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Pork Fat Rules

Pork Fat Rules

Health scientists have long touted the benefits of omega-3 fatty acids, compounds that may decrease the risk of potentially fatal heart arrhythmias, lessen levels of dangerous triglycerides and slow the growth rate of atherosclerotic plaque. But getting those benefits into people isn't as easy as it might be.

Nutritionists say the best way to boost one's omega-3 level is to consume certain species of fish. They also recommend plant oils or dietary supplements. But these methods are far from perfect.

Take fish, for instance. Those that are rich in omega-3, such as swordfish, salmon, cod and tuna, often have high levels of mercury. Each is also in danger of depletion due to over-fishing. Flax seed oil, perhaps the best plant-based source of omega-3, is expensive and no good for cooking. Fish-oil based supplements, according to the American Heart Association, can sometimes cause fishy breath, belching or abdominal bloating.

So what's a health-conscious consumer to do? Easy, says renowned MU geneticist Randall Prather: Eat more bacon.

Prather, a professor of reproductive biology who works with MU's National Swine Resource and Research Center, has, along with Yifan Dai and Rhobert Evans of the University of Pittsburgh and Jing X. Kang of the Harvard Medical School, for the first time created a litter of transgenic pigs whose cells are chock-full of omega-3. And while it may be some time before the cousins of these heart-healthy porkers end up in the nation's frying pans, a Tufts University scientist, Alice H. Lichtenstein, is already on record saying the achievement represents a "new era" in human nutrition.

Creating the pigs was a group effort. To stimulate production of omega-3 fatty acids in pigs, Pittsburgh's Dai transferred a gene from roundworms, known as fat-1, to "pig primary fetal fibroblasts," the cells that give rise to porcine connective tissue. Prather's group at the Swine Center then used nuclear transfer cloning to create the piglets from these cells. Next, the pigs' tissues were analyzed for omega-3 fatty acids both at Kang's Massachusetts General Hospital lab and by Dai and Evans at Pitt. The analysis confirmed that the fat-1 gene did indeed create an enzyme that converted the pigs' less desirable, but more abundant, omega-6 fatty acids into omega-3 fatty acids.

The team announced their breakthrough in the March 26 online edition of the journal Nature Biotechnology. An avalanche of publicity followed. In a front-page story appearing in the Sunday New York Times, for example, Alexander Leaf, an emeritus professor of clinical medicine at Harvard, said he was confident heart-healthy pork would one day appear in American kitchens, and that consumers would be better for it. "People can continue to eat their junk food,'' Leaf told the Times. "You won't have to change your diet, but you will be getting what you need."

During a taped appearance on Comedy Central's Daily Show, meanwhile, Prather found himself describing, in all seriousness, how the fat-1 gene "converts omega-6 fatty acids to omega-3 fatty acids" while host Jon Stewart cautioned that "the study was funded mostly by rich salmon."

Kidding aside, the researchers say the dietary benefit represents only one aspect of their findings, perhaps not even the most important one. "Pigs and humans have a similar physiology," says Prather. "We could use these animals as a model to see what happens to heart health if we increase the omega-3 levels in the body. It could allow us to see how that helps cardiovascular function. If these animals are put into the food chain, there could be other potential benefits. First, the pigs could have better cardiovascular function and therefore live longer, which would limit livestock loss for farmers."

Prather and the other researchers' work was supported by the National Institutes of Health, the American Cancer Society and an unrestricted gift to the Thomas E. Starzl Transplantation Institute from the Robert E. Eberly Program for Transplant Innovation.

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Published by the Office of Research.