
Soy protein exerts minor effects on reproductive hormones in young men (2005) - vertig0h
https://www.ncbi.nlm.nih.gov/pubmed/15735098
======
pulisse
For what it's worth, the finding in TFA doesn't seem to have held up:
"Clinical studies show no effects of soy protein or isoflavones on
reproductive hormones in men: results of a meta-analysis"[1].

[1]
[https://www.sciencedirect.com/science/article/pii/S001502820...](https://www.sciencedirect.com/science/article/pii/S0015028209009662)

------
justinjlynn
study conducted in 2005; n=35; p-values vary based on measurements; study
conclusion is "[...] soy protein, regardless of isoflavone content, decreased
DHT and DHT/testosterone with minor effects on other hormones, providing
evidence for some effects of soy protein on hormones."; further study on
larger/more diverse populations required.

Read study entirely and in context before judging effect size based on study
alone but the data indicates further study is worth pursuing.

~~~
astrea
I've noticed that's rather common with NIH studies. Small sample sizes and
large conclusions.

------
amitutk
DHT causes hair loss, perhaps you can hope to keep your hair longer with Soy
protein

------
0xff00ffee
On one hand: YAY SCIENCE AND DATA!

On the other hand: Ahhhh, figs.

The sample size is incredibly small (n=35), but it appears to be a well-
constructed & controlled study. This merits further investigation. And that's
exactly what the abstract ends with.

My husband and I switched to soy milk about 15 years ago. Anecdote, he had his
testosterone tested recently and it was fairly high [he's completely bald], I
have not had mine tested ever. We like soy milk because we get the raw stuff
without the gross thickeners like xantham gum or carageenan, everything else
seems to add that (oat, rice, hemp, almond, etc.).

But data is data.

Hopefully this isn't one of those "un-reproducable studies" but it was done by
the NIH and not a university.

~~~
snapetom
Larger sample sizes increase the possibility of Type II errors. Too small
versus too large is a common line researchers walk. n=35 is completely
reasonable and common in this type of study.

~~~
0xff00ffee
Really? Huh. I thought confidence interval mattered which is proportional to
sample size, e.g. bigger is always better.

So more samples is worse for a study like this?

Seems counter-intuitive, but I'm not a stats guy.

~~~
snapetom
For things like polling, yes. Bigger is better. But scientific studies deal
with the question "does this have an effect." In that aspect, you introduce
Type I and Type II errors, and sample sizes play into the chances of making
them.

------
ArcVRArthur
Why was this flagged?

~~~
wtmt
It’s 15 years old and has been refuted by a meta analysis some years later.
See the current top comment here at
[https://news.ycombinator.com/item?id=22345421](https://news.ycombinator.com/item?id=22345421)

~~~
ArcVRArthur
Hmm. Perhaps that would be better to mention in the thread so as to allow
people to consider that for themselves. Flagging the thread based on a
disagreement about the validity of the source material seems counter-
productive and like something that would be more appropriate to discuss in the
thread itself.

------
terrycody
What a bullshit title! If this is true....

------
commoner
This was published in 2005, and the title of the submission should be dated
appropriately.

~~~
geofft
The sidebar suggests this "similar article" from 2010: "Clinical studies show
no effects of soy protein or isoflavones on reproductive hormones in men:
results of a meta-analysis."
[https://www.ncbi.nlm.nih.gov/pubmed/19524224](https://www.ncbi.nlm.nih.gov/pubmed/19524224)

That meta-analysis says: "Given that isoflavone-depleted isolated soy protein
is not commercially available and the composition of the product is altered by
the ethanol-washed processing used to extract isoflavones, the isoflavone-
depleted isolated soy protein treatment groups used in three studies 39, 40,
62 were excluded from all analyses except the subgroup analysis of the effects
of soy protein dose." Citation 40 is this article.

------
tmarsden
So the soy boy meme is now backed by a scientific study.

EDIT: I didn’t realize the study was from 2005. In that case the research
predates the meme.

~~~
Eleopteryx
I'm almost certain that's what op meant to get across.

------
avocado4
Human body is complicated - when we think we know something today, it's not
uncommon that eventually the evidence will come out proving us wrong. Doctors
used to recommend smoking to people for stress release, all based on solid
scientific evidence that was available at that time.

So whenever people make a dramatic switch to soy-based diet from a carnivore
diet that we evolved with over millions of years, it's always important to
acknowledge a possibility of side effects that we don't currently know about.

