Fish Is Not Necessarily The Best Source Of Long Chain Omega-3 Fatty Acids- An Evolutionary Perspective
The building of brain tissue, unlike other body tissues, is dependent on an adequate supply of long chain omega-3 fatty acids- specifically docosahexaenoic acid (DHA). DHA is a long chain omega-3 fatty acid that appears to have played a key role in the evolution of human intelligence due to its central role in the creation of grey brain matter.[1,2,27] As a result, long chain omega-3’s- (specifically preformed DHA) is added to infant formulas today as almost every professional pediatric organization supports its role as an essential nutrient for infants. In addition, we have a number of studies conducted over the past ten years that show inclusion of long chain omega-3 fatty acids in our diet being as beneficial to our health[5,6,7,8,9,10] Abundant in the marine food chain, preformed DHA and long chain omega-3’s are said to be relatively scarce in terrestrial food sources which raises an important question; How could we, as a species, have evolved within the environmental context of the African plains[2,11,12,13,14, 15] if fish and other marine food sources were not plentiful in this part of the world? The answer goes against most of the literature published regarding optimal sources of long chain omega-3’s as fish and seafood did not become a common part of the human diet until about 20,000 years ago. Considering that we began our time on the planet as humans 1.7 million years ago, it thus becomes apparent that our main source of omega-3’s must have come from the tissues of mammals and other land based foods and not from fish and other marine sources.[3,16] In this article, we take a hard look at the original sources of long chain omega-3’s and highlight that fish oils are not necessarily the best sources for optimal health.
The Role Of The Fish Industry In Promoting Fish Oils As The Best Source Of Omega-3’s
One of the first questions that each of us should ask when investigating the validity of any health claim is ‘Cui bono’- or ‘who stands to gain’. In this case, the extensive efforts of the powerful American and international fish industry lobby played a significant role in the promotion of fish and fish oils as the de facto source of long chain omega-3 fatty acids here in the United States. One would like to think that health claims come as a result of tried and tested scientific proofs or observations, but the reality isn’t as objective as you might like to think. In fact, qualified health claims for fish oils come as a result of decades of pressure piled upon the Food and Drug Administration (FDA) by fish industry lobbies. Initial FDA findings only allowed seafood products to be labeled as ‘rich in omega-3’s’ but were not permitted to attribute any protection against heart disease as there was not enough objective evidence to support such claims.[21,22] In the year 2000, however in response to a major fish industry sponsored lawsuit and continued petitions, the FDA was forced to relax their stance on required scientific standards for health claims on omega-3 fish oil supplements, which in 2004 lead to the following ‘qualified health claim’ that brings up more questions than it answers:
‘Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease’.
There is little argument against the fact that long chain omega-3 fatty acids do appear to play key roles in human development, but there is some question as to the universal effectiveness of added omega-3’s in the human diet from fish oil sources. Current data neither proves nor disproves a beneficial or a detrimental effect for subgroups of patients with specific underlying pathologies while some studies have found that among certain individuals it may actually increase the likelihood of death from cardiovascular related disease.[18,19,20,45] One review concluded that while fish oils may beneficial in reducing some incidences of sudden death due to cardiac arrhythmias, fish oil supplementation might not be advisable for all patients.
In spite of the many studies conducted and observations of thousands of individuals under controlled and self-reported conditions, the benefits of adding fish oils and fish sources of omega-3’s are not as clear cut as we are often lead to believe. The Agency for Healthcare Research and Quality- the organization responsible for clinical practice guidelines here in the United States, did not find the conclusive evidence for the addition of fish oils to the public diet that you might expect. In fact, their review of 123 studies where the amount of fish oils or omega-3 fatty acids intake was quantified as being significant found that while a higher intake increased measured levels of EPA and DHA, the only consistent benefit across the board was a reduction in triglycerides. Little or no benefit was found for a variety of other cardiovascular risk factors and markers of cardiovascular disease. The review, which without question has been the most comprehensive one thus far with regard to added dietary omega-3 fatty acids concluded that the optimal amounts and sources of omega-3’s are not known, nor is the effects of higher ratios of dietary omega-6 to omega 3 fatty acids- an argument often put forward as a justification for increased fish oil consumption. The review ends with the statement that far more research is needed before any conclusive statements can be made, which is main reason the FDA did not allow any health claims to be made by fish and fish oil producers before being coerced into some concession as a result of lobbying pressures.
