Tag: ALA converts to DHA and EPA

Omega 3 Supplements = Snake Oil

An impressively comprehensive systematic review 1 has just been published by the Cochrane Heart group. They analysed the results of seventy-nine randomised trials involving 112,059 people to see whether omega-3 supplements really do help to prevent/treat heart disease as the manufacturers and many other responsible medical/nutritional authorities have been claiming for years. But do fish and EPA 2 /DHA 3 supplements work, or are they just another form of snake oil 4 ?

The authors’ conclusions make their opinions crystal clear:

“We can be confident in the findings of this review which go against the popular belief that long-chain omega 3 supplements protect the heart. This large systematic review included information from many thousands of people over long periods. Despite all this information, we don’t see protective effects….

“…The review provides good evidence that taking long-chain omega 3 (fish oil, EPA or DHA) supplements does not benefit heart health or reduce our risk of stroke or death from any cause. The most trustworthy studies consistently showed little or no effect of long-chain omega 3 fats on cardiovascular health.”

This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date.

Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias.

ALA from plants

There’s low-quality evidence suggesting that ALA may slightly reduce CVD event risk, CHD mortality and arrhythmia. ALA 5 converts to EPA/DHA in our bodies and comes from plants (including flaxseeds, chia seeds, walnuts etc), as discussed in detail in previous blogs 6 7 , and is the safest and best source of omega-3 fatty acids. There are a small number of people who have a reduced ability to convert ALA to EPA/DHA and may need to take additional supplementation. Algae is the best source of EPA/DHA if you find that you are one of this small percentage of low-converters. Dr Greger gives some sound advice on this in a short video 8 .

Is fish okay for omega-3?

Whilst the authors comment briefly on oily fish, stating that: “…it is unclear from the small number of trials whether eating more oily fish is protective of our hearts” , they are careful to add the (by-now) usual warnings about the additional risks involved in consuming fish:

“...reports of high levels of various toxic compounds such as mercury, dioxins and polychlorinated biphenyls (PCBs) in oily fish and fish oils are concerning 9 10 11 12 . These are all fat soluble and accumulate over time in the body, so harms may be exhibited only after long-term fish consumption or supplementation with fish oils. Animal intervention studies and human cohorts who have suffered accidental exposure to dioxins and PCBs suggest that pre-natal exposure may cause sub-fertility problems, and adult exposures may lead to an excess of total cancers 13 .

“Human cohorts exposed to high levels of mercury exhibit neurological problems12 . As many people eat oily fish once or twice a week or take fish oil supplements, it is important to explore the potentially harmful effects of fish-associated omega-3 intake. It is also possible that omega-3 fats themselves may exhibit harm, for example through extension of bleeding times or suppression of normal immune responses 14 .”

It’s just as well that they mention some of the many health problems associated with eating fish – especially now that we have turned our oceans, rivers and lakes into cesspits for all our toxic human waste products 15 . I’ve explained in more detail elsewhere 16 why it’s probably best NOT to consume fish or fish products of any sort.

Eat vegetables instead

A Daily Telegraph article 17 covering this research includes the following quote from Tim Chico, Professor of Cardiovascular Medicine and Honorary Consultant Cardiologist, University of Sheffield:

“Such supplements come with a significant cost, so my advice to anyone buying them in the hope that they reduce the risk of heart disease, I’d advise them to spend their money on vegetables instead.”

Joe’s comments

These latest systematic review findings about the ineffectiveness (and possible harmful effects) of fish oil and EPA/DHA supplements come as no surprise. It’s reassuring, though, to see mainstream media covering the research with such directness – indeed, BBC News covered the article with an unusually powerful headline: “Fish oil supplements for a healthy heart ‘nonsense’.” 18 .

It’s worth noting that there’s always some “however” or “but” when it comes to talking about any perceived benefits of animal foods. This is something that you don’t often get when talking about whole plant-foods. As I pointed out in an earlier blog, when you’re looking around for the causes of disease, animal foods are almost always the smoking gun 19 .

