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Diet Smart
Understanding Omega-3s
By Katherine Tallmadge, Washington Post
Wednesday, March 24, 2004
I first became interested in the power of omega-3 fatty acids when
psychiatrists I work with began prescribing them for their depressed
patients. Then I started hearing about their benefits for arthritis and a
host of other diseases. And I couldn't help but wonder, could it be possible
that one simple change in the diet could provide so many benefits?
The connection between omega-3 fatty acids and health was first observed in
the 1970s. Scientists noted that compared with their counterparts in
Scandinavia, Greenland Eskimos had a reduced rate of heart disease,
rheumatoid arthritis and other conditions even though they were eating a
high-fat diet. The scientists hypothesized that the type of fat -- marine
derived -- might play a role.
Since then, study after study has confirmed that omega-3 fatty acids, a type
of polyunsaturated fat found primarily in fish, have a potent and positive
effect on heart disease patients. Omega-3s prevent irregular heart beat,
reduce plaque inside artery walls and decrease blood clotting, triglycerides
(blood fat), blood pressure and inflammation.
"Omega-3s favorably affect a number of risk factors for cardiovascular
disease and at the top of the list is reducing the risk of sudden death from
heart attack," says Penny Kris-Etherton, a nutrition professor at
Pennsylvania State University.
But the healing powers of omega-3s don't stop there. Research suggests they
may reduce the risk of diabetes, reduce insulin resistance in people with
diabetes, enhance bone density and inhibit proliferation of cancer cells in
the breast, prostate and colon and improve skin condition by curbing
psoriasis. Inflammatory diseases such as rheumatoid arthritis, ulcerative
colitis and Crohn's disease seem to improve with more omega-3s. In infants,
it improves cognition and visual acuity. And emerging research indicates
omega-3s may boost levels of the brain chemicals serotonin and dopamine,
decreasing depression and violent behavior.
While not an answer to every ailment, omega-3 fatty acids possess
considerable healing powers. As an indication of their importance, the Food
and Nutrition Board of the National Academy of Sciences recently established
a minimum daily requirement: 1.1 grams for adult women, 1.6 grams for adult
men.
But in nutrition, balance is everything. There is another essential fatty
acid, omega-6. Each type of fatty acid has its important functions. But if
the level of one of the fatty acids is too high, it competes with and
interferes with the functioning of the other.
"If you eat too much omega-6, as is the case with today's American diet,
this interferes with omega-3 action, promotes inflammation, blood clotting
and constricts blood vessels, and causes a huge array of diseases," says
Joseph Hibbeln, a psychiatrist at the National Institutes for Alcohol Abuse
and Alcoholism.
However, the ideal ratio of omega-6 to omega-3 is a source of heated debate
among researchers. If you followed the fatty acid recommendations of the
National Academy of Sciences, your ratio would be 11 to 1. But many omega-3
researchers say a far lower ratio is ideal for optimal health. Still other
researchers believe a specific ratio doesn't matter but the amount of
omega-6 and omega-3 you're eating is important.
What all the scientists do agree on is the need to consume more omega-3s.
Americans don't come close to getting their omega-3 requirement. But we used
to.
"Early humans ate plenty of high-omega-3 foods, wild greens, seafood, lean
animals that grazed on high-omega-3 grasses, such as purslane, and our
bodies evolved a need for it," says Artemis Simopoulos, president of the
Center for Genetics, Nutrition and Health and author of "The Omega Diet"
(Harper Collins, 1999).
Today, the highest concentration of omega-3s is found in fish. The two most
potent omega-3 fatty acids are known as DHA and EPA and are usually found in
oily fishes, such as mackerel, salmon and tuna. These fatty acids end up in
every single cell membrane in the human body. They act as a cell lubricant,
improve flexibility and communication among cells.
Omega-3s are also found in plant sources, especially flaxseed oil, canola
oil, walnuts and some vegetables. These fatty acids, while valuable, are not
as beneficial as the more potent omega-3s found in fish.
But for those who are concerned about the discovery of mercury and other
contaminants in seafood, plant sources are important to consider. These
omega-3s occur as ALA, a type of fatty acid that must be converted in the
body to the more usable forms of DHA and EPA.
