New Study Links Seafood With High Levels of Mercury to ALS
A new study presented at the 2017 Annual Meeting of the American Academy of Neurology suggests a link between eating fish high in mercury and ALS, also known as Lou Gehrig’s Disease. ALS is a disease that causes progressive damage to the nuerons that control voluntary muscle movements leading to atrophied muscles that make movement, speaking, eating and eventually breathing difficult.
The study surveyed 518 people – 294 of whom had ALS and 224 who didn’t – and recorded their seafood intake. Those in the top 25% of eating mercury rich fish were nearly twice as likely to have ALS and 61% of those who had ALS were in the top quarter of estimated mercury intake.
What Fish Are High in Mercury?
While this study in itself isn’t a smoking gun, when added to the growing body of evidence that levels of mercury in fish are increasing, we need to be sure that we are making educated decisions about the fish that we eat.
There are 2 things that you need to know about mercury in fish. The first is that mercury biomagnifies which means that fish at the bottom of the food chain and that have shorter lives will have less mercury than fish at the top of the food chain or have longer lifespans. You can see a full list here of the most contaminated seafood but here is a short list.
Seafood with Low Amounts of Mercury
Seafood with Moderate Amounts of Mercury
Seafood with High Amounts of Mercury
The second thing you need to know is that there is also a small but growing opinion in the scientific community that eating fish high in selenium will offset the harmful effects of mercury. Selenium is an important mineral that helps the brain clear out the toxic Reactive Oxygen Species (ROS) formed in the brain as the cells in the brain resperate. The mercury binds with the selenium, preventing it from doing its important job. Eating fish higher in selenium ensues that there is enough selenium left over after all the mercury has bound with it.
The best thing to do is to eat fish lower on the food chain that has been wild caught as that seafood tends to have more selenium than farm-raised seafood. You can also supplement your selenium or try to eat other foods high in selenium like Brazil Nuts, seeds, beef liver, spinach and eggs.
Sometimes when a new study like this comes out, the knee jerk response is to just swear off seafood but seafood is an important component of any healthy diet but especially a keto/Paleo diet. After all, remember that seafood was probably our first diet as mankind evolved mainly around large bodies of water. We have been designed to need the nutrients that seafood provides. Just be smart; limit your exposure to mercury and maximize your exposure to the selenium that protects you and you will be fine.