References

  1. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Asmaa S Abdelhamid, Tracey J Brown, Julii S Brainard, Priti Biswas, Gabrielle C Thorpe, Helen J Moore, Katherine HO Deane, Fai K AlAbdulghafoor, Carolyn D Summerbell, Helen V Worthington, Fujian Song, Lee Hooper. First published: 18 July 2018. Cochrane Heart Group. DOI: 10.1002/14651858.CD003177.pub3. [↩]
  2. Wikipedia: EPA or Eicosapentaenoic acid [↩]
  3. Wikipedia: DHA or Docosahexaenoic acid [↩]
  4. What is Snake Oil? Wikipedia: Snake Oil definition. [↩]
  5. Wikipedia: alpha linolenic acid or ALA [↩]
  6. Non-Fish Sources of Omega-3 [↩]
  7. Chia Seeds To The Rescue Of Type 2 Diabetics [↩]
  8. Should We Take EPA & DHA Omega-3 For Our Heart? Michael Greger M.D. FACLM March 7th, 2016 Volume 29 [↩]
  9. Food Standards Agency UK. Dioxins and PCBs in the UK diet: 1997 Total diet study samples. Food Surveillance Information Sheet. Number 4/00; 2000. [FSIS 4/00] [↩]
  10. Liem AKD, Theelen RMC. Dioxins: Chemical Analysis, Exposure and Risk Assessment. Utrecht: Universiteit Utrecht, 1997. [ISBN 90 393 2012 8] [↩]
  11. MAFF UK. Concentrations of metals and other elements in marine fish and shellfish. Food Surveillance Information Sheet no.151; 1998. [FSIS 151] [↩]
  12. US Food, Drug Administration. What You Need to Know About Mercury in Fish and Shellfish. www.fda.gov/food/foodborneillnesscontaminants/metals/ucm351781.htm (accessed May 2018). [↩] [↩]
  13. Joint FAO/WHO Expert Committee on Food Additives. Summary of the fifty-seventh meeting of JEFCA, 2001. http://apps.who.int/iris/bitstream/handle/10665/42578/WHO_TRS_909.pdf?sequence=1. [↩]
  14. U. S. Food, Drug Administration. Center for Food Safety and Applied Nutrition, Office of Nutritional Products. Labeling, and Dietary Supplements: Letter Regarding Dietary Supplement Health Claim for Omega-3 Fatty Acids and Coronary Heart Disease (Docket No. 91N-0103). www.fda.gov/Food/LabelingNutrition/ucm073992.htm#cardio 2004. [↩]
  15. Scripps Institution of Oceanography: Study Finds Toxic Pollutants in Fish Across the World’s Oceans. Scripps researchers’ analysis shows highly variable pollutant concentrations in fish meat. Jan 28, 2016. [↩]
  16. But I thought Fish Was Good For Me! [↩]
  17. The Telegraph: Buy more vegetables instead of omega-3 supplements to improve heart health, report says . 18th July 2018. [↩]
  18. BBC News: Fish oil supplements for a healthy heart ‘nonsense’. 18th July 2018 [↩]
  19. Animal Foods Are The Smoking Gun [↩]

Non-Fish Sources of Omega-3

You don’t need to eat fish or take fish oil supplements in order to get sufficient omega-3. In fact, eating fish or taking fish oil supplements just in order to get your omega-3 (also known as n-3) is probably one of the unhealthiest 1 2 ways you could go about ensuring your body is fuelled with this essential fatty acid. So, if not from fish, then where can we get it from?

Shown below are the major plant sources of omega-3 in the form of ALA (alpha linolenic acid) 3, which is known as the ‘parent’ omega-3 fatty acid and can be converted into EPA 4 and DHA 5 (the bioactive long-chain fatty acids) within the body. EPA and DHA are important partly because they can help form eicosanoids 6 (such as prostaglandins 7, prostacyclins 8 , leukotrienes 9 thromboxanes 10 , resolvins 11 and protectins 12 ) which are highly anti-inflammatory. These long-chain fatty acids are vital for the flexibility and functioning of our cell membranes (including, of course, our brain cells).

