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Omega-3: Fishy claims for fish oil

interns Contributor
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IF I told you that one cheap pill could boost your brain power, protect you from heart disease and cancer, and even alleviate depression, all with no known side effects, would you want it? Who wouldn’t?

You’ve probably heard of the pill’s main ingredient: omega-3, a substance found in fish oil and other natural products (see diagram). If the flood of headlines and adverts from food and supplement manufacturers are to be believed, you need only boost your intake of omega-3 and all these benefits will be yours.

Omega-3 supplements first appeared in the early 1980s. Given they are still going strong 30 years later, you would be forgiven for thinking that claims of their beneficence have all been substantiated. Yet several new studies, as well as recent reviews of existing evidence, call this received wisdom into question. So before you splash out on supplements and food fortified with extra omega-3 it might be worth taking a closer look at the evidence. Do any of the claims stand up under scrutiny?

Omega-3 is the name of a family of fatty acids made of chains of carbon atoms of varying length. They cannot be synthesised in the human body, and so must be obtained from our diet. Three members of the family are particularly important to human health. Short-chain alpha-linolenic acid (ALA) is a key molecule found abundantly in green leafy vegetables, walnuts and flax (linseed), rape (canola) and soybean oil, broccoli and algae. It is the vital precursor molecule that gets converted by all mammals into two important long-chain relatives in the omega-3 family, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

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