Are girls maturing faster due to hormones in meat?

[carlitos]

Hi all,

I don't post much in the science forum, but I was curious about what I think is a piece of pseudo-science. I had a conversation with someone today, and they assured me that it has been "scientifically proven" that girls mature faster today, because of growth hormones in beef, chicken, and the like. I am mostly against organic food, because it's largely a marketing scam in my opinion. However, I have now heard this specific claim in a few different places, and wasn't sure what led to this being 'common knowledge' amongst the Whole Foods set.

My initial response was that we have had relatively cheap protein in the Western world for at least 4 generations, so it makes sense that people are maturing faster and growing taller, being better-fed. I noted that the Netherlands eat and drink a lot of dairy, and are the tallest in Europe, while many Southeast Asians eat mostly rice and are much smaller in stature. I also mentioned the effect that diet has on gymnasts, who look much younger than their age in adolescence.

Am I wrong that this is nutrition, or is there something to the hormone argument?

Full disclosure - I am traveling this week and won't be posting much. If you post links, I will read them as soon as I can and educate myself. I searched the forum here and didn't see any old topics on the subject, so I apologize if it's redundant.

 

[This is The End]

Hello, there was a topic on this about a month ago, I believe this is the link.

 

[carlitos]

Thanks. What I found most interesting from the wiki link from that thread was the fact that Bovine Growth Hormone was only introduced in 1993 in the US, and that it is banned in the EU. So any observation of early puberty pre-1993 or in the EU would have to be explained due to another cause.

Sounds like I was on the right road with nutrition as the cause, but I have to read more.

 

[Rolfe]

Well, that was a short thread! (I was coming to make the argument that there is no BST in the meat we eat and I don't see any different between Britain and the USA in this respect.)

Rolfe.

 

[Jorghnassen]

It's not hormones in meat but nutrition is not the only possible other explanation. If it was, indeed, only nutrition, boys would likely mature earlier too. AFAIK, that is not observed.

 

[paximperium]

It's not hormones in meat but nutrition is not the only possible other explanation. If it was, indeed, only nutrition, boys would likely mature earlier too. AFAIK, that is not observed.

Fat produces different hormones.

 

[TubbaBlubba]

Fat produces different hormones.

Indeed, isn't it known that heavily overweight people produce excessive amounts of estrogen? I had an acquaintance with that problem.

 

[luchog]

Indeed, isn't it known that heavily overweight people produce excessive amounts of estrogen? I had an acquaintance with that problem.

Yes.

There have been multiple threads on this subject in the past. The upshot of all of them was that early onset of puberty, and development of secondary sexual characteristics, is pretty much due to better nutrition, high availablity of food, and high-fat diets resulting in higher levels of estrogen.

 

[zooterkin]

What I've read before suggests that age of menarche correlates with weight, so better nutrition (or even obesity) is a factor. For example, this paper. This paper, with a bigger sample size, suggests (if I read the summary correctly), that nutrition is a limiting factor, and once that is adequate, obesity may be the cause of earlier menarche.

Girls with early menarche were more likely to be overweight at ages 7, 11, and 16 years than those with late menarche, although early menarche was also reported by girls who were underweight or of average weight. These findings support the hypothesis that in well nourished populations the relation between menarche and body size is largely regulated by genetic factors and that nutrition is less important.

 

[Dancing David]

It's not hormones in meat but nutrition is not the only possible other explanation. If it was, indeed, only nutrition, boys would likely mature earlier too. AFAIK, that is not observed.

Except they do grow taller...

Nutrition, nutrition, nutrition.

(I am not sure the growth of pubic hair and voice changing has been trackerd.)

 

[Trakar]

It's not hormones in meat but nutrition is not the only possible other explanation. If it was, indeed, only nutrition, boys would likely mature earlier too. AFAIK, that is not observed.

"AFAIK," is not really an appropriate measure of accuracy, what does the available evidence say? If you are laying out a hypothesis, please provide some supporting information.

 

[Trakar]

Except they do grow taller...

Nutrition, nutrition, nutrition.

(I am not sure the growth of pubic hair and voice changing has been trackerd.)

This is probably more to the point. Menses is an obvious easy to latch onto marker for female development, with boys the onset of the various traits of maturity are generally more subtle and difficult to precisely determine.

 

[Jorghnassen]

"AFAIK," is not really an appropriate measure of accuracy, what does the available evidence say? If you are laying out a hypothesis, please provide some supporting information.

