BY MICHAEL ROIZEN, M.D., AND MEHMET OZ, M.D.

Know the truth about your anatomical fuse box, and you can keep your mind functioning at its peak.

Myth or Fact? You use only a portion of your brain

Myth! Of the 100 billion neurons floating around in your neurological galaxy, be assured you're using every one of them (yes, even teenagers). You just use different parts at different times. If you didn't need all of your brain, evolution would have made you a smaller one.

Myth or Fact? Coffee keeps it healthy

Fact! Drinking 24 ounces of coffee a day does decrease your risk of Parkinson's and Alzheimer's disease, possibly because caffeine has a beneficial impact on neurotransmitters.

Myth or Fact? Lots of DHA (900 mg) helps it work better

Fact again! Nine hundred milligrams a day of DHA the omega-3 fat from algae made people with early cognitive dysfunction have the mental powers of people seven years younger.

Myth or Fact? Ginkgo biloba is the ultimate brain booster

Myth! Many people believe that this supplement improves brain function by increasing blood flow and thinning your blood. But studies have been so inconsistent that we don't see a compelling reason to use it.

Myth or Fact? Mustard keeps your brain in shape

Fact! Many yellow mustards contain turmeric, a spice that activates the genes that help clear out brain-cell waste. Buildup of that waste can create inflammation, which destroys brain cells and interferes with thinking. A teaspoon of mustard a day (about 17 mg of turmeric) can keep things in your brain less gunky.

The YOU Docs, Mehmet Oz and Mike Roizen, are authors of "YOU: The Owner's Manual." Want more? See "The Dr. Oz Show" on TV (check local listings). To submit questions, go to www.RealAge.com.