Compounds that occur naturally in cranberries may be good for the heart, researchers at the University of Wisconsin-Madison have found.

Early results from studies indicate that feeding cranberry juice powder seems to relax and open blood vessels in pigs that are genetically susceptible to developing atherosclerosis, or clogged arteries. Kris Kruse-Elliott, a veterinary anesthesiologist at the UW-Madison School of Veterinary Medicine, presented her results at the American Physiological Society's annual meeting in San Diego in April.

She and co-researcher Jess Reed, a nutritionist in the Department of Animal Sciences, set out to evaluate various whole foods that contain antioxidants, flavonoids and polyphenols, all compounds that may protect against heart disease. Cranberries contain all three, so they fed cranberry juice powder to pigs that were genetically predisposed to develop high cholesterol and atherosclerosis, just as some humans are.

"When these pigs were fed cranberry juice powder made from whole cranberries for six months, their vessels acted more like normal pigs," Kruse-Elliott says, meaning that the pigs' blood vessels relaxed and opened more.

Abnormal blood vessel function is an important component of heart disease. Finding ways to improve vessel function in patients with high cholesterol and atherosclerosis is critical to helping protect these patients from consequences such as heart attack or stroke.

"The next step is to determine what specific components of cranberries are most important to the improvements in vascular function that we observed, exactly how they modify blood vessel relaxation, and how they can be most easily consumed as part of the diet," Kruse-Elliott says. That last factor may be key. While pigs may not mind the intense tartness of concentrated cranberries, someone will need to make cranberry juice powder palatable to people before the next "heart-protection" diet is born.