The Albacore tuna and the methylmercury dilemma
Albacore tuna, commonly sold as solid white tuna, is a fishy quandary. You can walk into almost any grocery store in the U.S. and find several canned varieties of Albacore tuna on the shelves, and if you’re visiting a specialty (read: fancy) grocery store it may even be the only tuna option available thanks to its premium price point. The problem with Albacore is that it is a large predatory fish, meaning it eats smaller fish, who ate smaller, who ate smaller fish and so on… and all these fish contain some amount of methylmercury. This is due to mercury pollution in most of our waterways, which then all piles up in the fatty tissue of the large Albacore. And when you enjoy that tuna salad sandwich at lunch, you’re bound to ingest some amount of this toxic chemical. But let’s see how the heck we got to a point where this toxin is overly abundant in the Earth’s waters, shall we?
Mercury is released into the air from human activities, in the U.S. the main culprits for mercury emissions are coal-burning power plants, which are a highly political subject. Marion Nestle, NUY Professor of Nutrition and Public Health, concisely sums up the topic in her astonishingly great book What to Eat:
“During the 1990s President Bill Clinton imposed rules that reduced mercury emissions from most other industries- except power plants. In 2000, with the environment-friendly vice president Al Gore running for president, the EPA decided to take on this last remaining source and ruled that power plant emissions violated the Clear Air Act. In 2003, however, Bush administration appointees at the EPA reversed that decision.”
In 2011, under President Obama, the EPA released Mercury and Air Toxics Standards, placing caps on mercury emissions from fossil fuels, including power plants. The Trump administration plans to roll back this decision, claiming the emission caps to be too costly. And so the mercury saga continues.
When mercury emissions from the air get into water it turns into methylmercury. This chemical is a neurotoxin for humans, and at extreme doses, such as those suffered by the citizens of Minamata, Japan from the 1930s until the 1960s due to the Chisso Corporation’s reckless dumping of methylmercury, it causes severe “seizure disorders, cerebral palsy, blindness, and deafness” to children exposed to the methylmercury in the womb. A study found that “At much lower doses that result from chronic maternal fish consumption, infants might appear normal during the first few months of life but might later display … IQ deficits, abnormal muscle tone, decrements in motor function, attention, and visuospatial performance.”
So, clearly, methylmercury is a massive problem. But let’s explain why it’s especially problematic with Albacore tuna. Since 1994 the FDA has issued seafood safety advisories in relation to mercury contamination, the latest advisory is from 2017 and it lists Albacore tuna as “Good Choice, eat one serving a week.” Bigeye tuna, however, is listed as “Choices to Avoid” by the FDA. You should always avoid Bigeye tuna, not only due to mercury, but because it is highly endangered. But when it comes to the mercury content, Albacore belongs in this same category as Bigeye since both of these species are large predatory fish. Then why is Albacore so prevalent? The answer is simple: lobbying. Tuna industry lobbyists work hard to keep Albacore on the shelfs and on the ‘Good Choice’ FDA advisory list.
In 2001, the FDA concluded, based on the results of focus group studies conducted by the agency, that if women were given more detailed information about which fish should be avoided or eaten only in moderation during pregnancy they would stop eating fish altogether. Thankfully the Environmental Working Group (EWG) felt there was more to the story and filed a Freedom of Information Act to obtain transcripts from these focus groups. From these transcripts the EWG found that “the word-for-word account of focus group discussions flatly contradicts” the FDA’s conclusion. The EWG also notes that in 2000, while the FDA was crafting the language for the mercury advisory, they took three meetings with several of the biggest names in consumer tuna — Chicken of the Sea, StarKist, Bumble Bee, U.S. Tuna Foundation, and National Food Processors Association. Although the original advisory drafts contained warnings for pregnant women about mercury in tuna, the final product had no mention of tuna at all, and set no limits to Albacore consumption, and that’s good ‘ol lobbying in action. However, in 2004, the FDA and EPA set the limit for Albacore to 6oz a week - which is about the size of your palm. The current serving size is 4oz a week, which is progress, even if it is progress at a snail’s pace.
While tuna is certainly a great source of nutrients like selenium, vitamin B-12, and omega-3 fatty acids, there are great differences between the best and worst choices of species. Skipjack tuna is the fish known in cans as light chunk— it’s a smaller tuna species that’s still abundant and not only is it less expensive, but also hoovers up less ocean critters and thereby gathers less methylmercury into itself. Skipjack is also listed as “Best Choices eat 2 to 3 servings a week” on the FDA advisory, although it is written out as “tuna, canned light (includes skipjack)”, which puts the responsibility on the consumer to figure out what other types of tuna might belong in this ‘Best Choices’ category.
This is all to say that it is worth your while to compare those tuna cans at the store and make informed choices to promote your health instead of corporate interest, especially if you are or are hoping to become pregnant. The silver lining to this issue is that methylmercury’s half-life is two to three months, which means that if you were to stop consuming anything containing methylmercury today, it, along with its side effects, would disappear from your system within a year.