There’s some confusion about the importance of omega-3’s in a vegan diet. On the one hand, vegans tend to eat fewer omega-3’s than diets that include animal foods, and have higher ratios of omega-6 to omega-3 fatty acids. On the other hand, vegans tend to have lower levels of the diseases that omega-3’s are often cited as preventing (heart disease, cancer, blood pressure, inflammation).
I think that vegans (and vegetarians) should make an effort to include omega-3’s in their diet for a few reasons:
- This is a conservative choice, as vegan omega-3 levels are lower than that of other healthy diets, and omega-3’s may have protective effects.
- Pescetarians sometimes outperform vegans in epidemiological studies. Omega-3’s are usually proposed as an explanation. (Some of this effect may be caused by B12 deficiency among vegans who do not supplement B12.)
- High ALA intake (the omega-3 fatty acid found in plants) is associated with over a 50% reduction in heart disease rates in multiple studies.
- There are (inconsistent) studies that suggest that LDL-lowering diets (but not LDL-lowering drugs) may be associated with higher levels of mental health problems. Some researchers suspect that lower levels of omega-3’s may explain this.
- Ex-vegans sometimes cite mental health issues as reasons they changed their diet. Even though some may be playing this up, we should take their claims seriously, and look out for ways to improve mood-altering aspects of our diet.
It’s worth noting that plant foods do not contain DHA or EPA, long-chain omega-3 fatty acids. There is good evidence that ALA (the common vegan omega-3 fatty acid, found in flax seeds, chia seeds, canola oil, walnuts, etc.) is converted efficiently to EPA, so I’m not convinced that vegans need to be concerned about EPA specifically, and I’ll focus on DHA.
DHA is important in neurological development, especially in prenatal and early childhood development, and in old age. Breast milk from vegan mothers contains less than half the DHA than that of omnivore mothers. Difference in DHA intake may explain some of the subtle ways in which breastfed children tend to outperform formula-fed children. (Note: some formulas contain DHA now, and you can always add supplemental DHA if breastfeeding is not an option.)
Higher DHA levels also correlate with lower rates of neurodegenerative disease like dementia, and vegetarians have less DHA than non-vegetarians. I think we should pay attention to this, even though vegetarians have less dementia than non-vegetarians. The rate could be even lower for DHA-supplementing vegans.
For comprehensive recommendations about omega-3’s, see VeganHealth.org.
The summary is this — until we know more, it would be wise for vegans to take a vegan DHA supplement a few times a week. If you’re an elderly, pregnant or breastfeeding vegan, then a daily supplement is probably best. I’d also recommend supplementing infants, especially if they are not breastfed.
It is also probably wise to include some dietary source of omega 3’s (which will be ALA for plant foods) on a daily basis.
I’ll follow up with more about how I’ve gone about doing the latter myself.