Vitamin D helps your body absorb calcium. Calcium is one of the main building blocks of bone. A lack of vitamin D can lead to bone diseases such as osteoporosis or rickets. Vitamin D also has a role in your nerve, muscle, and immune systems.
You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. However, too much sun exposure can lead to skin aging and skin cancer. So many people try to get their vitamin D from other sources.
Vitamin D-rich foods include egg yolks, saltwater fish, and liver. Some other foods, like milk and cereal, often have added vitamin D.
You can also take vitamin D supplements. Check with your health care provider to see how much you should take. People who might need extra vitamin D include
- Breastfed infants
- People with dark skin
- People with certain conditions, such as liver diseases, cystic fibrosis and Crohn’s disease
- People who are obese or have had gastric bypass surgery
If you’ve dealt with severe menstrual cramps, you might want to double-check that you’re getting enough of the sunshine vitamin. Women who received a single high dose of vitamin D before the start of their menstrual period had 41 percent less pelvic pain than women who did not take the vitamin, plus they didn’t need their usual pain-relief medication, a small study published in the Archives of Internal Medicine found.
Earlier studies have shown that a shortage of D is associated with menstrual pain and that getting regular amounts of vitamin D — even less than the average recommended daily amount of 1,200 IU — reduces the chances of period pain . For vitamin D without supplements, add plenty of vitamin D-fortified milk, juice, salmon, and tuna to your diet.
Assuming that a person gets virtually no vitamin D from sunshine — and that this person gets adequate amounts of calcium — the IOM committee recommends getting the following amounts of vitamin D from diet or supplements (Note that the IOM’s upper limit is not a recommended intake, but what the IOM considers the highest safe level):
- Infants age 0 to 6 months: adequate intake, 400 IU/day; maximum safe upper level of intake, 1,000 IU/day
- Infants age 6 to 12 months: adequate intake, 400 IU/day; maximum safe upper level of intake, 1,500 IU/day
- Age 1-3 years: adequate intake, 600 IU/day; maximum safe upper level of intake, 2,500 IU/day
- Age 4-8 years: adequate intake, 600 IU/day; maximum safe upper level of intake, 3,000 IU/day
- Age 9-70: adequate intake, 600 IU/day; maximum safe upper level of intake, 4,000 IU/day
- Age 71+ years: adequate intake, 800 IU/day; maximum safe upper level of intake, 4,000 IU/day
That’s not enough, says Boston University vitamin D expert Michael Holick, MD, PhD, professor of medicine, physiology, and biophysics, Boston University Medical Center. Holick recommends a dose of 1,000 IU a day of vitamin D for both infants and adults — unless they’re getting plenty of safe sun exposure.