We're told repeatedly to consume more omega-3 fatty acids to guard against heart attack, stroke, even Alzheimer's disease. It's also advice that might protect children from Type 1 diabetes, according to a study published in today's issue of the Journal of the American Medical Association.
More than 200,000 Canadians have Type 1 diabetes, a lifelong condition that occurs mainly in childhood and early adolescence and requires daily insulin injections for survival.
In Type 1 diabetes, the body makes little or no insulin, the hormone that clears sugar from the bloodstream. The body's immune system behaves inappropriately by producing auto-antibodies, compounds that destroy the insulin-producing cells of the pancreas.
Scientists speculate that genetic background and environmental factors - including diet - play a role in the autoimmune process that leads to diabetes. Studies suggest that inflammation is involved in the development of Type 1 diabetes. Since omega-3 fats have strong anti-inflammatory properties, it's thought they might help reduce the risk of the disorder.
Without enough insulin, glucose builds up in the bloodstream instead of going into the cells where it's used for energy. Symptoms of Type 1 diabetes include thirst, weight loss despite increased appetite, increased urination, abdominal pain and fatigue.
In the study, researchers from the University of Colorado at Denver and Health Sciences Center examined the influence of omega-3 fatty acid intake on diabetes in 1,770 children, aged 1 or older, who were at increased genetic risk for developing Type 1 diabetes. (Children were considered "increased risk" if they had a parent or sibling with Type 1 diabetes or they possessed certain genes associated with greater risk for the disease.)
Parents were asked annually to recall the diets of their children, including how often they ate certain types of fish and seafood and which oils were used in cooking. Omega-3 fat intake was measured at 3, 5, 7 and 9 years of age.
Three omega-3 fatty acids are found in food: DHA (docosahexaenoic acid), EPA (eicosapentaenoic acid) and ALA (alpha linolenic acid). Cold-water fish such as salmon, trout, sardines, tuna, mackerel and herring contain DHA and EPA. ALA is plentiful in flax, canola and walnut oils as well as soybeans. Once consumed, some ALA is converted to EPA and DHA in the body.
Children also took regular blood tests to detect the presence of auto-antibodies that attack the cells of the pancreas. During the study, children who consumed more omega-3 fats were less likely to test positive for the auto-antibodies.
For each 800-milligram increase in daily omega-3 fat intake - the amount found in 1.3 ounces of Atlantic salmon, two teaspoons (10 ml) of canola oil, or four walnut halves - the risk of developing diabetes auto-antibodies in the bloodstream was reduced by 55 per cent over the course of the study.
Children in this study consumed most of their omega-3 fats from plant sources rather than seafood.
Previous research has also hinted that omega-3 fats help prevent Type 1 diabetes. A study from Norway revealed that children with diabetes were less likely to have been given cod liver oil during infancy than children without diabetes. And studies conducted in animals have demonstrated the ability of omega-3 fats to reduce diabetes risk.
While the link between omega-3 fats and prevention of Type 1 diabetes needs further research, there are other good reasons to boost your intake of these healthy fats.
Strong evidence suggests that a regular intake of DHA and EPA reduces the risk of heart attack and stroke. That's why Health Canada and the Heart and Stroke Foundation advise Canadians to consume fatty fish at least twice per week.
DHA may also help relieve depression and inflammatory disorders such as rheumatoid arthritis, asthma and colitis. It's also needed for the development and maintenance of the brain, eye and nerve tissues throughout life. DHA supplements have even been shown to enhance learning in children.
