Are you exhausted, forgetful and lacking energy? You may suffering from a vitamin B12 deficiency. Find out what causes this deficiency and what you can do about it.

Click here for Part 1 of America's B12 Deficiency.

Click here for Part 3 of America's B12 Deficiency.

Click here to read more about Vitamin B12.

Want to help lower your risk of getting cancer? The answer could be in the food you eat! Dr. John Whyte, chief medical officer at WebMD and the author of "Take Control of Your Cancer Risk," says there are three kinds of foods that could really help prevent cancer: garlic, fish and grapes. And what three kinds of foods should you avoid? Red and processed meats, refined grains, and alcoholic and sugary drinks. Watch the videos below to learn more about how food could be connected to your cancer risk.