Healthnotes Newswire (December 27, 2007)—Eating well can take us a long way toward enjoying good health into old age. In a new study, eating fruits, vegetables, omega-3-rich vegetable oils, and fish were found to reduce Alzheimer’s disease risk.

People with age-related dementia experience a chronic, progressive loss of mental functioning. Alzheimer’s disease, which has a strong genetic component, is the most common cause of dementia in the elderly. There is increasing evidence that diet and lifestyle alter the risk of dementia, including Alzheimer’s disease, even in people who carry the Alzheimer’s-related genetic pattern.

In previous research, physical activity has been shown to reduce the risk of dementia in older people. Regular exercise has also been found to improve mental functioning in people who already have Alzheimer’s disease. Other studies have found that eating foods rich in antioxidants (primarily fruits and vegetables) and omega-3 polyunsaturated fats (primarily from fish) reduce the risk of age-related dementia.

The new study, published in Neurology, examined the eating habits of 8,085 people over 65 who lived in urban communities in France. All of the people in the study had medical exams and were found to have no dementia at the beginning of the study. They were then followed for signs of dementia for about three and a half years.

Eating fish once per week decreased the risk of dementia and Alzheimer’s disease—but only in people without the genetic pattern associated with Alzheimer’s disease. However, eating fruits and vegetables protected people with and without the genetic vulnerability: the risks of dementia and Alzheimer’s disease were both about 30% lower in those who ate fruits and vegetables every day compared with those who never ate them. 

Walnut oil, soybean oil, and colza oil (an oil similar to canola oil that is used extensively in many parts of Europe) are good sources of omega-3 polyunsaturated fatty acids. Although their fatty acids differ somewhat from the fatty acids in fish, in this study they appeared to strongly protect against dementia and Alzheimer’s disease.

“This study shows an apparent protective effect of dietary sources of both essential (vegetable oils) and long-chain (fish) omega-3 polyunsaturated fatty acids against dementia,” the study’s authors concluded. “A diet rich in fruits and vegetables also seems to exert protective effects which may be attributed to their antioxidant compounds (vitamin C, carotenoids, flavonoids) but also to vitamins B, phytoestrogens, and fiber.”

The researchers also pointed to evidence that some interaction between the omega-3 fatty acids and antioxidants is responsible for reducing dementia risk. In other words, it appears that the best way to prevent dementia and Alzheimer’s disease is to include vegetables and fruits and fish or omega-3-rich vegetable oils in your regular diet.

(Neurology 2007;69:1921 –30)