Optimal vitamin D dosage for infants uncertain
In a comparison of the effect of different dosages of vitamin D supplementation in breastfed infants, no dosage raised and maintained plasma concentrations within a range recommended by some pediatric societies. However, all dosages raised and maintained plasma concentrations within a lower range recommended by the Institute of Medicine, according to a study in the May 1 issue of JAMA, a theme issue on child health.
Hope Weiler, R.D., Ph.D., of McGill University, Montreal, presented the findings of the study at a JAMA media briefing.
“Vitamin D is important during periods of rapid bone mineral accrual. Nursing infants are susceptible to vitamin D deficiency because vitamin D in breast milk is limited,” according to background information in the article. “A supplement of 400 IU of vitamin D per day is thought to support plasma 25-hydroxyvitamin D (25[OH]D) concentrations between 40 and 50 nmol/L; some advocate 75 to 150 nmol/L for bone health. … the lack of well-defined recommendations supports the need for dose-response studies.”
Dr. Weiler and colleagues conducted a study to investigate the efficacy of different dosages of oral vitamin D in supporting 25(OH)D concentrations in infants. The randomized clinical trial, which included 132 one-month-old healthy, term, breastfed infants, was conducted between March 2007 and August 2010. Infants were followed up for 11 months ending August 2011 (74 percent completed the study). Participants were randomly assigned to receive oral cholecalciferol (vitamin D3) supplements of 400 IU/d (n=39), 800 IU/d (n=39), 1,200 IU/d (n=38), or 1,600 IU/d (n=16).
The researchers found that the percentage of infants achieving the primary outcome of 75 nmol/L of 25(OH)D differed at 3 months by group (for 400 IU/d, 55 percent; for 800 IU/d, 81 percent; for 1,200 IU/d, 92 percent; and for 1,600 IU/d, 100 percent). “This concentration was not sustained in 97.5 percent of infants at 12 months in any of the groups. The 1,600-IU/d dosage was discontinued prematurely because of elevated plasma 25(OH)D concentrations.”
Overall, 97 percent of infants in all treatment groups achieved the secondary outcome of 50 nmol/L or greater of plasma 25(OH)D by 3 months of age, with no differences among groups. This concentration was sustained in 98 percent of infants at 12 months.
Is your baby at risk for vitamin D deficiency?
First of all, babies rarely need vitamin D supplements. The babies who do need these supplements need them due to a lack of sufficient sunlight. Factors that put your breastfed baby at risk for vitamin D deficiency (rickets) are:
- Baby has very little exposure to sunlight. For example: if you live in a far northern latitude, if you live in an urban area where tall buildings and pollution block sunlight, if baby is always completely covered and kept out of the sun, if baby is always inside during the day, or if you always apply high-SPF sunscreen.
- Both mother and baby have darker skin and thus require more sun exposure to generate an adequate amount of vitamin D. Again, this is a “not enough sunlight” issue – the darker your skin pigmentation, the greater the amount of sun exposure needed. There is not much information available on how much more sunlight is needed if you have medium or darker toned skin. See the section below regarding amount of sunlight needed.
- Mother is deficient in vitamin D – there is increasing evidence in the last few years indicating that vitamin D deficiency is becoming more common in western countries. The amount of vitamin D in breastmilk depends upon mom’s vitamin D status. If baby gets enough sunlight, mom’s deficiency is unlikely to be a problem for baby. However, if baby is not producing enough vitamin D from sunlight exposure, then breastmilk will need to meet a larger percentage of baby’s vitamin D needs. If mom has minimal exposure to sunlight (see above examples) and is not consuming enough foods or supplements containing vitamin D, then she may be vitamin D deficient. More below on supplementing mom with vitamin D.
Vitamin D supplementation is often recommended, particularly in Canada and other northern latitudes since these areas don’t receive much sunlight during certain parts of the year. If you don’t get much sunlight exposure, consider taking a vitamin D supplement. The 2002 results of the Canadian Paediatric Surveillance Program confirmed 20 cases of nutritional rickets in Canada during 6 months of study.
Bone mineral concentration increased over time for lumbar spine, femur, and whole body but did not differ by group.
“Our primary objective was to establish a vitamin D dosage that would support a plasma concentration of 25(OH)D of 75 nmol/L or greater in 97.5 percent of infants at 3 months of age. Only the 1,600-IU/d dosage of vitamin D met this criterion; however, this dosage was discontinued because most infants in that group developed elevated plasma 25(OH)D concentrations that have been associated with hypercalcemia [higher-than-normal level of calcium in the blood],” the authors write. “Thus, the primary outcome was not achieved at 3 months, when plasma 25(OH)D concentrations were highest; all dosages failed except the highest dosage, which appears to be too high.”
“Additional studies are required before conclusions can be made regarding higher targets or the needs of high-risk groups.”
Recommended vitamin D intake
In the US, the recommended intake of vitamin D for infants and children (including adolescents) is 400 IU (10 micrograms) per day. The recommended intake of vitamin D for lactating mothers is currently 200 IU (5 micrograms) per day, the same as for all adults under the age of 50. Many feel that the recommended level for adults is too low, based upon recent research on vitamin D; per the AAP’s 2008 Policy Statement on prevention of vitamin D deficiency, “New evidence supports a potential role for vitamin D in maintaining innate immunity and preventing diseases such as diabetes and cancer.”
Infants 0-12 months should not exceed 1,000 IU (25 µg) per day. Anyone aged 1-50 years should not exceed 2,000 IU (50 µg) per day.
The amount of vitamin D in human milk is small: 0.5-3.4 µg/liter (20-136 IU/liter) [Hamosh 1991, Good Mojab 2002] in mothers who are not vitamin D deficient. However, the vitamin D in human milk is in a form that is very easily used by the baby and therefore adequate for most infants, when combined with a small amount of sun exposure.
How much sunlight is needed to generate adequate vitamin D?
The best way to get vitamin D, the way that our bodies were designed to get the vast majority of our vitamin D, is from modest sun exposure. Going outside regularly is generally all that is required for you or your baby to generate adequate amounts of vitamin D. (Keep in mind that there is a concern of sunburn and increased risk of skin cancer with too much sun exposure, however.)
Per “Infant feeding: the physiological basis” [WHO, 1991] by James Akre,
“…it is now understood that the optimal route for vitamin D ingestion in humans is not the gastrointestinal tract, which may permit toxic amounts to be absorbed. Rather, the skin is the human organ designed, in the presence of sunlight, both to manufacture vitamin D in potentially vast quantities and to prevent the absorption of more than the body can safely use and store.”
Per Cynthia Good Mojab, MS, IBCLC, RLC in Frequently Asked Questions About Vitamin D, Sunlight, and Breastfeeding:
The amount of sunlight exposure needed to prevent vitamin D deficiency depends on such factors as skin pigmentation, latitude, degree of skin exposure, season, time of day, amount of pollution, degree of use of sunscreen, altitude, weather, the vitamin D status of the lactating mother, and the current status of vitamin D stores in the infant’s body. Recommendations do and should, therefore, vary around the world, taking into account local conditions and practices.