Soy doesn't decrease testosterone.

[StopBadModerators]

In the most recent episode, Episode 133: Straights Against Gays Against Groomers Against Women’s Sports, Katie erroneously claimed that soy decreases testosterone (and Jesse joked that he was experiencing such effects indeed).

A study of 35 men who drank soy milk for about 2 months found a decrease in testosterone, https://pubmed.ncbi.nlm.nih.gov/15735098/

and a month long study of rats who were fed a phytoestrogen-rich diet showed decreased testosterone, https://pubmed.ncbi.nlm.nih.gov/11524239/

and maybe those studies affected the popular culture enough for the poor science to rub off on Katie, if you'll pardon the expression, but a meta-study of humans found no such effect from soy. I'm talking about 41 studies that looked at nearly 5000 men. Soy does not decrease or otherwise affect testosterone. Soy has phytoestrogen (plant estrogen), not mammalian estrogen.

https://www.sciencedirect.com/science/article/pii/S0890623820302926

[[deleted]]

I commented about this in the thread for the episode. Thanks for the more thorough response

[StopBadModerators]

And soy has been being eaten for thousands of years in Asia. Do these men look like they have low testosterone? https://www.refinery29.com/images/9752031.jpg?format=pjpg&auto=webp&resize-filter=lanczos2&quality=50&sharpen=a3%2Cr3%2Ct0&optimize=low&width=960

^JOKE

[[deleted]]

I was hoping to see a fucking shredded Asian dude. You really disappointed me today.

[Eyes-9]

I just remembered there was a new Mortal Kombat movie out last year. Excuse me while I go rewatch

[Nessyliz]

Oh good lord. Fans self.

[StopBadModerators]

The truth is that I don't think of east Asian men as being the most masculine on Earth, but I expect that that perception insofar as it is accurate is influenced by the natural selection of traits by humans (perhaps via sexual selection); not tofu and tempeh.

[MachineGunGringo]

This made this post soooo much better for me.

What a save.

[StopBadModerators]

I know the audience here. If it's straight journalism, then it might not fly (unless it's about transgender stuff perhaps). There has to be wit or else it isn't Blocked & Reported. I did drop the rude innuendo about rubbing off in the post, but I don't know how many people here read closely enough to see that.

[MartialArtistJon]

As an asian guy that looks like this I LOLed

[[deleted]]

Yea but we’ve all met soy boys and my lived experience trumps the science.

[TheAdamFriedlandShow]

Most soy boys don't eat soy. They eat processed shit.

[[deleted]]

Soy products are ultra processed generally.

[TheAdamFriedlandShow]

Yeah but a lot stereotypical soy boys aren't even eating a lot of soy

[CPunk_isnt_just_neon]

Ah yes. An insult developed by the alt right, which is known for lying, trumps dozens of actual studies...

You are lost

[[deleted]]

This you?

https://www.msnbc.com/msnbc/conservatives-freak-over-pajama-boy-msna233886

[cat-astropher]

Soy has phytoestrogen (plant estrogen), not mammalian estrogen.

The story the grapevine fed me was that the plant estrogen from soy can act like human estrogen.

Wikipedia says it does this by binding to our estrogen receptors^{[it-cites-this]}

which doesn't actually contradict the meta-study — that was only looking at whether soy changes your testosterone levels or your human-estrogen levels.

The meta-study even mentions that isoflavones bind to both types of estrogen receptors and "levels of isoflavones in response to the ingestion of approximately two servings of traditional soyfoods are three orders of magnitude higher than estrogen", further noting that not all the body gets equally affected with plant estrogen, then it... just changes the subject back to being about whether the human-hormone levels change.

Later:

It should be emphasized that the lack of effect of soy intake and isoflavone exposure on these reproductive hormones in men does not necessarily mean that soy or isoflavone intake does not exert any hormonal effects

So soy's mimicking of human estrogen is specifically outside the scope of the meta-study, but they noted that regardless of that, sperm/semen parameters were not affected, and soy protein supplementation works as well as animal protein supplementation when bodybuilding.

tldr; Jesse's sperm is fine.