Highest plant sources of omega-3

  • flax seed contains over 50% ALA
  • salvia sclarea (also called clary or clary sage) seed oil contains ~51% ALA
  • chia (salvia hispanica) seed contains ~30%
  • kukui (candlenut) contains about 30%
  • hemp seed contains ~20% 13
  • pumpkin seed oil contains up to 15%
  • canola contains up to 10%
  • walnut oil contains between 3 to 11%
  • soybean oil contains between 5 to 7%

The conversion of ALA to EPA and DHA is a relatively slow process which can be interfered with by having too much omega-6 fatty acid (LA or linolenic acid, also known as n-6) 14 in the diet. This is because the omega-6 and omega-3 compete for the same desaturase enzymes 15 which desaturate and elongate the ALA. If there is too high a ratio of omega-6 to omega-3, the conversion of ALA to EPA and DHA can be reduced considerably, and this is not good for the body.

The list below (with % content of LA) shows the oils that are high in omega-6 and, as you can see, these oils are the ones that are used most in the preparation of much of the unhealthy modern western diet.

Highest plant sources of Omega-6 fatty acid (LA or linoleic acid)

  • safflower oil (75.3%)
  • grapeseed oil (70%)
  • sunflower (68.5%)
  • vegetable oil (58%)
  • wheat germ oil (55.7%)
  • corn oil (54%)
  • walnut oil (53 7%)
  • soybean oil (53%)
  • cottonseed oil (52 7%)
  • sesame oil (45%)
  • canola oil (19%)

Salvia sclarea seed oil, by the way, contains only an average of 14% LA. If you want to read a really detailed review of salvia sclarea, an Israeli PDF 16 (with all its odd spellings) should be of great interest to you.

(Source: Genesmart 17 )

Whilst n-3:n-6 ratio is, of course important 18 , it’s just worth pointing out that the above gives a further suggestion of why consuming any isolated oils (from animals or plants) is to be avoided 19 , since any single food item containing that quantity of oil is going to be treated, to some extent, as a toxin by the body (even if it’s cold-pressed, organic extra virgin olive oil 20 ) .

If you want to see a little about the ratios of fats, the following chart 21 is a useful snapshot:

Eat a lot of fish and your enzyme conversion rate drops

If you come from a fish-eating culture, your body adapts to this and your body produces less enzymes for the conversion of ALA to EPA/DHA. This reveals the body’s amazing ability to adapt to its environment. A corollary of this is that those people who eat a plant-based diet will tend to have more enzymes and thus be better placed to derive their long-chain fatty acids (EPA/DHA) from the ALA that they are consuming in their diets. This is supported by recent research 22 which concluded that: “Substantial differences in intakes and in sources of n-3 PUFAs existed between the dietary-habit groups.” This subject is covered in a little more detail in a Nutraingredients.com article 23 .

How many fish need to die to produce a bottle of fish oil?

Simple answer: a LOT!

We are raping the oceans in order to produce a supplement that is increasingly being shown to be very harmful to human health 24 25 26 27 . This is happening at a rate which is unsustainable, as the human population increases, with fish stocks already depleted to alarming levels 28 .

Fish are not the original source of omega-3

Fish get their omega-3 from the algae and water vegetables 29 that they eat. Bigger fish, who don’t eat the green stuff, get their omega-3 from eating the other fish that do! Simple as that. If we grow our own omega-3- containing algae (free from all the pollutants 30 in our oceans. rivers and lakes), then we can cut out the “middle fish” and get the fatty acid benefits without the PCB’s 31 and mercury 32 .

Final thoughts

This is a broad subject and it will be covered in more detail in future blogs. What may be taken away from this short overview is that you cannot be confident about getting your omega-3 from fish sources. That’s something which even the dyed-in-the-wool advocates of fishy diets are having to admit, if for no other reason than the proven pollutant risk that exists in pretty much all major fish sources now – farmed organic salmon included 33 34 .

For my part, I recommend eating 6 half walnuts, a tablespoon of flaxseeds, a teaspoon of chia seeds every day. I just plonk it all on my morning muesli. Dr Greger gives his own recommendations, including taking a plant algae supplement 35 as can be seen in the following short videos 36 37 38 :

