We’ve all read or heard that eating fish is good for your brain. Indeed, a large study in 2008 hit the headlines when it claimed that eating oily fish can reduce the harmful brain lesions that are associated with Alzheimer’s disease.
But do these claims stand up to scrutiny? A good source of information are Cochrane Reviews, which independently analyse all the available evidence to inform healthcare decision-making. And the evidence for oily fish and its impact on the brain isn’t convincing. For example, a 2012 Cochrane Review showed that fish oils made no difference in preventing dementia.
A similar Cochrane Review in 2016 found that fish oils also made no difference for people who already had Alzheimer’s disease. What about depression? Unfortunately, a 2015 Cochrane Review found that more evidence was needed as to whether fish oils have any benefit.
So it looks like there is little hard evidence that oily fish improves cognitive function, protects against conditions such as dementia, or helps people with depression. However, some studies have shown a benefit in mice, so maybe more research is needed.
Nonetheless, the NHS still recommends eating oily fish as part of a healthy diet, because it is likely to have some positive health benefits, including reducing the risk of heart disease.