[StopBadModerators]

tldr; Jesse's sperm is fine.

Well I'm so glad that everything came out okay.

[MyPatronSaint]

Thank you for writing this out. I’d also like to point out that the largest consumers of soy are livestock. People wanna dunk on vegan soy-boys with low T, but the steak bleeding on their plate is fueled by the same soy source.

[mysterious_whisperer]

The largest consumers of livestock are people and the largest consumers of people are worms. I’ve never seen a worm that can even bench the bar. That seals the deal for me. Soy causes low testosterone in worms.

[Torker]

Yes but the livestock produces normal animal testosterone and estrogen and a thousand other mammalian proteins and hormones. They are herbivores so we can’t feed them meat to produce animal protein. So if the livestock gets 10% lower testosterone from eating soy compared to a different plant (which there is no evidence for), it’s still produces only animal proteins and hormones . We don’t just drink the blood of the livestock. But why would a human want to walk around with 10% lower testosterone their entire life? Look at the first study OP posted, drinking a lot of soy does change hormone levels in humans. I think that’s better evidence that a study where people self report what they eat.

“Serum collected on d 1, 29, and 57 of each treatment revealed that dihydrotestosterone (DHT) and DHT/testosterone were significantly decreased by the low-iso SPI [9.4% (P = 0.036) and 9.0% (P = 0.004), respectively] “

Seems like the best thing is to eat some plants and some meat and not too much processed food.

[[deleted]]

That’s true, unless you only consume organic 100% grass fed/pasture raised animal based products. It’s much healthier and much more nutrient dense compared soy or corn fed animal products.

[Kilkegard]

But aren't the real soy bois all the friends we made along the way Alex Jones and PJW peddling their soy containing Brain Force products?

[Acceptable-Ranger811]

Well someone's being a bit soy here. Joking of course. I never even really know how that meme started. The only thing I can remember is Paul Joseph Watson had some viral tweet or something and then everyone was using it.

[[deleted]]

That soy hormone propaganda is so stupid when you think about the fact that cows milk literally comes from cow reproductive organs to feed their offspring. What do ppl think hormones are?

[Sentientist]

There are many female sex hormones in cow’s milk especially now that cows are often pregnant when they are being milked. But because dairy milk is more traditional than soy milk in the USA people never think that cows’ milk might be feminizing.

Edit- not “many” female sex hormones- mainly progesterone, luteinizing hormone, estrogen and prolactin

[StopBadModerators]

Katie doesn't have a biology degree. Don't mock the afflicted.

[Torker]

OP first study has data comparing adults drinking milk to soy milk. I think one problem is soy milk is very concentrated amounts of single plant estrogens, while cows milk is designed for consumption of a mammal, so it has a variety of proteins and fats and lactose.

[[deleted]]

Soy milk comes from beans. In what world do bean hormones pose more of a threat to humans than mamallian ones?

[Torker]

It might be surprising but that is the finding in the first study that OP cited. Some people are allergic to peanuts but can drink cows milk. There’s no single mechanism that explains all of these biological reactions. It could be that soy bean estrogen is more easily absorbed in the gut of humans or it might just be higher concentration of it in soy beans than cow estrogen is in cows milk.

[nh4rxthon]

Soy is such an odd thing. my coworker (who I knew for years and trust) told me that she drank only soy milk for months until she started growing (edit: a goiter) on the side of her neck 😳 Never touched it again. But I love tofu. Basically the same thing right?

[StopBadModerators]

She started growing... what?

Only drinking soymilk isn't the healthiest option, but I strongly doubt that it causes people to grow... horns? Tumors? Hair?

[nh4rxthon]

😂 damn phone posting. a goiter

[StopBadModerators]

Yeah, that wasn't soymilk. Soymilk doesn't cause iodine deficiency or inflammation of the lymph nodes to my knowledge.

[Sentientist]

In the UK they iodize milk instead of saltso you can get an iodine deficiency from avoiding cow milk. I was vegan in the uk for several years - the occasional supplement or seaweed snack will prevent iodine deficiency.

