A Growing Problem? Research Behind Younger Puberty in Girls, Part 2

Continuing with Part 2 of our discussion.  If you missed it, last week we discussed non-food agents that may contribute to the trend in early puberty onset.

Puberty is no easy thing for anyone involved, the parent or the child.  Throw in the great possibility of the onset of puberty at an earlier age than 20-30 years ago, and you may have a bigger set of issues.  The anxiety of watching your daughter experience early onset of puberty is not specific to just the adolescent stage in development though.  Because of the increased exposure time to estrogen, early pubertal girls are at higher risk of developing breast and endometrial cancer as adults.

Two weeks ago, we discussed the potential benefits or possible negative effects of the consumption of soy.  One of the possible negative effects that has been suggested is the presence of phytoestrogens in soy.  These phytoestrogens combined with the FDA’s increase in the allowable amount of soy fillers in school lunches and restaurant food, has some theorizing that soy is to blame for the growing trend in the earlier onset of puberty in girls.  As always, let’s dive right into this issue and see what the research says.

A 2010 study published in the journal Pediatrics showed that the early pubertal development in girls is greater today than that reported 10 to 30 years ago.  There are two different types of precocious (or early) puberty: central and peripheral.  Peripheral is where our focus is in this post; however, the mayo clinic indicates that this type of early puberty is less common than central (medical condition).  Peripheral precocious puberty is caused by the “release of estrogen or testosterone into the body.”

Potential Food-Related Causes of Early Puberty

  • Meat Hormones-Unfortunately there have been no adequate wide-spread studies focused on examining the amount and type of hormones used in meat and how it may relate to early development in girls or boys.  Some early investigation demonstrated possible links, but more recent studies have not been able to replicate these earlier findings.  Furthermore, researchers are uncertain of how the processing, cooking and digestion of meat may reduce these hormonal risks.  For this reason, there have been no recommendations or changes to the way the meat industry uses hormones or steroids in livestock.
  • Meat Diet – A 2010 study published in Public Health Nutrition showed a link between the amount of meat consumed by girls and early maturation (specific meat hormones were not examined).  The greater level of animal protein girls ate during the age of 3 and 7 may also influence the development of breast cancer and osteoporosis at later ages.  Although researchers are not suggesting stripping meat from a girls diet because the protein is very vital, they urge girls to eat a well-balanced diet consisting of fruits, vegetables and whole grains, and like always, eat everything in moderation.
  • Soy – A 2005 report by the American Academy of Pediatrics discounted the speculation that the isoflavones (estrogen-like hormones) present in soy formula causes early development in children.  Human studies are either non-existent or inconclusive on the possible damaging effects of a high soy diet.  But a number of researchers are finding very conclusive evidence in animal studies of negative effects.  Studies conducted at the National Center for Toxicological Research have found that rats fed high amounts of soy produced early pubertal development, decreased egg production and smaller litters in females.  In male rats, early breast development was noted, but it did not cause cancer or the feminization of male reproductive organs.  According to scientists, the frightening reality about these findings is that the reproductive system in rats is very similar to that in humans.  While they don’t know the actual effective risk of soy (I don’t know why!!), some researchers are suggesting we “tread lightly.”
  • Cow’s Milk (rBST growth hormone): According to the FDA, WHO, AMA, ADA, NIH, there has been no evidence to suggest that the use of artificial growth hormones in  cows is unfit for human consumption.  Regardless, there has been a move over the past few years in the market away from the use of rBST-treated dairy products.

Future Research

  1. I found no studies researching the link between soy-based infant formula and early puberty, but this would be a very informative long-term project to undertake.  It could, in reality, support or refute the hypothesis that soy infant formula is related early puberty.  On a personal side note, I cannot see how soy formula does not have an affect on puberty when research has found that the amount of phytoestrogens in soy formula is equivalent to at least 5 birth control pills.
  2. It is very frustrating to me to write some of the posts the last few weeks with the common wordage of “researchers suggest,” “researchers don’t know,” “tread lightly,” “just eat a well-balanced diet and exercise,” and not be able to provide to you some definitive answers.  You would think that with as advanced as we are, we could provide more truths about the products we consume.  And perhaps we can, but choose not to for one reason or another.  (Ok, I’m off my soapbox.)


Like so many issues, there is no conclusive evidence that soy or other foods are linked to early puberty.  There is definitely a trend, but it may not be a singular causative effect.  Rather, it may be the combination of many factors like, soy, meat hormone content, plastics, and obesity.  Whatever the cause, it is of great concern and should not be taken lightly.  What do you do about it? I guess like most things, use/consume all things in moderation and be well-balanced with your diet and include exercise in your and your child’s weekly activity.  Sound familiar? Yes!

