For those that have heart disease or the risk factors for it, taking 500 milligrams of vitamin C a day helps tiny blood vessels dilate, which in turn reduces the risk of a heart attack. UC Berkeley Wellness Letter, November 99   The amount of water you need is dependent on your body weight, lifestyle, age, sex and the climate you live in.  A woman's body is made up of 45 to 50 percent water, a man's body 55 to 60 percent water. More muscular people have a higher proportion of water because muscle tissue contains almost three times as much water as does fat tissue. Sharon Howard, nutrition expert from DrKoop.com   As a general rule, adults should consume about four glasses of water for every 1,000 calories in their diet. Drinking eight glasses of water a day for a 2,000-calorie intake is a good idea. Sharon Howard, nutrition expert from DrKoop.com