Age-related macular degeneration is the most common cause of vision loss among people over the age of 60, affecting millions of older adults every year.
Lutein, a carotenoid found in dark green vegetables, has in recent years become a popular supplement taken to help prevent this condition, based on a growing body of research showing its action on eye health.
However a pair of French researchers believe that the resveratrol found in walnuts could also protect against age-related macular degeneration.
"Among the antioxidants of edible vegetables, resveratrol has been shown to be a potent angiostatic compound in vitro as well as in vivo and in particular administered orally," Dr Claude Bonne, honorary professor of pharmacology at the University of Montpellier, told NutraIngredients.com.
Resveratrol's angiostatic mechanism, or that which stops the development of new blood vessels, appears to both inhibit production of VEGF, one of a number of genes associated with angiogenesis, aswell as the effects seen after activation of VEGF receptors.
"This unique profile of resveratrol activity represents a scientific basis for a novel nutritional supplement to slow the evolution of AMD to the neovascular form," Dr Bonne continued.
The neovascular, or 'wet' form, of AMD affects only 10 per cent of those diagnosed with the disease yet it accounts for almost 90 per cent of the severe vision loss associated with the condition.
No tests have yet been carried out on the walnut extract and its effects on AMD, however the researchers claim that there is some support for the product in peer-reviewed literature.
"Nuts have been chosen over grapes because they are a more original source of resveratrol and there is also some evidence of their protection against AMD," said collaborator Dr Daniel Sincholle.
In 2003 Harvard University researchers reported in the Archives of Ophthalmology (vol 121, issue 12, pp1728-37) that they had founds nuts to be protective against AMD.
This could be a result of their polyphenols, including the compound resveratrol.
The French team has filed a patent in France covering the AMD treatment. A process of extraction is described but does not appear in the claims.
The researchers are seeking industry partners focused on supplements for the prevention of ageing, particularly in the area of eye health. They already hold several patents for plant extracts used around the world, particularly in cosmetics.