Every three seconds, someone in the world develops Alzheimer's disease. It's a devastating disease: millions of people, as well as their caretakers, spend years dealing with disabling disorientation and memory loss. Today, it's the sixth leading cause of death in the U.S. By 2050, an estimated 15 million people in America will have Alzheimer's—the combined populations of New York, Chicago, and Los Angeles. But, after years of failed drug trials, scientists are now realizing that the disease begins with structural changes in the brain decades before sufferers show any symptoms. And some researchers now believe that diet may be the most important factor in determining whether or not those brain changes take place. Listen in now to find out: Can changing what you eat prevent Alzheimer's?

In 1906, German psychiatrist Alois Alzheimer dissected and stained the brain of a deceased patient. Auguste Deter had died in her fifties, after suffering from memory loss and delusions. In his postmortem examination, Alzheimer noticed Deter's brain was clogged with gunk: agglomerations of proteins had formed pathological structures that are now called amyloid plaques and tau tangles. Though dementia has been recognized for millennia—the ancient Greek physician Galen called dementia "morosis"—Dr. Alzheimer was the first to see the physical effects of the disease's most common cause on the brain.

Today, more than a century later, and despite hundreds of millions of dollars spent studying it, there is no cure for Alzheimer's disease, and not much in the way of treatment, either. There are a few medications that help manage symptoms, but as Lisa Mosconi, a specialist in neuroscience and nuclear medicine and associate director of the Weill Cornell Alzheimer's Prevention Clinic, told Gastropod, "They work for a few years, for some people they work longer, for some people they don't work at all. But they can't stop Alzheimer's, so they're not a long-term solution." In part, this seems to be because drugs designed to cure Alzheimer's have focused on ridding the brain of amyloid plaques. Some of them even managed to remove the plaques, Mosconi told us. "But cognition did not improve," she said. "There were an enormous amount of side effects, and some patients actually got worse. Some died. And that really begs the question: What are we doing wrong?"

For Mosconi and her colleague, Richard Isaacson, who founded and directs the Alzheimer's Prevention Clinic, the first of its kind in the U.S. and still one of only a few in the world, the answer to that question has involved a shift in approach: from cure to prevention. Over the past decade, observational studies have revealed patterns that seem to link Alzheimer's with exercise, sleep, cognitive stimulation, and, especially, diet. Based on the patterns in the data, it seems as though such so-called lifestyle factors make up to half a person's risk of developing Alzheimer's.

But, of course, correlation is not causation. And so Isaacson and Mosconi have set out to see whether they can prove that implementing changes in diet and lifestyle in middle age can actually prevent Alzheimer's. Working with a cohort of healthy patients with a family history of the disease, Isaacson and Mosconi study whether a rigorous diet and exercise regime can actually prevent Alzheimer's disease, or at least delay its onset. Meanwhile, Mosconi also puts her patients in a brain scanner to look for early signals of Alzheimer's—and she's seeing how what people eat is the biggest factor in changing brain structure.

These findings are brand new, but the emerging evidence for the power of lifestyle changes for Alzheimer's prevention is now so compelling that the Alzheimer's Association has just launched a $20 million, two-year clinical trial to study just that in 2,000 volunteers around the U.S. So, what should you eat to protect your brain? Listen in now for Gastropod's scoop on this exciting new research.

Episode Notes

Lisa Mosconi

Lisa Mosconi is a specialist in neuroscience and nuclear medicine, as well as the associate director of the Weill Cornell Alzheimer's Prevention Clinic. You can find links to her publications here. She's also the author of Brain Food: The Surprising Science of Eating for Cognitive Power.

Richard Isaacson

Richard Isaacson is a neurologist and the founder of the Weill Cornell Alzheimer's Prevention Clinic. His most recent paper based on his work at the clinic can be found here, and he expects to publish full results later this year.

Heather Snyder

Heather Snyder is the senior director of medical and scientific operations at the Alzheimer's Association.

FINGER and POINTER

If you're looking for more information on the FINGER study, the results were published here in 2015. The POINTER study is underway now, you can find more information here. (Together, are they the Pointer Finger? Sorry, we couldn't resist.)

Illustration by Lauren Cierzan

The special illustration for today's show was created by artist and Gastropod listener Lauren Cierzan. You can find more of her gorgeous work here. Thank you, Lauren!

Sloan Foundation and Burroughs Wellcome Fund

Speaking of thanks, we'd like to thank the Alfred P. Sloan Foundation for the Public Understanding of Science, Technology, and Economics for supporting our science coverage, as well as the Burroughs Wellcome Fund for supporting our coverage of biomedical research.