Recommended Daily Dose for Omega-3 May Be on the Way

New Analysis May Pave the Way for Greater Acceptance of Fish Oil Nutrient

Fish oil appears to have withstood the test of both time and controlled trials; now some cardiologists say it is time for omega-3 polyunsaturated fatty acids to join others nutrients for which a daily recommended intake has been established.

(ABC News Photo Illustration)

By PEGGY PECK and DAN CHILDS
ABC News Medical Unit in Collaboration with MedPage Today

A new analysis could lead to heated debate among heart dictors over whether omega-3 polyunsaturated fatty acids deserves its own recommended daily intake levels.

Fish oil -- a centuries-old pharmacy shelf fixture -- has recently been the subject of much research to determine its heart-protecting properties. Now, some cardiologists say it is time for omega-3 polyunsaturated fatty acids to join others nutrients for which a daily recommended intake has been established.

Dr. Carl Lavie, medical director of Cardiac Rehabilitation and Prevention at the Ochsner Heart and Vascular Institute in New Orleans, is one such cardiologist. He says that healthy people should consume at least 500 mg per day of eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) in order to meet their daily needs for the nutrient.

Lavie and his colleagues made the recommendations in a paper released Monday in the Journal of the American College of Cardiology.

Those with known cardiovascular disease, the researchers added, should consume 800 to 1,000 mg per day of the nutrient.

Such recommendations, if widely established, could solidify omega-3's place in the pantheon of nutrients that diet experts recommend.

But other cardiologists were more measured in their assessment and at least one -- the oft-quoted contrarian Dr. Steven Nissen, director of cardiovascular medicine at the Cleveland Clinic -- said Lavie's conclusions are premature.

"I don't find the evidence for widespread usage of omega-3 particularly compelling," Nissen said.

Others, including Dr. Robert Bonow, past president of the American Heart Association and co-director of the Bluhm Cardiovascular Institute at Northwestern University in Chicago, attempted to temper the enthusiasm by pointing out that while advising patients to increase consumption of fish oil may be "good advice," it should be tempered by adding the caveat that the data are "strongest in those with established heart disease ... with the principal benefit being a reduction in serious rhythm problems.

"The other benefits do appear to be real, but there is less evidence -- and in some cases no evidence -- that these lead to better patient outcomes," Bonow added.

Lavie based his recommendation on a review of findings from four studies that, in total, looked at about 40,000 study participants -- ranging from healthy individuals to those who had experienced a heart attack or other cardiac problem.

Studies May Garner More Acceptance for Fish Oil Supplements

The studies revealed a number of potential advantages to taking in omega-3 fatty acids. One piece of research showed that in men who had recently experienced a heart attack, those who took omega-3-rich fish oil were 29 percent more likely to be alive after two years than their non-fish-oil-eating counterparts.

Even Lavie noted, however, that not all studies have been kind to omega-3s. In his study, he writes that one previous trial showed that patients who have experienced a form of heart-related chest pain known as angina who are treated with fish oil "seem to have a higher risk of [sudden cardiac death] than untreated control subjects." At least one other study has shown the benefits of omega-3 for those who have suffered a heart attack to be questionable.

This has not stopped some heart doctors from using omega-3 supplements in their patients, however. Dr. Melvyn Rubenfire, director of preventive cardiology at the University of Michigan in Ann Arbor, says he is currently using EPA + DHA supplements in patients with coronary artery disease because "available evidence supports it."

But Rubenfire added that he would like to see a "trial in the modern era in patients on other evidence-based treatments such as aspirin, [blood pressure] control, statin and non smoking" to confirm an omega-3 benefit on top of standard care.

And then there is the question of whether people who take commercially available supplements will be getting enough of the nutrient to make a difference. Rubenfire warned that the lack of regulation in the supplement industry means "that 1,000 mg of fish oil caplets may contain as little as 300 mg of EPA+DHA."

American Heart Association Already Backs Omega-3

The American Heart Association (AHA) appears to already be on board with omega-3 guidelines. The organization's current recommendation is that people with confirmed coronary heart disease should consume 1,000 mg daily of combined DHA + EPA. For healthy adults, the AHA recommends consuming 500 mg per day, which works out to consuming at least two servings of fatty fish a week.

