For years scientists claimed healthy eating can prevent specific chronic diseases. Now, a team of researchers in the human nutrition department at Ohio State are discovering why.
The team is learning that common foods such as grapes, oats, dairy products and tomatoes contain more than essential nutrients; they also may be capable of preventing heart disease, cancer, arthritis or Type II diabetes.
“Your grandparents, your great-grandparents said, ‘Eat all your fruits and vegetables,’ ” said Minnie Holmes-McNary, associate professor of human nutrition. “They knew that it kept you healthy, but they didn’t know how.”
Termed “functional foods,” these healthy dietary staples provide useful compounds for inhibiting disease.
“Basically, it’s just a food that has an added benefit over traditional vitamins and minerals,” said Kim DeDino, a graduate student and dietetic intern.
DeDino, along with a team of interns, cited tomatoes as an example of a functional food. Tomatoes contain vitamin C, potassium and fiber — nutrients required by the human body. But they also contain the non-essential phytochemical lycopene, which can effectively reduce prostate cancer.
Though there is some hope functional foods may contain clues on managing the progression of certain diseases, research at OSU focuses on their preventative properties.
Holmes-McNary studies red grapes as a natural source for a cancer-inhibiting agent called trans-resveratrol. Studies have shown trans-resveratrol can fight several types of cancer — including breast, colon and liver cancer — as well as arthritis.
Holmes-McNary and her team worked to understand why this happens. Their research indicates that resveratrol limits a transcription process in cancer cells. In other words, the compound stops cancer gene expression.
“We were able to show resveratrol could inhibit the transcription process,” Holmes-McNary said. “It’s exciting to have a cellular target we can see changes in.”
She finds the properties of red grapes so beneficial, she keeps a supply at her desk.
Maureen Geraghty, a doctoral student at OSU and a licensed dietitian, emphasized that although functional foods have preventative properties, they do not serve as cures to afflictions.
“It gives you a benefit to protect from a chronic disease like heart disease or cancer,” Geraghty said.
Another associate professor, Martha Belury, studies dietary fatty acids as a possible preventative for Type II diabetes, the most common form of the disease. One of her primary research topics is conjugated linoleic acid, which has multiple beneficial properties.
“People often mistakenly think that all dietary fat is bad,” Belury said. “In fact, a few types of fat are required for growth and maintenance of your tissues.”
Other fatty acids have additional benefits.
Humans manufacture very little quantities of CLA, and thus require more from an outside source. These sources include beef, lamb and dairy products.
Belury explores how CLAs affect the signaling of insulin sensitivity. This may allow a diabetic more efficient use of the insulin in their bodies. CLAs could also affect fat and glucose metabolism in the liver. One of her studies, conducted over an eight-week period, showed that people with Type II diabetes who consumed CLAs as a dietary supplement had significantly reduced body weight in comparison to subjects given a placebo, with no apparent adverse effects.
Though this might suggest images of a future where a few pills could give the body its daily needs, Belury agrees with her colleagues: Dietary sources are probably healthiest.
“What you miss in a supplement is all the other good things in food,” Belury said. “Plus, we all know that taste is an important part of why we all choose the foods we do.”
Dietitians will soon be able to recommend a balanced diet that not only provides all the essential nutrients, but additional benefits such as prevention of some chronic diseases.
“It’s much more than just interest, although that’s the fun part of science,” Belury said. “It’s getting to that level of thinking, ‘Wow, you can make a difference.’ “
Belury and Holmes-McNary also said Ohio State is unusual because the school has all the resources necessary to build a full research program. Various departments can test functional foods from the cellular level through laboratory research and eventually clinical trials.