Next week, I hope to take a closer look at other products/foods that contain phytoestrogens.  Plastics and soy are not the only offenders.

What are your thoughts on the link between food and early puberty onset? Please share any anecdotal or research evidence on this topic with our readers.

Sources: Scientific American; Pediatrics, September 2010; USA Today; Mayo Clinic; livestrong.com

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Post shared at Monday Mania, Fat Tuesday, Traditional Tuesdays, Tasty Tuesday and Homestead Barn Hop.

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14 Responses to A Growing Problem? Research Behind Younger Puberty in Girls, Part 2

  1. It seems to me that it’s only recently that the possible link came up between soy and early onset puberty, so there just hasn’t been time to study things fully. Yes, we’re advanced, but we also still have a LOT of things to study, so scientists are kept busy.

    Interesting post. Makes me glad that I had already planned on packing most school lunches, and that I cook most of the time at home.

    • Cook says:

      I know, Annaliese. I feel the same way about my cooking at home and packing lunches. I thought a soy allergy might not be all that bad, afterall.

  2. Kristen says:

    This make me want to go buy a farm and produce all of my own food! We very rarely eat out, but it seems as though there is just as much stuff in what we buy at the grocery store. Interesting point about meat consumption between ages 3-7 causing early puberty. Does this include poultry, fish, etc.? We usually eat a meat protein at least once a day here. Thanks for all of the very interesting research!

    • Cook says:

      Doesn’t it, though? There are other issues with poultry, pork and fish, of course. Glad this was helpful to you!

  3. connie says:

    I think I’ve commented on soy before…and it’s something we will NEVER use in our home…too much proven theories about the “bads” of soy.

    Also, we have adopted from Africa…and with one of our daughters she was not in puberty even slightly…we adopted her at the age of 12…and within 6 months…she got her period…started developing….food and the things we eat here in North America definitely have a huge part to play in onset puberty.

    • Cook says:


      Wow! Thanks for your experience. Very interesting about your daughter. America is so terribly spoiled when it comes to food. And it’s not even good for us, in many ways.


  4. Sandy Toes says:

    Right now- I cannot handle “early” puberty! I really CAN’T!

    sandy toe

  5. Jill says:

    I agree that food is a huge contributor. Young girls still ate the same stuff 20 years ago (meat in the diet, etc) and they were fine. But now, we have – just as you listed – growth hormones, additives, way more junk food made with chemicals, etc.

    And look at the increase of grown women experiencign fertility issues. You can’t tell me it’s not all connected! It’s maddening that researchers don’t see this as enough an issue to study more – this will have an effect on the next generation’s ability to reproduce itself.

    I hate to be a conspiracy theorist, but let’s connect some dots: researchers depend on government funding…which has to be approved by Congress…the members of which are elected and, therefore, need financial donations….which are often made by the big chemical and agro-business corporations….who don’t want researchers to find out and reveal what they’re up to. Am I crazy….or could my theory have some truth? Hmm.. Great series – very thought provoking!

    • Cook says:


      Someone recently asked me about fertility issues and various food allergies. She is convinced that her problems are related to food. I should do a post on it (after I do some research for her).

      I was saying just about the same thing the other day about your conspiracy theory. I hate going down that path, but it’s hard not to. It’s hard to find the truth out there anymore on issue that is debatable.

      Thank you for your encouragement and I’m glad you’ve enjoyed the series.


  6. jill says:

    Thanks for linking your great post to FAT TUESDAY. Hope to see you next week! Be sure to visit RealFoodForager.com on Sunday for
    Sunday Snippets – your post from Fat Tuesday may be featured there!


    If you have grain-free recipes please visit Wednesday night for a grain-free linky carnival in support of my 28 day grain-free challenge starting Wednesday!

  7. Mary says:

    Puberty has actually been starting at an increasingly earlier age for over 150 years. Studies have shown that it occurs earlier in developed, stable countries. The trend has been shown in Europe and the US so it cannot be a strictly American diet issue. Specific foods may accelerate the trend or may be a contributing factor but I am pretty sure that soy or hormones in meat did not play a part in the fact that girls were reaching puberty earlier in 1875 than in 1850.

    • Cook says:

      You’re right, Mary, puberty has been getting younger for a couple of centuries. Researchers believe that the reason for late (17-18 years old) puberty a couple of centuries ago was because of poor nutrition. How ironic? However, over the past 20 or so years, the increase in early age has made a huge leap, particularly in the African-American community. Researchers are not contributing it solely to our food, but consider it to be a possible factor, along with other environmental factors.

      Thanks for your input!

  8. Pingback: Phytoestrogen-Containing Foods | The Willing Cook

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