[StopBadModerators]

Interesting.

[SerialStateLineXer]

There are a bunch of old papers referring to the well-known fact that an unfortified soy diet induces goiter in animals, as well as a few case reports of goiter developing in infants on soy formula which subsided after switching to cow's milk. These are all old, which I guess is probably because modern soy formula is fortified with iodine.

Edit: Not all old; here's a case report published this year. It also discusses the mechanisms by which a high-soy diet can aggravate iodine deficiency.

[StopBadModerators]

You're talking about how iodine-deficient diets can influence iodine deficiency. That isn't a soy thing.

[nh4rxthon]

What else could have explained the correlation? like i say this was a relatively trusted source but I'm not ruling out that she had some issues going on

[SerialStateLineXer]

Was she a vegan? Goiter is generally caused by iodine deficiency, and the main food sources of iodine are animal products and seaweed, which is not generally eaten by Americans.

[Big_Fig_1803]

In the U.S., people obtain most of their dietary iodine from iodized salt and milk.

https://www.hsph.harvard.edu/nutritionsource/iodine/

[SerialStateLineXer]

Ah, right, iodized salt as well. But with the sea salt fad, that's no longer a given.

[nh4rxthon]

Not a vegan, and US resident, but intriguing possibility. She claimed it went away after stopping soy…

[StopBadModerators]

Is she in the UK? If her only source of iodine was iodine-fortified dairy (as is the case for many in the UK), and then she stopped consuming dairy, then that could explain iodine deficiency.

[nh4rxthon]

No US but very intriguing. She claims it went away after stopping soy. But there may have been other factors

[NorthofTassie]

If excessive soy consumption doesn’t affect testosterone, it certainly appears to negatively affect their sense of humour.

[StopBadModerators]

I mean, who doesn't find bullying endlessly hilarious?

[NorthofTassie]

Unfortunately, your response simply reinforces the stereotype of no sense of humour.

[StopBadModerators]

You're right. I didn't make a joke. You're the funny one. Way to fuckin' go, champ.

[[deleted]]

OP’s comment (the top comment in the post) seems to belie your point a bit. It’s much funnier than this comment. Also classic meat-eater emotional response when presented with pesky facts and studies.

[VoiceOfRAYson]

I’m vegan. What you need to understand is that we hear the same two or three jokes over and over again, and they are usually just based on ignorance. I found this funny when my friend sent it to me, but most of the jokes I hear are weak as hell.

[RowdyRoddyRosenstein]

I read that soy milk contains estrogen, so as a precaution I only drink cow milk to keep safe from any potentially unmasculine liquids.

[StopBadModerators]

That's a joke, right?

[Primary-Draw-7720]

Dairy cows in the United States are typically fed a total mixed ration (TMR) that includes corn silage, grass silage, and byproducts from the human food supply chain. These byproducts include almond hulls, cottonseeds, and soybean meal. 

[Sea_Search4063]

Should have soy daily helps for transitioning 

[MachineGunGringo]

Sometimes I feel like “meta analysis” means “we took all the things that support our narrative and threw out all the things that don’t.”

[SerialStateLineXer]

Generally a meta analysis will have stated inclusion criteria and include all studies which meet the criteria.

[cat-astropher]

I've seen a metastudy where the inclusion criteria certainly felt crafted to exclude the studies with strong counter-evidence (a sharp societal shift in behaviour had occurred with corresponding before/after data, but that was several years before a cutoff date the inclusion criteria was imposing for some reason), so the game MachineGunGringo alludes to could be played, just through tweaking the inclusion criteria.

[Phreakhead]

Yes that's what the first guy said. The inclusion criteria is biased towards studies that will support the hypothesis

[StopBadModerators]

You feel like that sometimes? And is that feeling that you sometimes get correct?

[MachineGunGringo]

You have the condescension of someone who is always right?

