Living with a Bile: How Low-Caloric Acid Triggers the Health Benefits of Low-Carbohydrate Diets
Across the ancient world, physicians from Greece to China touted the health benefits of bile and fasting. Today, the focus is on regular meals and exercise, but perhaps those ancient doctors were onto something. In two papers in Nature, Qu and colleagues1,2 make a compelling case that a component of bile called lithocholic acid (LCA) triggers many of the age-defying and potentially lifespan-extending health benefits of low-calorie diets.
D.A.S. is a co-founder, consultant, board member and equity owner of Galilei Biosciences and MetroBiotech, companies working to treat diseases with SIRT6 activators and NAD boosters, respectively. He is an equity owner of the company. The sinclair.hms.harvard.edu has other activities.
The metabolic changes caused by the restriction of calories in mice have been analysed by Biochemist Sheng-Cai Lin. It was a daunting task: most of the compounds made during metabolic reactions change in abundance during starvation or calorie restriction, says Lin. “We took a brute-force approach.”
But constant hunger is not the only price of calorie restriction, which can involve slashing caloric intake by more than half; studies have also linked it to loss of lean muscle mass, difficulty in regulating body temperature and possibly increased risk of infection, says Andrea Di Francesco, who studies the biology of ageing at Calico Life Sciences, a biotechnology company in South San Francisco, California.
Longevity and Ageing of Mice, Flies and Nematodes: Evidence of Supplementation with Lithocholic Acid
The team then fed lithocholic acid to nematodes, fruit flies and mice. The fruit flies and nematodes lived significantly longer than those that had not consumed added lithocholic acid.
The study of ageing and longevity is littered with claims that certain compounds extend lifespan — claims that did not survive closer scrutiny. The papers are very thorough according to Nicholas Schork, lead investigator on the Longevity Consortium of the US National Institute on Aging. “I found them very compelling,” says Schork, who was not involved in the works. “They went way beyond what many other groups have done to make claims about potential health benefits.”