Doctors say vitamin D provides people with many benefits besides building strong bones.

A recent Harvard study of 1,000 people discovered that those who took a vitamin D supplement had longer telomeres, which are the protective caps on chromosomes.

Other data showed that vitamin D reduces the risk of advanced cancer and inflammation in the body.

Doctors say you need to spend about 20 minutes outdoors several times a week to help your body produce vitamin D. Filling your plate with produce and protein, such as salmon, can also help you get vitamin D.

Exposure to the sun, specifically UVB rays, helps the kidneys and liver make vitamin D.

If people do not receive vitamin D, they can experience fatigue, bone or joint pain, muscle weakness, muscle cramping and mood changes. Anyone who believes they are deficient should speak to their doctor about possibly taking the 25 hydroxy vitamin D blood test.

The recommended daily allowance of vitamin D for adults is 600 to 800 international units. A doctor can help determine if a person needs more, but too much vitamin D can be toxic.