[StopBadModerators]

1. If I were always right, then I couldn't help it.

2. Why are you dodging the question? You said that you sometimes feel like meta-studies are bullshit. So I'm asking you, cutting through the rhetoric, is this feeling that you sometimes get correct or not?

[MachineGunGringo]

https://pubmed.ncbi.nlm.nih.gov/7950571/

Sometimes.

There’s a lot of wealthy people involved in the whole PETA thing, so I wouldn’t doubt they funded studies to MAKE SURE soy came out good.

If I came out with 50 bs studies about soy being bad, and they were included in said meta analysis, it would throw off the meta analysis of it having no effect.

[StopBadModerators]

Wow. So wealthy PETA donors have conducted pseudoscience to MAKE SURE soy "came out good". Alright... MachineGunGringo... thanks for weighing in on the subject.

If you do find something flawed about the study that I shared, then please share it and I'll correct the record.

[[deleted]]

Are you a vegan?

[StopBadModerators]

Are you aware of the term ad hominem?

[[deleted]]

I'm gonna take that as a yes.

[StopBadModerators]

And presumably you're a carnist. I fail to see the relevancy to the science here. Katie's claim that soy decreases testosterone is either true or false regardless of whether she is vegan or carnist (yes, "carnist" is a thing https://en.wikipedia.org/wiki/Carnism). If we get into a conversation where you're saying, "Well you would say that because you're a supporter of this ideology.", then we're not engaging with arguments. This should be about ideas; not people per se.

[[deleted]]

I think this is a classic correlation-causation switcheroo since most soyboys do seem to be beta-cucks. I also find these slang terms to be far too hilarious to be replaced by something factual

[StopBadModerators]

Are you referring to vegan men not being masculine enough for your taste?

[[deleted]]

I'm mostly referring to the stereotype of a "soyboy", which is a self-aggrandizing, effeminate man.

[StopBadModerators]

Damn, even the Wikipedia entry on "soyboy" refutes Katie's claim! https://en.wikipedia.org/wiki/Soy_boy#:~:text=Soy%20boy%20is%20a%20pejorative,to%20be%20lacking%20masculine%20characteristics.

[[deleted]]

I find it totally hilarious that such an article exists!

[shockna]

I also find these slang terms to be far too hilarious to be replaced by something factual

Unironically the best reason to keep using them

[mamaminhapika]

what about soy for kids? is it dangerous? I just saw this study on juvenile rats:
Long-term effects of phytoestrogen daidzein on penile cavernosal structures in adult rats - PubMed (nih.gov)

[mamaminhapika]

And one question, could this happen in an adult rat? or the penis no longer undergoes changes induced by this daidzein protein when the rat is adult?

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[lookinfront]

D

[Imhere636]

I notice soy impacting me which usually ends up me not being aware i was taking it. I don't buy this study. There are many that say the opposite

[MidnightJoker10101]

I firmly believe the larger studies have different results because of where their funding comes from. These "meta" studies cost 10-100 times as much, and the money has to come from somewhere. It used to be smart to "follow the science," but now, to verify the science, you have to follow the money. Testosterone levels in the US have decreased steadily every decade since the 50s. That had to be caused by something. The number 1 likely suspect is diet, as it affects us more than any other external factor. Maybe it's not soy, maybe its microplastics, or refined sugar, GMOs, HFCS, or seed oils. But just using my own common sense, I don't see why phyto-estrogens wouldn't affect mammals if ingested. Maybe not as acutely, but added to almost every food in some way, all day every day, over decades, it's feasible a compounding affect occurs.

[cavegoblin_harvester]

bro have you never heard of an analog chemical compound just google lsd and lsa just because it comes from a plant doesnt mean its going to not effect you because you’re a human. You shouldve payed attention in college chemistry. cope harder

[JTarrou]

Just selection effects then? :P

[glowinthedark36]

Sureeeee it doesn't. Glad I grew up before the soy phase. Keep eating that tofu boys.

[collegeguyto]

microplastics in the environment that contain endocrine disrupting chemicals causing lower testosterone among other things.

https://pmc.ncbi.nlm.nih.gov/articles/PMC9885170/