The Worst Foods For Your Brain

Likely sources: Your favorite sandwich. Bread, cheese, cured meats and cold cuts and are full of this mineral.

What they have in common: They're high in sodium.

Science says: A study in Neurobiology of Aging tracked the activity levels and sodium intake of more than 1,200 men and women between the ages of 67 and 84 and found that tons of sodium plus little activity led to poorer cognitive health. Interestingly, salt appeared to be more of a problem than couch potato–ness, as adults with low sodium and low activity fared better over time. Just as sodium does in other parts of the body, it can lead to a narrowing of the blood vessels that transport oxygen and other essential nutrients, Molano says, which means your brain can't get the resources it needs to work at its highest levels.

The amount it's okay to eat: What defines "too much" when it comes to sodium is a hotly debated topic, with some experts saying the standard guidelines (no more than 2,300 grams per day for healthy people; 1,500 mg if you're over 50, African-American, or have high blood pressure) are too restrictive. Talk to your doctor about what's best for you.