Salmon, tuna, and other fish are loaded with heart-healthy omega-3 fatty acids, so they must be good for you, right? Not so fast—some types of fish have more mercury than others, and others are harvested from the ocean or farmed in a way that’s harmful to the environment.

Now, a new list has come to the rescue: It sorts through the confusion by rating fish in terms of levels of omega-3 fatty acids, mercury and other toxins, and in terms of their sustainability or ocean-friendly status.

Other lists have looked at one or two of the factors, but ocean-conservation advocates at the Monterey Bay Aquarium, in California, looked at all three, including whether fish are caught faster than they can reproduce (overfished) or in ways that have a negative impact on the ocean. They included eight types of seafood on a “super green” list after working with researchers at the Environmental Defense Fund and the Harvard School of Public Health.

The list includes albacore tuna—as long as it is troll- or pole-caught and from the United States or British Columbia. Troll-caught fish are lured using a hook and line towed behind or alongside a boat. It is considered an environmentally friendly technique because unwanted fish are released soon after the line is reeled in.

Farmed mussels, farmed oysters, wild-caught Pacific sardines, wild-caught pink shrimp from Oregon, wild-caught salmon from Alaska, wild-caught spot prawns from British Columbia, and farmed rainbow trout are also on the list of healthful, sustainable fish.

All fish on the list have relatively low levels of mercury and other contaminants, and relatively high levels of omega-3 fatty acids, according to government databases and peer-reviewed scientific studies. A second list (with slightly lower omega-3 fatty acids but low levels of contaminants) includes farmed Arctic char, farmed bay scallops, and farmed crayfish, among others.

Floss every day
What do loving licorice and hating the idea of flossing have in common? Both can contribute to plaque on your teeth, which is surprisingly bad for your brain. “The plaque between teeth can cause an immune reaction that attacks arteries, which then can’t deliver vital nutrients to brain cells,” says Michael Roizen, MD, co-author of YOU—The Owner’s Manual: An Insider’s Guide to the Body that Will Make You Healthier and Younger. Solution? Floss every day. Can’t remember? Keep the floss where you store your morning makeup.

Multitask at the gym
Just as working out can keep your body in good shape as you age, stretching your brain can keep it in top form, too. And doing them together is double the fun: Do a crossword puzzle while riding a stationary bike or listen to language lessons on your iPod while running. Scientists say that working the body and mind at the same time revitalizes brain cells. Don’t like multitasking? Hit the crossword right after the gym, when your brain is energized.

Go fish
Look to the sea for healthy ways to feed your brain. DHA, a type of omega-3 fatty acid found in salmon, trout, and some fortified foods such as yogurt, is a super saver for your memory. “DHA decreases arterial inflammation and improves repair of the protective sheath around nerves,” Dr. Roizen says. “The result is less age-related memory loss, less Alzheimer’s disease, less depression, and a quicker mind.”

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The studies were done because of “a long history of epidemiological studies that related fish consumption to cognitive function,” explained Bill Thies, chief medical and scientific officer of the Alzheimer’s Association. Fish is rich in DHA, but the research scheduled to be presented Sunday at the association’s annual meeting in Vienna, Austria, used DHA derived from algae.

An 18-month study of people with mild to moderate Alzheimer’s disease “did not show treatment benefit in the study population as a whole, and does not support use of DHA for treatment of Alzheimer’s disease,” said study author Dr. Joseph Quinn, an associate professor of neurology at Oregon Health and Science University.
However, Quinn added that there was “an encouraging analysis of a subpopulation of the larger study,” showing a slower rate of decline in mental function among those who did not have the e4 version of the APOE gene. That version is known to increase the risk of developing Alzheimer’s disease. Between 70 percent and 80 percent of people have that gene version, Quinn estimated.

Still, “we’re not prepared to conclude that e4-negative people should be on DHA,” Quinn said. “We don’t know a mechanism that would account for a benefit in e4-negative people and we don’t know if our exploratory analysis would be confirmed in future trials.”

His study, funded by the U.S. National Institute on Aging, included 402 people, average age 76, with a daily dietary intake of less than 200 milligrams a day. Some took 2,000-milligram DHA supplements while others took a placebo. All underwent standard tests of mental function over the 18-month trial. The slower rate of decline seen in e4-deficient participants did not reach statistical significance.

The second study was a six-month trial of 900 milligrams a day of DHA in 485 people, average age 70, who did not have Alzheimer’s disease but had mild complaints about memory loss. Those taking the supplement made fewer errors on one memory test.

That trial was funded by the Martek Biosciences Corp., which markets the DHA used in both studies.

The results indicate that DHA supplements are appropriate for “people who have very mild memory complaints, which applies to a large percentage of the population at this age,” said Karin Yurko-Mauro, associate director of clinical research at Martek Biosciences. “We’re not talking about a disease stage here.”

The company is “looking at the potential for more trials,” but is still evaluating data from the completed study, Yurko-Mauro said.

“The results are certainly interesting,” Thies said. “There was some improvement in memory. Then you can get into a debate about what the real-world benefit would be of that improvement in memory.”

What is needed, Thies said, is a major trial for people with no Alzheimer’s disease but some memory problems. “DHA is a great candidate for such a trial because it is a food supplement that is currently available,” he said.

Meanwhile, Thies said, “it is too early” to make a recommendation about use of DHA supplements to prevent loss of mental function. “You would want to see more information in normal people before you make a recommendation,” Thies said. “In high doses, DHA does have side effects, so you would want to see a benefit to justify the risk you are taking. We need more work for that.

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