References

  1. PCRM: Don’t Take the Bait – Fish is NOT a Health Food [↩]
  2. Killer Fish: How Eating Aquatic Life Endangers Your Health Paperback – August 27, 2012. by Brian Clement [↩]
  3. Wikipedia: alpha linolenic acid or ALA [↩]
  4. Wikipedia: EPA or Eicosapentaenoic acid [↩]
  5. Wikipedia: DHA or Docosahexaenoic acid [↩]
  6. Wikipedia: Eicosanoids [↩]
  7. Wikipedia: Prostaglandin [↩]
  8. Wikipedia: Prostacyclin [↩]
  9. Wikipedia: Leukotriene [↩]
  10. Wikipedia: Thromboxane [↩]
  11. Wikipedia: Resolvin [↩]
  12. Wikipedia: Protectin D1 [↩]
  13. The European Industrial Hemp Association (EIHA) – Hemp Seeds & Hemp Oil as Food. [↩]
  14. Wikipedia: Omega-6 Fatty Acid [↩]
  15. Wikipedia: Fatty Acid Desaturase [↩]
  16. An update on Salvia Sclarea oil [↩]
  17. Genesmart.com:High Omega 6 Foods Omega 6 Sources [↩]
  18. How relevant is the ratio of dietary n-6 to n-3 polyunsaturated fatty acids to cardiovascular disease risk? Evidence from the OPTILIP study. Article · Literature Review in Current Opinion in Lipidology 19(1):57-62 · March 2008. [↩]
  19. Video: Caldwell B Esselstyn: No Oil — Not Even Olive Oil! – Caldwell Esselstyn MD [↩]
  20. Pritikin.com: Olive Oil Nutrition – What’s Wrong With Olive Oil? [↩]
  21. Manitoba Canola Growers: Comparison of Dietary Fat Chart [↩]
  22. Am J Clin Nutr. 2010 Nov;92(5):1040-51. doi: 10.3945/ajcn.2010.29457. Epub 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 product-precursor ratio [corrected] of α-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort. Welch AA, Shakya-Shrestha S, Lentjes MA, Wareham NJ, Khaw KT. [↩]
  23. Omega 3: ALA intakes enough for EPA/DHA (sic.) levels for non-dish eaters? [↩]
  24. The Risks of Fish Oil Supplements. Written By Michael Greger M.D. FACLM on February 20th, 2018 [↩]
  25. X M Mai, A Langhammer, Y Chen, C A Camargo Jr. Cod liver oil intake and incidence of asthma in Norwegian adults–the HUNT study. Thorax. 2013 Jan;68(1):25-30. [↩]
  26. J T Ashley, J S Ward, C S Anderson, M W Schafer, L Zaoudeh, R J Horwitz, D J Velinsky. Children’s daily exposure to polychlorinated biphenyls from dietary supplements containing fish oils. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2013;30(3):506-14. [↩]
  27. Fish Oil Supplements May Not Help Your Heart: Study [↩]
  28. EcoWatch: Global Fish Stocks Depleted to ‘Alarming’ Levels [↩]
  29. WUR: Algae: our original omega-3 source [↩]
  30. NRDC: Ocean Pollution: The Dirty Facts. We’re drowning marine ecosystems in trash, noise, oil, and carbon emissions. January 22, 2018 [↩]
  31. Ecotoxicology and Environmental Safety. Volume 8, Issue 2, April 1984, Pages 129-151. Ecotoxicology and Environmental Safety. Polychlorinated biphenyls (PCBs) in the marine environment, particularly in the mediterranean. Harald Geyer, Dieter Freitag, Friedhelm Korte. [↩]
  32. Water Air Soil Pollut. 2016; 227(10): 371. Published online 2016 Sep 7. doi: 10.1007/s11270-016-3060-3. Mercury in Marine and Oceanic Waters—a Review. Barbara Gworek, Olga Bemowska-Kałabun, Marta Kijeńska, Justyna Wrzosek-Jakubowska. [↩]
  33. The Guardian: Salmon farming in crisis: ‘We are seeing a chemical arms race in the seas’ [↩]
  34. Greenpeace: Organic farmed salmon a hoax, don’t buy in [↩]
  35. nutritionfacts.org: Omega-3 Fatty Acids [↩]
  36. Plant-Based Omega-3 Supplements. Michael Greger M.D. FACLM September 12th, 2008 Volume 2 [↩]
  37. Should We Take EPA & DHA Omega-3 For Our Heart? Michael Greger M.D. FACLM March 7th, 2016 Volume 29 [↩]
  38. Should We Take DHA Supplements to Boost Brain Function? Michael Greger M.D. FACLM September 26th, 2016 Volume 32 [↩]