It starts with small mishaps, like forgetting keys or difficulty recalling the word for “that thing I read.” Then it develops into more debilitating symptoms like hallucinations or wandering, until finally, one day your own child becomes a stranger.

Alzheimer’s disease affects one in 10 people over the age of 65. September 21 is World Alzheimer’s Day, and it’s never too soon to learn what steps you can take to keep your mind healthy. Experts aren’t quite sure what causes this mysterious disease, but scientists at the Veterans Affairs Puget Sound Health Care System in Seattle came one step closer with a groundbreaking study that found certain diets can affect the substances tied to Alzheimer’s.

The study involved both healthy adults and those showing early signs of memory loss. Half of participants ate foods high in saturated fat and high-glycemic-index carbohydrates like sugar-sweetened sodas. The other half followed a low-fat, low-glycemic diet rich in whole grains, fruits, veggies and beans. After one month, the first group had increases in spinal fluid levels of beta-amyloid. These proteins can form plaques and tangles in the brain and have long been associated with the development of Alzheimer’s disease.

But those who dieted on low-fat and low-glycemic foods actually lowered their beta-amyloid levels. They also showed improvement in the ability to remember and identify complex patterns.

Adults in the early stages of Alzheimer’s were especially sensitive to high-fat diets, which caused their cholesterols level to skyrocket.

So in honor of World Alzheimer’s Day, nosh on some brain-healthy beans, whole grains, fruits and veggies to keep blood sugar stable and your mind sharp. A nutritious diet is a key component in maintaining not only a strong body, but a stable mind.