Ask the Dietician: Do We Need to Eat Fish?

Q: I just read a book that says vegans would be healthier if we started eating fish. Is that true? I hear about health benefits of fish all of the time.

Ginny Messina, R.D.: I read that book, too! And it definitely didn’t convince me that vegans need fish.

For a long time, we thought that fish could be an important source of vitamin D for humans. Since very few foods provide this nutrient (unless they’re fortified with it), this seemed like a unique benefit. But recent research suggests that the amount of vitamin D in fish varies a lot and that it’s not enough to meet vitamin D needs. You still need either sun exposure, supplements or fortified foods. So eating fish wouldn’t really change what you need to do in order to meet vitamin D requirements.

The bigger issue is that fish provides the long chain omega-3 fatty acids DHA and EPA. These are found in very few other foods. Our body can convert another fatty acid, called ALA, into these long chain fats, though. ALA is found in plant foods like walnuts (as in Scampi Pasta with Asparagus and Walnuts), canola oil and flaxseed meal. So technically, if we eat enough ALA, we can make DHA and EPA. The truth is that conversion is not especially efficient. So people who don’t eat fish tend to have lower blood levels of DHA and EPA.

But does it matter? That’s the big question. DHA and EPA may help protect against chronic disease but the research on this if very conflicting. And, even if they offer some protection, it’s not clear that people who are already eating a healthy vegan diet need that protection.

Many vegans do like to include DHA and EPA in their diets, though, so they use supplements of these fats that are derived from microalgae. And since this is exactly where fish get their DHA and EPA, it’s a perfectly reasonable and healthy way to get these omega-3 fats.

So skip the fish. Instead get vitamin D the same way the rest of the world does—through regular sun exposure or with a daily supplement providing 600 IUs. And consider a supplement that provides 300 milligrams of DHA and EPA combined two or three times per week.

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