Researchers at Stanford University found that feeding roundworms the monounsaturated fat in olive oil prolonged their lifespan. Given the similarities in monounsaturated fat metabolism between roundworms and humans, they believe it’s possible the longevity effect could extend to people.
Fat composition rather than fat level is important for longevity and that not all fatty acids have the same effect on health.
The authors were surprised the monounsaturated fat that extended life also caused the roundworms to gain weight. As calorie restriction is associated with longevity, they didn’t anticipate that an accumulation of this particular kind of fat would be beneficial in that regard. However, since the pudgy roundworms fed the monounsaturated fat lived longer than their thinner counterparts, it indicated a certain type of fat buildup could be healthful.
“We have known for some time that metabolic changes can affect lifespan, but we expected the long-lived animals in our study would be thinner,” said senior author Anne Brunet, professor of genetics. “Instead, they turned out to be fatter. This was quite a surprise.”
The study originated as an investigation into the role of epigenetics in lifespan regulation. Epigenetics is the process by which gene expression changes in response to environmental stimuli. The researchers’ objective was to determine how epigenetic complexes, which modify the proteins that package DNA (also known as histones), might influence roundworm metabolic changes in a manner that affects lifespan.
With this intent, Brunet and lead author Graduate student Shuo Han evaluated the effect of blocking the expression of an epigenetic complex called COMPASS on the metabolism of roundworms. The COMPASS proteins are known to change the chemical composition of proteins that package DNA (histones) in a way that can affect whether or not genes are expressed. After they blocked the expression of COMPASS proteins, the worms lived 30 percent longer. Han wanted to understand why.
“We thought that this epigenetic modification change caused by COMPASS deficiency might mimic dietary restriction,” Brunet said. “So we began looking at the metabolism and fat content of the worms deficient for COMPASS.”
Han observed that the roundworms with the blocked COMPASS proteins not only lived longer, but they also accumulated fat in their intestines. Analysis of the fat revealed it was primarily composed of monounsaturated fatty acids, which is the type of fat contained within olive oil, avocados, and nuts. Han found that suppressing the COMPASS proteins caused a rise in the expression of enzymes that change saturated fats into monounsaturated fat in the intestines. Because monounsaturated fats have been linked to a lower risk of cardiovascular disease and diabetes, the finding was intriguing.
In an effort to ascertain if the accumulation of monounsaturated fats affected lifespan, the researchers fed both monounsaturated and polyunsaturated fats to the worms. “We found that the monounsaturated fats accumulated in the worms’ guts and increased their life span even when COMPASS was not mutated. In contrast, polyunsaturated fats did not have the same effect,” said Brunet.
Prior research shows the type of fat consumed has a much greater influence on health than the quantity, and the recent experiment builds upon what is known on the topic. “Our study suggests that fat composition rather than fat level is important for longevity and that not all fatty acids have the same effect on health,” Brunet told Olive Oil Times.
Currently, the research team is seeking the answer to why monounsaturated fat buildup appears to extend life. While they have yet to learn the mechanism of action that underlies the benefit, this recent discovery provides more evidence that the fat in extra virgin olive oil is most healthful.
The study was published in the journal Nature.