Vitamin D is known as the “sunshine” vitamin because it is produced in the skin when exposed to sunlight. Vitamin D helps bodies absorb calcium and is needed for bone growth, strength, and structure. Without vitamin D, bones would be thin, brittle, or misshaped.

The Daily Reference Intake for vitamin D is 200 International Units (IU) for adults to age 50, and 400 IU to age 70. In addition, the 2005 Dietary Guidelines for Americans recommend that older adults, people with dark skin, and those exposed to insufficient ultraviolet radiation (i.e., sunlight) consume 1,000 IU per day.

So while 200 IU is sufficient for most adults, children need more because they are growing; and parents and caregivers need to make sure they are getting the proper amount. Vitamin D can be acquired naturally from being in the sun and eating vitamin D enriched foods.
The increased use of sunscreen products, coupled with children spending more time inside and drinking less milk than in previous generations, has decreased the amount of vitamin D that children receive.

Why Is Vitamin D Needed?

The two main disorders caused by insufficient vitamin D are rickets, which affects children, and osteomalacia, found in adults.

Rickets in infants is characterized by failure of bone to mineralize. Rickets is generally found:

• In infants who have been exclusively breastfed without vitamin D supplementation.
• In dark skinned infants fed breast milk or formula.
• In infants who receive no sun exposure due to excessive use of sunscreen or being continually covered from head to toe.

Osteomalacia in adults leads to soft bone and bone pain. Older adults often do not eat vitamin D rich foods and are not exposed to the sun for long enough times.

Elderly adults also have weaker organ functions so the body does not make vitamin D as efficiently as it once did. A vitamin D deficiency also can lead to an increased risk in adults for breast cancer, multiple sclerosis, heart disease, arthritis, and type 1 diabetes.

New AAP Vitamin D Recommendations

The American Academy of Pediatrics (AAP) now recommends that all children receive 400 IU a day of vitamin D, beginning in the first few days of life. The previous recommendation, issued in 2003, called for 200 IU per day beginning in the first two months of life. AAP recommends that:

• Breastfed and partially breastfed infants should be supplemented with 400 IU a day of vitamin D beginning in the first few days of life.
• All non-breastfed infants, as well as older children, who are consuming less than one quart per day of vitamin D-fortified formula or milk, should receive a vitamin D supplement of 400 IU a day.
• Adolescents who do not obtain 400 IU of vitamin D per day through foods should receive a supplement containing that amount.
• Children with increased risk of vitamin D deficiency, such as those taking certain medications, may need higher doses of vitamin D.

Supplements

Childcare programs can plan meals and snacks that include vitamin D enriched foods but should not provide supplements to children. Before choosing a supplement, parents should consult their pediatrician and consider how much the child is getting from food (both natural and fortified) in order to determine how much supplemental vitamin D should be given.

Many children’s multiple vitamins include vitamin D. When choosing a supplement, it is important that parents make sure it is in the proper form, which is D3. There are two forms of Vitamin D, D2 (ergocalciferol) and D3 (cholecalciferol). D3 is the naturally occurring form and is three times more active than D2.

Sunlight and Vitamin D

The ultraviolet (UV) rays from the sun starts the process of making vitamin D in the skin. Research suggests that 5-30 minutes of sunlight at least twice a week to the face, arms, legs, or back without sunscreen is sufficient to produce the required vitamin D.

Children should not be directly exposed to sunlight without sunscreen just to obtain vitamin D. Since many parents and childcare providers only apply sunscreen when children are going to be outside for activities, there are many times during the week when children are briefly exposed to direct sunlight such as coming and going from childcare, going to the store with mom or dad, or when walking the dog with an older sibling.

During the course of a week, it is likely that a child might receive a total of 30-60 minutes of exposed sun time during these routine activities; therefore, no additional exposed sun time is needed to get the required vitamin D.

Vitamin D from Food

Vitamin D is not found naturally in many foods, so it is added directly to foods, such as milk. Before vitamin D was added to milk beginning in the 1930s, many children developed rickets.

Few foods naturally contain vitamin D, and they are not foods which children often eat. For example, 1 tablespoon of cod liver oil contains 1360 IU; a 3.5-ounce portion of salmon or mackerel contains about 350 IU, and sardines or tuna canned in oil contain around 200-250 IU. However, few families eat sufficient amounts of these foods.

Therefore, vitamin D is added to foods to make sure everyone can get enough from the food supply. Typically, it is added to foods such as milk products, orange juice, and cereals.

Too Much Vitamin D?

The body uses vitamins in different ways. The B vitamins and vitamin C are water-soluble, and excess amounts are excreted in the urine. Vitamin D, like the other fat-soluble vitamins A, E and K, is stored in body fat, and there is a health risk linked with too much vitamin D.

Vitamin D overdose can cause nausea, vomiting, poor appetite, constipation, weakness, and weight loss. Too much vitamin D can cause calcium to build up in places it would not usually be, such as the kidneys.

Taking in too much vitamin D through diet alone is not likely unless you consume large amounts of cod liver oil daily. Also, too much sun exposure does not cause vitamin D overdose. Overdose is more likely to occur from high intakes of vitamin D in supplements.

Madeleine Sigman-Grant,PhD, RD
MCH Area Extension Specialist, University of Nevada Cooperative Extension
and Korrie Vance, BS

Resources

Vitamin D Council, 9100 San Gregorio Rd., Atascadero, CA 93422; www.vitamindcouncil.org

Internet Resources

American Academy of Pediatrics, aap.org/pressroom/nce/nce08vitamind.htm

Medline Plus, www.nlm.nih.gov/medlineplus/druginfo/natural/patient-vitamind.html

National Institute of Health, ods.od.nih.gov/factsheets/VitaminD_pf.asp