Some nutritionists have suggested that the omega-3 fat DHA should be considered essential for humans. But DHA isn’t easy to get from the food supply. It’s found mostly in fatty fish, with smaller amounts in eggs and dairy. Over the past couple of decades, a diet high in DHA has been linked to improved heart health. It may also play a role in preventing depression, Alzheimers Disease, cancer and diabetes.
But where do you get DHA if you are vegan? Well, fish get their omega 3 fats by eating microalgae, and people can get them the same way. Research published in the Journal of the American Dietetic Association last year compared fish oil supplements to DHA from microalgae. They found that both were equally effective in raising blood levels of DHA in the subjects.
And it looks as though vegan sources of DHA may actually be the preferred source—if we need these supplements at all. A commentary in last month's Canadian Medical Association Journal spoke against recommendations to increase fish oil supplements. The authors noted that evidence for health benefits is not as convincing as many people believe. The most compelling evidence is for heart disease—but groups like vegetarians, who eat a heart healthy diet that does not contain fish, are already at low risk for this disease. It’s not clear that adding DHA to healthful diets is useful.
Most importantly, the authors noted that an increase in fish oil consumption is not sustainable in view of declining global fish stocks and the environmental damage associated with fish farms. Instead of relying on fish, they proposed that we need to develop more renewable sources of omega-3s from algae—the very sources that vegans already depend upon for DHA.
Source: Jenkins DJA et al. Are dietary recommendations for the use of fish oils sustainable? Canadian Medical Association Journal. March 17, 2009.