Protein, Puberty, & Pollutants

Protein, Puberty, & Pollutants
4.53 (90.59%) 17 votes

The early onset of puberty in girls associated with animal protein consumption may be due to endocrine-disrupting chemical pollutants in the meat supply.

Discuss
Republish

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“Early onset of puberty is considered a…risk factor…[for] a number of diseases in adulthood, including hormone-related cancers, [a shorter lifespan], metabolic syndrome, and cardiovascular disease.” The conventional thinking has been that the reason the age of puberty has been getting earlier and earlier is because our children have been getting fatter and fatter.

Well, our kids have been getting heavier, especially in the United States—we’re #1! But, while the age of a girl’s first period has been dropping in the US and Asia, in Europe—despite their kids getting heavier, too—there hasn’t been a steady decline in puberty onset. So, maybe it’s less about how much kids are eating, and more about what they’re eating.

The most consistent link between diet and premature puberty has been animal protein consumption. For example, every gram of daily animal protein intake—that’s the weight of a paperclip—has been associated with about a 17% increase in the risk of girls starting their periods earlier than age 12. Why this link between animal protein and premature puberty? Well, we know meat increases the levels of the growth hormone IGF-1, and that alone is associated with early-onset puberty. But, maybe animal protein is just a proxy for the endocrine-disrupting chemicals that build up the food chain in animal products.

Recent reports found “significant associations between exposure to environmental pollutants and sexual maturation.” This was done over in Europe. In the U.S., a similar relationship was found with the flame-retardant chemicals, for example, which are found mostly in poultry and fish, unless you’re eating cat food.

“Over the last three decades, human exposure [to these levels of industrial pollutants] in the U.S. have increased from virtually nonexistent to [almost everyone carrying them around now].” They appear to have multiple adverse effects, but of all the potential toxicities, endocrine disruption (meaning hormonal disruption) may be the main concern in children. Girls with the most circulating in their bloodstream appeared up to ten times more likely to start their periods early.

But, since these chemicals are found most concentrated in fish and chicken, maybe the level of these chemicals in their bloodstream is just kind of a proxy for their meat consumption. Whatever the reason, animal protein intake is associated with early-onset puberty, whereas plant protein has the opposite effect. Children with higher levels of vegetable proteins starting puberty seven months later than average, and children eating more animal protein may start puberty seven months earlier than average.

Soy seems most protective. “[G]irls with the highest levels of dietary isoflavone intake [the phytonutrients in soy foods] may experience their onset of breast development…approximately 7 or 8 months later than girls with the lowest levels of intake.”

What effect might these shifts have on disease rates? Well, delays in the timing of puberty in response to beneficial dietary habits (higher intakes of vegetable protein and soy, and lower intakes of animal protein) “may be of substantial public health relevance.” A later age of starting one’s period is related to a reduced risk of breast cancer, and a later first period is associated with lower total mortality (meaning a longer lifespan).”

Hence, “a delay in the timing of puberty by approximately 7-8 months,” which is “achievable with dietary modifications”—either more plants or fewer animals—”may translate into about a 6% reduction in breast cancer risk,” and up to a 3% decrease in total mortality. And, it’s not just a problem in girls; boys eating more meat in childhood appear to be more likely to grow up with the kind of abdominal fat deposits that increase risk for heart disease.

Please consider volunteering to help out on the site.

Image thanks to kodomut via flickr

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“Early onset of puberty is considered a…risk factor…[for] a number of diseases in adulthood, including hormone-related cancers, [a shorter lifespan], metabolic syndrome, and cardiovascular disease.” The conventional thinking has been that the reason the age of puberty has been getting earlier and earlier is because our children have been getting fatter and fatter.

Well, our kids have been getting heavier, especially in the United States—we’re #1! But, while the age of a girl’s first period has been dropping in the US and Asia, in Europe—despite their kids getting heavier, too—there hasn’t been a steady decline in puberty onset. So, maybe it’s less about how much kids are eating, and more about what they’re eating.

The most consistent link between diet and premature puberty has been animal protein consumption. For example, every gram of daily animal protein intake—that’s the weight of a paperclip—has been associated with about a 17% increase in the risk of girls starting their periods earlier than age 12. Why this link between animal protein and premature puberty? Well, we know meat increases the levels of the growth hormone IGF-1, and that alone is associated with early-onset puberty. But, maybe animal protein is just a proxy for the endocrine-disrupting chemicals that build up the food chain in animal products.

