Although eating fish confers some health benefits, a growing body of evidence suggests there's less support for the value of fish oil supplements.
Oily fish such as salmon, trout and herring are excellent sources of omega-3 fatty acids, which are associated with protective effects on the heart.
Years of research studies have tested whether omega-3 fatty acid supplements such as fish oil are also beneficial.
This week, researchers who looked at heart surgery patients who took fish oil supplements before and after the procedure said that taking the supplements didn't seem to help patients heal better.
Investigators in the U.S. randomly assigned 1,516 patients scheduled for cardiac surgery in the U.S., Italy and Argentina to take one-gram capsules containing omega-3 fatty acids or a placebo of olive oil before and after their procedure, such as valve replacement.
They hoped to reduce post-operative atrial fibrillation or flutter (AF), an irregular heartbeat that occurs in about one in three patients undergoing cardiac surgery.
"Our findings provide no evidence that short-term omega-3-[polyunsaturated fatty acids] supplementation provides clinically relevant antiarrhythmic effects in the acute setting of cardiac surgery," Dr. Dariush Mozaffarian of the Harvard School of Public Health in Boston and his co-authors concluded in the Journal of the American Medical Association.
Participants took fish oil capsules containing at least 840 millligrams of long-chain omega-3 polyunsaturated fatty acids (PUFAs), a prescription strength of the supplements.
Fish versus supplements
The total number of days in the intensive care unit or coronary care unit were about the same in both groups.
The study is the latest to question the benefits of supplements and fortification, an industry worth an estimated $25 billion globally in 2011.
"It may be something else that's in the fish that's providing the benefits because fish have all sorts of minerals and other ingredients that are healthy," said Dr. Andreas Wielgosz, a cardiologist in Ottawa and a spokesperson for the Heart and Stroke Foundation.
"It may be that when you eat fish you eat less saturated foods. The exact answer isn't known but what we can say is natural source is better than supplements."
Two other research papers earlier this year found the supplements don't reduce heart attacks or strokes in people at high risk for them, and they don't prevent cognitive decline or dementia in healthy older people.
Although the initial study on the heart benefits of fish oil capsules in the late 1990s showed a reduction of 45 per cent in sudden cardiac death, use of medications like statins has increased dramatically since then, said Ken Stark, a professor of applied health sciences at the University of Waterloo who studies the metabolism of polyunsaturated fatty acids.
The use of medications could be masking benefits conferred by omega-3.
"This isn't to say omega-3s aren't working,” said Stark.
People tend not to keep taking the supplements, based on their blood levels, and the dosages have been lowered over the last 20 years, he added.
"We're suddenly giving 500 milligrams in some of these clinical studies when the Japanese are eating two grams per day."
Stark's laboratory research suggests that anti-inflammatory properties of omega-3s could help treat or prevent arthritis or eye disease, although those ideas haven't been tested in high-quality trials.
Fish oil flip
Dr. Hertzel Gerstein of the Population Health Research Institute at McMaster University in Hamilton cautions there could be an indirect harm from taking supplements instead of medications such as statins or lowering blood pressure.
"If people are taking a medication for which there is no good evidence … [and] they’re not taking proven medications, then that actually can put them at harm."
When omega-3 supplements were actually tested in clinical trials, they didn't pan out, Gerstein said.
For the most part, omega-3 supplements don't cause side-effects, though some people complain of a fishy smell or nausea from taking high doses, Gerstein added.
Janet Torge of Montreal used to spend $250 a month on supplements recommended by a naturopath. Torge recalled reading that omega-3s were supposed to help prevent dementia, so she added the supplements to her regimen. But later she gave up supplements in favour of watching what she eats more closely.
"I think the lesson is that you go with healthy living, like the basics," said Torge.
Gerry Harrington is director of public affairs for Consumer Health Products Canada in Ottawa, which represents the makers, marketers and distributors of vitamins, diet supplements and other health products.
"I think the challenge is for people to be able to take each individual study into context and realize that it's an ongoing process and the miracle vitamin one year may be much less attractive next year," said Harrington.
Harrington acknowledged contradictory research findings are confusing and frustrating for people who are trying to make healthy choices. He suggested that people talk to their pharmacist before taking supplements.
