| The life-prolonging
benefits of long-chain omega-3 fatty acids are hardly front-page
news any longer. We have all heard by now that it is important to
eat at least two servings of fatty fish per week for optimal cardiovascular
health. After all, no less an authority than the American Heart Association
recommended just such a dietary plan for all Americans in 2000, and
again late last year, after reviewing years of research on the impressive
health benefits of omega-3 consumption.1,2
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The recommendation reflects the culmination of decades of research
that began in the 1950s, when scientists first examined the traditional
diets and lifestyles of the Inuit (Eskimos) in Greenland in an effort
to understand the Eskimos’ almost
startling absence of cardiovascular and other diseases. While heart and circulation
disorders rank among the top killers in the industrialized world, they are virtually
unknown among the hunter-fishers of the Arctic Circle. The Inuit’s amazing
health, scientists eventually understood, is a direct result of consistently
eating large quantities of fish and marine mammals, which are rich sources
of long-chain omega-3 fatty acids.
But intriguing new research from around the globe indicates that the much-heralded
heart benefits represent little more than the tip of the proverbial iceberg when
it comes to this versatile and utterly essential nutrient.
A 21st Century
Optimal Supplement
Exciting new studies suggest that omega-3s play
an integral role in overall health. When deficiencies exist, as is
alarmingly common in the industrialized West, supplementation with
the right omega-3s, in the right balance, has the potential to improve
everything from vision to brain function. Far from simply decreasing
blood pressure, and protecting against heart attack and stroke,3-10 omega-3s may also prevent (or play a role in the treatment of) everything
from depression to autism.11-24 Certain omega-3s are crucial to the
optimal development of the brain and sensory organs in preterm infants,25-28 and
omega-3s have been shown to reverse the symptoms of rheumatoid arthritis
and possibly to play a role in preventing Alzheimer’s
disease.29-34
And the list doesn’t stop there, as new research suggests
even more potential benefits of omega-3s. Cutting-edge research from
facilities all over the world indicates that omega-3s may also prevent
age-related macular degeneration, suppress cancer cell growth (while
simultaneously promoting cancer cell death), decrease susceptibility
to the most common form of stroke, ameliorate complications of Type
II diabetes, and even improve the health of those whose lungs have
been damaged by smoking or diseases such as asthma, cystic fibrosis, and
emphysema.35-45
But even that list fails to encompass the full scope of this essential nutrient’s
absolute importance to virtually every aspect of health. About 60% of the brain
consists of lipids, and the omega-3s are among the most important of these.
They are key components of cell membranes throughout the body, and are richly
invested in neural tissue.
The omega-3s are known as essential fatty acids (EFAs) because they are necessary
nutrients that must be obtained from the diet. Unlike cholesterol, for instance,
the body cannot manufacture the omega-3s it needs. While certain plant sources
provide the building blocks of the most crucial omega-3s, they are most readily
and plentifully obtained from marine sources.
Data gathered from populations around the world paint a clear picture: societies
with the lowest fish consumption have the highest rates of suicide, depression,
and violence. Conversely, among populations where fish is eaten frequently,
these costly social ills are dramatically lower. The jury is still out on certain
promising aspects of omega-3 supplementation therapy, but one thing is clear:
omega-3s play a crucial role in maintaining health. What is equally clear is
that the average American does not get nearly enough omega-3 fatty acids from
the diet.
Some scientists have even speculated that the lack of adequate omega-3s in
the Western diet may account for escalating levels of neurological disorders
such as autism, depression, bipolar disorder (manic depression), and attention
deficit hyperactivity disorder (ADHD).11-24 Others are investigating the benefits
of omega-3 supplementation in the treatment of everything from asthma to inflammatory
bowel disease and schizophrenia.46-48 Studies have shown that omega-3s can
reduce the risk of sudden death from heart attack,5 improve vessel elasticity,49 lower serum triglycerides,50 and coax an unsteady heartbeat back into a stable
rhythm.51-53 It is no fish story: Fish oil is beginning to look like a panacea
for the 21st century.
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Omega-3 vs. Omega-6– A Harmful
Imbalance?
The human body has
evolved to thrive on a roughly equal intake of omega-3 and omega-6
long-chain fatty acids. Although the important omega-3s, eicosapentaenoic
acid (EPA), and docosahexaenoic acid (DHA) are available only from
marine sources, it is not necessary to eat seal meat, as the Inuit
do, to reap the benefits of these ocean-borne nutrients. They are
plentiful in fatty cold-water fish such as salmon, tuna, bluefish,
sardines, herring, and king mackerel. A three-ounce serving of salmon,
for instance, yields roughly 3 grams (3,000 mg) of combined EFAs.