Recent reports found “significant associations between exposure to environmental pollutants and sexual maturation.” This was done over in Europe. In the U.S., a similar relationship was found with the flame-retardant chemicals, for example, which are found mostly in poultry and fish, unless you’re eating cat food.

“Over the last three decades, human exposure [to these levels of industrial pollutants] in the U.S. have increased from virtually nonexistent to [almost everyone carrying them around now].” They appear to have multiple adverse effects, but of all the potential toxicities, endocrine disruption (meaning hormonal disruption) may be the main concern in children. Girls with the most circulating in their bloodstream appeared up to ten times more likely to start their periods early.

But, since these chemicals are found most concentrated in fish and chicken, maybe the level of these chemicals in their bloodstream is just kind of a proxy for their meat consumption. Whatever the reason, animal protein intake is associated with early-onset puberty, whereas plant protein has the opposite effect. Children with higher levels of vegetable proteins starting puberty seven months later than average, and children eating more animal protein may start puberty seven months earlier than average.

Soy seems most protective. “[G]irls with the highest levels of dietary isoflavone intake [the phytonutrients in soy foods] may experience their onset of breast development…approximately 7 or 8 months later than girls with the lowest levels of intake.”

What effect might these shifts have on disease rates? Well, delays in the timing of puberty in response to beneficial dietary habits (higher intakes of vegetable protein and soy, and lower intakes of animal protein) “may be of substantial public health relevance.” A later age of starting one’s period is related to a reduced risk of breast cancer, and a later first period is associated with lower total mortality (meaning a longer lifespan).”

Hence, “a delay in the timing of puberty by approximately 7-8 months,” which is “achievable with dietary modifications”—either more plants or fewer animals—”may translate into about a 6% reduction in breast cancer risk,” and up to a 3% decrease in total mortality. And, it’s not just a problem in girls; boys eating more meat in childhood appear to be more likely to grow up with the kind of abdominal fat deposits that increase risk for heart disease.

Please consider volunteering to help out on the site.

Image thanks to kodomut via flickr

Doctor's Note

For more videos on this topic, see:

If you’re not familiar with IGF-1, I have a series of videos about this growth hormone (though mostly in relation to cancer risk). See, for example, The Answer to the Pritikin Puzzle, and Cancer-Proofing Mutation. And, if you’ve never heard of metabolic syndrome, I talk about it in Metabolic Syndrome & Plant-Based Diets. Is it possible to overdo soy? Yes, but you’d have to work at it: How Much Soy Is Too Much?

I talk more about endocrine disrupters in:

For additional context, check out my associated blog posts: Why Are Children Starting Puberty Earlier? and Schoolchildren Should Drink More Water.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

31 responses to “Protein, Puberty, & Pollutants

Comment Etiquette

On NutritionFacts.org, you'll find a vibrant community of nutrition enthusiasts, health professionals, and many knowledgeable users seeking to discover the healthiest diet to eat for themselves and their families. As always, our goal is to foster conversations that are insightful, engaging, and most of all, helpful – from the nutrition beginners to the experts in our community.

To do this we need your help, so here are some basic guidelines to get you started.

The Short List

To help maintain and foster a welcoming atmosphere in our comments, please refrain from rude comments, name-calling, and responding to posts that break the rules (see our full Community Guidelines for more details). We will remove any posts in violation of our rules when we see it, which will, unfortunately, include any nicer comments that may have been made in response.

Be respectful and help out our staff and volunteer health supporters by actively not replying to comments that are breaking the rules. Instead, please flag or report them by submitting a ticket to our help desk. NutritionFacts.org is made up of an incredible staff and many dedicated volunteers that work hard to ensure that the comments section runs smoothly and we spend a great deal of time reading comments from our community members.

Have a correction or suggestion for video or blog? Please contact us to let us know. Submitting a correction this way will result in a quicker fix than commenting on a thread with a suggestion or correction.

View the Full Community Guidelines

  1. I’m wondering if 0.90 and 0.91 are that different (although I totally believe in general message – another point from China Study which gets verified by another resource I trust). btw I noticed Caucasian teen guys who do wrestling get bald extremely early – so I was wondering if it is meat and/or excercise or probably both leading to excessive hormone production..

