Formula feeding and early puberty

Formula feeding and early puberty



The Breast Cancer Fund commissioned ecologist and author Sandra Steingraber to write The Falling Age of Puberty, the first comprehensive review of the literature on the timing of puberty to help us better understand this phenomenon so we can protect our daughters health.

http://www.breastcancerfund.org/site/pp.asp?c=kwKXLdPaE&b=3266509

Excerpted from the report:

Several studies show that formula-fed infants have higher body fat than breastfed babies, a difference that persists into adolescence. Breastfed infants tend to self-regulate their energy intake and are less likely to overeat (Novotny, 2003). Formula feeding in infancy
also alters lipid metabolism in ways that have life-long consequences.


Individuals who were formula-fed in infancy have higher blood cholesterol levels in adulthood (Bergstrom, 1995). A recent national study of overweight among three-year-olds found that prolonged bottle-feeding was an important predictor of childhood obesity (Kimbro, 2007). There are deep racial disparities in breastfeeding rates among U.S. mothers. In 2004, 71.5 percent of U.S. white infants were ever breastfed, as compared to only 50.1 percent of U.S. black infants. Differences between black and white breastfeeding rates existed within most socio-economic subgroups studied (Centers for Disease Control, 2006).

Is formula feeding a risk factor for early puberty? Only one study has pursued this question directly. In an investigation of 300 girls in Hawaii, those who were formula-fed as infants deposited more fat as adolescents and reached menarche significantly sooner (Novotny, 2003). Supporting evidence for this study comes from the veterinary literature. In the U.S. dairy industry, precocious puberty among heifers is a desirable outcome. It is accomplished by early weaning of infants followed by confinement and continuous feeding of a high-calorie diet (Gasser, 2006). These feeding practices are roughly mimicked by many human families in the United States, which has the lowest rate of breastfeeding in the developed world and the highest rate of childhood obesity.

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CONCLUSIONS


The contribution of formula feeding on pubertal timing is a critical question that deserves further study. Breastfeeding appears to protect against early sexual maturation in two ways: certainly because it contributes fewer calories during infancy; and, quite possibly, because it contain hormones and other growth factors that may program the development of the HPG axis in ways that inhibit its premature activation. Lower rates of breastfeeding in black families may partially explain the earlier maturation of U.S. black girls when compared to whites. Cultural and economic barriers to breastfeeding within communities of color need to be identified and addressed.


http://www.ibfan.org/site2005/Pages/article.php?art_id=501&iui=1