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Please Pass The Disease Prevention

September 21, 1999
Purdue University
These days we expect food to protect us from disease as well as chase away hunger, says Bruce Watkins, a Purdue University professor of food science. "In the future, foods may be matched to an individual's risk for chronic disease. This is how food and agriculture are going to develop as we move into the next century," he says.

WEST LAFAYETTE, Ind. -- These days we expect food to protect us from disease as well as chase away hunger, says Bruce Watkins, a Purdue University professor of food science.

"In the future, foods may be matched to an individual's risk for chronic disease. This is how food and agriculture are going to develop as we move into the next century," he says. "We'll be creating foods that are better for people. We'll be going back and looking at more food components that are not classical nutrients, but that seem to be health protectants."

Watkins is the director of Enhancing Foods to Protect Health, a new center at Purdue where scientists find and create new and healthier foods for us and for domestic animals. They're working to bring "nutraceuticals," "phytochemicals," "functional foods" and "designer foods" to your table.

Fat-balanced, designer eggs

Most of Watkins' research has revolved around dietary fat and bone health. We need fats in our diets, he says, but it's no secret that some fats are better for us than others. For optimum health, we need to include more omega-3 fatty acids (common in fish and canola oil) and fewer omega-6 fatty acids (common in corn, soy and safflower oil).

In recent history, we've moved away from the good fats, say Watkins and his co-workers.

"We've altered our fatty acid intake over the last centuries, because we've moved from a hunting-gathering lifestyle to an industrial lifestyle," says Amy Devitt, a master's student working with Watkins. "The Western diet has changed so that the ratio of omega-6 to omega-3 fatty acids in our diet is 25-to-1."

It used to be, and should be, somewhere between 10-to-1 and 4-to-1, she says.

Adds Watkins: "Because we've moved to intensive animal production and changed the rations they're fed, we've altered the fat composition of beef, pork and poultry from 100 years ago. Now meat and poultry contain less of the omega-3 fatty acids. The way we're eating, with high omega-6 to omega-3 ratios, we're increasing our risk for arteriosclerosis, certain cancers and inflammatory diseases."

While Devitt doesn't figure she can improve the eating habits of the entire population, she's trying to take us a step in that direction. She's hoping to create a designer egg that delivers a better balance of fatty acids. She picked eggs because they're eaten the world over, and because consumers already accept and buy different kinds of designer eggs.

At first Devitt fed laying hens two different levels of supplemental conjugated linoleic acid, which is thought to help prevent cancer, arteriosclerosis and inflammation. Yolks from the eggs of these hens contained more CLA than did yolks from hens fed the same diet without CLA.

Because adding one dietary fat worked so well, Devitt decided to try a blend of two fatty acids. She fed laying hens a diet that contained more CLA plus docosahexaenoic acid, which is an omega-3 fatty acid known to reduce the risk of cancer and cardiovascular disease. It also promotes neural and retinal development in infants.

Egg yolks from hens that ate both of these beneficial fatty acids had higher levels of each of the fatty acids than did eggs from hens fed only one of the supplements.

Devitt's supplements didn't change egg production, weight or consistency, but you won't see fat-balanced eggs in stores next week. Compared to traditional eggs, the enhanced eggs from her final study have oranger yolks, a tougher texture and a bit different flavor. However, Devitt says she is sure that by fine-tuning hens' diets, food scientists will come up with a marketable, fat-balanced egg.

In search of antioxidants

Purdue plant breeder Rick Vierling approaches the problem of making food healthier from a different angle. Vierling, a Purdue geneticist with a joint appointment as director of the genetics laboratory at the Indiana Crop Improvement Association, goes looking for plants already rich in health-promoting compounds. Once he finds a plant with promise, he identifies the good genes and breeds the promising traits that go with them into plants already grown for market.

One group of health-promoting compounds Vierling looks for in plants is antioxidants.

Antioxidants protect cells from the damaging effects of free radicals, which are molecules that chemically break down fats, proteins and DNA in the body. Some of the most notable antioxidants in the human diet are vitamin E, vitamin C and carotenoids.

Some plants produce higher levels of antioxidants than do others, but tests to locate and measure them can be expensive and time-consuming. So Vierling created his own, new technique. He calls it TNAP: total, nonenzymatic antioxidant potential test.

"TNAP is really a broad screening tool," he says. " It's inexpensive, fairly quick and can be automated."

The new antioxidant test uses only a tiny bit of a plant, one-one-thousandth of an ounce. So if a seed, for example, tests high in antioxidants, it can still be planted to produce more seeds with the same trait. In fact, seed banks could be quickly screened for plants with antioxidant potential without destroying the saved seeds.

So far, Vierling has tested herbs, spices and the seeds of rainforest trees, looking for plants that promise the benefits of antioxidants.

Antioxidants against cancer

David Waters might be able to use the antioxidants Veirling harvests. Waters, an associate professor of surgery and comparative oncology in Purdue's School of Veterinary Medicine, is also the associate director of the gerontology program and director of Drug Development Shared Resource at the Purdue Cancer Center. He studies the link between aging and cancer.

"The older people get, the higher the risk of cancer," Waters says. "More than half of cancers occur in people 65 and older, but we don't know why."

He wants to find out.

We know that oxidative damage is linked with aging, Waters says, and that oxidative damage to DNA can cause cancer. He suspects a link. To check out his suspicions, Waters is using a test developed by researchers that can tell how much oxidative damage there is in cells such as lymphocytes in the blood, or epithelial cells in the breast and prostate.

He'll compare lymphocytes in dogs on regular diets to lymphocytes in dogs eating diets rich in antioxidants. He'll also watch for development of prostate cancer, to see if there is any link between oxidative damage and cancer development.

Why prostate cancer?

Because it shows the strongest link with aging, and potentially with oxidative damage, says Waters. Eighty percent of 80-year-old men have cancer in their prostate gland at autopsy, he says.

And why dogs?

"Dogs and people have been tied together since our early history," Waters says, "and dogs are the only nonhuman species that spontaneously develops prostate cancer. Also, because of their compressed lifespan, two years of antioxidant supplements in dogs is the equivalent of 15 to 20 years in humans."

Waters says he hopes that someday doctors will be able to test people for oxidative damage through a simple blood test, then recommend dietary changes or treatment to reduce their cancer risk. "Just as in cardiovascular and neurodegenerative diseases such as Alzheimer's, disease prevention is the ultimate key," Waters says.

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