Some online breast milk might contain cow's milk

Human breast milk has been sold online for years, and health experts have warned about possible dangers. Now they have a new warning: Some of the milk for sale isn't strictly human — it's been topped off with cow's milk.

That milk could be dangerous for some babies, says Sarah Keim, a researcher at Nationwide Children's Hospital in Columbus, Ohio.

Keim led a study published Monday in Pediatrics that shows 10 out of 102 breast milk samples purchased online contained at least 10% cow's milk. The added milk could have come straight from cartons or from baby formula, Keim says.

"It could be very harmful to babies with allergies or intolerance" to cow's milk, she says.

In a previous study using the same samples, Keim found 75% were contaminated with viruses or bacteria.

The Food and Drug Administration has warned since 2010 that milk sold or shared online could be unsafe.

The samples in the study, purchased in 2012, came from several sites, Keim says, including one called Only The Breast that continues to operate and appears to be the leading site for such transactions. Other sites, such as Eats on Feets and Human Milk 4 Human Babies, facilitate the sharing of milk but discourage sales.

In ads at Only The Breast, thousands of nursing mothers offer to sell excess breast milk for prices that appear to range from $1 to $6 per ounce. Many feature pictures of mothers and children and boast that the sellers eat organic diets, are free of drugs, alcohol and caffeine, and have other healthy habits. Some say they have been screened for drug use and for diseases such as HIV by milk banks — non-profit and for-profit operations that provide milk to premature and sick babies in hospitals.

In an emailed statement, Only The Breast, a corporation based in Reno, said the site's terms of use forbid members from adding any contaminants to milk sold or donated there. The statement says: "We believe most OTB members are honest, abiding by OTB terms and are simply looking to provide safe milk for babies in need."

If some sellers are intentionally adding cow's milk to their supplies, the obvious motive would be profit, Keim says: "Sellers might have an incentive to try to increase their production. … It could really add up."

Who is buying this milk? Most buyers are families who want breast milk for babies and, for whatever reason, don't have enough milk from the babies' mothers, says a recent editorial in the journal BMJ. The editorial, which called online milk sales and sharing unsafe, said buyers also include "a narrow group of adult consumers (including people with cancer, gym enthusiasts, and fetishists)."

The market for breast milk exists largely because health authorities "have done a really good job over the past 20 years of promoting the benefits of breastfeeding," Keim says. "Unfortunately, some women are very focused on feeding their babies breast milk at all costs."

Keim's samples did not include milk shared free online. She says such milk is unsafe because it has not been screened for contamination.

Sites for sharing and selling milk include instructions for home pasteurization — heating the milk to kill harmful microbes — and say it is necessary. But home methods are unlikely to be as reliable as the procedures used by milk banks, Keim says.

The 18 non-profit banks in the Human Milk Banking Association of North America do not get enough donations to provide safe, screened breast milk to the general public, says Kim Updegrove, executive director of the Mothers' Milk Bank in Austin. Their milk is needed for sick and low-weight babies for whom it is "life-saving," she says. It is available only by prescription.

Women who have trouble breastfeeding should seek help from lactation counselors and other health professionals rather than turning to the internet for possibly tainted supplies, Updegrove says.

"Body fluids are dangerous, and milk is a body fluid," she says. The addition of cow's milk is "alarming," because it could cause symptoms ranging from stomach upset to bloody diarrhea and eczema in some infants, Updegrove says.

Women thinking of selling or donating their milk could do more good by donating to the neediest infants through milk banks, she says.

"I do believe that most of those women looking to share or sell their milk are compassionate women who want to help other women," Updegrove says.