Restricting one amino acid extends lifespan in mice

What's the news: Isoleucine restriction improves health and longevity in mice.

Why should we believe it: This news is based on a new study published yesterday by scientists at the University of Wisconsin. The scientists looked at the effects of restricting the amino acid isoleucine by 67% in the diets of lab mice. The treated mice showed:

• Greater leanness

• Improved metabolic health

• Reduced frailty

• Extended lifespan (33% longer)

Why this is a big deal: This study offers another clue that restricting specific amino acids can have beneficial health and longevity effects and feeds into similar research in humans. For example, at the start of this year, scientists found that restricting methionine and cysteine in humans lowered body weight, improved cholesterol and other blood markers, and improved metabolic function.

So what's next: Entirely eliminating isoleucine from your diet is neither practical nor desirable. Isoleucine is found in most protein sources, including plant protein. It's also an essential amino acid, meaning your body needs a base level.

That said, we might soon start to see interventions that restrict specific amino acids. This could happen at the food level, such as amino acid supplements that have specific amino acids removed.

It could also happen inside us. An interesting new approach is gut bacteria that break down specific amino acids before they are absorbed into the body, effectively giving us all the benefits of amino acid restriction without any of the hassle.