Researchers at the University of Southern California tested whether daily fish oil supplements could protect brain health. Their two-year study involved 365 adults ages 55 to 80 who rarely ate fish and had an increased risk of Alzheimer's disease. Participants were randomly divided into two groups. One received fish oil, while the other received a placebo, an inactive treatment used for comparison.
The supplements contained DHA, an omega-3 fat that supports brain cells and communication between them. After six months, DHA levels in the fluid surrounding the brain and spinal cord rose by an average of 17% in the supplement group. However, after two years, these participants performed no better on memory and thinking tests than those taking the placebo. Brain scans also showed that the supplements did not prevent shrinkage of the hippocampus, a region important for forming memories.
The findings do not mean that omega-3 fats are unnecessary or that eating fish has no health benefits. Instead, they show that increasing DHA through supplements did not provide measurable protection in this group. Researchers are investigating how the brain uses these nutrients and whether diet and overall health affect that process. They recommend regular exercise, quality sleep, and a balanced diet rather than relying on fish oil alone.
