [1,2,3] there is only a 5-17% conversion to EPA, and 0.5-0.7% to DHA.

The review by Plourde and Cunnane, 2007 [1], makes it clear that ".... in healthy, nonvegetarian humans, even large amounts of dietary ALA have a negligible effect on plasma DHA, ...." . DHA (more than EPA) is essential for proper brain function

The response..

Calling this conversion rate 'poor' is a petitio principii: it ASSUMES that we need some higher level of DHA, or rate of conversion of ALA to DHA, and finding that the conversion rate is lower than this cites its own premise as proof that conversion from ALA is inadequate. Again, as so often in these cases, the reasoning is backward. You want to first look at actual health outcomes -- age-related and developmental neurological disease and dementia, eg -- and see if there's any actual evidence of deficiency in populations getting reasonable ALA intakes but low long-chain n3.

In short, as posted repeatedly in the past, there is not. Aside from (5), which as (has been) dutifully notes finds "Vegetarian diets are associated with healthy mood states" cross-sectionally, (6) a small study of Adventists in California finds that wahen subjects are "matched for age, sex, and zip code (1 vegan, 1 lacto-ovo-vegetarian, and 2 'heavy' meat eaters in *each* of *68* quartets ... [to] ensure a wide range of dietary exposure", " subjects who ate meat (including poultry and fish [!]) were more than twice as likely to become demented as their vegetarian counterparts (relative risk 2.18, p = 0.065) and the discrepancy was *further* widened (relative risk 2.99, p = 0.048) when past meat consumption was taken into account."

Indeed, a recent review of "DHA status in vegetarians" (7) notes that "Dietary analyses show that vegan diets are devoid of DHA and vegetarian diets that included dairy food and eggs only provide about 0.02 g DHA/d," goes thru' all of the presumptive problems in bioconversion, and the resulting low levels of DHA observed in body fluids of average veg(etari)ans, but still concludes that "There is no evidence of adverse effects on health or cognitive function with lower DHA intake in vegetarians. "

Indeed, animal studies show a selective incorporation and retention of DHA in the brain and retina when dietary supply is limited, despite a lowering of membrane DHA in other tissues (10).

Therefore, the actual intakes of these populations seems to be adequate to generate enough DHA to make their outcomes worse than the general population; hence, the 0.5-0.7% conversion rate (if correct and reflective of what's going on in the tissues) is 'adequate,' not 'poor.'


1. Extremely limited synthesis of long chain polyunsaturates in adults: implications for their dietary essentiality and use as supplements. Plourde M, Cunnane SC. Appl Physiol Nutr Metab. 2007 Aug;32(4):619-34. PMID 17622276 Erratum in: Appl Physiol Nutr Metab. 2008 Feb;33(1):228-9.

2. Omega-3 long chain fatty acid synthesis is regulated more by substrate levels than gene expression. Tu WC, Cook-Johnson RJ, James MJ, Mühlhäusler BS, Gibson RA. Prostaglandins Leukot Essent Fatty Acids. 2010 Jun 21. PMID: 20573490

3. Quantitation of alpha-linolenic acid elongation to eicosapentaenoic and docosahexaenoic acid as affected by the ratio of n6/n3 fatty acids.
Harnack K, Andersen G, Somoza V. Nutr Metab (Lond). 2009 Feb 19;6:8. PMID: 19228394

4. Effects of alpha-linolenic acid vs. docosahexaenoic acid supply on the distribution of fatty acids among the rat cardiac subcellular
membranes after a short- or long-term dietary exposure.

Brochot A, Guinot M, Auchere D, Macaire JP, Weill P, Grynberg A, Rousseau-Ralliard D. Nutr Metab (Lond). 2009 Mar 25;6(1):14. PMID:
19320987 http://www.ncbi.nlm.nih.gov/pubmed/19320987

5. Vegetarian diets are associated with healthy mood states: a cross-sectional study in seventh day adventist adults.

Beezhold BL, Johnston CS, Daigle DR. Nutr J. 2010 Jun 1;9:26. PubMed PMID: 20515497; PubMed Central PMCID: PMC2887769. http://www.nutritionj.com/content/9//26

6. : Giem P, Beeson WL, Fraser GE. The incidence of dementia and intake of animal products: preliminary findings from the Adventist Health Study. Neuroepidemiology. 1993;12(1):28-36. PubMed PMID: 8327020.

7. Sanders TA. DHA status of vegetarians. Prostaglandins Leukot Essent Fatty Acids. 2009 Aug-Sep;81(2-3):137-41. Epub 2009 Jun 4. Review. PubMed PMID: 19500961.

8. Craig WJ, Mangels AR; American Dietetic Association. Position of the American Dietetic Association: vegetarian diets. J Am Diet Assoc. 2009 Jul;109(7):1266-82. PubMed PMID: 19562864.

9. Sanders TA. Essential fatty acid requirements of vegetarians in pregnancy, lactation, and infancy. Am J Clin Nutr. 1999 Sep;70(3 Suppl):555S-559S. Review. PubMed PMID: 10479231.

10. Abedin L, Lien EL, Vingrys AJ, Sinclair AJ. The effects of dietary
alpha-linolenic acid compared with docosahexaenoic acid on brain, retina, liver, and heart in the guinea pig. Lipids. 1999 May;34(5):475-82. PubMed PMID: 10380119.

