Fish oil doesn't benefit the brain, study shows

two-years study of people in their 70s didn't find any cognitive change

Fish oil may be good for your heart, but it doesn't seem to help preserve your smarts, a new two-year study shows.

"This is an important finding because a lot of people are taking fish oil in the hopes that it will be good for their cognitive function," Dr. Alan D. Dangour of the London School of Hygiene and Tropical Medicine in the UK, one of the study's authors, told Reuters Health. But he didn't rule out the possibility that taking fish oil for a longer period of time might have beneficial effects.

Numerous studies have shown that people who eat more fish have better mental function, and are less likely to develop dementia. "The problem with a lot of these studies of course is there are lots of reasons why people eat more fish," Dangour pointed out.

To better answer the question of whether fish oil, in and of itself, benefits the brain, Dangour and his team randomly assigned 748 men and women in their 70s — none of whom had any dementia or other impairment of mental function — to take 200 milligrams of eicosapentaenoic acid (EPA) plus 300 mg docosahexaenoic acid (DHA) every day for two years or a placebo capsule containing olive oil. EPA and DHA are the two main omega-3 fatty acids found in fish oil.

Neither group showed any change in cognitive function over the 24-month trial, as measured by a battery of tests of mental function they took at the beginning and end of the study. The percentage of people who died or dropped out was similar in both groups.

"We can clearly say that after two years there's no evidence for a benefit" in terms of cognitive function, Dangour said. He and his colleagues note in their report that theirs is the largest and longest randomized controlled trial to date investigating omega-3s and mental function in older people.

This doesn't mean that people might benefit their brains by taking fish oil capsules for longer than two years, he added. But, he said, "There's no good evidence at the moment from randomized controlled trials that it's good for cognitive function."

 

Fish oil supplements 'beat psychotic mental illness'

Taking a daily fish oil capsule can stave off mental illness in those at highest risk, trial findings suggest.

A three-month course of the supplement appeared to be as effective as drugs, cutting the rate of psychotic illness like schizophrenia by a quarter.

The researchers believe it is the omega-3 in fish oil - already hailed for promoting healthy hearts - that has beneficial effects in the brain.

A "natural" remedy would be welcomed, Archives of General Psychiatry says.

"The finding that treatment with a natural substance may prevent, or at least delay, the onset of psychotic disorder gives hope that there may be alternatives to antipsychotic drugs," the study authors said.

Antipsychotic drugs are potent and can have serious side effects, which puts some people off taking them.

Fish oil supplements, on the other hand, are generally well tolerated and easy to take, say the scientists.

The international team from Austria, Australia and Switzerland tested the treatment in 81 people deemed to be at particularly high risk of developing psychosis.

Natural choice

Their high risk was down to a strong family history of schizophrenia, or similar disorders, or them already showing mild symptoms of these conditions themselves.

For the test, half of the individuals took fish oil supplements (1.2 grams of omega-3 fatty acids) for 12 weeks, while the other half took only a dummy pill. Neither group knew which treatment they were receiving.

Dr Paul Amminger and his team followed the groups for a year to see how many, if any, went on to develop illness.

Two in the fish oil group developed a psychotic disorder compared to 11 in the placebo group.

Based on the results, the investigators estimate that one high-risk adult could be protected from developing psychosis for every four treated over a year.

They believe the omega-3 fatty acids found in the supplements may alter brain signalling in the brain with beneficial effects.

Alison Cobb, of the mental health charity Mind, said: "If young people can be treated successfully with fish oils, this is hugely preferable to treating them with antipsychotics, which come with a range of problems from weight gain to sexual dysfunction, whereas omega-3s are actually beneficial to their general state of health.

"These are promising results and more research is needed to show if omega-3s could be an alternative to antipsychotics in the long term."