Finish up those autumn apples. They're good for your brain.

Apples are high in quercetin, a compound with antioxidant properties that may decrease the risk of neurodegenerative conditions such as Alzheimer's by protecting brain cell membranes. Quercetin has an even higher antioxidant capacity than vitamin C, studies suggest. Other ways to get your fill: tea, onions, and cranberries.

Quercetin is a member of the flavonoid family found in apples, onions, tea, cranberries, blueberries, broccoli, cherries, cocoa, grapes, apricots, red wine, and kale. Quercetin may be one of the reasons why eating an apple a day is so good for you. High intake of quercetin may reduce your risk of lung cancer, asthma, respiratory conditions, heart attack, and cataracts, and new research suggests it may protect against Alzheimer's disease, too. Remember, however, that no one food or supplement can offer complete protection against any condition, so eat a balanced, varied diet to maximize your nutrition intake. In addition to eating a diverse, healthful diet, other ways to preserve your cognitive function include exercise, mental stimulation, social interaction, and regular check-ups and health screenings, all of which affect disease risk.