Milk and Early Puberty in Girls

It’s one of the most popular current misconceptions about milk:  that it causes early-onset puberty in girls – known clinically as precocious puberty.  This notion gained widespread exposure after the mid-1990s, when some animal-rights and anti-biotechnology advocates suggested a link between precocious puberty and consumption of milk from cows supplemented with recombinant bovine somatotropin (rbST – also known as “bovine growth hormone”).  To those unarmed with the facts, such a suggestion had a certain plausibility:  an animal growth-inducing hormone, ingested via cow’s milk, might promote accelerated growth rates in humans – and show itself in the form of early-onset puberty. It made for a scenario guaranteed to scare any responsible parent.  But is any of it true? According to scientists who have examined the theory, no – it isn’t true.  There is no conclusive evidence to support the suggestion that consumption of milk – whether derived from a rbST-supplemented cow or not -- causes early-onset puberty in girls.  Although some studies suggest a decrease in the age of onset of puberty in recent decades (Kaplowitz, P. Curr. Opin. Obstet. Gynecol. 18: 487, 2006; and Kaplowitz, P. Pediatrics 121 (suppl 3): 208s, 2008), the causes behind this trend have not been confirmed.  Among the possible culprits, socioeconomic conditions, psychological conditions (including stress), nutritional status, dietary quality, chronic diseases, birth weight and early postnatal growth have all been examined (Ellis, B.J., and M.J. Essex. Child Develop. 78: 1799, 2007; Semiz, S., F. Kurt, D.T. Kurt, et al. Turk. J. Pediatr. 51: 49, 2009; Karaolis-Danckert, N., A.E. Buyken, A. Sonntag, et al. Am. J. Clin. Nutr. 90: 1559, 2009; and Cheng, G., S. Gerlach, L. Libuda, et al. J. Nutr. 140: 95, 2010). Several studies link higher body mass index or increased body fatness in girls with earlier initiation or progression of puberty – and in fact, overweight and obesity have emerged as the favorite candidates for explaining precocious puberty among many scientists (Kaplowitz, P. Curr. Opin. Obstet. Gynecol. 18: 487, 2006; Kaplowitz, P.B. Pediatrics 121(suppl 3): 208s, 2008; Lee, J.M., D. Appugliese, N. Kaciroti, et al. Pediatrics 119: e624, 2007; DiVall, S.A., and S. Radovick. Curr. Opin. Endocrinol. Diabetes Obes. 16: 1, 2009; and Buyken, A.E., N. Karaolis-Danckert, and T. Remer. Am. J. Clin. Nutr. 89: 221, 2009).  There’s a rationality about the theory that’s appealing.  Many – probably too many – American girls carry more weight compared to previous generations and many have lifestyles that are sedentary compared to previous decades.  Most enjoy access to high-quality food and medical care.  The development of the human body responds to external stimuli.  When it is well-fed, well-rested and disease-free, it will prioritize its next basic requirement:  reproduction.  It may well be that American girls are experiencing higher incidences of precocious puberty because we have built a society that encourages precocious puberty. Circumstantial evidence tends to let milk off the hook, as well.  The studies cited above suggest that precocious puberty has been on the rise at the very same time that per capita consumption of dairy foods – especially by girls – has been in decline (Kaplowitz, P.B. Pediatrics 121(suppl 3): 208s, 2008; and Nielsen, S.J., and B.M. Popkin. Am. J. Prev. Med. 27: 205, 2004).  Further, there has been little if any evidence to suggest that boys are maturing at faster rates – even though per capita consumption of dairy by boys is and has been significantly higher than that among girls. And what about rbST – which allegedly induces faster growth rates in human children?  Bunk, says mainstream science.  While all foods derived from animals contain minute traces of growth hormones, such hormones are species specific – that is, they only work on their own kind.  Decades of tests on bovine growth hormone have confirmed that it is inactive in human biology (U.S. Food and Drug Administration. Report of the Food and Drug Administration’s Review of the Safety of Recombinant Bovine Somatotropin. April 23, 2009; please visit  Only human somatotropin (hST or “human growth hormone”) is effective in stimulating growth in humans. So the next time someone tells you that milk causes early-onset puberty, do two things:  first, continue to allow your children to drink milk (it’s full of nutrients they need); and then consider the source of the information you’re hearing.



I agree Kim- I AM against the dairy industry though- big business BS and murder of cows that don't produce milk anymore...they make it seem like the animals are all happy and well taken care of. They should be honest and say what really goes on behind closed doors...its all about MONEY MONEY MONEY -

Are you kidding me? Early onset puberty? You think that is why people are opposed to rBST products? You're kidding, right?

I did a google search on rBST, because I don't know much about it (except that no one is worried about it causing premature bleeding), and I prefer to adequately educate myself before entering the oral boxing ring. I immediately was given a list of websites opposing the use of the added hormone. No one encourages it. And only those profiting financially from its use will defend it. I chose to post the following. It is not from a radical animal rights website- its from a competitors. Stonyfield. A valid and successful member of the dairy business world. They're not concerned for the health of pre-pubescent girls, they're concerned for the well being of their cows and the dairy community as a whole. For an organization that blogs about how healthy cows have names, and brags about how Washington cows are the most productive (funny, you didn't mention the use of rBST in that blog...), I'd think you'd be more concerned about "Sunshine" and her friends, too.

Early Puberty? Really?

From the Stonyfield website:

Why we oppose rBST
All our products are made without the use of rBST, and we were the first dairy processor in the nation to pay farmers a premium to not treat cows with rBST.

A synthetic version of bovine growth hormone, rBST boosts milk production by 10–25%. USDA organic standards strictly forbid its use, and Canada and the EU have banned it.

Here’s why we oppose the use of rBST:

Family farm survival. We think the widespread use of rBST could economically devastate family farms. An increase in milk supply generally leads to a drop in the price paid to farmers. Price drops have put many farms out of business.

Cow health. rBST packaging lists many possible side effects, including swollen and ulcerated udders, skin rashes and hoof disorders. Experts say rBST increases the risk of mastitis and other udder infections by 25% and the risk of lameness by 50%. Increased cow infections could lead to increased antibiotic use, which could result in new strains of antibiotic-resistant bacteria.

There are other ways. Farmers can increase milk production safely and humanely through sound animal husbandry: good animal hygiene, optimizing cows’ living conditions and nutrition and not over-stressing cows.

Things you can do
To help keep rBST out of food production, tell your grocery store manager you’ll buy only products made without its use. With a phone call, letter or email message, thank the companies that buy milk from farmers who don’t use rBST. Anti-rBST farmers and companies need to know they’re answering consumer demand.

Urge your local parent/teacher association to prohibit your local school from buying food made with the use of rBST. You can also contact the U.S. Food and Drug Administration and urge the immediate withdrawal of rBST approval. Ask for, at the very least, federal labeling of products made with its use. The address:

U.S. Food and Drug Administration
5600 Fishers Lane
Rockville, MD 20857

For more information about rBST and products made without its use:

Consumers Union (publishers of Consumer Reports)
The Humane Farming Association
According to the FDA, no significant difference has been shown, and no test can now distinguish, between milk from rBST-treated cows and untreated cows.

Sorry, my kids won't be drinking your milk as long as you use rBST. And it has nothing to do with their menstrusl cycles.