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[1] 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.[4] 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[11] 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[16].
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
While
the fish industry lobby has successfully manipulated government
guidelines on omega-3 sources, health claims from fish oils are yet to
be fully substantiated.
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.[22] 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[22], 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’.[17]
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[18] 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.[18]
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.[21] Little or no benefit was found for a variety of other
cardiovascular risk factors and markers of cardiovascular disease.[21]
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[21]-
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 fortify infant formula is with omega-3′s comes more from speculation than science.
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.[23] 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.[22] 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.[22]
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.[25] 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
Wild foragers such as buffalo are much higher sources of long chain omega-3′s than even grass fed beef.
Conventional nutrition studies can often produce conflicting and
inconsistent data[26] 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.[27] 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.
[27] 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 (ALA) does
appear to inhibit tissue absorption of long chain omega-3′s- especially
DHA.[27]) 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.[28] 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]
The
long chain omega-3 content for wild game is 2-3 times higher than grass
fed and grain fed beef but brain tissue contains as much as 8.6mg/g of
long chain omega-3′s far in excess of what is found in fish sources.
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[29]. 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[29] –
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 8
th 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. [30]
The Omega-3 Paradox- Omega-6 Ratios & Processed Foods
Breast
milk from mothers in the U.S. is far lower in long chain omega-3′s when
compared to the Bolivian Indians- even though they eat large amounts of
grain.
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.[32] 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.[33] 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.[33] 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. [36] 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.[36] 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.
Related Articles in Our Omega-3 Series
Part 1: Omega-3 Sources
Part 2: Omega-3 Fortification- all Omega-3′s Aren’t Created Equal
Kevin Richardson is an award winning health and fitness writer, natural bodybuilding champion, creator of
Naturally Intense High Intensity Training and one of the most sought after
personal trainers in New York City. Get a copy of his free weight loss ebook
here!
