High levels of omega-3 in the blood increases life expectancy by nearly five years – the equivalent of stopping smoking.

A long study of the omega-3 levels in just over 2,200 people aged 65 and over found that “having higher levels of these acids in the blood, as a result of regularly including oily fish in the diet, increases life expectancy by almost five years”.

The study, involving the Hospital del Mar Medical Research Institute (IMIM), in collaboration with The Fatty Acid Research Institute in the United States and several universities in the United States and Canada, used data from a long-term study group, the Framingham Offspring Cohort, which has been studying residents of the American town since 1971.

Study author Dr Aleix Sala-Vila, a postdoctoral researcher from the IMIM, said: “Being a regular smoker takes 4.7 years off your life expectancy, the same as you gain if you have high levels of omega-3 acids in your blood.”

The results of the study suggest that four types of fatty acids, including omega-3, are good predictors of mortality. Two are saturated fatty acids, which are normally associated with cardiovascular risk, but in this case, indicate longer life expectancy. Their levels in the blood cannot be changed by diet, whereas omega-3 can.

Dr Sala-Vila said: “This reaffirms what we have been seeing lately – not all saturated fatty acids are necessarily bad.”

The research team say the findings could aid the development of personalised dietary plans, based on an individual’s blood concentrations of different fatty acids.

The American Heart Association advises people to eat oily fish, such as salmon, anchovies or sardines, twice a week to boost levels of omega-3 acids.

Dr Sala-Vila added: “What we have found is not insignificant. It reinforces the idea that small changes in diet in the right direction can have a much more powerful effect than we think, and it is never too late or too early to make these changes.”

The study has been published in The American Journal of Clinical Nutrition.

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