True, it may be somewhat harder to observe than girls hitting puberty, nonetheless, if boys also hit puberty earlier it would have been noticed it the literature. This suggests precocious puberty is much less common in boys and that it is unclear if a similar trend (to what is clearly happening for girls) is occuring.

Really, all I'm saying is that to model the trend, nutrition may not be the only factor at work here. Other factors (including pollutants, "environmental" estrogens, etc) have been considered in the literature but are also harder to reliably measure. Of course, if the only cause is nutrition, maybe we can blame phytoestrogens^WP, because, you know, soy is everywhere in food nowadays .

 

[Checkmite]

Since cooking something causes chemical changes to take place within it, I'm not sure the chicken grown hormone (for example) is even in the food anymore as such after cooking. This is assuming that chicken growth hormone has any effect on humans to begin with, of course.

 

[Rolfe]

Well, there's an obvious marker for boys too, and that is the voice breaking. Back in the 18th century, getting into a cathedral choir was a guaranteed education for a boy right through to 18 or so. The fiendishly hard treble parts written by Bach and his contemporaries were not intended to be sung by a choir entirely composed of the under-12s.

Nowadays, all these famous choir schools have upper forms entirely composed of retirees.

Rolfe.

 

[ThunderChunky]

True, it may be somewhat harder to observe than girls hitting puberty, nonetheless, if boys also hit puberty earlier it would have been noticed it the literature. This suggests precocious puberty is much less common in boys and that it is unclear if a similar trend (to what is clearly happening for girls) is occuring.

Really, all I'm saying is that to model the trend, nutrition may not be the only factor at work here. Other factors (including pollutants, "environmental" estrogens, etc) have been considered in the literature but are also harder to reliably measure. Of course, if the only cause is nutrition, maybe we can blame phytoestrogens^WP, because, you know, soy is everywhere in food nowadays .

Considering that sexual development is different for males and females, I see no reason to expect that a change in nutrition would affect both processes in similar way.

 

[Trakar]

True, it may be somewhat harder to observe than girls hitting puberty, nonetheless, if boys also hit puberty earlier it would have been noticed it the literature. This suggests precocious puberty is much less common in boys and that it is unclear if a similar trend (to what is clearly happening for girls) is occuring.

Well, there are other issues with the menses threshold, in that it is both obvious and carries significant other concerns for both the individual and the parents of girls reaching that development point (health issues, sexuality issues and emotional/psychological issues), whereas a boy sprouting pubic hair, experiencing a gradually deeping voice or putting on more muscle mass usually goes unnoticed by parents and is generally associated with much less concern about generally less significant health, sexualtiy or emotional issues. If boys bled, or developed horns on their foreheads as they entered adolescence, we might have a more comparable means of comparing and contrasting. As you speculate there probably are a variety of influences and factors and they may vary among the populations studied, but improved nutrition and more bountiful consumption overall, seems to be the primary and most influential factor in the studies I've seen so far.

Forgive any potential ignorances betrayed here, but does anyone know if increased phytoestrogens in the diet (as is common in some vegetarian fares) could be playing a role here as well? I don't know that much about the subject, but it would seem ironic if those intent on slamming residual hormones in beef as the root of this problem had to deal with high plant hormones as the actual source. Probably not the case.

 

[Jorghnassen]

Considering that sexual development is different for males and females, I see no reason to expect that a change in nutrition would affect both processes in similar way.

Why wouldn't it though? At the basic level, inadequate nourishment will slow down/hinder the growing/maturation process, thus adequate nutrition will hasten it (compared to lower levels of nutrition). There is probably a point where overconsumption would hinder normal growth as well, but I don't see why nutrition could simply be discounted in accelerating boys' sexual development.

 

[Jorghnassen]

Forgive any potential ignorances betrayed here, but does anyone know if increased phytoestrogens in the diet (as is common in some vegetarian fares) could be playing a role here as well? I don't know that much about the subject, but it would seem ironic if those intent on slamming residual hormones in beef as the root of this problem had to deal with high plant hormones as the actual source. Probably not the case.

The jury is still out on this one. But one reason why phyto and environmental estrogens are an appealing hypothesis is that it's a potential factor in other issues, like declining sperm counts and sex ratios at birth.

 

[Skeptic Ginger]

I haven't had a chance to vet the claims in this NYTs article but I'll put it out here for starters:

Factors linked to a risk of early puberty - Health & Science - International Herald Tribune

Maybe it was posted in the other thread?