Consuming what's known as a Mediterranean diet - one loaded with fruits, vegetables, grains and olive oil - may help Alzheimer's patients live longer, a new study suggests.
The observation comes after researchers tracked the dietary habits of people diagnosed with early-stage Alzheimer's. It follows on earlier work by the same team that suggests these diets may lower the risk of developing Alzheimer's in the first place.
"This time, we found that Alzheimer's patients who were following the Mediterranean diet had longer survival as compared to those who were following the diet less," said study lead author Dr Nikolaos Scarmeas, an assistant professor in the department of neurology at Columbia University Medical Centre in New York City.
The study is published in the Sept. 11 issue of Neurology.
According to the American Heart Association, diets native to the 16 countries bordering the Mediterranean Sea vary somewhat from region to region. However, most regimens include a high intake of fruits, vegetables, breads, cereals, potatoes, beans, nuts, seeds and olive oil. More than half of all fat-sourced calories in the Mediterranean diet come from monounsaturated fats, such as olive oil. Dairy, fish, poultry and other sources of saturated fats are eaten at low to moderate levels, the AHA says.
Less heart disease in Mediterranean
Heart disease rates in Mediterranean nations are lower than in the United States, the AHA adds, although it's not clear that diet alone is responsible for the difference.
To further examine the potential health benefits of the Mediterranean diet, Scarmeas' team compared nutrition and disease progression between 1992 and 2002 among 192 patients with early-stage Alzheimer's, all of whom lived in New York City.
All the patients were 65 and older, most were non-white, and all underwent initial physical and neuro-psychological exams to assess their cognitive capacities. Such evaluations were repeated every 18 months.
In addition, the patients completed questionnaires regarding their food consumption over a one-year period. Daily caloric intake was tallied for seven categories, including dairy, meat, fruits, vegetables, legumes, cereals and fish.
At no time were patients given any information about nutrition, or instructions about what to eat or how much to eat of any particular food group.
Throughout the full study period, the researchers tracked patients for an average of four-and-a-half years, during which time 85 patients died.
Extends life by four years
Scarmeas' group found that patients whose consumption habits most closely tracked that of the Mediterranean diet were 76 percent less likely to die in the study period than those whose food intake least mimicked the diet.
Compared with those whose diets most closely resembled a Western diet, Alzheimer's patients who most closely followed the Mediterranean diet lived an average of four years longer.
Findings not definitive
Greg M. Cole is associate director of the Alzheimer's Disease Research Centre at the UCLA David Geffen School of Medicine and a neuroscientist with the Greater Los Angeles VA Healthcare System. He described the findings as provocative but not definitive.
"It could be that the Mediterranean diet is slowing the progression of Alzheimer's," he acknowledged. "But there could also be other explanations. For example, a lot of people who have Alzheimer's also have cardiovascular disease. The risk factors for both illnesses show a lot of overlap. And it is a pretty well established benefit that the Mediterranean diet protects against heart disease."
"So, it could be that the Mediterranean diet is actually slowing down the accompanying spectrum of vascular problems that leads to stroke and heart attack and other problems associated with a cardiovascular disease that lead to mortality," explained Cole. "So, death is not as good a measure here as the progression of cognitive decline. Is the diet actually slowing down the cognitive decline of Alzheimer's itself? That's the next question. And, if so, that would certainly be a very significant result." – (Alan Mozes/HealthDay)
Mediterranean diet extends lives
Eat Mediterranean, live longer