Some Infants and Toddlers Have Vitamin D Deficiency

At least 40 percent of American infants and toddlers are not getting enough vitamin D, according to a report in Archives of Pediatrics and Adolescent Medicine.

Twelve percent of the youngest children in the US are already deficient in vitamin D, and another 28 percent are at risk for vitamin D deficiency, according to the study.

Because human breast milk lacks sufficient vitamin D, the number of babies in the research sample being breast-fed were important to the findings.

"These data underscore the fact that breast-fed infants should be supplemented with vitamin D," says study author Dr. Catherine Gordon at Children's Hospital in Boston.

She adds that mothers who are breastfeeding often need vitamin D supplements as well.

Breastfeeding is a known risk factor for low vitamin D levels in infants, which is why many pediatricians routinely recommend vitamin D supplementation for breast-fed infants.

Other factors that may contribute to low levels of vitamin D include not drinking enough vitamin D-fortified milk (for toddlers), staying out of the sun, or using sunscreen.

Low Levels a Risk for Disease

Vitamin D, also known as the sunshine vitamin, is produced naturally when the body reacts to sunlight.

However, the use of sunscreen and advice to stay out of the sun - which is important for preventing skin cancer - may also be reducing levels of vitamin D in people.

Few foods naturally contain vitamin D, which is essential for strong bones because it helps the body absorb calcium.

In addition to helping maintain bone health, Dr. Gordon says that vitamin D also appears to play a role in maintaining the immune system.

Persons with low levels of vitamin D may be more susceptible to autoimmune diseases, such as type 1 diabetes and multiple sclerosis, and to certain cancers.

Previously, Dr. Gordon studied vitamin D levels in adolescents and found very high levels - about 42 percent - of vitamin D deficiency in teens. That finding made her interested in assessing levels in younger children.

The current study included 380 children between eight and 24 months old. About 80 percent were from urban areas, and the majority of the youngsters were African American or Hispanic, according to the study. However, the study made no association between skin pigmentation and vitamin D levels.

For this study, the researchers defined severe vitamin D deficiency as blood levels of less than 8 nanograms per milliliter (ng/mL), vitamin D deficiency as less than 20 ng/mL and suboptimal as less than 30 ng/mL.

Dr. Gordon says there is some debate within the medical community about what truly signifies vitamin D deficiency, but that they felt current evidence supports the levels they used, and less than 20 ng/mL is the level her hospital uses as a cut-off point.

Supplement Breastfeeding with Vitamin D

In an accompanying editorial, Dr. James Taylor, at the University of Washington, says that although he believes the study was well done, Dr. Gordon and her colleagues used a "higher cut-off" than what has been used by other researchers.

But, he adds, because Dr. Gordon's team found X-ray evidence of low bone density in children who fell into their category of low levels of vitamin D, "it might be that this might be an indication of long-term problems.

“If this is the case, then [Dr.] Gordon and colleagues might have picked the right definition,” says Dr. Taylor. “However, it might be that for many of the children with osteopenia [low bone density], the changes are transient and not indicative of disease. Time and more research will tell."

The key findings from the study say that breastfeeding without vitamin D supplementation is a risk factor for vitamin D deficiency, and that a higher body- mass index was associated with a risk of vitamin D deficiency.

There was no association between the seasons - an indication of possible sun exposure - and vitamin D deficiency.

There was no association between skin pigmentation and vitamin D deficiency. Consumption of vitamin D-fortified milk confers protection against deficiency.

Dr. Gordon says it is very difficult to consume too much vitamin D, so she recommends vitamin D supplements for breastfeeding infants and lactating mothers. She also recommends a multivitamin containing vitamin D for older children.

Dr. Taylor is not as convinced about the need for routine supplementation, however.

"I think that more research is needed before routine vitamin D supplementation is recommended for all children," he says.

Always consult your physician for more information.