People with Alzheimer's disease who took the common supplement glucosamine were 25% more likely to die within five years than those who didn't. That's the key finding of a new study that my colleagues and I published in the journal Nature Metabolism . Glucosamine is a sugar molecule that's sold over the counter as a remedy for joint pain and arthritis. More than 40 million Americans take it each year. We found that glucosamine also affected people in the earliest stage of memory loss, a