Human milk is best for babies but not if it s bought online, study finds.

Happy Baby, Happy MomMany new mothers want to feed their infants breast milk, but some are unable to do so for various reasons. Now there are internet sites that offer to set these women up with providers of human milk so it might seem that this is one answer for these moms. But a new study published in the journal Pediatrics finds that these sources may not be as good as they seem.

Lead author Dr. Sarah A. Keim from the Nationwide Children s Hospital, Columbus, Ohio, and colleagues anonymously purchased 102 samples of supposedly pure human milk from online purveyors. They then extracted DNA from each sample, and determined whether that DNA came from cows or humans. They found that all the samples contained human DNA, which was to be expected, but 11 of the samples also contained DNA from cows, and most of these had enough bovine DNA to indicate that the samples had been mixed with at least 10 percent cows milk.

Some babies cannot drink cows milk because of sensitivity or allergy to cows milk protein. These infants must be given either human milk or formula in which the protein has been modified to avoid reactions. In addition, very premature babies do best on human milk, and there are human milk banks run by the Human Milk Banking Association of North America which make donated human milk available to such infants. They do not, according to the authors of the study, have enough milk to provide it freely to all infants. The authors commented, Because buyers have little means to verify the composition of the milk they receive, all should be aware of the possibility that it may be adulterated. They also noted that previous studies have found that such milk may also be contaminated with pathogenic bacteria.

ACSH s Dr. Ruth Kava commented, Certainly breast milk is the best source of nutrition for young babies, but parents should be aware that purchasing human milk on the internet is not necessarily a good option. Indeed, if human milk from a known source is not available, then infant formula, which is designed to mimic the benefits of human milk, is the better choice.