Single protein promises to extend healthy human lifespan

A new study shows that manipulating a single protein may offer the life-extending value of calorie restrictions – without actually cutting calories.

Limiting the calorie intake of flies, worms and mice has been found to enhance their lifespan in laboratory conditions. For years, no one knew why. And, no one knew if it would work with humans.

Yale researchers studying the benefits of calorie restrictions on humans found that PLA2G7, a protein produced by immune cells known as macrophages, may be the answer.

Their study began by focusing on the human thymus gland, which is located between the lungs and above the heart. Researchers chose the thymus because it ages faster than other organs. By the time a healthy adult reaches age 40, about 70% of the thymus is fatty and non-functional. As a result, it produces fewer T cells to protect the body from infection. This explains why older people are more susceptible to illness.

After setting calorie baselines for 200 study participants, the Yale team reduced calorie intake for some. For two years, this restricted group consumed 14% fewer calories than the baseline and researchers analyzed the health effects.

They found that thymus glands in calorie-limited participants had less fat and greater functional volume after two years. They also found the thymus produced more T cells after calorie restriction than before. There was no T cell improvement with the other group.

Effectively, the study found that the thymus can be rejuvenated, to restore its more youthful function. It surprised Yale researchers, who set out to understand why.

They turned to mice studies, which pinpointed PLA2G7 by focusing on group VII A platelet activating factor acetylhydrolase, a gene that is significantly inhibited after calories are restricted.

Reducing the protein resulted in the aged mice’s thymus glands functioning longer, protecting them from inflammation. This mirrored benefits that calorie restriction caused in humans.

The question now is whether manipulating PLA2G7 will actually deliver the benefits of restricting calories, without actually “dieting,” since calorie restriction may be harmful for some people.

The research may also be useful in ending the arguments over what is the “best way” to cut calories -- low-carb, no-carb, low-fat, high-fat, high-protein or fasting diets. This study suggests that how someone restricts calories – or the kinds of calories they restrict – may not matter much.

Yale’s findings once again shows that there are many layers to the issue of longevity.  Decades of work clearly demonstrate there is no magic anti-ageing pill.  No single solution will undo all the effects of aging. 

To achieve Methuselah Foundation’s goal of making 90 the new 50 by 2030, we need to keep exploring multiple avenues. If you’d like to help us achieve our mission, donate.