(NaturalNews) Fruits rich in polyphenols may help protect against the oxidative stress that has been linked to cognitive decline and Alzheimer's disease, according to a study conducted by researchers from three Korean universities and published in the Journal of Food Science.
"Our study demonstrated that antioxidants in the major fresh fruits consumed in the United States and Korea protected neuronal cells from oxidative stress," the researchers wrote. "Therefore, additional consumption of fresh fruits such as apples, bananas, and oranges may be beneficial to ameliorate chemopreventive effects in neurodegenerative disease."
Researchers took a cancer cell line derived from the forebrains of rats, intended to simulate human neurons. These cells were exposed to hydrogen peroxide after being treated with varying concentrations of fruit extracts.
Treatment with fruit extracts led to a significant increase in cell viability and decreased oxidative damage compared with the control group. The most effective extract was from apples, but the orange and banana extracts also functioned well. At the highest concentration, the orange and banana extracts provided 103 and 118 percent more cell protection than the control treatment.
Researchers believe that Alzheimer's disease might be caused by the build-up of amyloid plaque deposits in the brain, due to increased cell death from oxidative damage. Because the fruit extracts in the current study protected nerve cells against oxidative stress, the researchers believe they might provide a protective benefit against Alzheimer's as well.
A prior study found that when mice with Alzheimer's disease were given apple juice with naturally occurring antioxidants, they exhibited improved cognitive performance and their brain tissue appeared to be protected from oxidative damage. More recently, a different study found that the flavones hesperidin, hesperetin, and neohesperidin - naturally occurring chemicals found in citrus fruits - protected against DNA and cell damage, including from hydrogen peroxide.
An estimated 13 million people around the world suffer from Alzheimer's disease, the most common cause of dementia.