The scientific literature overwhelmingly demonstrates health improvements for most people who supplement their essential fatty acid nutrient intake. Yet much controversy surrounds essential fatty acid supplementation. It has been documented that some brands of fish oil soft gels contain low quality and sometimes rancid oil. Other products are adulterated for marketing and other reasons but negatively impact quality. Some experts suggest krill oil over fish oil. Other experts suggest plant sourced omega fatty acids are the best source.
As discussed below, there is overwhelming research support that essential fatty acid supplementation helps maintain health and helps in the treatment of many disease conditions. “Regarding the best supplement source, I am strongly in favor of using unadulterated cod liver oil (CLO) rather than fish oils with no vitamins A and vitamin D to speak of. I think the benefits of vitamin A and D are considerable and I have never recommended fish oil supplements per se; always cod liver oil, often in a dosage of two or three tablespoons daily (liberal amount of EPA and DHA along with the A and D). And I recommend eating lots of wild salmon, and using krill oil,” Dr. Ron Schmid, ND.
“This is based on my understanding of traditional diets. My point about using a traditional food like cod liver oil rather that extracted Omega 3 EPA/DHA rich fish oil that is devoid of A and D is an important one. This means high dosage of A and D – up to 100k and 10k IU of each in the two or three tablespoons of CLO, sometimes for extended periods, are indicated depending upon one’s health condition,” Dr. Ron Schmid, ND.
Dr. Schmid continued … “This essential fatty acid supplement source preference of mine is based on the dynamics of traditional diets as well as old research from the first half of the twentieth century about the beneficial use of such doses when from natural sources containing vitamins A and D in proper balance – as in unadulterated CLO.” (OWC Editor’s note: not all Cod Liver Oil products are unadulterated, including some of the most popular brands, so be very careful in your selection).
Some have suggested that increased intake of omega-3 fatty acids, such as those found in fish oil supplements, may increase susceptibility to cancer (See Professor Peskin’s white paper presented at a recent anti-aging conference). But this flies in the face of a veritable mountain of research generated over the past few decades, which has consistently shown that omega-3 fatty acids are exceptionally beneficial and important for overall health.
In fact, breaking research clearly indicates that increased consumption of the bioactive forms of these conditionally essential nutrients, namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is associated with a reduced risk of cancer, reduced inflammation, better cardiovascular disease risk, decreased risk of dementia, lower risk of depression, optimal immune system functioning, decreased insulin resistance, lower risk of chronic kidney disease, and reduced risk of breast cancer, among other benefits.1-11 These important nutrients play multiple roles.
For example, as noted recently by Taiwanese scientists, “[Essential fatty acids], as messengers, are involved in the synthesis and functions of brain neurotransmitters, and in the molecules of the immune system.”12 And as American researchers noted recently in the science journal Molecular Nutrition and Food Research, “…omega-3 fatty acids actually regulate neurotransmission in the normal nervous system, principally by modulating membrane biophysical properties and presynaptic vesicular release of…neurotransmitters.”13 In contrast, deficiency of these crucial nutrients is associated with “diminished synaptic plasticity and impaired learning, memory and emotional coping performance later in life.”13
Regarding omega-3 fatty acids and cancer, it is instructive to consider this statement, published recently in Nutrition and Cancer: “Considerable knowledge has been recently gathered on the possible beneficial effects of [omega-3 polyunsaturated fatty acids] administered in combination with different antineoplastic [cancer chemotherapy] drugs and radiotherapy against melanoma, leukemia, neuroblastoma, and colon, breast, prostate, and lung cancer. The efficacy of these combinations has been demonstrated both in [living subjects and in laboratory studies]…”14 It’s also interesting to note that a recent meta-analysis of studies regarding fish consumption and prostate cancer risk concluded: “There was an association between fish consumption and a significant 63% reduction in prostate cancer-specific mortality.”15 This contradicts the notion that high amounts of dietary omega-3 fatty acids adversely affect cancer risk. On the contrary, omega-3 consumption, both from fish and from supplements, has consistently been associated with a reduced risk of cancer.
