Lower your diabetes risk by eating a healthy diet, and keep your brain active by always learning.

A healthy diet may lower your dementia risk by lowering your diabetes risk.

RODALE NEWS, EMMAUS, PA—No one wants to experience, or watch a loved one experience, the stages of dementia: memory loss, difficulty communicating, paranoia, hallucinations. So when a recent report from the National Institutes of Health found that no solid scientific evidence exists to support theories that supplements, drugs, diet, exercise, or robust social interaction will help prevent Alzheimer's disease or other forms of cognitive decline, it understandably had people perplexed. But healthcare professionals responding to the report insisted that people should maintain a healthy lifestyle that includes plenty of exercise and a healthy diet because there is some evidence that it might help. And a new study backs them up. The study, published recently in the British Medical Journal found that, among a group of French adults, staying intellectually active and warding off diabetes were the two most protective things they could do to prevent dementia.

THE DETAILS: The researchers first identified as many possible risk factors for dementia as they could: socio-demographic factors such as age and educational level; clinical factors including genetics, heart disease, stroke, and diabetes; and lifestyle influences, for instance, being socially active or regularly consuming the Mediterranean diet (both of which decrease dementia risk) or smoking (which increases it). Then they collected information on clinical diagnoses of dementia and mild cognitive impairment, a precursor to dementia, from a group of 1,433 French adults age 65 or older who'd participated in a seven-year-long study.

Of those 1,433 individuals, 405 were diagnosed with either dementia or mild cognitive impairment. The authors found that the largest influence on developing either disorder was a lack of something called "crystallized intelligence." That's the amount of knowledge you accumulate over a lifetime, and your verbal, reasoning and problem-solving skills. The next biggest influences were the presence of depression, diabetes, and a genetic predisposition towards dementia. The greatest protective measure was found to be a diet heavy on fruits and vegetables. Because you can't change genetics and because health departments don't have much influence on education policy, the authors concluded that promoting fruit and vegetable consumption and preventing diabetes are the two greatest public-health measures that could reduce the projected 100 percent increase in dementia that's expected in developed countries over the next 10 years.

WHAT IT MEANS: Lowering your risk of diabetes can lower your risk of dementia, too. "We do not know the precise cause of Alzheimer's disease, nor do we have a real treatment," says Karen Ritchie, PhD, senior research director at the French National Institute of Health and Medical Research and professor of neuroepidemiology at Imperial College, London. "But we may be able to decrease the number of new cases by detecting insulin resistance early on, screening and treating depression, and encouraging a healthy lifestyle." She adds that insulin has a number of protective effects on the brain, and those protections are decreased with insulin resistance. Diabetes in general, she adds, increases hardening of the arteries, which raises your risk of stroke, which in turn, her study found, increases the risk of developing dementia.