The decision to include DHA in infant formula is equally controversial as research has shown that infants can synthesize long chain omega-3 fatty acids themselves from other dietary sources, especially during the last trimester and as such additional omega-3’s may not be required. Some studies suggest that premature infants may benefit from direct consumption while others showed no benefit whatsoever. Blood levels of the long chain omega-3 fatty acids DHA and ARA in breast fed infants are typically higher than levels found in formula fed infants but the scientific evidence for long term benefits remain mixed.[23,24] It should be noted however that most of the studies conducted on the addition of DHA and ARA supplementation in infant formula were sponsored by the infant formula manufacturers themselves and even they were unable to provide any conclusive long term benefits. Once again, and as is custom with the American public health system, pressure from formula makers forced the FDA to agree that the long chain omega-3 fatty acids are naturally occurring components of a regular diet and were thus able to add it to infant formulas without having to prove that such additions would provide any long term benefit.
Understanding The Complexities Of Qualifying Omega-3 Health Benefits In An Imperfect World
What we do know from observations of epidemiological studies is that consumption of plant and marine-derived omega-3 fatty acids seem to be correlated with a reduced incidence of cardiovascular disease[3,37,38,39,40,41] and reduces all-cause mortality, but whether simply adding fish or fish oils to your diet is the answer isn’t very clear. The simple truth is that we do not know as much about omega-3’s and their effects on our bodies from fish oil sources as the fish industry would like us to believe. Global recommendations to eat more fish are problematic not only from a point of view of sustainability, given today’s shrinking fish populations and the fact that aquaculture does not represent a sustainable source if it takes three pounds of menhaden to increase the weight of farmed salmon by one pound. (See Part 1 in our series on omega-3 sources.)
The problem with trying to identify any one nutrient as being responsible for major positive or adverse outcomes is that there are so many other variable that must be taken into consideration- a factor that food industry marketing conveniently overlooks. For example, a cohort study of over 11,875 children found that consumption of less than 340 grams per week of seafood during pregnancy was associated with the child being in the lowest quartile for verbal intelligence as opposed to mothers who consumed over 340 grams of seafood each week. On the surface this sounds like a call for all mothers to start eating more fish but it fails to mention the reality that mothers who ate less seafood were in lower income brackets, had lower education levels and lived in less ideal conditions than the mothers who ate 340 grams of seafood. The association is correlative but not necessarily causative as it is fairly obvious when all the parameters are exposed that the long chain omega-3’s in seafood may not have been the reason for the lower test scores. All of these such associations take away from the reality that fish and seafood were not always staples in our diet and as such they might not be necessary for optimal health.
Natural Land Plant & Animal Sources of Long Chain Omega-3’s
Conventional nutrition studies can often produce conflicting and inconsistent data but an understanding of human dietary habits during the period of our evolution and beyond by observing the practices of healthy populations in modern forging tribes can provide useful and unbiased ways of looking at dietary information. Information that is more in keeping with how we should eat as opposed to how we want to eat in our food abundant environment. One of the key questions as to how early man was able to find adequate sources of long chain omega-3 fatty acids is answered by a simple observation of what we ate at that time. Firstly, Stone Age humans and hunter-gatherer populations today consume not just muscle tissue but relished certain fatty portions of their meats that are not eaten today in our lower omega-3 environments such as brain and bone marrow. While so much fish industry sponsored research is poured into marine sources the fact that the total DHA content of whole brain is 8.6mg/g which is higher than the mean value for a high value omega-3 source fish such as salmon which only yields 6.7 mg/g. Equally important is the fact that the wild animals consumed by by our ancestors and modern foragers such as deer, elk, buffalo and antelope have far higher levels of omega-3’s than grain fed livestock.  Grain fed beef has 2-3 times more saturated fat than game meat and 3-4 times less omega-3 polyunsaturated fats. Furthermore, the ratio of omega-6 to omega-3 fats is more than twice that of game animals -An important fact since the presence of omega-6 fatty acids (LA) does appear to inhibit tissue absorption of long chain omega-3’s- especially DHA.) Excessive omega-6 consumption at the expense of omega-3 fatty acids as is common in developed countries with grain fed livestock has also been shown to possibly increase risk of cardiovascular disease and other chronic diseases. Even pasture fed beef, which is much lower in saturated fats and looked upon as the de facto healthy meat choice has 2-3 times less omega-3 polyunsaturated fats than wild game since muscle tissue from both grass and grain fed beef have lower concentrations of long chain omega-3’s. It makes perfect sense since a deer that forages on ferns and mosses (which are in fact high in long chain omega-3’s-especially those growing nearer to water) would have much higher concentrations of long chain polyunsaturated fats when compared to a pasture fed animal.[30,31]