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Flaxseed Or Flaxseed Oil
Flaxseed is one of the most highly-recommended plant sources for omega-3s. Ground flaxseed is a staple in my kitchen -- it keeps for a long time in the freezer, and because flaxseed is virtually tasteless, I throw it in all sorts of things -- cereal, oatmeal, smoothies -- to boost my omega-3 intake. You can use ground flaxseed goo as an egg substitute in vegan baking. Flaxseed oil has <a href="http://www.krispin.com/omega3.html#Supplementing" target="_hplink">7980 mg omega-3's per 1-tbsp serving</a>. <strong>More from Blisstree.com:</strong> <a href="http://blisstree.com/move/best-fitness-trackers-similar-to-the-nike-fuel-band-658/" target="_hplink">The Best Fitness Trackers</a> <a href="http://blisstree.com/eat/supplements/which-is-better-krill-oil-or-fish-oil-841/" target="_hplink">Krill Oil vs. Fish Oil</a> <a href="http://blisstree.com/feel/eat-for-your-teeth-omega-3s-could-prevent-gum-disease/" target="_hplink">Eat for Your Teeth: Omega 3s Could Prevent Gum Disease</a> <em>Flickr photo by <a href="http://www.flickr.com/photos/alishav/3462217890/" target="_hplink">Alisha Vargas</a></em>
Chia seeds are another plant source of omega-3's that I like to sneak into my diet. You can throw chia seeds into stir fry, salads, seitan, dips and more. Like ground flaxseed, chia seeds have a mild -- if any -- taste. But they'll add a dose of omega-3's and a slight crunch wherever they're added. <em>Flickr photo by <a href="http://www.flickr.com/photos/notahipster/4998594527/" target="_hplink">little blue hen</a></em>
Vegan and gluten-free, hemp seeds also have the most essential fatty acids of any nuts or seeds and a perfect 3:1 <a href="http://today.msnbc.msn.com/id/16637630/ns/today-food/t/nutty-hemp-hot-food-trend/" target="_hplink">ratio of omega-3 to omega-6</a>. They're also high in protein, minerals and rare polyunsaturated fatty acids like gamma-linolenic acid (GLA) and stearidonic acid (SDA). Like flax and chia seeds, you can sprinkle hemp seeds into lots of different things. Store in the freezer to keep them from going bad. <em>Flickr photo by <a href="http://www.flickr.com/photos/restlessglobetrotter/3425782783/" target="_hplink">Jason Rogers</a></em>
Perilla oil comes from the seeds of the herb perilla. Over 50 percent of perilla oil consists of ALA, with about <a href="http://www.krispin.com/omega3.html#Supplementing" target="_hplink">8960 mg omega-3 fatty acids</a> per tablespoon (compared to 1680 mg omega-6's).
"Many people are not aware that cauliflower contains a good amount of omega-3 essential fatty acids, making this veggie great for heart health," says nutritionist Margaux Rathbun. "In addition to the omega-3, cauliflower contains other heart-friendly nutrients including potassium, magnesium and niacin." <a href="http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2390/2" target="_hplink">One cup contains about 37 mg of omega-3's</a>. To retain the nutrients in cauliflower, Rathbun recommends steaming it for no more than five to six minutes, then adding lemon juice and cold-pressed extra-virgin olive oil. <em>Flickr photo by <a href="http://www.flickr.com/photos/wordridden/4626951567/" target="_hplink">Jessica Spengler</a></em>
"Hummus is a vegan source of omega-3's," with about 300 mg in a one-cup serving, explains Charis Freiman-Mendel, author of "Cook Your Way Through the S.A.T.". That's because hummus is made with tahini, which is made from omega-3-packed sesame seeds. "Delicious, healthy, great brain food," says Freiman-Mendel. <em>Flickr photo by <a href="http://www.flickr.com/photos/alga/3122887625/" target="_hplink">Albertas Agejevas</a></em>
Purslane is a salad or cooking green with a slightly peppery taste. It's got <a href="http://www.health.com/health/gallery/0,,20487719_5,00.html" target="_hplink">400 mg of omega-3's per serving</a>. It's also high in <a href="http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2604/2" target="_hplink">vitamin A</a>, calcium, potassium and iron.
One serving of Brussels sprouts contains about 430 milligrams of alpha-linolenic acid -- more than one-third of the <a href="http://www.nal.usda.gov/fnic/DRI//DRI_Energy/energy_full_report.pdf" target="_hplink">daily ALA amount recommended</a> by the National Academy of Sciences. "These tasty little green veggies are loaded with nutrients, including omega-3 fatty acids," says nutritionist Margaux Rathbun. "They're the perfect food for promoting healthy and beautiful skin. Try steaming them for about five minutes to keep all of the health-promoting nutrients intact." <strong>More from Blisstree.com:</strong> <a href="http://blisstree.com/move/best-fitness-trackers-similar-to-the-nike-fuel-band-658/" target="_hplink">The Best Fitness Trackers</a> <a href="http://blisstree.com/eat/supplements/which-is-better-krill-oil-or-fish-oil-841/" target="_hplink">Krill Oil vs. Fish Oil</a> <a href="http://blisstree.com/feel/eat-for-your-teeth-omega-3s-could-prevent-gum-disease/" target="_hplink">Eat for Your Teeth: Omega 3s Could Prevent Gum Disease</a> <em>Flickr photo by <a href="http://www.flickr.com/photos/39975765@N05/6399983389/" target="_hplink">Mallory Dash</a></em>