Omega-3 pills are among the most popular dietary supplements in the US. But these pills may not be living up to their claims.
A new study from the National Eye Institute found that omega-3 long-chain polyunsaturated fatty acids (LCPUFAs) supplements may not safeguard against cognitive decline.
Dementia is a general term for a decline in mental ability severe enough to interfere with daily life. Alzheimer’s disease is the most common form of dementia.
Other health conditions can also cause cognitive decline.
Previous research has found that diets high in LCPUFAs may reduce the risk of cognitive decline. Once dementia occurs, however, supplements cannot reverse this process.
Michelle Papka, PhD, a neuropsychologist and the founder of the Cognitive and Research Center of New Jersey, told dailyRx News, "Most of the studies assessing the efficacy of dietary supplements on cognition have not revealed significant effects, however additional research is needed. It may be that individual supplements by themselves are not efficacious, but a particular cocktail of supplements is — and we don’t know yet what combination is most promising."
Emily Y. Chew, MD, of the National Eye Institute and the National Institutes of Health, led this study of more than 4,000 patients. Most were women, with an average age of 73.
These patients also participated in the Age-Related Eye Disease Study 2, which focused on dietary supplement use to protect against age-related eye degeneration.
Dr. Chew and team randomly assigned the patients to one of three groups.
The first group was given LCPUFAs, while the second group was given LCPUFAs with a combination of lutein and zeaxanthin.
Lutein and zeaxanthin are nutrients in leafy green vegetables that have been found to reduce the risk of chronic eye diseases.
The third group was given a placebo.
The patients were followed for five years. Cognitive testing was conducted after one, three and five years.
Dr. Chew and team found no differences in cognitive function for any of the three groups.
In a related editorial, Sudeep S. Gill, MD, and Dallas P. Seitz, MD, PhD, both of Queen’s University in Ontario, Canada, noted that healthy lifestyle choices may be more important for preventing cognitive decline.
“It is still likely that lifestyle factors such as diet and physical activity have important roles in the prevention of cognitive decline, dementia, and performance of the activities of daily living," Drs. Gill and Seitz wrote. "Physicians should encourage patients of all ages to optimize physical activity levels throughout their life [and] adherence to Mediterranean or heart healthy diets throughout life..."
Dr. Papka told dailyRx News that the earlier a patient engages in healthy lifestyle choices, the more they may stand to benefit.
"However, there is also research to suggest that healthy eating and exercise initiated at later ages still reduces risk factors for dementia, so it is never too late to start," Dr. Papka said.
This study and editorial were published in the August issue of JAMA.
National Institutes of Health, The National Eye Institute, the Office of Dietary Supplements and multiple other organizations funded this research.
No conflicts of interest were disclosed.