Plant nutrients called polyphenols are known to protect nerves from damage, but to expect a similar effect in case of Alzheimer's would be 'unwise,' warns Indian-Canadian researcher Charles Ramassamy.

Ramassamy, associate professor at INRS-Institut Armand-Frappier, and colleagues in Canada analysed more than 200 lab and animal studies on these nutrients found in fruits, vegetables, wine, chocolate, coffee, tea, and other foods.

They found ample evidence that polyphenols do protect nerves from the kind of damage that occurs in Alzheimer's and other chronic brain disorders.

The researchers concluded, however, that 'it is not at all clear whether these compounds reach the brain in sufficient concentrations and in a biologically active form to exert beneficial effects.'

Resolving those uncertainties will take years of additional research, they said in the report, which includes a list of the 50 foods containing the highest amounts of polyphenols.

Ramassamy's research programmes involve the understanding of the neurobiology of oxidative stress and of antioxidants using cell culture and animal models as well biochemistry, pharmacology, cellular and molecular tools.