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

© 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.