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Seafood FAQ: Surveying the sources of omega-3s
How do dietary supplements compare to seafood?
By James Wright
July 01, 2006
Seafood marketers got a shot in the arm back in the 1980s
when omega-3 fatty acids - particularly long-chain omega-3s
found in oily fish - were revealed as crucial to human health.
When the American Heart Association openly praised omega-3s in
2002 for thwarting heart disease, capitalizing on health
benefits was in the best interests of every seafood supplier.
Further, omega-3s aid in the prevention of cancer and strokes,
among other benefits, and are key to proper brain function and
normal growth and development.
Dietary-supplement makers also benefited from the
groundswell and quickly transformed omega-3s from a marketing
buzzword to a driving force in the health-products industry;
U.S. consumers spent about $300 million on fish oil supplements
last year, according to the Nutrition Business Journal .
Derived from both fish oil and plant sources, omega-3
supplements in shelf-stable pill and gel form can be found in
nearly every drug store and supermarket, prompting consumers to
ask, "Why eat fish when I can get my omega-3s from a pill?"
As supplement sales continue to grow, seafood suppliers and
retailers should learn the difference between seafood's
nutritional benefits vs. those of omega-3 supplements and
communicate that information to their customers.
Q. What are omega-3
Omega-3 fatty acids are polyunsaturated fats found in the
tissue of oily fish like salmon, herring, anchovies and
mackerel, as well as in vegetable and plant sources such as
flaxseeds, soybeans and walnuts, to name a few. Omega-3s are
classified as essential; they cannot be manufactured by the
body and must be obtained from food sources.
The three main omega-3 fatty acids in human diets are
alpha-linolenic acid (ALA), eicosapenaenoic acid (EPA) and
docosahexaenoic acid (DHA). DHA is widely regarded as the most
essential omega-3 and is more abundant in fish and fish oil
than in any other food source. Plant-based sources contain
mostly ALA, which is a short-chain fatty acid.
Long-chain polyunsaturated fats like EPA and DHA are key
building blocks in the brain and contribute to efficient
transmission of signals between nerve cells.
Q. Is there a difference
in the way our bodies
process omega-3s from
"There is no difference, in a general sense," says Joyce
Nettleton, Ph.D., author of "Omega-3 Fatty Acids and
However, the rate at which our bodies convert plant-based
ALA into EPA and DHA is very slow, Nettleton notes. The type of
omega-3, it seems, is more important than the source itself.
"Studies do show that these fatty acids are slightly more
available from [seafood]," she says.
"With fish, you get the omega-3s in a form in which they are
protected in the tissue of the meat, but you also get
heart-healthy nutrients like selenium and trace minerals like
Vitamin D, which we also don't get enough of. The issue is
getting enough omega-3s into our bodies in the first place.
"And if you eat fish as part of
your meal," she adds, "it's
replacing something else, like a cheeseburger."
Q . Are all omega-3 supplements created equal?
No. Omega-3 content varies greatly among supplements, and
lab studies have shown that the actual amount doesn't always
match the claim on the label. The average 1-gram fish-oil
supplement has 300 milligrams of omega-3s, comprised of EPA and
DHA, says Dr. William Harris, professor of medicine at the
University of South Dakota in Sioux Falls.
While supplements based on plant sources such as flaxseed
contain 55 percent omega-3s, it's nearly all ALA, which the
body converts to EPA "very poorly," he says, adding that our
bodies' ability to convert flaxseed oil into DHA is
"Long-chain omega-3s from fish are far better evidenced for
health benefits," Harris adds. "No contest. EPA and DHA are
both way more important than ALA."
If it sounds a bit confusing, it is. As Nettleton points
out, some supplements claim to have omega-3s, omega-6s and
omega-9s, leaving consumers to rely on packaging claims and the
opinions of health-store clerks.
"Few people actually understand it all," Nettleton says.
"You're at the mercy of the vendors and what you can find
yourself if you're seeking information. All manner of snack
bars, mayonnaise, chewable supplements - this, that and
everything - claim to have omega-3s."
While spoilage is a concern for all supplements, as with any
food products, the refining process for fish oil eliminates
contaminants like methylmercury and PCBs (polychlorinated
biphenyls), which are present in the environment and in some
Flaxseed oil is the most abundant omega-3 product on the
supplement market, mainly because it is the easiest and
cheapest to manufacture, says Nettleton.
Q. Who should take omega-3 supplements?
Supplements help many people - particularly those who don't
or won't eat fish - because there simply aren't many sources of
essential long-chain fatty acids.
Those with cardiovascular disease, high triglyceride (fat)
levels and type-2 diabetes can benefit the most.
The AHA advocates two servings of fish per week for healthy
people and at least 1 gram of omega-3 fatty acids daily for
those with coronary heart disease. For those with serious
conditions, up to 3 grams of omega-3s are recommended.
Supplements seem an obvious choice to meet that need, but
the Food and Drug Administration says no more than 2 grams per
day should come from supplements.
Heavier doses of omega-3s can lead to excessive bleeding in
some people and should be taken only under a physician's care,
the agency says. Additionally, Omacor is the only FDA-approved
omega-3 prescription medication on the market.
The 1-gram capsules, partially derived from fish oil and
comprising 465 mg of EPA and 375 mg of DHA, are prescribed to
"It's hard to get a gram [of omega-3s] a day unless you eat
fish," says Nettleton. "Supplements can contribute; they're
easy, inexpensive and effective.
"But there's no question that consuming nutrients from the
original source has a lot going for it."
Assistant Editor James Wright can be e-mailed at