Dr's Casebook: ​More fish and less fast food make depression less likely

More research is needed, but this study is highly suggestive that a diet rich in LCPUFA, as found in seafood and low in PUFA as found in fast food may reduce the risk of depression. Photo: AdobeStockMore research is needed, but this study is highly suggestive that a diet rich in LCPUFA, as found in seafood and low in PUFA as found in fast food may reduce the risk of depression. Photo: AdobeStock
More research is needed, but this study is highly suggestive that a diet rich in LCPUFA, as found in seafood and low in PUFA as found in fast food may reduce the risk of depression. Photo: AdobeStock
​​The other week I mentioned that I recently met up with a doctor friend who emigrated to Australia, where he has practiced for several decades. As happens when medics get together, we talk about health and compare treatments and research. Among the topics we talked about was depression and research into the relevance of diet.

Dr Keith Souter writes: Depression affects about one in seven people at some point in their life. Its cause is often difficult to pin down. Indeed, for some people it is just like a shutter suddenly descending. Fascinating research from two universities in Australia suggests that a healthy seafood-based diet might combat severe depression.

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This was an unusual study done by scientists from James Cook University, involving two hundred Torres Strait islanders. The researchers looked at the link between depression and diet on two islands by interviewing one hundred people on each island. On one island fast food was readily available, while on the other there were no fast food outlets. All participants were asked about their diets, screened for depression and had blood samples taken.

Nineteen people were identified with moderate to severe depression. Sixteen of them lived on the island with processed fast food outlets, as opposed to only three on the island without fast food availability. People with major depression were all younger and had higher take-away food consumption.

The blood samples were analysed in collaboration with the University of Adelaide.

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They found differences between the levels of two fatty acids in people living on the two islands. One of the fatty acids, called PUFA is linked to depression and is found in many take-away foods. The other, called LCPUFA is actually depression fighting and is found in traditional seafood-based diets.

The ratio between the two fatty acids is interesting. In countries with a traditional diet with high fish content and low fast food consumption, the ratio of PUFA to LCPUFA is 1:1.

However, in industrialised countries with fast food availability the ratio is 20:1 That is, the odds are significantly stacked towards the depression associated fatty acid PUFA.

More research is needed, but this study is highly suggestive that a diet rich in LCPUFA, as found in seafood and low in PUFA as found in fast food may reduce the risk of depression.