For those who do not like fish or prefer the convenience and safety of supplements,
fish oil is available in capsule form. But even fish do not generate these
essential polyunsaturated fatty acids. They get them courtesy of their own
diets, which include marine algae or seaweed. Humans can too, of course, although
it seems unlikely that the average American will be able or willing to order
fresh seaweed at McDonalds any time soon. A third essential fatty acid, alpha-linolenic acid (ALA), is available from
certain plant sources, most notably flax seed, avocados, and walnuts. The body
can convert ALA into EPA and DHA, but the process is slow and the rate of conversion
probably varies according to age, gender, and other factors.54-56 Fish and
fish oil thus remain the best sources of vital DHA and EPA. For millions of years, humans evolved on a diet rich in natural
omega-3 food sources, including free-range game, fish, marine mammals,
nuts, and fresh seaweed. In the early 20th century, however, food
manufacturers in the industrialized nations began literally pouring
soybean oil—a source of omega-6 fatty acids—into the
food chain. A concurrent decline in fish and wild game consumption,
accompanied by the heavy use of grains (another omega-6 source) as
feed for livestock, conspired to drastically alter the balance between
omega-6s and omega-3s in the Western diet. While an omega-6 to omega-3
ratio of roughly 2:1 is optimal, most Americans consume far more
omega-6s than omega-3s, yielding a ratio skewed at least 10:1 in
favor of omega-6s. Some estimates put the ratio as high as 40:1.
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One researcher calculates that consumption of omega-6s has increased
1,000-fold since the early 20th century, literally changing the
composition of our brains and bodies. Studies have shown that when
cells are deprived of vital omega-3s, they attempt to compensate
by incorporating saturated fats in cell membranes. The result is
a stiff and ineffectual structure that must serve as the cell’s
means of “commerce” and exchange with the rest of the body. Because
omega-6s break down into arachidonic acid in the body, and arachidonic acid
is converted to highly inflammatory chemicals, a huge increase in the availability
of arachidonic acid translates into a huge increase in the potential for
inflammatory and autoimmune diseases. Omega-3s, on the other hand, are converted
by the body to series 1 and 3 prosta-glandins which serve to counterbalance
the inflammatory effects of the series 2 prostaglandins, derived from arachidonic
acid.
Here’s a look at some of the diverse ways in which omega-3s can improve
health and extend life.
Promise Shown
Treating Arthritis
Arthritic complaints are rare among the Inuit,
and the omega-3s in their diet are evidently the reason. Clinical
trials have examined the effectiveness of omega-3 supplementation
in a variety of inflammatory and autoimmune diseases, including rheumatoid
arthritis, Crohn’s
disease, lupus erythematosus, psoriasis, multiple sclerosis, and
migraine headaches. Many of these placebo-controlled trials have
demonstrated significant benefits. In some cases patients have been
able to reduce reliance on anti-inflammatory drugs, such as non-steroidal
anti-inflammatories (NSAIDs), for relief from painful symptoms.32
Arthritis is actually a range of diseases, all of which have joint inflammation
in common. Omega-3s excel at quelling inflammation. Although experts have recognized
this beneficial effect for years, recent research has shed light on the exact
mechanisms involved.
A number of diseases are associated with a high level of interleukin-1B (IL-1B),
a pro-inflammatory cytokine. Arthritis is associated with an increase in IL-1B
and the pro-inflammatory leukotriene LTB(4), which is indirectly produced by
the body from arachidonic acid. Arachidonic acid is derived from omega-6 fatty
acids and gives rise to a class of immune system compounds that promote pain
and inflammation. Studies have shown that when omega-3 and omega-6 fatty acids
are balanced (that is, when the ratio of omega-6 to omega-3 in the body is
about 1:1 to 4:1), far less arachidonic acid is available for conversion to
harmful eicosanoids and cyto-kines. Fewer of these compounds in circulation
means less inflammation.
Besides “crowding out” excess arachidonic acid, the omega-3s aid
the body in other ways, too. They have been shown to act on intracellular signaling
pathways, to influence transcription factor activity, and to modulate gene
expression. All of these effects may combine to alleviate inflammation and
disease. As one researcher noted: “Many of the placebo-controlled trials
of fish oil in chronic inflammatory diseases reveal significant benefit, including
decreased disease activity and lowered use of anti-inflammatory drugs.”32 Another
scientist reviewed nearly two decades of published research on the use of fish
oil in the treatment of rheumatoid arthritis and concluded: “Treatment
with fish oil has been associated with improvement…in rheumatoid arthritis.”34
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