Breastfed infants in South Korea carry a significant risk of vitamin D deficiency, according to new research.
Researchers enrolled 117 infants of Mongolian descent aged 1 to 6 months who visited the CHA Bundang Medical Center in Seongnam, South Korea, into their study. Fifty-two of the infants breastfed while the other 65 were on formula.
The researchers found that 49% of the infants had levels less than 20 ng/ml (“vitamin D deficiency”), while 51% had levels over 20 ng/ml (“vitamin D sufficiency”). The mean level was 20.2 ng/ml.
In those who fell into the deficient category, the children were severely deficient, with a mean vitamin D level of 8.2 ng/ml. In contrast, those who were in the sufficient category had a mean vitamin D level of 31.6 ng/ml.
A startling 90% of children who were breastfed were deficient, compared to just 15% of the formula group. This is likely explained by the fact that formula has vitamin D in it, while breast milk can lack vitamin D if the breastfeeding mother doesn’t have levels over 40 ng/ml herself, which can be rare in the developed world. This also likely explains why the breastfed infants were severely deficient, as they didn’t have any consistent source of vitamin D.
The levels were so low in the deficient children that researchers took X-rays of 13 children to see if they had rickets. Of the 13, 3 of the children presented with subclinical rickets.
The researchers concluded, “Our study shows that there is a high prevalence of vitamin D deficiency of infants aged 1 to 6 months in South Korea, especially exclusive breast milk feeding infants.”
The researchers note that in South Korea, there has not been a public recommendation for vitamin D supplementation during infancy, thus putting breastfed infants at high risk for vitamin D deficiency. They call for urgent policy for vitamin D supplementation for infants and the need for publicity to ensure awareness among breastfeeding mothers.