At home as at work, Hibbeln practices what he preaches. An avid cook, he recently oversaw the renovation of the kitchen at his Woodside home, where he had a brick wood-fired oven installed. He’s experimenting with bean dishes these days. (“Beans are really low-fat and very high-protein,” he says.) And of course “we eat moderate amounts of [fresh] fish, one or two servings a week,” usually salmon or sustainable Chilean sea bass, he says, as well as taking supplements.
Hibbeln often juggles as many as 10 clinical tests of his theories simultaneously, then travels the world to present the results. He keeps a suitcase packed at home, he says, mostly to respond to public health emergencies, such as when he was deployed to help after Hurricane Katrina in 2005.
As he surveys what’s happening in the world today, Hibbeln sees his message as more urgent than ever. In 2009, he hosted a conference with military brass and omega-3 scientists to consider a correlation between low omega-3 levels and soaring suicide rates in the American military.
Hibbeln and his team compared omega-3 levels in 800 individuals in the military who had committed suicide with those in 800 randomly selected service members of similar age, sex and rank. When he and five colleagues published the results in the August 2011 Journal of Clinical Psychiatry, the report sparked headlines.
“They found that all the service members had low omega-3 levels, and that suicide risk was greatest among individuals with the lowest levels of docosahexaenoic acid (DHA), the major omega-3 fatty acid concentrated in the brain,” according to NIH.
In June, the Pentagon said the suicide rate among active-duty military personnel had spiked this year, surpassing the number of troops dying in battle and “on pace to set a record annual high since the start of the wars [in Iraq and Afghanistan] more than a decade ago.”
Hibbeln is optimistic that the military eventually will provide “nutritional armor for the war fighter.” The cost of altering military diets would be relatively low, he says, compared to the medical savings.
Even as there’s still work to be done, Hibbeln has to be gratified to see the results of his labors. Food producers have jumped on the omega-3 bandwagon in the past two decades—with labels touting omega-3s on everything from vitamin bottles to cereal boxes to granola bars.
Fifteen years ago, only 3 percent of the population understood the term “omega-3,” Hibbeln says. Now 95 percent of people know what it means. But not everyone knows why it’s important, how omnipresent omega-6s are, and how the two differ. Hibbeln considers it his job to make that crystal clear.
Sit with him in his cubby at an NIH biomedical research facility on Fishers Lane in Rockville and he’ll pull up computer images of autopsied mice engorged with fat after their brains were altered to mimic the effects of omega-6 on appetite control. Then he’ll pull up charts showing the steep climb in major depression rates of those who rarely eat seafood vs. those who eat it all the time.
“Twenty years ago, when I first started researching this, I was considered out of the box,” he says. “Now I am the box.”
The American Heart Association (AHA) recommends at least two servings a week of fish, especially fatty fish. A serving consists of 3.5 ounces cooked, or about three-quarters of a cup of flaked fish, and it’s better baked or grilled, not fried.
The group says to “choose low-sodium, low-fat seasonings such as spices, herbs, lemon juice and other flavorings in cooking and at the table.”
Fatty fish such as salmon, mackerel, herring, lake trout, sardines and albacore tuna, the AHA says, are high in two omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which have demonstrated benefits in reducing heart disease.
“We also recommend eating tofu and other forms of soybeans, canola, walnut and flaxseed, and their oils,” the association says. “These foods contain alpha-linolenic acid (ALA), another omega-3 fatty acid. Large-scale epidemiologic studies suggest that people at risk for coronary heart disease benefit from consuming omega-3 fatty acids from marine and plant sources. However, more studies are needed to show a cause-and-effect beneficial relationship between ALA and heart disease.”
Taking in more omega-3s through foods is “preferable,” the AHA says. But “coronary artery disease patients may not be able to get enough omega-3 by diet alone. These people may want to talk to their doctor about taking a supplement. Supplements also could help people with high triglycerides, who need even larger doses.”
The National Institutes of Health’s Joe Hibbeln says poultry is “particularly rich in [potentially problematic] omega-6 fats. We are working on diets [for chickens] to improve the omega-3 composition of chicken,” he says. Omega-6 fats are also abundant in safflower, corn and soy oils, he adds, which is why, despite the AHA’s recommendation, he doesn’t like them as a source of omega-3s. “Canola, high oleic sunflower, high oleic safflower and flax are better choices.”
But What About Mercury?
Even as scientists suggest eating more fish to obtain omega-3s, concerns exist over the possible risks from trace levels of methylmercury and other industrial contaminants—in particular, the risks to fetuses.
Since 2004, the U.S. Food and Drug Administration has recommended that pregnant and nursing mothers limit consumption to 12 ounces of fish weekly, and advises that they avoid swordfish, shark, tilefish and king mackerel, which have the highest levels of mercury.
Consumers Union asked the FDA in 2010 to consider more carefully the possible risks from canned tuna, the most popular fish in the U.S. and the most common source of mercury in the American diet. However, the Western Fishboat Owners Association, a fishing industry group, countered that “the benefits of consuming quality seafood far outweigh any risk for the vast majority of people, and that the hyperbole associated with some of these mercury campaigns does more to damage consumers’ health by driving them to less healthful foods.”
In a 2007 paper in the British medical journal The Lancet, National Institutes of Health biochemist Joe Hibbeln examined the FDA’s 2004 advice and found it “detrimental to children’s IQ and behavior because it caused nutritional deficiencies for developing brains and [because] the health benefits from reducing exposure to the trace levels of PCBs and methylmercury [in fish] were sparingly small.”
Hibbeln notes that the FDA confirmed in a draft document in 2009 that the nutritional benefits of seafood outweigh the risk of methylmercury. The World Health Organization confirmed it again in 2010. Hibbeln says a bipartisan group of 22 U.S. senators has written President Barack Obama to ask that the FDA increase its recommendations on eating fish for pregnant women and nursing mothers.
To see the American Heart Association’s list of omega-3 and mercury levels in fish, click here.
Sandra Fleishman is a copy editor for the magazine and lives in Kensington.