But while it does promote heart healthy diets for all, the AHA remains wary about mercury contamination in fish and cautions that fish with the highest potential for contamination -- namely shark, swordfish, king mackerel or tilefish -- should be avoided.

Copyright © 2009 ABC News Internet Ventures

All Fats Are Not Created Equal

By: Nancy Snyderman, M.D.

c squared studios

We need a little fat in our diets for good health, and some fats are better for you than others. Fatty acids, the building blocks for fat, are divided into three chemical classes according to their hydrogen content: saturated, monounsaturated, and polyunsaturated. Here’s a rundown.

Saturated Fatty Acids

Saturated fats are the main culprit in raising low- density lipoproteins (LDL, or “bad” cholesterol). They are found primarily in meats and dairy products. Many of these foods also contain cholesterol. Cutting down on saturated fat means going easy on beef, veal, lamb, pork, beef and poultry fat, butter, cream, whole milk, and cheeses as well as other dairy products made from whole milk. Saturated fatty acids are also found in plant-based products, including palm and coconut oils and cocoa butter. The American Heart Association recommends that you limit your saturated fat intake to less than 10 percent of total calories each day. The less the better. This is a “bad” fat.

b.webber

Polyunsaturated Fats

These are typically found in the liquid oils that come from vegetables. Common sources include sesame, sunflower, and safflower oils; sunflower seeds; and corn and soybeans and their oils. Only the polyunsaturated fats are considered “essential,” meaning they cannot be manufactured by the body. Like minerals and vitamins, they must be ingested as food. If we don’t eat enough, then we won’t get enough. And that would be unfortunate, for these compounds—principally linoleic acid and linolenic acid— are vital to the maintenance of cell membranes and to the manufacture of potent chemical messengers that regulate everything from blood pressure to the firing of nerves.

When essential fatty acids are in short supply, the body compensates by substituting other types of fatty acids that have a less supple biochemical structure. As polyunsaturates are replaced by these other compounds, cell membranes become more rigid, leading to progressive hardening of the arterial walls. Polyunsaturated fats should make up 10 percent or less of your total daily calories. They are “good” fats.

I should also emphasize another type of essential polyunsaturated fat: omega- 3 fatty acids. These are found in fatty fish, like salmon, tuna, and trout, as well as in canola oil and flaxseed. Known as eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA, they help maintain and protect your heart, blood vessels, and brain function. Two fish meals a week will supply you with the right amount of these fats.

somos/veer

Monounsaturated Fatty Acids

Monounsaturated fats come from avocados and olive, canola, and peanut oils, as well as from nuts. For more than thirty- five years, studies have shown that diets containing monounsaturated fats, such as the traditional Mediterranean diet, are good for the heart. These fats can help lower cholesterol, blood pressure, and blood sugar levels.

The Mediterranean diet is moderately high in fat (about 30 percent of fat calories mostly from olive oil) and emphasizes fresh fruits and vegetables, whole grains, legumes, nuts, and a high intake of fish and little red meat. If your HDL (high- density lipoprotein, or “good”) cholesterol is low (35 or less), add a daily serving or two of canola or olive oil, nuts, avocado, or fatty fish (like salmon). In exchange, subtract a serving or two of sweets or refined bread, pasta, crackers, or cereal.

These “good” fats should make up about 15 percent of your total calories. Both polyunsaturated and monounsaturated fats are better than saturated fats because they may aid in lowering cholesterol. But remember they are fats and should still be used sparingly. They are not a license to add oil; their calories do count.

Trans Fats

One type of bad fat to eliminate entirely is trans fat, also known as partially hydrogenated vegetable oil. Trans fats are formed during a process called hydrogenation, which transforms liquid oil into shelf- stable solid fat. Trans fats clog arteries, and are found in many packaged cookies, crackers, snacks, and other processed foods.

Excerpted from:
Diet Myths That Keep Us Fat by Nancy Snyderman, M.D.
© 2009, Crown.

Get more weight-loss truths.