Researchers have given people another reason to consume a diet rich in vegetable and fruit juices. A new study has found that people whose consumption of fruit and vegetable juices was three servings or more per week, lowered their risk of developing Alzheimer's by 76%.
The research was conducted by Dr. Qi Dai, M.D., Ph.D., assistant professor of Medicine and colleagues at Vanderbilt University. The researchers followed 1,836 dementia-free people living in the Seattle area, over a 10 year period. Information regarding their dietary intake of fruit and vegetable juice was collected and monitored. The subjects also had their cognitive function assessed at every two year intervals for up to 10 years.
The researchers found that those people whose consumption of juice was three times or more per week had a 76% lesser likelihood of developing Alzheimer's disease as compared to their counterparts whose juice consumption was less than one serving per week, even after accounting for other factors such as smoking, physical activity, fat intake and education. Among those people who carried the genetic marker-apolipoprotein E-4 allele, which has been linked to late onset Alzheimer's, the benefit of juice intake appeared to be particularly improved.
Initially the researchers felt that antioxidant vitamins might protect against Alzheimer's. However they said one particular class of antioxidant called polyphenols could play a positive role in protecting against Alzheimer's. Polyphenols are present mainly in the skins and peels of vegetables and fruits and are non vitamin antioxidants. Dr. Dai said the next step was to test blood samples of the volunteers to confirm the role of polyphenols in lowering Alzheimer's risk.
“We thought that the underlying component may not be vitamins, that there was maybe something else,” said Dr. Dai. “Also, animal studies and cell culture studies confirmed that some polyphenols from juices showed a stronger neuroprotective effect than antioxidant vitamins. So we are now looking at polyphenols. We don't know if it is a specific type of juice (that reduces risk). That information was not collected in the current study. But we can use plasma to narrow down the kinds of juices,” he added.
Nevertheless, Dr. Dai cautioned people not to overdo juice intake as a precaution against Alzheimer's, as more study was needed regarding its benefits. “A few years ago, hormone replacement therapy, NSAIDs (nonsteroidal anti-inflammatory drugs) and antioxidant vitamins showed promise (in preventing or slowing Alzheimer's disease), but recent clinical trials indicate that they do not. More study, I think, is needed,” he said.
The study details have been published by The American Journal of Medicine in their September issue.
