It’s time to start trusting your gut — at least when it comes to staying young and living longer. Research has shown that the gut microbiomes of healthy older people — including those in their 90s over age 100 — often resemble those of people who are decades younger. But your gut microbiome isn’t just a matter of chance: Fine-tuning it can turn back time, leading to better metabolism, sleep, thinking and immunity, according to microbiome expert Colleen Cutcliffe, Ph.D. “Even though our