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It’s winter in New England, and even though the snow has been elusive, shorter days and more indoor time can put children at risk for vitamin D deficiency.
What is Vitamin D? Vitamin D is one of the four fat-soluble vitamins (the other three are A, E, and K) available in our diet, which means they can be stored in our bodies and used over time. However, vitamin D is unique since it also behaves like a hormone in the body, relaying chemical messages. Vitamin D signals the intestines to absorb calcium from foods and to regulate its uptake by bone cells.
In October 2008, the American Academy of Pediatrics (AAP) released guidelines about vitamin D intake. There is strong evidence that adequate vitamin D intake will not only help prevent vitamin D deficiency (Rickets) and osteoporosis but may also play a critical role in the prevention of some chronic diseases of adulthood.
What are the specific recommendations from the AAP?
- Breastfed and partially breastfed infants should be supplemented with 400 international units (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 (32 ounces) 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. Talk with your pediatrician about your child’s specific needs.
In 2010, the Institute of Medicine issued new guidelines that raise the recommended dietary allowance (RDA) for vitamin D to 600 IU (15 micrograms) daily for healthy children 1 to 18 years of age, which was higher than the AAP’s last-published guidelines from 2008. These recommendations were restated in a subsequent report from the Endocrine Society.
What are the recommendations for older children?
Vitamin D inadequacy has been reported in approximately 36% of otherwise healthy young adults and a higher percentage in hospitalized patients across the United States, and in even higher percentages in Europe. It is therefore not just a problem of breastfed infants as it was once thought; the problem is pervasive across age groups. As a result, at-risk older children should also take supplements as noted above.
Why does it matter if my child’s vitamin D level is low?
In addition to causing Rickets, insufficient vitamin D prevents children from attaining their genetically programmed peak bone mass; it therefore contributes to and exacerbates osteoporosis later in adult life. Adequate vitamin D is also important for proper muscle functioning. As mentioned, there is growing new evidence that it may play a preventive role in certain adult diseases.
What is Rickets?
Rickets, or “osteomalacia,” is a disease that causes softening of the bones. It has many different causes but can be the result of a dietary deficiency of vitamin D. Rickets from vitamin D deficiency remains a worldwide problem. Although Rickets is more common in developing countries, American pediatricians continue to see cases in otherwise healthy children. This is partially due to the increase in breastfeeding nationwide. Those at highest risk include dark-skinned infants and children, those with little sunlight exposure, and those who ingest a diet low in vitamin D (such as breastfed infants of a malnourished mother or vegetarian mother, children themselves with a vegetarian diet or children with a diet lacking vitamin D rich foods).
In addition to weakened bones, children with Rickets may have decreased appetite, increased susceptibility to infections, and generalized weakness. Due to their weak bones as well the systemic symptoms mentioned above, children with Rickets might also have poor growth.
What about pregnant women?
Due to the fact that there is growing evidence that sufficient vitamin D levels are important to developing fetuses and that many in our general population are vitamin D deficient, the AAP has suggested that vitamin D levels be measured and adequate amounts be taken by pregnant women, too, but the recommendation for universal testing of vitamin D levels in pregnancy has not made by other national organizations including the American Congress of Obstetricians and Gynecologists and The Endocrine Society. If you are pregnant, speak with your clinician about what is best for you.
What foods provide vitamin D?
Foods naturally containing vitamin D are scarce. The most available sources are milk, eggs, and fish. Seafood such as cod liver oil, salmon, mackerel and tuna are good sources. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks. Milk is fortified with 100 IU per 8-ounce serving (it can therefore take 32 ounces of milk per day to reach the recommended 400 IU of vitamin D per day for children of all ages.) Some yogurts and cheeses also contain vitamin D, as do breakfast cereals and juices.
What is the role of sunlight?
Vitamin D is different than other nutrients that are ready to be used by the body once they are consumed. Vitamin D begins as a relative of cholesterol and needs to be processed in the body before it can be put to use.
Most people meet their vitamin D needs through sunlight exposure. When ultraviolet (UV) rays from sunlight strike the skin, it triggers vitamin D synthesis. However, from November until early March, the UV energy above 42 degrees north latitude (a line approximately between the northern border of California and Boston) is insufficient for vitamin D synthesis through the skin. In addition, cloud cover, shade, pollution, sunscreen and skin types can reduce UV energy even further. Given these factors are so changeable, it is difficult for experts to make specific recommendations about sunlight exposure and vitamin D needs.
The “D” bottom line:
Given where we live and the time of year, we all could probably use a little extra vitamin D in our diets. At a minimum, consider starting your children (of any age) on 400 IU of vitamin D through a pediatric multivitamin.