The cell's waste collection

The cell does not throw damaged parts away. It takes them apart and builds the pieces back in. With age, this cleanup slows down.

How the cleanup works

Faulty proteins and worn-out parts are wrapped in a membrane, broken down, and their components are reused. The technical term is autophagy, which literally means "self-eating". The older the body, the more sluggish this process becomes, and as a result, damaged material builds up.

Spermidine

In 2009, research showed that spermidine triggers this cleanup and extends lifespan in several kinds of laboratory animals. In 2016, there followed signs of protective effects on the heart in mice.

What the population data say

The most important observation in humans comes from South Tyrol. In the Bruneck study, participants were followed for twenty years. Those who took in the most spermidine through their diet had a clearly lower mortality than the group with the lowest intake.

And what the studies with supplements say

Here the picture is mixed, and it is worth taking a close look. A one-year study with a hundred participants missed its main goal: memory performance and lab values did not differ from the dummy treatment.

On the other side are the positive results of the smaller pilot study, the observational data from Bruneck pointing in the same direction, and a solid body of animal data.

The most sound reading at present is not that the link has been disproved, but that it looks different over different time spans: visible over decades of diet, but not within a single year and when measured by memory. For a process aimed at maintenance, this is hardly surprising.

Apigenin

Apigenin, a plant substance found in celery among other foods, is being studied for a different route: it slows down the enzyme CD38, which breaks down NAD. This closes the circle to the topics of cellular energy and metabolic switches.