Omega-6s are found in safflower, soybean and corn oil, which are in many
processed foods. Because of Americans' increased intake of processed and
fast foods over the past 50 years, omega-6s have largely replaced omega-3s
in the modern diet.
Though grass-fed animal meat, available in some stores and farmers markets,
contains at least two times more omega-3s than grain-fed animal meat, it
doesn't come close to the levels you can find in fish. Animal scientists are
working on improving the omega-3 fatty acid content of beef, chicken and
other meats by feeding the animals flax and other high-omega-3 foods, but
these products are a long way from being sold in your grocery store.
You can now buy omega-3-enhanced eggs from chickens that are fed algae, flax
and/or fish. The reported amount of omega-3s contained in each egg, however,
varies according to brand. These amounts of omega-3s are still considerably
lower than levels found in fish.
Omega-3 supplements can be effective, though it is possible to take too
much. For example, by reducing inflammation, omega-3s also may reduce the
immune response. There is also a slight increased risk for hemorrhagic
stroke or excessive bleeding. Large doses should be taken only under a
doctor's supervision.
How much fish do you need to consume? Most of the studies on omega-3s found
a positive benefit with 500 to 1,000 milligrams per day. In response, the
American Heart Association now recommends all adults eat a variety of fish,
particularly oily fish, at least twice weekly (three-ounce portions), which
would provide an average of 500 milligrams per day. For patients with
coronary artery disease, the AHA recommends 1,000 milligrams daily -- but
never above 3,000 milligrams.
As usual, balance is paramount.
Katherine Tallmadge is a Washington nutritionist and author of "Diet Simple"
(Lifeline Press, 2002). Send e-mails to her at food@washpost.com.
© 2004 The Washington Post Company
Psychology
Today
Omega-3s For Boosting Mood
Omega-3s found in fish are a building block of happy
brains.
By Willow Lawson, Psychology Today
We've known for a few years that people who eat a diet rich in fish are less
likely to be depressed. But new research shows that one nutrient in fish
might actually be more effective against depression than traditional
antidepressants. The nutrient is an omega-3 fatty acid called EPA (eicosapentaenoic
acid).
British scientists gave a group of patients with stubborn depression a daily
dose of EPA. After three months, over two thirds of the group reported a 50%
reduction in their symptoms—particularly feelings of sadness and pessimism,
inability to work, sleeplessness and low libido. All of the patients had
previously tried other medications, including Prozac, other SSRIs and
tricyclic antidepressants, the researchers reported in the Archives of
General Psychiatry.
"This is one of the largest potential associations of a nutrient with
depression," says Joseph Hibbeln, M.D., a psychiatrist at the National
Institutes of Health who has pioneered research into the diet-depression
link. "The important issue in this study is that the omega-3 worked above
and beyond the antidepressants."
Healthy brains and nerve cells depend on omega-3s because the nervous system
is made mostly of fat. The signals that travel through our flesh—feelings,
thoughts, commands to our bodies—skip along cells and their arms sheathed in
fat.
But not just any fat. Omega-3 essential fatty acids are one of the basic
building blocks of the brain. Brain cell membranes are about 20 percent
fatty acids and they seem to be crucial for keeping brain signals moving
smoothly. Doctors call this class of fat "essential" because, unlike many
nutrients, our bodies cannot produce it. We can get it only from very
specific parts of our diets.
Found in seafood, also in walnuts, leafy greens and flaxseed, omega-3s are
polyunsaturated fats that also protect against cancer and promote
cardiovascular health. They may explain why heart disease and depression
often occur together.
A growing body of research suggests that seafood can ward off other mental
disorders. Countries with diets rich in fish have lower rates of depression,
bipolar disorder, postpartum depression and suicide. The complete story of
these fats is yet to be told. Scientists haven't nailed down how they
interact in the brain with each other, other nutrients and even medications.
