Australasian Science: Australia's authority on science since 1938

Omega-3 Controls Zinc In Brain

By Stephen Luntz

Light has been shed on one mechanism by which omega-3 fatty acids benefit the brain, but the research also indicates how much we still have to learn about the role of diet on brain health.

Light has been shed on one mechanism by which omega-3 fatty acids benefit the brain, but the research also indicates how much we still have to learn about the role of diet on brain health.

“Previous research has suggested that there is a link between low levels in the brain of the omega-3 fatty acid DHA –docosahexaenoic acid to give it its full name – and Alzheimer’s disease,” says Prof Leigh Ackland of Deakin Biomolecular Sciences. “Also, the incidence of neuro-degenerative diseases such as Alzheimer’s appears to be reduced in populations with a high omega-3 fatty acid diet.”

The mechanism has been a mystery. However, when providing cultured brain cells with DHA Ackland found that lower levels of zinc resulted. Alzheimer’s is associatedwith high zinc concentrations in the brain, although the direction of causality is unclear. “We believe that having omega-3 fatty acids in the diet helps keep the levels of zinc in the brain in balance and helps prevents the increase in levels that triggers cell death,” Ackland says.

Ackland’s findings were published in the molecular biosciences journal FEBS Letters, but she acknowledges that many questions remain. “Future studies will be directed to understanding the details of the mechanisms by which DHA controls zinc in the brain,” Ackland says. She also wants to find out whether EPA, another omega-3 fatty acid thought to benefit the brain, has the same effect on zinc.

Alzheimer’s is only one of many brain conditions thought to benefit from DHA intake, with Parkinson’s disease, Huntington’s disease and depression also on the list. Ackland suspects that DHA affects these through independent processes rather than zinc being the link in every case.

Many studies suggest that the ratio of omega-3 to omega-6 intake is at least as important as omega-3 levels, but Ackland says that her research sheds no light on this. However, she is confident that reducing zinc intake is not an appropriate response. “Dietary zinc is completely different to mechanisms of zinc operating in body cells,” Ackland says. “Zinc deficiency is a major cause of disease, and possibly mental illness.”