Omega 3

Long before the FDA said Omega three might be a healthy thing to consume, there was much talk about the potential value of increasing our intake of Omega 3 fatty acids.

In 2004 the FDA issued a "qualified health claim" for two types of omega-3 fatty acids (eicosapentaenoic acid - EPA and docosahexaenoic acid - DHA). The FDA report said "there is supportive but not conclusive research to show that these fatty acids are beneficial in reducing the risk of coronary heart disease."(1)

The American Heart Association had been reporting the benefits of omega-3 since 1996. The Science Advisory report was titled "Fish Consumption, Fish Oil, Lipids and Coronary Heart Disease". Then in 2002, the AHA released a new report indicating how omega-3 reduced the risk of cardiovascular disease. It said omega-3's make the blood less likely to form blood clots that cause heart attacks and protect against irregular heart beats that cause sudden cardiac death.

In addition to that finding, it was also found that omega-3 decreases triglyceride levels as effectively as any cholesterol medication and lowers blood pressure slightly.

What are essential fatty acids?

Essential fatty acids are polyunsaturated fatty acids that the human body needs for metabolic functioning but cannot produce and therefore had to obtain from food.

What are omega-3 fatty acids?

Omega-3 fatty acids are a class of essential polyunsaturated fatty acids. Omega-3 fatty acids are found in food such as anchovies, bluefish, carp, catfish, halibut, herring, lake trout, mackerel, pompano, salmon, striped sea bass, tuna (albacore), whitefish, walnuts, flax seed oil and canola oil.

There are six main types of omega-3 fatty acids:

EPA and DHA seem to offer the most benefits. Fish oil contains both of these fatty acids. That is why it is recommended to eat certain fish at least twice a week.

Alpha-linolenic acid is found in flax seed, olive oil, soy bean, lin seed and certain nuts.

Do you have to eat fish in order to get omega-3?

No, you can also get omega-3 from other sources like:

How much omega-3 should you consume?

The AHA suggests people with coronary heart disease should consume a gram of EPA and DHA each day, preferably  from fatty fish.

People without coronary heart disease should eat fatty fish at least twice a week. They should also eat foods rich in alpha-linoleic acid such as flax seed, canola oil, soy beans and walnuts.

It is recommended that no one should consume more than three grams of omega-3 a day. No more than 2 grams should come from a dietary supplement.

How much fish would you have to eat to exceed 3 grams?

You would have to eat about 640 grams of cod to get one gram of EPA and DHA. But it would only take about 55-85 grams of sardines and between 55-235 grams of mackeral to reach one gram. It would take five grams of cod liver oil.

What about contamination of the fish?

Certain species of fish can be high in levels of mercury or PCB's. These tend to be older, predatory fish who are higher in the food chain. Health Canada has issued guidelines on shark, swordfish and tuna. Pregnant woman and children should eat no more than one meal a month of these fish.

What are the risks from consuming omega-3 fatty acids?

If you do consume more than 3 grams a day your risks could be:

Omega-6 to omega-3 consumption

The average American consumes about 1.6 grams of omega-3 fatty acids each day, of which about 1.4 grams (~90%) comes from linolenic acid, and only 0.1-0.2 grams (~10%) from EPA and DHA. In Western diets, people consume roughly 10 times more omega-6 fatty acids than omega-3 fatty acids. These large amounts of omega-6 fatty acids come from the common use of vegetable oils containing linoleic acid (for example: corn oil, evening primrose oil, pumpkin oil, safflower oil, sesame oil, soybean oil, sunflower oil, walnut oil, and wheat germ oil). Because omega-6 and omega-3 fatty acids compete with each other to be converted to active metabolites in the body, benefits can be reached either by decreasing intake of omega-6 fatty acids or by increasing omega-3 fatty acids.(2)

Links:

Footnotes:

(1)Omega-3 Fatty acids your heart loves - CBC News January 15, 2007

(2)Omega-3 fatty acids, fish oil, alpha-linolenic acid - Mayo Clinic Drugs