When Preston Estep walked into a meeting room at Tsinghua University on a recent sunny afternoon, he looked lively despite his busy travel schedule in China. Estep is the director of gerontology of Harvard's Personal Genome Project, a study being conducted by the medical school of the university.

Estep, who spoke in Shanghai two days prior to Beijing, was to do a presentation on the influence of diet not only on physical but on mental longevity.

A recent study shows that deaths due to Alzheimer's and other kinds of dementia rose more than threefold between 1990 and 2010. Deaths due to Parkinson's around the world doubled during the same period.