The World Health Organization (WHO) and the American Academy of Pediatrics recommend exclusive breastfeeding for the first six months of life. It is good for both mothers in that it can reduce the risk of breast and ovarian cancers and for babies in that it protects against disease and infection.

Bryan said the concentration of nitrite and nitrate found in breast milk calls into question the amount recommended by the Joint Food and Agricultural Organization/WHO Acceptable Daily Intake (WHO ADI) standards. Total daily nitrite intake for nursing infants is 20 times that recommended by the WHO ADI, he said.

Too much nitrite/nitrate or too little nitrite/nitrate can be bad for health, Bryan said. Much of the concern about nitrite/nitrate levels stems from a condition associated with too much nitrite in the blood system called methemoglobinemia (blue baby syndrome). Typically, this is caused by infant formulas made from bacteria and nitrate contaminated well water. The levels of nitrite and nitrate that cause blue baby syndrome are much higher than what is present in breast milk, he said.

"These data, considered together with nitrite and nitrate exposure estimates from foods, show that humans are exposed from birth to dietary sources of nitrite and nitrate. The presence of nitrite and nitrate in breast milk argues for a fundamental role in physiology, which is supported by a number of basic science studies and some clinical trials," Bryan said.

"Contrary to the prevailing scientific opinion about the biological effects of nitrite and nitrate, our data support the view that humans may require these dietary components from birth - from nature's most perfect food," said Norman G. Hord, Ph.D., M.P.H., R.D., the study's lead author and an associate professor of food science and human nutrition at Michigan State University (MSU).

SOURCE University of Texas Health Science Center at Houston