Can we improve how we age and how long we live by restricting what we eat? Nearly all signs point to yes. In this article, I will describe three major categories of dietary restriction that have been explored, the evidence of efficacy, and some of the limitations that stand in the way of our understanding of this topic.
Numerous studies on a diverse range of organisms, including bacteria, yeast, worms, flies, rodents, and primates, have shown that dietary restrictions, such as chronic or intermittent fasting, can slow down biological aging and increase maximum lifespan substantially, by up to 50% in some protocols. Some of the mechanisms by which these different dietary-restriction regimens work have been identified. Many of them are metabolic pathways that are shared across species, including humans. It is therefore reasonable to think that the beneficial effects on lifespan, in let’s say a worm or mouse, could also occur in humans. Definitively proving this, however, is difficult because longevity studies to utilize any type of intervention in humans inherently require decades of adherence to a protocol, along with decades of follow up by the research team. That’s why we love to do aging research in worms that have a twenty-day lifespan! But ultimately, in order to move from non-human intervention to safe and effective human application, we need to study promising interventions in humans. The good news is that human studies have been carried out, but instead of directly measuring lifespan, biomarkers are used. Biomarkers are biological characteristics that can be objectively measured today that can predict important health outcomes—in this case, biological aging. (Read More)