The question: I'm a vegetarian. How can I get omega-3s in my diet without eating fish?
The answer: As a vegetarian, you'll want to ensure you meet your daily requirements for alpha linolenic acid, or ALA, a plant-based omega-3 fatty acid. It's plentiful in flaxseeds, chia seeds, hemp seeds, walnuts, soybeans and soy products. The other two omega-3 fatty acids – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) – are found in oily fish and fish oil supplements. Even if you don't eat fish, however, you can still get DHA in your diet.
The three types of omega-3 fatty acids are metabolized differently in the body and, as a result, can have different effects in cells. Studies have found that higher intakes and higher blood levels of DHA and EPA helps protect from heart disease, heart attack, Type-2 diabetes, macular degeneration, arthritis, Alzheimer's disease, depression and possibly some types of cancers. It's DHA that has the most potent health benefits in the body, particularly in the brain.
ALA has health benefits too. There's some evidence that higher intakes of ALA guard against heart disease and stroke, although the data isn't as compelling as that for DHA and EPA. Research also suggests consuming more ALA lowers the risk of Type-2 diabetes. It's thought that ALA, more so than DHA and EPA, helps improve how the body uses insulin, the hormone that clears sugar from the blood stream.
Once consumed, ALA is converted to EPA, which is then converted to DHA. Unfortunately, our bodies are unable to convert very much ALA to EPA and DHA. In order to maximize this conversion, you need to include good sources of ALA in you diet everyday.
Women need 1,100 mg of ALA each day and men require 1,600 mg. The very best food sources are as follows: flax oil (1 tsp = 2,400 mg ALA), ground flaxseed (1 tbsp = 1,200 mg), shelled flaxseed (e.g. Omega Crunch, 1 tbsp = 2.2 mg), chia seeds (1 tbsp = 1.8 mg) and walnuts (7 halves = 1,280 mg). Walnut oil, hemp seed oil and hemp beverages are also good sources of ALA.
Provided you're getting enough ALA every day, your body will be able to convert more ALA to EPA. However, research suggests that supplementing your diet with ALA doesn't increase the level of DHA in the blood. And remember, it's DHA that's so important for the proper functioning of your brain as an adult.
For this reason, I advise vegetarians to get a direct source of DHA from a supplement made from algae. Take 200 to 400 mg of algae-based DHA per day. Fish are actually the middlemen when it comes to delivering DHA. They get their DHA by eating microscopic algae, which produce it.
Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto. She can be seen every Thursday at noon on CTV News Channel's Direct; lesliebeck.com.