Monday, November 24, 2008
Study Shows Kiwi Ranked Among Highest in Antioxidants
The antioxidants found in kiwifruit are absorbed by the body more effectively than those from other antioxidant-rich fruits, according to a study conducted by researchers from the U.S. Department of Agriculture's Arkansas Children's Nutrition Center in Little Rock, and published in the Journal of the American College of Nutrition.
Researchers fed 300 grams per day of green Hayward kiwifruit to seven healthy women volunteers who had fasted overnight before the beginning of the study. The researchers took blood samples from the women before they ate, as well as 1.5, 3 and 4.5 hours afterward. They measured the antioxidant capacity of each blood sample, then exposed the blood cells to hydrogen peroxide and recorded the degree of oxidative damage suffered.
The researchers found that kiwifruit had an antioxidant intake score of 12.5, substantially higher than the known score of 4.2 for grapes and 1.7 for strawberries. This means that eating kiwifruit resulted in the highest absorption and metabolism of antioxidants.
The mechanisms behind the differences in antioxidant absorption from different fruits are still unknown, although the researchers speculated that kiwifruit's high vitamin C content might be partially responsible.
Antioxidants are believed to be important for their ability to remove free radicals from the body. Free radicals have been linked to various kinds of cell damage, including some that cause cardiovascular disease, cancer, dementia and various symptoms of aging.
"We're learning that anti-oxidants should be consumed with every meal," lead researcher Ronald Prior said, "and if you routinely skip anti-oxidants in your diet, over time, the excess number of free radicals being produced may begin damaging cellular components, ultimately leading to atherosclerosis and cancer."
The researchers noted that while it can not be proven that eating kiwifruit will have any specific health effects until more studies are carried out, the antioxidants in the fruit are known to lower rates of heart disease and cancer.