A study of 1,800 people in their seventies, undertaken by Columbia University, found that diet and exercise are both factors in preventing the development of Alzheimer's, whether alone or in combination.

This is believed to be the first study where diet and exercise have been considered as separate factors in reducing the chances of developing Alzheimer's.

The research, led by Dr. Nikolaos Scarmeas, was published in the Journal of the American Medical Association (JAMA). None of the participants suffered from Alzheimer's at the start of the study, but after an average of 5 years, 282 cases of Alzheimer's were diagnosed (out of 1,800 study participants).

The data indicated that:

  • The people following the healthiest diets were 40% less likely to develop Alzheimer's than those with the worst diets
  • Those getting the most exercise were 37% less likely to develop Alzheimer's than those who didn't exercise at all
  • People in the top third for both diet and exercise were 59% less likely to develop Alzheimer's than those in the lowest third

A healthy diet was defined by the researchers as a Mediterranean-type diet, ranked on a scale of 0-9. Both the duration and the intensity of exercise were also taken into account.

The New York Times explained that:

Diet may be protective because it can improve metabolic factors and reduce cardiovascular risks, inflammation and oxidative stress, [Dr Scarmeas] suggested, while physical activity has been associated with positive changes in the brain along with other positive effects.

With previous studies indicating that staying a healthy weight in middle age could cut Alzheimer's risk, this study adds to evidence that maintaining a healthy lifestyle throughout middle age and senior years can be a strong factor in preventing the development of Alzheimer's.