Mediterranean Diet abridges Alzheimer’s Risk

U.S. researchers report that people who have a rich ‘Mediterranean’ diet have lower risk of developing Alzheimer’s disease.

The Mediterranean diet is a nutritional model inspired by the traditional dietary patterns of the countries of the Mediterranean basin, particularly Southern Italy, southern France, Greece, Cyprus, Portugal and Spain.

Common to the diets of these regions are a high consumption of fruit, vegetables, bread, cereals, olive oil and fish; making them low in saturated fat and high in monounsaturated fat and dietary fiber.

The research was published on-line on Monday and will also appear in the print edition of the ‘Archives of Neurology’, a publication of the Journal of the American Medical Association (JAMA) group in December 2006.

It was found out that the diet could also help to reduce diseases like cancer, obesity, high cholesterol and blood pressure, problems with processing glucose that may lead to diabetes, coronary heart disease and death. One of the main explanations is the large amount of olive oil used in the Mediterranean diet. Unlike the high amount of animal fats typical to the American diet, olive oil lowers cholesterol levels in the blood. In addition, the consumption of red wine is considered a possible factor, as it contains flavonoids with powerful antioxidant properties.

In a recent study, Dr. Nikolaos Scarmeas and colleagues at Columbia University Medical Center in New York tried to find a possible link between the Mediterranean diet and lower risk of Alzheimer’s disease- a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes.

The study was conduced on 1,984 people, 194 of whom had the disease and the rest did not. They were given complete physical and neurological examinations and a series of tests of brain function.

Their diets of the previous year was studied and given scores ranging from 0-9, depending on how close it was to the Mediterranean diet, with higher numbers indicating eating patterns that aligned closely with the diet. The researchers also obtained information about vascular disease diagnoses.

It was found out that the people who strictly adhered to the regime had lower risks of Alzheimer’s and with each additional point on the diet score, the risk reduced by 19-24%. In fact, people in the top one-third of diet scores had 68% lower risk of developing Alzheimer's disease, compared with people in the bottom third. In addition, people in the middle third had a 53% lower risk of developing the disease.

"We have confirmed the association of a Mediterranean diet with Alzheimer's disease," said lead researcher Dr. Nikolaos Scarmeas, an assistant professor of neurology at Columbia University Medical Center in New York.

The most striking early symptom of Alzheimer’s is loss of short term memory. As the disorder progresses, cognitive injury extends to the domains of language (aphasia), skilled movements (apraxia), recognition (agnosia), and those functions (such as decision-making and planning) closely related to the frontal and temporal lobes of the brain.

Average duration of the disease is approximately 7–10 years, although cases are known where reaching the final stage occurs within 4–5 years, or up to 15 years.

In a separate study published in the October issue of ‘Archives of Neurology’, researchers from Sweden's Karolinska Institute and Uppsala University Hospital investigated the link between Omega-3 supplements and Alzheimer’s, concluding that overall results were disappointing, but a positive benefit was seen in 32 patients.

Alzheimer's disease is the most frequent type of dementia in the elderly and affects almost half of all patients with dementia. Advancing age is the primary risk factor for Alzheimer's. Among people aged 65, 2-3% show signs of the disease, while 25-50% of people aged 85 have the symptoms.

The share of Alzheimer's patients over the age of 85 is the fastest growing segment of the Alzheimer's disease population in the U.S., although current estimates suggest the population between the age of 75-84 has about the same number of patients as the over 85 population.

Today, according to Dr. Haass, Professor at the Ludwig Maximilian University Munich, alone in Germany approximately 1.2 million people suffer from Alzheimer's. In the European Union, there are around 5 million people with dementia, of whom 60–70% are Alzheimer's patients. Around 4.5 million Alzheimer's patients live in the U.S.

With people's life expectancy rising, scientists fear that the number of dementia and Alzheimer's patients will double in the next 25 years if the disease cannot be successfully treated or prevented.