Pigging Out Healthfully: Engineered pork has more omega-3s

Bringing home the bacon may soon lead to a healthier meal. In a feat of genetic engineering, scientists have created pigs that sport much higher concentrations of omega-3 fatty acids in their tissues than normal pigs do.

LITTLE PIG, LITTLE PIG. These transgenic animals have four to five times pigs’ normal concentration of healthful omega-3 fatty acids in their tissues. Univ. of Missouri–Columbia

Many studies have suggested that eating omega-3 fatty acids can prevent or reduce heart disease and other health problems. These natural oils are found only in cold-water fish, flax seeds, and a handful of other foods that are often expensive or difficult to obtain. Yet a person must consume a gram or two of omega-3 fatty acids each day to experience health benefits, says geneticist Yifan Dai of the University of Pittsburgh.

Seeking a cheap and readily available source of omega-3 fatty acids, Dai and his colleagues engineered pigs to produce large amounts of the nutrient. Their work expanded on a study published 2 years ago in which Dai’s colleague Jing X. Kang of Harvard Medical School in Boston engineered omega-3–making mice (SN: 3/6/04, p. 157: Gene transfer puts good fats in mammals).

The secret to producing the omega-3–rich animals lies in a gene called fat-1, which was isolated from the roundworm Caenorhabditis elegans. The worm uses this gene, which isn’t normally present in mammals, to convert the less healthful, more common oils known as omega-6 fatty acids into the omega-3 variety.

The researchers inserted fat-1 into cells isolated from male fetal pigs. They then put the nuclei of these cells into pig eggs that had had their own nuclei removed. These altered eggs were transplanted into sows, which served as surrogate mothers.

Of 10 piglets born to these sows, 3 had omega-3 concentrations four to five times as high as normal. Dai’s team reports these results in the April Nature Biotechnology.

Nutrition researcher Alice Lichtenstein of the Friedman School of Nutrition at Tufts University in Boston notes that it’s unclear whether the engineered pork will be as healthy as fish and other natural sources of omega-3s. “If you’re going to eat bacon from these pigs, you’re also going to get lots of saturated fat,” she says. A heavy dose of heart-unhealthy saturated fat could overshadow the omega-3 fatty acids’ benefits, and lean cuts of the engineered pork contain little of the health-promoting fatty acids.

It will take years of study—and approval from the U.S. Food and Drug Administration—before pork products derived from genetically engineered animals may become publicly available. But if the omega-3–rich pigs eventually make it to market, perhaps even people who are reluctant to consume genetically modified foods could be convinced to eat the other white meat, notes neuroscientist Greg M. Cole of the Veterans Affairs Medical Center in Sepulveda, Calif.

“Those who have issues with transgenic foods should be reminded of the current issues with omega-3 from fish, including mercury, fat-soluble toxins, high prices, and diminishing supplies,” he says. “If we want the whole world to receive the health benefits of omega-3s, we shouldn’t say, ‘Let them eat salmon.'”