    1. 1. Is this a genuine question or just a straw man? Why is non-GMO plant protein not an option?

      2. Let’s pretend it’s not an option: 80% of corn and 90% of soy in the U.S. is fed to animals, not people. A pound of meat requires sixteen pounds of grain to produce. Now which seems worse? Especially when you add in all of the other persistent fat soluble environmental toxins accumulated in the animals’ tissues?

      The answer is pretty clear.

      1. The answer is clear. Buy meat that is fed what it’s supposed to eat: grass. The difference between a grass-fed cow and a grain-fed cow is night and day. Just like you can buy homegrown organic vegetables you can buy farm raised hormone free animal products.

        1. Grass fed, organically raised beef A. Isn’t an option for 98% of the world, due to the sheer resources it would require to raise it. B. doesnt change the fact that the animal is still subjected to toxins in the air and general environment that are unavoidable and get stored in the animal.
          So you subject yourself to the animals toxins and your own.

        2. What are these magical hormone-free animals you speak of pray tell? What exactly do the use for cell-cell communication, soft whispers?

          Organic vegetables are not contaminant free. Nothing is. Your only choice is between more contaminated and less contaminated.

          A grass fed cow will consume even more food than a grain fed cow due to the lower caloric density. Their food may not be genetically modified, but they are still part of the food chain, their food still contains environmental pollutants, and they are still concentrating them in their tissues.

          How people can think that the nutritional profile of an animal completely changes with its diet is beyond me. If I eat mostly kale, or mostly corn, sure an analysis of my tissues may lead to some detectable differences, but it’s still going to be human flesh. I still produce hormones, I still have dioxin, pcbs, flame retardants in my tissues, I still have saturated fat in my tissues, arachidonic acid, etc.

  2. Learning about how much chemicals are circulating through our blood – so disheartening.

    It’s a shame we this info isn’t presented to all parents. It’s so vital.

  3. This may be a relatively crazy question, but could early-onset puberty have benefits in promoting earlier brain development? I’m thinking especially of prefontal cortex development, which could in theory reduce risky behaviors and therefore reduce overal (all-cause) mortality, despite increasing the risk of certain cancers, etc. I saw that one study says it is not. But this subject/phenomenon is, on the whole, poorly understood.

    1. From a purely subjective viewpoint having spent 7yrs in rec:

      Young bodies getting ahead of social development never amounted to better behavior. Pointing brain development in the direction of ‘breeding behavior’ ie preening flirting and showing off, ain’t what I call a benefit.

  4. I’m so glad I found this way of eating before i have my own children (which will probably happen in the next few years or so). I’m sure there will be all sorts of comments from the in-laws, but thanks to Dr. Greger I’ll have a mountain of information to respond to them with. I’ll be darned if people want to shame me into intentionally poisoning my children with animal products just to make themselves feel more comfortable.

    1. I am facing the same issue! My husband and I will probably start trying to get pregnant in a year or two and only one of the four future grandparents has agreed to feed them how I see fit. I foresee this being a big issue in my relationships with my family members.

    1. Based on the science vegan children should grow taller. Going through puberty early does cause a growth spurt but also closes off the growth plates. Males who have lost their testicles never go through puberty and continue to grow into their twenties and end up taller. A proper vegan diet should result in delay in onset of puberty and later growth spurt and closing off of growth plates. You can eat an unhealthy vegan diet and end up as a Fat Vegan or a Sick Vegan(see Dr. McDougall newsletters on those subjects) December 2008 and October 2002 respectively.

      1. I can substantiate with our experience.

        Post surgery, the hospital estimated my daughter’s adult size based on her parents and her age. Surprise surprise she is still growing at 15 where a tapering off was expected. Her first menstrual cycle was at 14 so she has years of growth ahead.

        Of course her ‘delay’ was treated as an aberration and likely caused by malnutrition *sigh*

  5. My four year old daughter has developed strong body odour, and has always been vegan. Do you have any advice on what I should try to eliminate from her diet? Chat rooms mostly talk of animal products, others sugar & I am thinking to start with removing processed soy products as a starting place eg tofutti cream cheese a d soy sausages! I would appreciate any diet related advice Thanks!

