A neighbor of mine was having some stonework done outside his home. The leader of the crew doing the work was a lively, muscular, good-natured fellow with a strong Italian accent. I took him to be in his mid-fifties, if that old. In fact, he was approaching 70.
I remarked on how young he looked and he told me his approach to life: a full day of hard physical effort followed by a good Italian meal, a little red wine and then to sleep like a baby.
It is fairly well established that people who adopt such habits live longer than others and are less prone to heart and blood vessel disease, cancer and — important for minding your mind — possibly degenerative nerve disease.
About the same time as I met this fellow, the Journal of the American Medical Association (JAMA) had published two articles providing scientific support for the stone worker's philosophy of healthy living. Dr. Nikolaos Scarmeas and colleagues at Columbia University demonstrated that both a Mediterranean-type diet and physical activity could reduce the incidence of Alzheimer's disease. The findings were part of their study of 1,880 New York City residents that began in 2006.
In a related study, Dr. Catherine Féart and colleagues at the University of Bordeaux analyzed the eating habits and brain health of 1,400 older French adults. Their study showed that people who most closely followed a Mediterranean-type diet had relatively slower decline in mental functioning as measured by a test called the Mini-Mental Status exam (MMSE).
There is no one diet that is the “official” Mediterranean diet. In general, this type of diet is low in saturated fat and high in fiber. Fruits, vegetables, grains, beans, nuts and seeds make up about half of the food eaten each day. Up to 40% of daily calories may come from fat, but much of it comes from olive oil, which is unsaturated.
The rest of the diet consists of small amounts of cheese, yogurt, fish, poultry and eggs. Red meat is consumed only on occasion. Red wine is taken in small amounts, typically with meals. Regular physical activity, as with the mason, is a part of daily life.
The two JAMA studies, in different ways, tried to deal with limitations that researchers saw in the original 2006 New York study. The study involved mostly Hispanics and African Americans. The scientists believed the results would need to be repeated in other ethnic groups.
The French investigators wanted to learn whether the effects of diet could be generalized to a population of 1,410 older adults living near Bordeaux, France. The researchers found that people who more closely followed a Mediterranean diet had a slower rate of mental decline according to the MMSE test.
Because there is little research published on the combination of diet and physical activity, the Columbia researchers were interested in how these two items were related. They predicted that each factor would, on its own, have beneficial effects on mental function. But they also thought that combining a Mediterranean diet with exercise would be even more helpful. As it turned out, the people who were most committed to the combination of diet and regular physical activity had a lower risk of developing Alzheimer's disease.
In the same issue of JAMA, Dr. David Knopman of the Mayo Clinic wrote an editorial about these studies. He wisely noted how difficult it is to tease out the connections between lifestyle and health, especially habits like diet that are a lifetime in the making. He suggested that we look at these results cautiously and pay attention to more than just diet and exercise. Dr. Knopman also suggested, for example, that we monitor blood pressure, avoid diabetes and not smoke.
It's helpful when the evidence supports our assumptions. Combining a healthy diet and regular physical activity does seem to increase our chances of enjoying good health later in life. And the earlier we adopt these habits the better. For example, you could start when you sit down for your next holiday meal.
And if I see the stonemason again, I will tell him that his lifestyle not only helps him sleep like a baby, but probably helps his brain stay as healthy and alert as a baby's too.
Michael Craig Miller, M.D. is editor-in-chief of the Harvard Mental Health Letter and an assistant professor of psychiatry at Harvard Medical School. Dr. Miller has an active clinical practice and has been on staff at Beth Israel Deaconess Medical Center for more than 25 years.