Eating oily fish rich in omega-3 fatty acids can add years to your life, a study has shown.
Higher blood levels of omega-3 reduce the chances of dying from heart disease by more than a third, according to the research.
They cut the overall risk of dying by as much as 27%.
Scientists found that people with the largest amounts of the fatty acids in their blood lived on average 2.2 years longer than those with lower levels.
"Although eating fish has long been considered part of a healthy diet, few studies have assessed blood omega-3 levels and total deaths in older adults," said lead researcher Dr Dariush Mozaffarian, from the Harvard School of Public Health in the US.
"Our findings support the importance of adequate blood omega-3 levels for cardiovascular health, and suggest that later in life these benefits could actually extend the years of remaining life."
The scientists analysed 16 years of data from around 2,700 US adults aged 65 and older taking part in the Cardiovascular Health Study (CHS). Participants gave blood samples and were questioned about their health, medical history and lifestyle. Three key omega-3 fatty acids, both separately and together, were associated with a significantly reduced risk of death.
One, docosahexaenoic acid ( DHA) , was linked to a 40% lower risk of death due to coronary heart disease. This was especially true for deaths caused by heart rhythm disturbances. Another omega-3 compound, docosapentaenoic acid (DPA) was strongly associated with a lower risk of death from stroke.
The third type of omega-3, eicosapentaenoic acid (EPA) was linked to a reduced risk of non-fatal heart attack. Overall, participants with the highest levels of all three types of fatty acid had a 27% lower risk of death from all causes.
The findings appear in the online edition of the journal Annals of Internal Medicine. Oily fish, such as mackerel, tuna and sardines, is the most important source of omega-3. The fatty acids can also be found in flaxseed, walnuts and rapeseed oil.