NORWICH, United Kingdom — What’s the secret to eternal youth? As scientists look for ways to extend life, a new study suggests the answer to healing older brains may be hiding in younger guts. Researchers say fecal transplants not only affect your gut health, they can alter your brain too. An international team finds fecal transplants from older to younger mice impacts the learning and memory abilities of the recipient. By altering the gut microbiome of the younger mice, researchers say they began to act more like their older donors. These changes included some of the same cognitive impairments older...