The omega-3 DHA (docosahexaenoic acid) improved memory, vision and motor control in boys, enhanced mental function in adult men and women, and may help prevent Alzheimer’s disease by regulating zinc in brain cells, three new studies reveal.
Doctors in a brain study said that earlier studies found DHA improves brain function, and wanted to see how DHA affects the cerebral cortex (the area of the brain involved in memory), attention, thought, language and awareness.
Thirty-three healthy boys, aged 8 to 10, took 400 mg or 1,200 mg of DHA per day or a placebo for eight weeks. Using an MRI, researchers scanned for brain activity as the boys played video games. Boys who took DHA had much more blood flow in the area of the brain for working memory, and in the vision processing and motor control centers. Researchers hope this research will help resolve brain-related problems such as attention deficit hyperactivity disorder and depression, where DHA is often deficient.
In another brain study, doctors measured blood levels of DHA in 280 men and women, aged 35 to 54, who were not taking fish oil or omega-3 supplements, and who had no major neuropsychiatric disorders. Researchers gave participants a 75-minute battery of mental tests and found that those with higher DHA levels performed better in nonverbal reasoning, mental flexibility, working memory and vocabulary compared to those with lower levels.
In another DHA study, researchers measured DHA in brain cells and found that as DHA levels fell, the level of zinc rose. Doctors said higher zinc levels can be toxic, causing cell death, a key feature of Alzheimer’s disease, and believe that DHA helps keep brain-cell zinc levels in balance. This is the first study to find a direct link between DHA and zinc levels in brain cells.