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Re: Omega 3

Postby JeffN » Tue Aug 25, 2015 10:40 am

Press Release

NIH study shows no benefit of omega-3 or other nutritional supplements for cognitive decline
Embargoed for Release: Tuesday, August 25, 2015, 11 a.m. EDT

http://www.nih.gov/news/health/aug2015/nei-25.htm

While some research suggests that a diet high in omega-3 fatty acids can protect brain health, a large clinical trial by researchers at the National Institutes of Health found that omega-3 supplements did not slow cognitive decline in older persons. With 4,000 patients followed over a five-year period, the study is one of the largest and longest of its kind. It was published today in the Journal of the American Medical Association.

“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Emily Chew, M.D., deputy director of the Division of Epidemiology and Clinical Applications and deputy clinical director at the National Eye Institute (NEI), part of NIH.

Dr. Chew leads the Age-Related Eye Disease Study (AREDS), which was designed to investigate a combination of nutritional supplements for slowing age-related macular degeneration (AMD), a major cause of vision loss among older Americans. That study established that daily high doses of certain antioxidants and minerals — called the AREDS formulation — can help slow the progression to advanced AMD.

A later study, called AREDS2, tested the addition of omega-3 fatty acids to the AREDS formula. But the omega-3’s made no difference. Omega-3 fatty acids are made by marine algae and are concentrated in fish oils; they are believed to be responsible for the health benefits associated with regularly eating fish, such as salmon, tuna, and halibut.*Where studies have surveyed people on their dietary habits and health, they’ve found that regular consumption of fish is associated with lower rates of AMD, cardiovascular disease, and possibly dementia. “We’ve seen data that eating foods with omega-3 may have a benefit for eye, brain, and heart health,” Dr. Chew explained.

Omega-3 supplements are available over the counter and often labeled as supporting brain health. A large 2011 study found that omega-3 supplements did not improve the brain health of older patients with preexisting heart disease.

With AREDS2, Dr. Chew and her team saw another opportunity to investigate the possible cognitive benefits of omega-3 supplements, she said. All participants had early or intermediate AMD. They were 72 years old on average and 58 percent were female. They were randomly assigned to one of the following groups:

- Placebo (an inert pill)
- Omega-3 [specifically docosahexaenoic acid (DHA, 350 mg) and eicosapentaenoic acid (650 mg)]
- Lutein and zeaxanthin (nutrients found in large amounts in green leafy vegetables)
- Omega-3 and Lutein/zeaxanthin

Because all participants were at risk for worsening of their AMD, they were also offered the original or a modified version of the AREDS formulation (without omega-3 or lutein/zeaxanthin).

Participants were given cognitive function tests at the beginning of the study to establish a baseline, then at two and four years later. The tests, all validated and used in previous cognitive function studies, included eight parts designed to test immediate and delayed recall, attention and memory, and processing speed. The cognition scores of each subgroup decreased to a similar extent over time, indicating that no combination of nutritional supplements made a difference.

Alzheimer’s disease, which is the most common cause of dementia and affects as many as 5.1 million Americans age 65 and older in the U.S., may triple in the next 40 years. Some research has examined the potential benefits of DHA for Alzheimer’s. Studies in mice specially bred to have features of the disease found that DHA reduces beta-amyloid plaques, abnormal protein deposits in the brain that are a hallmark of Alzheimer’s, although a clinical trial of DHA showed no impact on people with mild to moderate Alzheimer’s disease.

“The AREDS2 data add to our efforts to understand the relationship between dietary components and Alzheimer’s disease and cognitive decline,” said Lenore Launer, Ph.D. senior investigator in the Laboratory of Epidemiology and Population Science at the National Institute on Aging. “It may be, for example, that the timing of nutrients, or consuming them in a certain dietary pattern, has an impact. More research would be needed to see if dietary patterns or taking the supplements earlier in the development of diseases like Alzheimer’s would make a difference.”

For more information about AMD and AREDS2, visit https://nei.nih.gov/areds2.

* Other omega-3 fatty acids are found in plant foods such as flaxseed, walnuts, soy products, and canola and soybean oils. Specific omega-3 fatty acids from these sources were not studied.

The cognitive function component of AREDS2 was supported by the NEI Intramural Research Program and contracts HHS-N-260-2005-00007-C. Additional research funds were provided by the NIH Office of Dietary Supplements; the National Center for Complementary and Integrative Health; the National Institute on Aging; the National Heart, Lung, and Blood Institute; and the National Institute of Neurological Disorders and Stroke.

The AREDS trial is registered at http://www.ClinicalTrials.gov as NCT00594672. AREDS2 is registered as NCT00345176.

NEI leads the federal government's research on the visual system and eye diseases. NEI supports basic and clinical science programs that result in the development of sight-saving treatments. For more information, visit http://www.nei.nih.gov.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.


Reference Study

Age-Related Eye Disease Study 2 (AREDS2) Research Group. “Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, or other Nutrient Supplementation on Cognitive Function: The AREDS2 Randomized Clinical Trial.” JAMA, published online August 25, 2015.

http://jama.jamanetwork.com/article.asp ... id=2429713
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Re: Omega 3

Postby jay kaye » Tue Aug 25, 2015 11:17 am

Jeff,

Would you add this question/reply to your Nutrition & Health FAQ: Answers To The Most Asked Questions section for future reference.

Thanks.

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