Vitamin D

-Jane Henley MSRD

What does Vitamin D do?

Vitamin D helps you to maintain strong bones. It does this by helping the body absorb calcium, this prevents rickets in children, osteomalacia, and osteoporosis in adults. It also helps nerves carry messages to the brain which helps your muscles move. In addition to this it makes the immune system stronger and reduces inflammation.

How much Vitamin D do I need?

40 IU= 1 mcg

Birth-12 months

400 IU

Children 1-13

600 IU

Teens 14-18

600 IU

Adults 19-70

600 IU

Adults 71 and older

800 IU

Pregnant and breastfeeding woman

600 IU

Sources of Vitamin D

Your body makes vitamin D when its exposed to the sun. Most people get at least some vitamin D this way. Research has suggested that the best way to get vitamin D from the sun is 5-30 minutes of sun exposure between 10am and 3pm at least twice a week. Make sure you have the sun going on the face, arms, legs, or back without sunscreen. These procedures usually lead to sufficient vitamin D cells being made. However cloudy days, shade, and dark-colored skin can reduce the amount of vitamin D produced, and skin exposed through a window will not make any vitamin D.

Vitamin D in food

Only a few foods naturally have vitamin D. Fortified foods provide most of the vitamin D in American diets. Some foods that have natural vitamin D are: Milk, Fortified cereal, Fortified orange juice, fortified yogurt, fortified margarine, Fortified soy, rice, and almond milk, cooked salmon, swordfish, Canned tuna in water, Egg yolk, and Cod liver oil.

Groups at risk of not enough Vitamin D

  • Breastfed Infants
  • Older adults
  • People with dark skin and limited sun exposure
  • people with inflammatory bowel disease and any other condition that causes fat malabsorption
  • People who are obese
  • People who have undergone gastric bypass surgery
  • People with milk allergy or who are lactose intolerant
  • Vegans

Drug Interactions

Vitamin D has the potential to interact with several types of medications

  • Steroids: Can reduce calcium absorption and impair vitamin D metabolism
  • Orlistat: can reduce absorption of vitamin D and other fat-soluble vitamins
  • Cholestyramine: can reduce the absorption of vitamin D and other fat-soluble vitamins
  • Phenobarbital and phenytonin: inactivates vitamin D, reducing calcium absorption