In humans, the essential dietary omega-3 fatty acid, alpha-linolenic acid (ALA), which is found in plant foods, is converted to EPA and DHA, albeit with great inefficiency. To ingest EPA and DHA directly, it’s necessary to consume marine sources, such as cold-water fatty fish, or fish oil supplements. These omega-3-fatty acids are the two forms used by the body for incorporation in everything from immune system components to cellular membranes. ALA must be converted by the body to EPA and DHA before it is useful, but this conversion is notoriously inefficient. While consumption of supplemental EPA and DHA have consistently been shown to improve cardiovascular disease risk profiles, such an association has not been conclusively shown for increased consumption of ALA.16-18
Research strongly suggests that humans evolved to require a more or less balanced ratio of dietary omega-6/omega-3 fatty acids.19 Omega-6 fatty acids, however, are far more common in the modern Western diet than omega-3 fatty acids. Present in foods ranging from cooking oils (e.g. canola oil, corn oil, safflower oil) to many common prepared and packaged foods, omega-6 fatty acids provide the biochemical building blocks for compounds that are pro-inflammatory. They are converted in the body to arachidonic acid, a precursor of compounds known as eicosanoids, such as prostaglandin, leukotriene, and thromboxane, which are potent mediators of inflammation. Aspirin, for example, quells inflammation by interfering with the conversion of arachidonic acid to eicosanoids. Omega-3 fatty acids, on the other hand, are converted in the body to anti-inflammatory compounds.
Studies have repeatedly shown that Americans commonly consume these two classes of essential (biologically necessary) nutrients (omega-6:omega-3) in a ratio closer to 10:1, or even 30:1, rather than the 2:1 or 1:1 ratio that is considered optimal.19-21 Accordingly, it is considered beneficial to supplement such lopsided diets with extra omega-3 fatty acids in the form of fish oil, in order to achieve a more realistic balance of these two nutrients.
The important point here is this: Unless a person eats a strictly vegetarian diet, supplemented liberally with fatty fish, it is very likely that he or she is already consuming too many omega-6 fatty acids, and far too few omega-3 fatty acids. Advice to increase intake of omega-6 fatty acids is misguided, at best, and potentially harmful at worst. In a recent meta-analysis of studies that featured randomized, controlled trials of the effects of consumption of fatty acids on heart disease risk, published in The British Journal of Nutrition, investigators concluded: “Advice to specifically increase [omega-6 polyunsaturated fatty acids] intake, based on mixed [omega-3/omega-6 randomized controlled trial] data, is unlikely to provide the intended benefits, and may actually increase the risks of [coronary heart disease] and death.”22
A second point involves the conversion of the vegetable source of omega-3s, ALA, to the more useful forms; DHA and EPA. Although vegetarians probably consume more ALA from plant sources, such as flax seed and walnuts, than non-vegetarians, ALA conversion to EPA and DHA is highly inefficient. Anyone who relies on ALA alone to provide essential omega-3s in the diet, therefore, is likely to be deficient in these nutrients. It is simply not feasible to consume enough ALA to provide adequate DHA and EPA to keep the body functioning optimally, and to balance the intake of omega-6 fatty acids with intake of omega-3s. For this reason, vegetarians and vegans are strongly encouraged to consider supplementing their diets with fish oil.23
The bottom line regarding consumption of fish oil supplements is this: An overwhelming preponderance of scientifically-sound evidence clearly shows that it is highly beneficial to consume omega-3 fatty acids in quantities sufficient to balance the ratio of omega-3s to omega-6s in the diet. While eating enough fish to achieve this is problematic, due to rampant contamination of the marine food supply with methyl mercury, fish oil supplements are safe, effective and inexpensive. The average American already consumes ample omega-6 fatty acids; additional omega-3s are needed to counterbalance these abundant pro-inflammatory essential fatty acids, which are ubiquitous in the food chain.
1) Gopinath B, Harris DC, et al. Consumption of long-chain n-3 PUFA, α-linolenic acid and fish is associated with the prevalence of chronic kidney disease. Br J Nutr. 2011 Jan 24:1-8. [Epub ahead of print]
2) Welch AA, Shakya-Shrestha S, et al. 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 α-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort. Am J Clin Nutr. 2010 Nov;92(5):1040-51. Epub 2010 Sep 22.
3) Sofi F, Giangrandi I, et al. Effects of a 1-year dietary intervention with n-3 polyunsaturated fatty acid-enriched olive oil on non-alcoholic fatty liver disease patients: a preliminary study. Int J Food Sci Nutr. 2010 Dec;61(8):792-802. Epub 2010 May 13.
4) Sasazuki S, Inoue M, et al. Intake of n-3 and n-6 polyunsaturated fatty acids and development of colorectal cancer by subsite: Japan public health center-based prospective study. Int J Cancer. 2010 Nov 30. [Epub ahead of print]
8) Rondanelli M, Giacosa A, et al. Long chain omega 3 polyunsaturated Fatty acids supplementation in the treatment of elderly depression: effects on depressive symptoms, on phospholipids Fatty acids profile and on health-related quality of life. J Nutr Health Aging. 2011;15(11):37-44.