    1. Hi Sarah: My daughter also has this trouble; she is now twelve. She has been vegetarian all her life. I worked with her on good hygiene (washing under her arms). I didn’t get her a deoderant product until she was 10; and I make sure it is “clean” — no aluminum or other things we can’t pronounce! I do believe there is a link with sugars in her diet (she has a sweet tooth and will sneak sweets, which I limit, but occasionally still have). She admits she used to sneak down and consume leftover frosting from the refrigerator when she was four! I know she “cheats” to this day. My nutritionist suggested her gut flora (or lack there-of) could be a factor. Find a good probiotic for kids and try to give it to her daily. I hope this helps!

    2. I have recently read (looked for link, but didn’t find it quickly), that wearing of certain fabrics, usually man made synthetic materials will cause this in some folks. I am vegan, & experimented with myself and my clothes, noting when I wore, what, when I noticed strong odors. I did notice a significant difference when wearing clothes made from nylon and other synthetics, nylon being the worst. Cotton, hemp, linen became sweaty but had had little odor. Seems weird.

  6. Dr. G

    Thank you for the work you do! I am still going back and forth on the topic of animal protein and I just wish you could help. I read both sides of the debate and I’m just left feeling annoyed. Do any of these studies that point towards a plant based diet compare those who DO eat meat BUT that meat is entirely grass fed, eaten in moderation, cooked in liquid and eaten along with copious amounts of plant foods AND whom also live generally healthy (no smoking, excess sugar, etc.)? I mean really, is ALL meat consumption bad?

  7. Again Dr Greger is fascinating and enlightening. I am 53 and didn’t start periods until aged 17, I was mainly vegetarian back then, vegan now. Also , the so called ‘change of life’ in women , I believe can be transited in a more gentle way on a vegetarian or better still vegan diet. I had no problems. Thank you Dr Greger for all your work.

  8. The paper “Effects of lifestyle on the onset of puberty as determinant for breast cancer” is not included in the “Sources Cited” below the video. It can be found here: http://www.ncbi.nlm.nih.gov/pubmed/17220700

    And strangely, I haven’t been able to find the parts that are cited in the video; for example: «children with the highest intakes of vegetable proteins or animal protein experience at least their growth-related puberty onset up to 7 months later […]»

    Where does it come from?

    Thank you.

  9. In the early North American trials of water fluoridation Newburgh NY had its water fluoridated while Kingston NY was used as a control and the water did not have its water fluoridated. The trial was started in 1945 and terminated in 1950 and declared a success in reducing tooth cavities. In the mid 1950’s an MD, I don’t remember his name, reviewed the data. One of his many observations was that the girls in Newburgh started puberty 6 months earlier than the girls in Kingston. It should be noted that the water sources for the two cities was different at the time with differing mineral content also. This is described in Christopher Bryson’s book “The Fluoride Deception”.

    However in trials with monkeys and Mongolian gerbils a similar effect is
    observed. These trials were conducted with good protocol.

    Earlier, post 1950, a chinchilla rancher made the same observation in his chinchillas. He also believed that there was a transgenerational effect also.

    These studies give support to the idea that endocrine disrupters are a cause of the early onset of puberty.

    1. The cause of early puberty is probably multifactorial. The trend started before the introduction of the many artificial chemicals such as phthalates. Many of the persistent organic pollutants probably contribute to the problem. Fluoride is another issue that is complex. Interestingly as Dr. Greger pointed out in his video Avoiding Common Disorders dental caries appear to be a more recent problem for us.. courtesy of the food processing industry. From a complex systems perspective introducing one chemical to prevent one problem has the potential for unanticipated consequences which can be either good or bad. We will probably never know about these since we don’t invest the time or have the expertise to look for these effects. Our reductionistic approach to our health has led to many advances but we need to understand its limitations.

  10. Dear Dr. Greger, My family and I began eating a plant-based diet over 10 years ago. I allowed my children eggs and fish sticks for several years. About 4 years ago eggs and fish were eliminated from their diet after reading more about the effects of excessive animal protein. When we attend a social function they are allowed to choose their own food, but have to eat a salad or vegetable. More often than not they choose dairy and meat products. In other words, they don’t eat dairy and animal products often. My 8 year old daughter is beginning to show signs of puberty. I’m very concerned and unsure what to do. I’d like to hear your insight, advice, etc. Thank you.

Leave a Reply

Your email address will not be published. Required fields are marked *

Pin It on Pinterest

Share This