Globe & Mail • Friday, September 3, 2004

A diet rich in omega-3 fatty acids, which are found in fish such as salmon and sardines, and in fish-oil capsules, can help keep Alzheimer’s disease at bay, a new Canadian study suggests. The research, which was done on mice, provides the strongest evidence so far that a deficiency in a specific dietary component can have a direct impact on a person’s risk of developing the devastating neurological disease.

“What the public needs to take from this is that diet matters to your brain,” said Frederic Calon, a molecular endocrinology researcher at the Laval University Medical Centre in Quebec City. “If you have a diet that is poor in omega-3s, that will accelerate the process of Alzheimer’s, especially if you’re genetically predisposed,” he said in an interview.

A number of studies have suggested that people who eat a diet rich in fish are less likely to develop Alzheimer’s and heart disease. Although the mechanism was unclear, the hunch was that it was due to omega-3s. Omega-3 fatty acids have become so popular with health-conscious consumers that food manufacturers are adding them to products such as eggs and milk. The eggs are produced by feeding chickens a special diet of flaxseed, which is rich in omega-3. The milk, available from Canadian marketer Natrel in British Columbia, Ontario and Quebec, is enriched with organic flaxseed oil.

Carol Dombrow, a registered dietician and nutrition consultant with the Heart and Stroke Foundation of Canada, said the growing popularity of omega-3 could even rival the hugely successful Atkins diet craze. “I think people are looking for the magic bullet and, if this is a positive thing . . ., you are going to start to see more and more food products with the fatty acids,” she said. Frederic Calon is a molecular endocrinology researcher at Laval University. Results of his study have spurred him to alter his diet.

The researchers realized the diet the mice were being fed - soy and fish - was chock-full of omega-3s. So the researchers started a new study, feeding one group of mice the soy and fish diet and a second group a diet of safflower oil devoid of omega-3 fatty acids. After five months, they dissected the rodents’ brains. “We found high amounts of synaptic damage in the brains of the Alzheimer’s-diseased mice that ate the DHA-depleted diet,” said Sally Frautschy, an associate professor of neurology at the University of California at Los Angeles and co-author of the study. They also found low levels of DHA in the brains of the mice and evidence of inflammation and cell damage caused by oxidative stress, conditions that DHA is known to protect against. “These changes closely resembled those we see in the brains of people with Alzheimer’s disease,” Dr. Frautschy said. The mice fed a diet poor in omega-3s also did poorly in memory tests, further evidence of brain damage. The study was partly funded by the Canadian Institutes for Health Research.

Health Canada recommends that people consume about 1.4 grams of omega-3s daily, the equivalent of two servings of dark, fatty fish a week. Other groups such as the American Heart Association have more precise guidelines, suggesting that people get 900 milligrams daily of two key omega-3s, DHA and EPA (eicosapentaenoic acid), a level that is difficult to achieve without taking fish-oil supplements.

Dr. Calon said that while the new research does not provide the final answer, he believes that increasing the intake of omega-3s, and DHA in particular, likely offers some protection against Alzheimer’s disease. “We know that DHA is important to brain health and that deficiencies are unhealthy, and there’s no real downside to eating more fish or to taking capsules,” he said. “I can tell you that those of us who conducted this research have really increased our fish consumption,” he added.

Good sources of omega-3s include cold-water fish such as salmon, halibut, mackerel, sardines and herring, and fish-oil supplements. These fish consume algae, which is high in DHA.

Alzheimer’s is a degenerative disorder that destroys vital brain cells. It is characterized by the buildup of plaque in the brain. About 354,000 Canadians suffer from the disease, according to the Canadian Alzheimer Society. Beyond genetics, a number of factors are believed to contribute to Alzheimer’s and related dementias. They include other medical conditions such as diabetes and cardiovascular disease, obesity, poor nutrition, smoking and head injuries. Studies show that people with low incomes, and in certain occupations, are far more likely to develop Alzheimer’s. Studies have also shown that people who are mentally active - doing crossword puzzles, reading and playing games - are at lower risk.

BY ANDRE PICARD, PUBLIC HEALTH REPORTER, WITH A REPORT FROM ERIN POOLEY