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food for thought

Selection of healthy unsaturated fats, omega 3 - fish, avocado, olives, nuts and seeds, selective focus.JulijaDmitrijeva/iStockPhoto / Getty Images

The health benefits of omega-3 fats, especially the ones in oily fish, are well reported. Studies suggest that higher intakes of these fatty acids guard against inflammation, heart disease, macular degeneration and, possibly, Alzheimer’s disease.

Omega-6 fatty acids, however, aren’t often talked about. And when they are, their health effects sometimes come with controversy.

Here’s a primer on omega-3 and omega-6 fatty acids – their health benefits, best food sources and how to get the right balance in your diet.

Omega-3 and omega-6 basics

Omega-3 and omega-6 fatty acids, types of polyunsaturated fats, are both necessary for building strong cell membranes and synthesizing compounds in the body that regulate blood pressure, inflammation and the proper functioning of our nervous system.

Omega-3s help prevent abnormal heart beats, improve blood-vessel function and, in higher doses, lower blood triglycerides (fats). DHA is especially high in the brain and retina, where it’s thought to protect vision and brain health.

There are three omega-3 fatty acids: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), found in fatty fish, and alpha-linolenic acid (ALA), found in plant foods such as flaxseeds, chia seeds, hemp seeds, walnuts, canola oil and soybeans.

Omega-6 fatty acids (there are four of them) are found in vegetable oils including corn, soybean, sunflower, safflower, sesame and canola. They’re common in fried fast foods and processed packaged foods made with vegetable oils. Nuts, seeds, tofu and eggs also contain omega-6s.

Omega-6s are needed to maintain healthy cells and play a critical role in the body’s immune and inflammatory responses. And some research suggests that higher intakes of one omega-6 fatty acid, linoleic acid (LA), may protect against heart disease and stroke.

Essential fatty acids

The body can make all the fatty acids it needs, except for two: omega-3 ALA and omega-6 LA. These are considered “essential” fatty acids that must be consumed from diet.

Daily intake guidelines, established by the U.S. based National Academy of Medicine, advise adults to consume 1.6 grams (males) and 1.1 grams (females) of ALA a day.

Excellent sources include flax oil (2.4 g per teaspoon), ground flax (2.3 g per tablespoon), chia seeds (2.5 g per tablespoon) and walnuts (2.6 g per 14 halves). Hemp seeds (0.9 g per tablespoon) and canola oil (1.3 g per tablespoon) are also decent sources.

When it comes to LA, adults ages 19 to 50 should get 17 g (males) and 12 g (females) from foods each day. Older men and women need 14 and 11 g a day, respectively.

One tablespoon of sunflower oil and an ounce of sunflower seeds each provide 10 g of LA. Other sources include sunflower oil (9 g per tablespoon), corn oil (7.3 g per tablespoon), soybean oil (7 g per tablespoon) and pecans (6.4 g per 20 halves).

Is too much omega-6 bad for you?

In the body, ALA and LA compete for the same enzyme in order to be converted into other molecules. The molecules made from LA are more inflammatory than the ones synthesized from ALA.

As a result, consuming a lot more omega-6 fats than omega-3 fats can tip the balance in favour of inflammation.

Some researchers have proposed that our North American diet, which contains at least 10 times more omega-6s than omega-3s, can lead to heart disease and other health problems. The right ratio of omega-3s to omega 6s in our diet, they say, is 1:4.

Yet, the exact ratio of omegas that’s associated with protection from heart disease isn’t known. Rather than worrying about consuming the right ratio of fats in your diet, many experts contend we should instead focus on consuming more omega-3 fatty acids. Sounds much easier to me.

Increasing omega-3s

Eat oily fish such as salmon, trout, Arctic char, sardines and mackerel at least twice a week. If you don’t eat fish, consider taking an omega-3 supplement made from fish oil or algae oil to get DHA and EPA.

To boost your intake of ALA, add a tablespoon or two of ground flax, chia seeds and/or hemp seeds to your daily diet. Consider adding a teaspoon of flax oil to smoothies or shakes.

Snack on a handful of walnuts, add them to hot cereal and toss them into salads and whole-grain bowls.

To shift the balance in favour of omega-3s, limit your intake of fried fast foods and packaged snack foods and baked goods made with vegetable oils.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD

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