According to a new study, exercising regularly and eating a healthy, Mediterranean−style diet is linked to significantly lower rates of Alzheimer’s disease. Doing each separately was also associated with lowered Alzheimer’s risk, but combining the wholesome diet with routine exercise seemed to pack the most punch against the disease.

When the two variables, activity level and exercise, were considered separately, the team found that physically active participants had a 33% reduced risk for developing Alzheimer’s disease.

Nikos Scarmeas and his team at Columbia University Medical Center followed 1,880 healthy participants whose average age was 77. Participants were of many ethnic backgrounds and hailed the hospital’s surrounding area of upper Manhattan.

To find out about their physical activity levels, the researchers asked them to recount their exercise routines over the previous two weeks (subjects were interviewed every 18 months). Activity was classified as vigorous, moderate, or light (i.e., jogging fell under the “vigorous” category, while gardening was considered “light”). Participants were also queried about their eating habits to determine how similar or dissimilar they were to the Mediterranean−style diet, and a score was calculated based upon this information. The Mediterranean diet is high in fruits, veggies, fish, and grains, and low in saturated fat, most meats and dairy, and alcohol.

Participants were followed for approximately 5.5 years, and the researchers monitored which subjects developed Alzheimer’s disease and which did not (282 of the participants did develop the disease).

When the two variables, activity level and exercise, were considered separately, the team found that physically active participants had a 33% reduced risk for developing Alzheimer’s disease. Those who followed the Mediterranean diet most rigorously had a 40% reduced risk for developing the disease.

But participants who were both physically active and adhered to the Mediterranean diet had a 60% lower risk of developing Alzheimer’s than those who did neither.

Scarmeas points out that even people who just exercised a little bit had a lower risk level for Alzheimer’s.

The author does note that the study was based on participants’ recounts of their past activity levels and eating habits. The research was therefore observational, and a controlled, clinical study would need to be done to gain more insight into the relationship between exercise, eating habits, and Alzheimer’s risk. However, the results offer valuable insight into these connections, and Scarmeas says that the “study is important because it shows that people may be able to alter their risk of developing Alzheimer’s by modifying their lifestyles through diet and exercise.”

The findings are published in the August 12, 2009 issue of the Journal of the American Medical Association.