For the first time, researchers have identified a molecular mechanism that is involved in the benefits of dietary restriction.

Dietary restrictions are best known for having the ability to slow aging in laboratory animals, the Harvard School of Public Health reported.

The recent findings revealed restricting two amino acids, methionine and cysteine, increased hydrogen sulfide (HS2) production and reduced ischemia reperfusion injury (tissue damage occurring during interruptions in blood flow such as what occurs during a stroke). This effect has also been linked to an increased lifespan in worms, fleas, and yeast.

HS2 gas is extremely toxic in high amounts, but low levels of the substance have been known to hold health benefits. Mammalian cells also produce low levels of H2S.

"This finding suggests that H2S is one of the key molecules responsible for the benefits of dietary restriction in mammals and lower organisms as well," said senior author James Mitchell, associate professor of genetics and complex diseases. "While more experiments are required to understand how H2S exerts its beneficial effects, it does give us a new perspective on which molecular players to target therapeutically in our efforts to combat human disease and aging."

In the past dietary restrictions (such as reduced calorie consumption, cutting back on certain diet components like protein, and periods of fasting) have been linked to significant health benefits, but the molecular mechanisms behind these effects have been largely unknown.

"These findings give us a better understanding of how dietary interventions extend lifespan and protect against injury. More immediately, they could have important implications for what to eat and not to eat before a planned acute stress like surgery, when the risk of ischemic injury can be relatively high," said first author Christopher Hine, research fellow in the Department of Genetics and Complex Diseases.

The findings were published in a recent edition of the journal Cell.