Someday you could eat bacon and ham instead of fish and nuts to get heart-healthy omega-3 fatty acids into your diet.

	University of Missouri-Columbia The omega-3 pigs. Click photo for larger image.

Researchers from the University of Pittsburgh School of Medicine, the University of Missouri-Columbia's National Swine Resource and Research Center, and Massachusetts General Hospital have made pigs that produce the beneficial nutrients.

Omega-3 fatty acids cut triglyceride levels, the risk of irregular heartbeat, and the growth of artery-clogging atherosclerotic plaques, according to the American Heart Association. The association recommends eating fish, preferably fatty ones such as salmon, at least twice a week because it is rich in omega-3.

Federal officials currently don't allow transgenic, cloned livestock to be part of the food chain, said Dr. Yifan Dai, the Pitt scientist who spearheaded the work. In the meantime, the animals provide an excellent model to study the influence of omega-3 on cardiovascular function and disease risk.

"The pig is actually very close to humans in physiology," Dr. Dai said.

Animals can be fed a diet high in omega-3, but they still get a lot of omega-6 fatty acids, and the high overall fatty acid intake can affect meat quality.

In one study, pigs were fed flaxseed, leading to an elevation in one subtype of omega-3, and "the bacon tasted like fish," Dr. Dai said, laughing.

His transgenic pigs made mostly two other kinds of omega-3 and do not get extra fat in their diets, so pork quality should be unaffected, he added.

The flavor of the meat will be critical to its success, said Madelyn Fernstrom, director of UPMC weight management center.

"It doesn't matter how good something may be for you," she said. "If it doesn't taste good, then I'm not so sure how many people are going to use it."

Still, the research is intriguing and a step in the right direction, Dr. Fernstrom said.

"We need to make some options for people that are healthy and palatable and accessible," she said.

Leslie Bonci, director of sports nutrition at UPMC, said modified pigs could provide welcome alternatives to traditional sources of omega-3.

"It may indeed get a lot more people closer to that recommended 1.6 grams of omega-3 a day that most people don't get," she said.

Pork products might be less costly than omega-3 enriched eggs or fish, which many people don't like to eat anyway. " I love salmon, but it's not inexpensive to buy it," Ms. Bonci noted.

Federal rules will prevent Dr. Dai and the public from nibbling on his experiments any time soon, but perhaps other animals might eventually get to try some.

After all, "you don't need to make a transgenic chicken" to make it rich in omega-3, the scientist noted. "You just feed the chicken our pig."

Dr. Dai said the enzyme should be harmless because it doesn't make a toxin or promote antibiotic resistance, and it will break down with processing or cooking.

There could be some concern about eating genetically modified meat, Ms. Bonci said.

But, "I don't think there are that many people losing sleep over it," she said. "Actually, people are far more concerned about the intake of fish because of the mercury."

In the pig experiments, published in the current issue of Nature Biotechnology, the scientists first inserted a roundworm gene dubbed fat-1 into a fetal connective tissue cell.

Using nuclear transfer cloning, they fused the cell with an ovum, which had been emptied of its genetic material, and prompted the newly created embryo to grow.

The engineered piglets carried the fat-1 gene, which makes an enzyme that converts omega-6 fatty acids into the omega-3 variety, Dr. Dai explained. So, not only did tissues from the modified pigs contain more omega-3, they also had lesser amounts of omega-6 than normal pigs.

He noted that offspring of the modified pigs have a 50 percent chance of getting the gene. In the future, the pigs could be bred to have two copies of the gene, one from each parent, which could double the enzyme activity.

People and animals have a naturally occurring gene that converts omega-6 into omega-3, but it is almost completely inactive, Dr. Dai said.

Actually, fish don't do the conversion, either. Small fish eat micro-algae and other marine plants that contain omega-3. Then bigger fish eat small fish, accumulating omega-3.

"The problem is when they accumulate omega-3, they also accumulate other chemicals, like mercury," Dr. Dai pointed out. "The FDA always says you don't want to eat too many of this fish or that fish, but then people also need omega-3."