It's chuck full of protein, inexpensive, lasts forever and easy on the hips. We're talking canned tuna of course, and while you may be familiar with warnings to eat it in moderation, now the fresh kind is also under scrutiny.
Why? In a nutshell, mercury.
What's happening? Why now?
Just when you thought the fresh kind was okay, a report by the New York Times calls it into question. In a top-read story this week, "High Mercury Levels Are Found in Tuna Sushi," the NYT says lab tests run on fresh tuna sold at 20 different sushi outlets in Manhattan showed high levels of the neurotoxin mercury.
Specifically, the report says eating just six pieces of sushi from most of the places contained about the same amount of mercury that the Environmental Protection Agency considers suitable for a 154-pound adult to eat in a week.
The report says much of the fish tested was bluefin tuna.
Separately, the conservation group Oceana issued its own report on Wednesday, saying mercury levels in fish they tested nationwide exceeded levels the FDA considers safe to sell.
What does mercury do and how does it get in the fish?
Mercury is tied to a number of health issues, including vision impairment, memory loss and cardiovascular problems. But the biggest concern is for pregnant women, women planning to become pregnant, and children because mercury, as the EPA's site puts it, "can adversely affect a baby's growing brain and nervous system."
Methylmercury enters the environment through pollution from coal-powered plants. The older and bigger the fish, the more mercury it accumulates. Hence one reason why the bluefin tuna may be high in mercury—it can be huge, stretching 12 feet long, weighing over 1,000 pounds, and living 30 years. Watch how mercury gets into fish.
How much fish should you eat?
There are of course many health benefits to eating fish. However, the FDA and EPA agree high-risk groups (women and children) should limit their weekly fish intake to 12 ounces. This includes canned tuna, and the EPA suggests eating no more than 6 ounces of the albacore kind. The advisory says to not eat shark, swordfish, king mackerel and tilefish (whatever that is!) at all.
The big picture
It's a bad time to be a bluefin tuna. Recent reports say the fish is being depleted as sushi appetites explode worldwide. Last September Europe banned fishing for bluefin through the end of the year. And while fishing groups deny mercury's threat, other groups are pushing for stricter consumption guidelines. Eating fish, however, is just part of the issue; emission laws are another big piece. So for now it seems, enjoy that tuna—just not too much of it!
Love that tuna? Try the tuna calculator.
Ordering out? Download the Seafood Watch pocket guide.
One point we wanted to make is that in both of the tests we mention they found other kinds of tuna to be lower in mercury, such as yellowfin. The full Oceana report shows what they tested and they found fish from the Philippines and other places to be lower in mercury. (Shipping the fish seems to open a whole other can of worms.) But point being, it's probably a case by case basis and if anything there may be a need for better testing--either by private companies or the government. Here's the Oceana report. The tested fish in 23 cities.
http://www.oceana.org/fileadmin/oceana/uploads/mercury/Hold_the_Mercury/Hold_the_Mercury_Final.pdf
Posted by: Stacey | January 25, 2008 08:18 AM
Though I appreciate your reference to Japan's Fisheries Agency - because no country knows more about healthful diets rich in fish than Japan - I wanted to clarify that the Fisheries Agency is a regulatory government body, not a "fishing group."
Others have come out describing the potential public health consequences of the recent media-induced fish scare. I believe Dr. Dariush Mozaffarian, assistant professor of medicine and epidemiology at Harvard Medical School and the Harvard School of Public Health, said it best in TIME Magazine on Thursday, Jan. 24, 2008 (http://www.time.com/time/health/article/0,8599,1706623,00.html?iid=336x280_ad3).
"I know I sound like I'm trying to downplay the risk but I really think we are experimenting with people's lives when we give recommendations or write stories or reports that make people eat less fish. We know from very good human studies that fish intake reduces the risk of dying from a heart attack by about a third. And heart attack is the number-one cause of death in the U.S. among both women and men. It's the number-one cause of death in almost every country in the world. And eating fish once or twice a week reduces that risk by a third. So if we're causing people not to eat fish or to choose to eat something other than fish because they're worried that the fish has some mercury in it, they're increasing their risk of dying from a heart attack for a concern that has not been established."
Dr. Mozaffarian is co-author of one of the most comprehensive studies to date on the impact of fish consumption on human health. Articles published in the Lancet, February 2007 and the Journal of Nutrition, December 2007 came to a similar conclusion as his -- giving or following advice to limit fish consumption could be detrimental.
To that point, I feel it is important to remind your readers that - all things considered - major health authorities including the American Dietetic Association, American Heart Association and U.S. Dietary Guidelines recommend that for optimal health people eat a variety of seafood at least twice per week.
Sincerely,
Jennifer Wilmes, MS, RD
National Fisheries Institute
Posted by: JWilmes | January 27, 2008 05:54 AM