A fundamental mistake with many so called Paleolithic dietary approaches is that it neglects the inconvenient reality that wild game and not livestock animals were staples in our diet for millions of years and that the entire carcass was eaten unlike the practice in developed countries to eat mostly muscle tissue. Thus, wild game and meats such as buffalo are far more natural sources of long chain omega-3 fatty acids, especially when brain tissue is consumed- a factor that debunks the idea that humans required marine resources in order to evolve. As with any complex subject, there are still many other potential sources of long chain omega-3 fatty acids that are yet to be quantified. Hunter gatherers also consumed invertebrates, eggs, fungi and gums – the omega-3 content of which has yet to be studied thanks to emphasis on marine sources. Information on wild plant foods consumed as well is lacking as there are a number of uncultivated fruits and vegetables native to East Africa that have yet been analyzed for omega-3 fatty acid content. Wild plants such as purslane, which is the 8th most commonly distributed plant on the planet is the richest source of omega-3 fatty acids of any green leafy vegetable ever examined with an exceptionally high level of alpha-linolenic acid (ALA) and even trace amounts of EPA and DHA- commonly found in marine sources. 
The Omega-3 Paradox- Omega-6 Ratios & Processed Foods
Human studies have shown that the conversion of ALA to long chain omega-3’s was reduced by as much as 50% when dietary intake for LA was increased from 4.7% to 9.3% of caloric intake as a result of the competition between omega-6 and omega-3 fatty acids for desaturation. Thus, the higher body fat reserves of omega-6 fatty acids in modern vegans and omnivores in Western societies is thought to be a major reason why average tissue concentrations of long chain omega-3’s is not as high as is found in societies that consume lower levels of LA. However, a study of the Tsimane forager-horticulturist tribes of Bolivia found that breast milk concentrations of long chain omega-3’s (AA and DHA) were significantly higher than samples taken from mothers in in the United States, even though they frequently consume LA rich plant foods such as maize. Higher percentages of long chain omega-3’s was attributed by the study authors to be due to their diet of predominantly wild game and some freshwater fish but the authors did not take into account possible sources from animal brain tissue. They did acknowledge however that Amazon freshwater fishes are far lower in DHA than cold water species and that fish intake was not as frequent as among coastal populations. What was interesting was that in spite of the fact that Tsimane mothers ate corn almost daily, their average breast milk ratios of omega-6 to omega-3’s was 4/1 as opposed to the American mothers whose ratios came in at 8/1. One explanation put forward is that the higher percentages of LA (and trans fats) in milk samples from American women was due to their consumption of LA rich vegetable oils and processed foods containing LA and hydrogenated oils- thus the problem may not be so much a matter of a simple need for increased omega-3’s but also an avoidance of processed LA rich oils.
Vegetarians & Long Chain Omega-3’s- No Fish But High Omega-3 Levels
One final factor to consider in the argument against fish oil sources of omega-3 fatty acids is the seeming ability of those with low to no intake of fish or long chain omega-3 fatty acids sources to be able to convert plant sourced ALA’s to long chain omega-3 fatty acids in tissue levels comparable to regular fish eaters. One study of over 14,000 vegan men and women, with no intake of dietary EPA or DHA from marine sources still had very high levels of plasma DHA and EPA.  As incredible as such a finding may seem it does make sense that our bodies would have evolved in such a way so as to increase conversions from plant source ALA’s to long chain omega-3’s since fish was not a staple of our diet for several million years. Male vegans in the study had only slightly lower levels of DHA than female vegans, and only slightly lower levels than fish-eaters (195 compared to 240 μmol/L plasma). Of note as well is that EPA levels were higher in male vegans than in meat-eating and fish-eating males. Thus far there has only been one large population study to investigate polyunsaturated intakes and blood levels among vegans and far more research is needed as the implications of these findings are that plant and land based foods are more than sufficient sources of long chain omega-3 fatty acids. A finding that would allow for preservation of the global wild fish supply as reliance on fish and fish oils as the only source of health beneficial omega-3’s are not only unsustainable but scientifically questionable.
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