Jennifer Matthews: Theodore Chriss spent 15 of the best years of his life in the Navy.

Theodore Chriss: I loved it in the Navy. We seen a lot of fighting over there in Vietnam.

Jennifer Matthews: Now, he's in a different fight. Health problems have snuck up on him like an enemy submarine.

Theodore Chriss: You can't see them, but they're there. I wound up with glaucoma, and I had a stroke in one eye. I had open-heart surgery.

Jennifer Matthews: Then, came his most recent battle.

Theodore Chriss: They told me that my kidneys were disintegrating.

Jennifer Matthews: He has chronic kidney failure. The condition increases the risk of heart disease, heart attacks, and stroke. Doctors think one culprit may be a substance in the blood called homocysteine. Normal levels are four to twelve.

Albert Dreisbach: Patients may have levels of 15 or 20 or, in advanced renal failure, 50 or 60.

Jennifer Matthews: Now, doctors at the VA have embarked upon a twenty million dollar study to reduce homocysteine levels, with vitamins.

Albert Dreisbach: There's no medication that I know of that can lower homocysteine levels.

Jennifer Matthews: Now, doctors hope vitamins B-12 and B-6, along with folic acid may. Patients take high doses to reduce their risk of heart disease.

Theodore takes the vitamins every day. He thinks it's helping, but he still prefers his own medicine.

Theodore Chriss: The best medicine you have is a smile, and if somebody don't have a smile, I always give them one of mine.

Jennifer Matthews: This is Jennifer Matthews reporting.