Foods high in omega-3-fatty acids include salmon, halibut, sardines, albacore, trout, herring, walnut, flaxseed oil, and canola oil. (CBC)
There had been a lot of buzz about the benefits of eating fish long before September 2004, when the U.S. Food and Drug Administration raised the profile of omega-3 fatty acids by saying they're really good for your heart.
At the time, the FDA issued a "qualified health claim" for two types of omega-3 fatty acids — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — concluding that "there is supportive but not conclusive research to show that these fatty acids are beneficial in reducing the risk of coronary heart disease."
The American Heart Association, however, had been touting the benefits of omega-3 since 1996, when it released its Science Advisory, "Fish Consumption, Fish Oil, Lipids and Coronary Heart Disease." Six years later, the AHA released new information on how omega-3 fatty acids reduce the risk of cardiovascular disease. The report found that they make the blood less likely to form clots that cause heart attacks and protect against irregular heartbeats that cause sudden cardiac death.
In addition, omega-3 was also found to decrease triglyceride levels — as effectively as cholesterol medication — and lower 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 has to be acquired from food.
What are omega-3 fatty acids?
Omega-3 fatty acids are a class of essential polyunsaturated fatty acids. Foods high in omega-3-fatty acids include salmon, halibut, sardines, albacore, trout, herring, walnut, flaxseed oil, and canola oil.
There are six main types of omega-3 fatty acids:
- Alpha-linolenic acid (ALA).
- Stearidonic acid.
- Eicosatetraenoic acid.
- Eicosapentaenoic acid (EPA).
- Docosapentaenoic acid.
- Docosahexaenoic acid (DHA)
EPA and DHA seem to offer the most benefits to people and fish oils contain both, which is why health officials have recommended that most people eat certain types of fish twice a week.
I don't like fish. Are there other ways of getting enough omega-3 fatty acids?
Yes, there are fish oil supplements — omega-3 in a pill. Flax is another good source of omega-3 fatty acids, as is flaxseed oil. Some breads contain flax, making them a source of omega-3.
As well, some eggs have been developed to contain higher levels of omega-3 fatty acids. They're produced by altering the diets of laying hens so their feed contains 10-20 per cent ground flaxseed.
How much omega-3 should I consume?
The American Heart Association recommends that people who show no signs of coronary heart disease (CHD) should eat fish — preferably fatty fish — at least twice a week as well as food rich in alpha-linolenic acid, such as flaxseed, canola and soybean oils and walnuts.
People with documented cases of CHD should consume about a gram of EPA and DHA per day, preferably from fatty fish. Getting it from capsule form could be considered in consultation with a physician.
However, people should not consume more than three grams of omega-3 fatty acids, with no more than two grams coming from a dietary supplement.
Three grams doesn't sound like much. How much fish would I have to eat to meet that requirement?
To get one gram of DHA and EPA, you would have to consume about 640 grams of cod — but only 55 to 85 grams of sardines. You'd have to consume between 55 and 235 grams of mackerel.
Or, you could have five grams of cod liver oil.
Aren't fish susceptible to high levels of contamination?
Some species of fish can contain higher levels of mercury or PCBs than health officials would like to see. These tend to be older, predatory fish high up on the food chain. Contaminants can collect in fatty parts of their bodies. Health Canada has issued guidelines on the consumption of fish like shark, swordfish and fresh and frozen tuna. Pregnant women and children should limit their consumption of these types of fish to one meal per month.
Are there any risks associated with omega-3 fatty acids?
Only if you consume too much — more than three grams a day. Risks include:
- Increased bleeding.
- The possibility of hemorrhagic stroke.
- Increased levels of low-density lipoproteins (LDL or bad) cholesterol or apoproteins associated with LDL cholesterol among diabetics and hyperlipidemics.
- Reduced glycemic control among diabetics.
- Suppression of immune and inflammation responses leading to increased susceptibility to opportunistic bacteria.
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- Heart foundation urges action to cut fat
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- Ontario baker to shelve trans fats
- Nov. 25, 2003
- Omega-3
- Benefits outweigh the risks
- Fish diet outweighs defibrillators for preventing deaths, model shows
- Fish oil could help fight depression
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External Links
- TRANSforming the Food Supply
- Canadian Heart and Stroke Foundation - Trans Fats
- International Food Information Council: trans fats
- Statistics Canada: Canadian Community Health Survey: Obesity among children and adults
- Adult Obesity in Canada: Measured height and weight
- Laval University research chair on obesity
- Health Canada: Family guide to physical activity for children
- A parent's guide to healthy eating and activity
- International Food Information Council: trans fats
- Web MD: trans fats
- Surfwax.com: articles on trans fats
- Omega-3:
- American Heart Association
- Omega-3 fatty acids: the Mayo clinic
- U.S. Food and Drug Administration
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