Does fish oil improve mood, cognitive function?

Photo: Jenny Fontaine

“I’m a lipid biochemist,” said Papasani Subbaiah, professor of medicine in the department of diabetes/endocrinology and metabolism in the UIC College of Medicine.

Subbaiah’s career has focused on analyzing the role of lipids — the molecules that make up fat in the body — for more than 40 years. His contributions have added to knowledge in several fields including Alzheimer’s disease and other neuroinflammatory diseases, atherosclerosis and metabolism.

But he is most excited about the direction of his current research, which suggests that the fish oil capsules many people take to improve cognitive function and mood may not provide the benefits promised.

The main active ingredient in fish oil capsules is omega-3 fatty acids, which can take two different forms, one of which is docosahexaenoic acid, or DHA. DHA is present in the brain and acts as a powerful anti-inflammatory agent, but over time its function wanes. This deterioration in function is believed to play a significant role in the development of Alzheimer’s disease and other neuroinflammatory disorders.

Fish oil capsules are marketed based on the idea that supplementing DHA by taking the capsules will replace DHA lost or degraded in the brain. But Subbaiah has found that the form of DHA in these supplements does not cross the blood-brain barrier.

“DHA in fish oil can be absorbed by other organs of the body where it is beneficial, such as the heart and liver, but it can’t get into the brain to have any neurological or neurocognitive effects,” Subbaiah said. “There is another form of DHA called lyso-PC that can cross the blood-brain barrier, and we have shown in mice that we can increase DHA in the brain by about 100 percent when we feed mice lyso-PC for one month at low tolerable doses.”

Subbiah’s mice fed lyso-PC also performed better on tests of memory. He hopes to determine the effects of lyso-PC in a mouse model of Alzheimer’s disease.

“This isn’t a drug,” said Subbaiah. “It’s a dietary fat that represents a novel way to get DHA into the brain, and it could have a big impact on preventing or treating Alzheimer’s and other brain disorders.”