The fatty acids in cell membranes need constant replenishment by diet, which
seems to be where some complications set in. The omega-3s exist in a
delicate balance with another group of needed fats, omega-6s. The trouble
is, most Americans are consuming too much of the omega-6s, and they're
crowding out the omega-3s. The omega-6s are found in many vegetable oils,
such as corn and soy, that permeate processed foods.
Hibbeln says the overabundance of omega-6s in our diet is one of the most
critical issues facing U.S. public health. Over the last century, our
consumption of soybean oil has increased a thousand-fold, so that each of us
now eats about 25 pounds of the stuff a year.
"There's good data that this soybean oil has literally been flooding our
bodies and brains," Hibbeln says. He believes that many health problems,
including the steep rise in depression, might be due to this radical change
in our diet.
So next time you are in the grocery store, take a look at the ingredients on
boxes of crackers and cookies and even jars of peanut butter. Most likely
they are packed with soybean, cottonseed or corn oil. You might be doing
your brain a favor by feeding it a walnut or a sardine instead.
It's too early for prescribing fish as a sure-fire treatment for depression,
but Hibbeln says it's a good idea to have some in your diet. Whether fresh
or salt-water, all fish contain omega-3s, which originate in the algae and
seaweed they eat.
Hibbeln believes the American Heart Association's guidelines are on target
for the brain as well as the body: eat seafood, including shrimp, crabs and
oysters, two to three times a week for overall health.
Publication: Psyched for Success
Publication Date: 3 January 2003
Last Reviewed: 3 Jul 2006
(Document ID: 2513)
Benefits of Omega-3s Seem Fishy
Heart-Healthy Boost From Omega-3 Fatty Acids Not Clear
Cut
March 24, 2006 CBS News
| Fast Fact In a review of 89 studies that measured the effect of omega-3 fatty acids on heart attack, death, cancer, and strokes, researchers didn’t find any clear benefit of omega-3s in reducing the risk of these health hazards. |
(WebMD) The benefits
of omega-3s in fighting heart disease may be only so-so, according to a new
review of research on the fatty acids found in fish and some plant and nut
oils.
The study doesn’t rule out an important effect of omega-3 fatty acids on
health, but the results indicate that the evidence behind the fishy fats is
less conclusive than previously thought.
Eating foods rich in omega-3 fatty acids, such as fatty fish and some plant
and nut oils, such as olive and walnut, is thought to lower the risk of
heart disease, and several public health organizations have recommended that
people to eat more oily fish, such as salmon and tuna.
But in a review of 89 studies that measured the effect of omega-3 fatty
acids on heart attack, death, cancer, and strokes, researchers didn’t find
any clear benefit of omega-3s in reducing the risk of these health hazards.
Omega-3’s Health Benefits Questioned
In the review, which appears in the journal BMJ, researchers analyzed the
results of studies that looked at the omega-3 fatty acids on reducing health
risks in people who increased their intake of omega-3s through diet or
supplementation with fish oil capsules for six months or more.
After taking differences in study quality into account, researchers found
the pooled results of the studies showed no strong proof that omega-3 fatty
acids had an effect on reducing the risk of death or heart-related events,
like heart attack and stroke.
Researchers say other recent reviews of studies on omega-3s have shown that
people taking supplements of the fatty acids had a lower risk of death, and
they can’t explain why this review came up with conflicting results.
Therefore, they recommend that further study is needed to fully understand
the benefits and risks of omega-3 fatty acids.
In an editorial that accompanies the study, Eric Brunner of the department
of epidemiology and public health at the Royal Free and University College
London Medical School writes, "We are faced with a paradox."
"For the general public some omega-3 is good for health," writes Brunner.
"Health recommendations advise increased consumption of oily fish and fish
oils. However, industrial fishing has depleted the world's fish stocks by
some 90 percent since 1950, and rising fish prices reduce affordability
particularly for people with low incomes. Global production trends suggest
that, although fish farming is expanding rapidly, we probably do not have a
sustainable supply of long-chain omega-3 fats."
SOURCES: Hooper, Lee. BMJ, March 24, 2006, online first edition. News
release, BMJ.
By Jennifer Warner
Reviewed by Louise Chang, M.D.
© 2005, WebMD Inc. All rights reserved.