A Population-Level Decline in Serum Testosterone Levels in American Men (2007)
academic.oup.com
academic.oup.com
Obesity is still a huge contributor to reduced testosterone, and this study doesn’t disagree with that. It’s such a well-known effect that it’s one of the first things the authors note and try to account for. These studies are trying to identify factors beyond obesity and reduced physical activity, but it’s difficult to tell if they’ve developed an accurate model to subtract those effects from their study.
While it’s possible that environmental toxins like BPA can contribute to neuroendocrine disruption and should be investigated, lifestyle factors are still at the top of the list of things people can adjust to influence their own testosterone levels.
I'll also add this from the article:
Setting: This was an observational study of randomly selected men residing in greater Boston, Massachusetts.
There hasn't been a slew of studies since from around the US. "American Men" is a huge stretch for such a localized study. It very well could have been one of the studies that alerted to BPA, but it could also be a very localized environmental effect.
Either way, this study should not scare anyone, except in it's overreach.
Are you suggesting living specifically in Boston lowers testosterone?
Because Boston isn't health-wise, demographically, behaviorally, environmentally, or in any other way representative of the US.
> Are you suggesting living specifically in Boston lowers testosterone?
Maybe. Or in urban areas. Or in coastal areas. Or the American Northeast. Or in places, America or not, near the Atlantic Ocean. Nothing in a study of men from Boston tells you that the scope of any effect is likely to be “the US”, unless it is clear enough to determine the actual source of the effect, and that source is known to be common throughout the US.
For the same reason that a study conducted on Japanese men would not produce results sufficient to draw a conclusion about all men globally, you can't draw a conclusion about all men in the US from a result observed in men in Boston.
Boston has a local environment, diet, culture and ethnography that could be causal in any result seen in any study.
Taken at a very simple level, you couldn't run a poll in Boston alone about anything - politics, preferred beer brands, opinions about Saturday Night Live, whatever - and assume your results would be representative of the entirety of the United States.
One hypothesis for the cause of the effect being described in this study is that contraceptive pill use in women is affecting hormone levels in drinking water.
Can you see how the use of a particular type of contraceptive pill could change from town to town, state to state, and that the water filtration systems may differ from town to town, state to state? And that's a pretty simple environmental factor you'd need to control for, or you could investigate locally.
Nevermind the fact that this isn't the only study showing declines in testosterone all over the world.
https://www.forbes.com/sites/neilhowe/2017/10/02/youre-not-t...
>Studies show that men’s testosterone levels have been declining for decades. The most prominent, a 2007 study in the Journal of Clinical Endocrinology and Metabolism, revealed a “substantial” drop in U.S. men’s testosterone levels since the 1980s, with average levels declining by about 1% per year. This means, for example, that a 60-year-old man in 2004 had testosterone levels 17% lower than those of a 60-year-old in 1987. Another study of Danish men produced similar findings, with double-digit declines among men born in the 1960s compared to those born in the 1920s.
In the US there are such a wide variety of climate trends that it’s impossible to claim a nationwide effect for such a localized sample.
My first thought was BPA, but it appears the effects of plasticizers on the male endocrine system are mixed[1].
Still can’t help but think this is something environmental and chemical at work.
[1] https://rbej.biomedcentral.com/articles/10.1186/s12958-018-0...
I absolutely agree. I read a meta study where they concluded lab rats have been gaining fat since the 70s - and these rats have well documented genetics, very precisely controlled diets, tons of expertly collected high quality data. It was pretty damning
https://www.scientificamerican.com/article/how-lab-rats-are-...
Also in the absence of longer-term or non-American data, we don't know if this is a decline from 'normal'. There's a lot of weird chemicals out there nowadays with biological effects, but there were a lot of those in the 20th century too.
What I mean is, maybe instead of 'testosterone levels are low today because of all the soy', it's 'testosterone levels were inflated back then because of leaded gasoline (or DDT or asbestos or ....)'.
While this is generally considered a cultural change, I feel that hormonal changes cannot or at least should not be ruled out a priori.
https://lithub.com/it-turns-out-theres-not-a-lot-of-science-...
Obviously we don't have serum hormone levels for ancient Chinese warriors, so I don't know how well it matches up with the hormone theory.
The classic "easy answer" for this stat has generally been the removal of lead paint from most people's lives.
Women are not affected, but men get “womenized”.
Granted it will vary person to person. But there are major changes happening in the body that result from messing with hormones
If anything, the soyboy superstition probably comes from just drinking sugary beverages and meals that lack sufficient fats and proteins for muscle building. Lack of cholesterol could also be an issue if one's genetics are of a low-production type.
Soy itself is somewhat of a super legume. The only legume that comes close is peanuts. And it's not very common to find peanut milk. Elmhurst used to sell it, it was amazing.
I have no problem building muscle [1] and my last free T test was around 850. Anecdotally, I doubt soymilk is the issue.
What do you mean by watered down? All soy milks have water listed as the first ingredient.
[1] https://www.bluediamond.com/brand/almond-breeze/almondmilk/u...
[2] https://elmhurst1925.com/products/unsweetened-milked-almonds
What grinds my gears is that consumers get the idea that they are drinking a healthy beverage with a lot of these plant milks when if they aren't drinking the unsweetened versions, they are basically drinking sugar water!
And the unsweetened versions aren't stellar either but at least if you are drinking a bunch of overpriced water, your body won't be getting full off of it, since it's devoid of calories.
Elmhurst and Westsoy are expensive but you cannot beat their potency and quality. 365 is a decent brand at a good price for unsweetened soy milk. However its almond milk is just like all the other mass market brands, almost purely water. I think all these brands just fall in line since the taste expectations for plant milks are expectations for water.. :-/ Plus it's cheaper to peddle water than to peddle nuts.
Elmhurst has a backbone of integrity and Westsoy does too. But until a few years ago I didn't even know about them. That's capitalism for ya.
I'm reading this as: capitalism means willfully selling people whatever they want to buy, even if they didn't do their homework and buy based on brand name or taste rather than value (nutritional content).
But how does that contrast to consumer behavior in other systems like communism and dictatorships? Or.......
I mean, to me ignorance is a first order "issue" independent of economic systems. If anything, the often lamented state of education today represents the pinnacle of achievement in human history in terms of the portion of the population that is literate and can effortlessly access info with their literacy and google skills. If they wanted.
Dr. Shanna Swab has been on at least one big podcast that I’ve seen. The discussion was fascinating. I won’t name the podcast because people get weird about it here.
Before you prepare to downvote me for having Christian sentiment, know that semen retention is actually an old eastern practice known to boost libido and health.
And yes, (ready for the pedants), prostate health has been correlated to unclogging old fluid in "the pipes" but that doesn't require the frequency of masturbation that is commonly practiced by single men in America.
The mental effects of constant video arousal have already been documented to be the cause of underperformance and erectile dysfunction in men. It's not a far stretch to ask if this psychological effect has a feedback mechanism coupled to libido and testosterone production.
Sites should be mandated to charge a minimum fee per month (eg. $10), and ISPs should be instructed to block websites which do not comply.
In this way it will be restricted from minors, and be more easy for adults to control their own access to.
I can’t find good stats on the percent of trans men in the population but I imagine it’s both low, and increasing from 2007 to now.
May not be significant enough to affect the study if it includes some from random sampling, but I imagine trans men have lower testosterone than non-trans men.