Water

Over half of your body is made up of water. It's in every cell and every tissue. Biological processes like circulation, digestion, absorption and excretion depend on water. It forms the foundation of blood and lymph, maintains hearty muscles and young-looking skin, lubricates joints and organs and regulates body temperature. You can't function without it.

As you grow older, it becomes vital to pay attention to your water consumption. Mature persons hold less cellular water, with a loss of 10 to 15 percent of previous capacity by the age of 65. A contributing factor is the loss of thirst sensitivity. Because water is so important for digestion, a lack of fluid in your body might make it more difficult for you to digest food. You may suffer from cramps, bloating, gas, constipation, diveritculosis or even colon cancer. Drinking more water, combined with a high-fiber diet, can prevent these problems.