Omega-3 fatty acids protect against Alzheimer's

Apr 18 2007

Scientists in the United States say that diets rich in docosahexaenoic acid (DHA) can help prevent the development of the two brain lesions that are hallmarks of Alzheimer's disease.

DHA is an omega-3 fatty acid found in fish, eggs, organ meats, fortified foods and food supplements.

The team of researchers at the University of California, Irvine, discovered that DHA reduced levels of the protein beta amyloid in genetically modified mice.

Beta amyloid can clump together in the brain and form plaques which disrupts the communication between cells leading to symptoms of Alzheimer’s disease.

DHA also slowed down the accumulation of tau, a protein that leads to the development of neurofibrillary tangles which is another signature brain lesions of Alzheimer’s disease.

The mice in the control group were given food that mimics a typical American diet, with the ratio of omega-6 fatty acids to omega-3 fatty acids being 10:1, an ideal ratio to maintain health is 3:1 to 5:1.

A typical Western diet contains unhealthy ratios ranging from 10:1 to 30:1. Omega-6 fatty acids are found in corn, peanut and sunflower oils.

Mice in three test groups were given food with a 1:1 ratio of omega-6 fatty acids to omega-3 fatty acids; one of these groups received a supplement of DHA only, and two groups received DHA plus additional omega-6 fatty acids.

Three months later the mice in all of the test groups had lower levels of beta amyloid and tau than mice in the control group, but at nine months, only mice on the DHA diet had lower levels of both proteins.

The researchers say the results suggest that DHA works better on its own than when paired with omega-6 fatty acids.

Alzheimer’s affects more than 4.5 million adults in the United States; it is a progressive neurodegenerative disorder and the growth of an aging population means that figure could reach 20 million by 2050.

Five percent of people over 65 are affected, and up to fifty of people will be affected by age 80.

The study adds to growing evidence that diet and lifestyle changes may reduce the risk of developing Alzheimer’s disease.

Frank LaFerla a professor of neurobiology and behavior and a co-author of the study, says the study demonstrates that simple changes in diet can positively alter the way the brain works.

Lead author Kim Green says that people can significantly improve their odds against the disease with mental stimulation, exercise, other dietary intakes and by avoiding stress and smoking.