(NBC) - Are you getting enough vitamin D? New research says you're probably not.
Dr. Katherine Sherif followed 800 women for five years, checking their vitamin D levels.
"Of those 800 women only two women had optimal levels of vitamin D," said Dr. Sherif.
Sherif says that shows just how hard it is to get vitamin D, a vitamin she says she believes in so much, she takes it herself every day without fail.
"It's been known for a long time that vitamin D has remarkable properties," said Sherif. "There's a strong association between low levels of vitamin D and high rates of breast, colon, prostate and ovarian cancer."
Other studies link low levels of vitamin D to the development of high blood pressure, muscle weakness, pain and rickets. Having enough vitamin D has been shown to reduce inflammation and improve the immune system, asthma in children as well bone health.
Nicknamed the sunshine vitamin, because we absorb D from the sun, it's found naturally in very few foods.
Doctors say 15 to 20 minutes in the sun with the face, chest and arms exposed can be enough, but the very real fear of skin cancer has many using sun block, which also blocks the D.
Sherif recommends taking a vitamin D supplement. She recommends 2,000 units a day for adults and 1000 units a day for children, and she says don't think your kids are getting enough by drinking milk.
"Milk does not contain enough vitamin D for children to meet their daily requirements," she explained.