There’s been dozens of risk-benefit analyses lately, looking at nutrient and contaminant tradeoffs. Fish consumption provides nutrients, but all fish also provide methylmercury, a known neurotoxin. The more fish you eat the more omega 3’s you get, but the more fish you eat the more mercury you get too. Mercury is a cardiac toxin as well. So while fish omega 3’s are decreasing your risk of a heart attack, the mercury in that same fish is increasing your risk of having a heart attack. So studies like this look through the various species. Salmon has less mercury than tuna, but tuna has less dioxin. The only truly healthy fish in the world would be some fanciful creature made out of dark green leafy vegetables.
Once upon a time, routine childhood vaccinations used a mercury-containing preservative called thimerisol. I was always amused by parents who fed their kids tuna—yet, didn’t want vaccinations because they didn’t want to expose their childlen to mercury. Eating a single serving of tuna is the equivalent to getting injected with how many thimerisol-containing vaccines? One… hundred! One serving of canned tuna.
Sure, dietary exposure to mercury may harm child development, but if you cut down on fish you may get less omega 3’s. So they get out their calculators. In a city about the size of New York, if pregnant mothers ate lots of fish, because omega 3’s like DHA are so beneficial to brain development one would expect to see an improvement in 209,000 years of children’s lives (what’’s called quality adjusted life years). But at the same time the mercury in that very fish would damage 203,000 of children’s life years. So they do the math, comes out positive by a hair and you hear on the news such and such medical authority says the benefits outweigh the risks, eat fish.
Now of course this doesn’t take into account the dioxins, PCBs, which tip the scale the other way, but more importantly: why accept any risk at all? By getting DHA from plant sources you can get all the benefit, with none of the risks. All the benefit without the hundreds of thousands of life years of brain damage.
This reminds me of the dairy and calcium thing. Every time they come out with yet another study linking dairy consumption with something bad, they get out of saying “stop drinking milk” by ending the article with “but one has to balance the risk of cancer, or diabetes or whatever with the risk of not getting enough calcium.” As if the only source of calcium on the planet were dairy—where do you think cow gets it from in the first place? Plants. And the same thing, with DHA. Where do you think the fish get it from? Plants, and we can too—little tiny plants called golden algae.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Dianne Moore.
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For more context, check out my associated blog post, Mercury Testing Recommended Before Pregnancy