Vitamin D is a fat-soluble vitamin. These types of vitamins are stored in the body's liver and fatty tissues.

Vitamin D acts as both a vitamin and a hormone. It is found in some foods, but the main sources are vitamin D-fortified milk and sunlight.

Functions

Vitamin D plays a role in the growth and maintenance of strong, healthy bones. It also helps to maintain normal blood levels of calcium and phosphorus.

As a supplement, it may help treat osteoporosis and high blood pressure.

Recommended Intake

Here are the guidelines for vitamin D intake:

Age GroupRecommended Dietary Allowance or Adequate Intake (IU/Day)
0-12 months400
1-70 years600
71+ years800
Pregnant or nursing women600

IU: international units

Vitamin D Deficiency

Symptoms of severe vitamin D deficiency are rare today, but can lead to:

  • Rickets—a disease in children in which the bones become soft and weak
  • Osteomalacia—a disease in adults in which the bones become soft and weak
  • Muscle weakness

Mild deficiency is common, especially in places that have less sunlight.

Vitamin D Toxicity

Vitamin D is stored in the body and does not pass out through urine. It can build up and reach toxic levels. Here are safe upper level intakes for vitamin D:

Age GroupUpper Level Intake (IU/Day)
0-6 months1,000
7-12 months1,500
1-3 years2,500
4-8 years3,000
9 years and older4,000
Pregnant or nursing women4,000


Symptoms of toxicity are:

  • Nausea
  • Vomiting
  • Constipation
  • Weakness
  • Weight loss
  • Heart rhythm problems
  • Deposits of calcium in soft tissues from raised levels of calcium in the blood

Sunlight and diet are not likely to cause vitamin D toxicity.

Major Food Sources

Fortified foods have the most vitamin D. Examples of foods that may be fortified with vitamin D are:

  • Milk
  • Cereal
  • Orange juice
  • Yogurt
  • Margarine
  • Soy drinks

There are not many foods that are natural sources of vitamin D. They are:

  • Fatty fish, such as salmon, tuna, and mackerel
  • Beef liver
  • Cheese
  • Egg yolks
  • Mushrooms

Health Implications

Vitamin D deficiency is more common in:

  • Breastfed babies who do not get enough vitamin D from human milk. They should get a 400 IU vitamin supplement each day to make up for this.
  • People who live in places with limited sun exposure
  • Older adults who spend a lot of time indoors, such as in care centers or nursing homes
  • People who wear clothing that limits their exposure to the sun
  • Pregnant women
  • Dark-skinned people whose bodies are less able to make vitamin D from the sun
  • People with obesity

Tips to Raise Your Vitamin D Intake

Here are tips to help raise your intake:

  • Make sure your multivitamin contains vitamin D.
  • Drink vitamin D-fortified milk.
  • Spend time in the sun. You should still use sunscreen with an SPF of 30 or higher.
RESOURCES:

Eat Right—Academy of Nutrition and Dietetics
http://www.eatright.org

Office of Dietary Supplements—National Institutes of Health
https://ods.od.nih.gov

CANADIAN RESOURCES:

Dietitians of Canada
https://www.dietitians.ca

Health Canada
http://www.canada.ca

REFERENCES:

Calcium and vitamin D for treatment and prevention of osteoporosis. EBSCO DynaMed website. Available at:https://www.dynamed.com/management/calcium-and-vitamin-d-for-treatment-and-prevention-of-osteoporosis. Updated February 4, 2020. Accessed February 6, 2020.

Vitamin D. Office of Dietary Supplements website. Available at: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional. Updated August 7, 2019. Accessed February 6, 2020.

Vitamin D and skin health. Oregon State University Linus Pauling Institute website. Available at: http://lpi.oregonstate.edu/mic/micronutrients-health/skin-health/nutrient-index/vitamin-D. Accessed February 6, 2020.

Vitamin D intake and supplementation. EBSCO DynaMed website. Available at:https://www.dynamed.com/drug-review/vitamin-d-intake-and-supplementation. Updated November 26, 2018. Accessed February 6, 2020.

Last reviewed November 2019 by EBSCO Medical Review Board Dianne Scheinberg Rishikof MS, RD, LDN  Last Updated: 2/6/2020