Breast Milk May Deliver Enough Vitamin D With Maternal Supplements

By Lisa Rapaport

Infants may get enough vitamin D from breast milk if their mothers take high-dose vitamin D supplements, a U.S. study suggests, offering a potential alternative to the vitamin drops parents are currently advised to give nursing babies.

Pediatricians recommend that mothers exclusively breastfeed infants until at least six months of age. But because breast milk typically doesn't contain enough vitamin D to help infants develop healthy bones, the American Academy of Pediatrics also advises nursing mothers to give their babies daily supplements of 400 IU of vitamin D.

In the new study, 334 exclusively lactating at four to six weeks postpartum were randomized to either receive either 400, 2400, or 6400 IU vitamin D3 daily for 6 months.

Breastfeeding infants in the 400 IU group received oral 400 IU vitamin D3/day; infants in the other two groups received a placebo. 

"Compared with 400 IU vitamin D3 per day, 6400 IU/day safely and significantly increased maternal vitamin D and 25(OH)D from baseline (P <0.0001)," the authors reported September 28 in Pediatrics. "Compared with breastfeeding infant 25(OH)D in the 400 IU group receiving supplement, infants in the 6400 IU group whose mothers only received supplement did not differ."

"By supplementing the mother, the baby would no longer need to be supplemented," study coauthor Dr. Carol Wagner, at the Medical University of South Carolina in Charleston, told Reuters Health by email. "This would be a complete paradigm shift in clinical recommendations."

One limitation of the study is that over time, many of the mothers either stopped breastfeeding entirely or started offering babies some formula or solid foods, the researchers acknowledge. They also didn't test the levels of vitamin D in breast milk, relying instead on tests of vitamin D levels for the babies.

While the current study does suggest women may be able to take vitamin D supplements themselves instead of giving drops to their infants, a single study may not be enough to warrant a change in practice, Dr. Richard So, a pediatrician at Cleveland Clinic Children's, told Reuters Health by email.

"Vitamin D is not harmless," said Dr. So, who wasn't involved in the study.

Serious side effects haven't been reported to U.S. drug regulators for the doses mothers took in the study, the researchers report.

Women who take supplements may increase the number of infants who receive adequate supplies of vitamin D, since only about one in five breastfed babies receive the recommended daily drops, Dr. Lydia Furman notes in an editorial.

"For the infant, there is not a benefit or risk to receiving vitamin D through milk instead of via vitamin D drops," Dr. Furman, a pediatrician at UH Rainbow Babies & Children's Hospital in Cleveland and Case Western Reserve University, told Reuters Health by email. "Certainly the vitamin drops are not very delicious and sometimes make the baby gag - this is the main benefit I can think of for receiving the vitamin D via mom's breast milk."

The National Institutes of Health and the South Carolina Clinical & Translational Research Institute partially supported this research.

SOURCE: http://bit.ly/1O50AHG

Pediatrics 2015.

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