Peer-reviewed research shows that long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFAs) -- namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) -- feed the human brain and may improve psychiatric conditions as well as visual function.
A guest commentary on n-3 LC-PUFAs and the brain reveals that DHA helps cell membranes, intracellular metabolism, and regulation of gene expression. It also shows that DHA is key to brain metabolism and both DHA and EPA are beneficial in neuropsychiatric conditions.
"Manic-depressive illness, depression and schizophrenia are common neuropsychiatric disorders," writes Andrew Sinclair, Ph.D., professor of food science, RMIT University, Melbourne, Australia. "Results from case-control studies, clinical trials and case studies have shown that oils rich in n-3 LC-PUFAs play a beneficial role in these neuropsychiatric conditions."
Other studies show that DHA also plays a role in retinal cell signaling and, thus, helps optimize visual function. Vitamin A intake may enhance the beneficial effects of n-3 LC-PUFAs on eyesight.
"A diet rich in fish omega-3s with vitamin A supplementation may retard premature visual loss in retinitis pigmentosa," notes Joyce Nettleton, D.S.c, RD, editor, PUFA Newsletter.
More new research shows that fish consumption in a calorie-restricted diet among overweight subjects with high blood pressure enhances the beneficial effects of weight loss. With both caloric restriction and daily fish consumption, reductions in blood pressure and improvements in fat profile, heart rate and sugar metabolism are greater than with weight loss alone.
"These benefits are also effective in simultaneously reducing the risk of stroke, cardiovascular disease and myocardial infarction," Nettleton says.
Moreover, consumption of n-3 PUFAs may reduce allergic inflammation in airways, reducing the severity of asthma and improving the quality of life in children at high risk of developing asthma.
Some day, n-3 LC-PUFAs, which are only naturally occurring in fish and algae, may be available from bioengineered oilseed plants. Scientists recently took another step in this direction by getting yeast and linseed to synthesize DHA with only low levels of unwanted by-products.