Older adults who eat plenty of fish and vegetables may live longer than people who don’t, a large Swedish study suggests.

Among more than four thousand 60-year-old men and women, those with the highest blood levels of polyunsaturated fats (PUFAs), which come from fish and plants, were significantly less likely to die from heart disease or any cause over about 15 years than those with the lowest levels.

“The study supports current dietary guidelines that advise having sufficient intake of both fish and vegetable oils in a heart-healthy diet,” senior study author Dr. Ulf Riserus, a nutrition researcher at Uppsala University in Sweden, said by email.

Polyunsaturated and monounsaturated fats are the “good” kind that can promote healthy cholesterol levels, especially when used in place of saturated and trans fats, the “bad” actors.

These good fats are found in fish such as salmon, trout and herring, as well as in avocados, olives, walnuts and liquid vegetable oils such as soybean, corn, safflower, canola, olive and sunflower.

According to current dietary guidelines, most adults should get no more than 20 to 35 percent of daily calories from fats. Most of this should come from good fats, with no more than 10 percent from saturated fats and as little trans fat as possible.

Riserus and colleagues note in the American Heart Association journal Circulation that current evidence suggests the types of fats people consume may be more important than the quantity in affecting the fatty acids circulating in the blood stream as well as cardiovascular risk.

They tested for levels of different types of fats in 2,193 Swedish women and 2,039 men, then followed half of the participants for at least 14.5 years.

During the study, 265 men and 191 women died. In addition, 294 men and 190 women had cardiovascular events such as heart attacks.

Higher circulating levels of one of the fatty acids found in vegetable oils – known as linoleic acid (LA) - were linked to a 27 percent reduction in the likelihood of death during the study among the men, but not the women.

For both men and women, two fatty acids found in fish – EPA and DHA - were associated with roughly 20 percent lower odds of death.

One limitation of the study, the researchers acknowledge, is that the blood test for fats was only done a single time. In addition, the limited number of deaths from cardiovascular disease make it difficult to draw conclusions on the impact of fats, particularly when examined in men and women separately.

The authors also found to their surprise that women with the highest levels of ALA had 72 percent higher risk of cardiovascular disease compared to women with the lowest levels. But since that result isn’t in line with other studies, they speculate it doesn’t mean ALA increases heart risk – rather it could reflect high consumption of margarine, low muscle mass, or other health conditions, they write.

“It is not so clear why there were differences between men and women but it could simply be due to sample size differences and the differences in baseline risk for men and women,” Dr. Edmond Kabagambe, an epidemiology researcher at Vanderbilt University School of Medicine who wasn’t involved in the study, said by email.

The take-home message is one that people hear all the time: eat more plants and fewer animals, Samantha Heller, a nutritionist at New York University's Center for Musculoskeletal Care and Sports Performance who wasn't involved in the study, said by email.

“There is no one miracle food that will launch us into immortality,” Heller said. “The lifestyle as a whole must be considered, including daily physical activity and eating less (of) animal foods like meat, cheese and butter. It is easiest to encourage people to eat a variety of plant foods such as salads, trail mix, roasted vegetables, pasta primavera, almond butter and banana sandwiches, lentil soup, or edamame hummus.”