Talk:Phytoestrogen/Archive 1

Phytoestrogen and muscle building

Does phytoestrogen affect muscle building and/or weight lifting effectiveness? dfrankow (talk) 16:26, 23 July 2019 (UTC)

FSA report

i added a comment on cancer and phytoestrogens and rewrote the part on FSA report. is there a final report? i have only found draft reports on www.food.gov.uk Bedrupsbaneman 5 July 2005 11:45 (UTC) Added a new section including links to the two major classes of phytoestrogens.

Phytoestrogens in Men and Women

I can find a BBC report of the opinion of a Belfast physician, but no published article to go along with it. Dr. Anderson has published her opinion PMID 16234205, but where are her data? Shouldn't this be deleted?Pustelnik 20:17, 6 October 2007 (UTC)

Merged article

Since "phytoestrogen" and "phytoestrogens" is the same thing and the phytoestrogen article contained only one paragraph I have pasted it into this one. The other article is now redundant and can be deleted.--Tchoutoye

This arcticle still needs a lot of work, especially on the negative health effects of phytoestrogens in food (male infertility, disruption of menstrual cycle, thyroid damage) and on the scale in which they occur (unfermented soya is used in 60% of processed food). A mention could be made of the report of the British Royal Society called "Endocrine Disrupting Chemicals" and the CoT inquiry could be worked out in more detail. One of the committee members, Professor Richard Sharpe head of the Medical Research Council's human reproductive sciences unit at Edinburgh University, has done extensive research on phytoestrogens in food.

Interesting article: the health risks of soya --Tchoutoye 10:54, 26 July 2006 (UTC)

I would be quick to point out that "negative health effects" has a very different meaning for various people. The proper term should be "biological responses", which in this case is likely similar to estrogens. The point of removing the negative spin on the wording, is that there are people who are seeking hormonal alteration, or where such biological responses would not impact them. While thyroid damage could rarely be considered a good thing, disruption of the menstrual cycle is insignificant to those women who have gone through menopause and would gain a benefit from the better stabilization of hormones over any "menstrual distruption" (considering that their menstration is already disrupted.) Also, as for "male infertility", the proper term would be "feminization", which includes impacts upon fertility of men. But there are those people who are seeking this feminization such as transsexuals, and other transgenders, who would see this alteration of hormone levels as a positive rather than a negative. As with anything, negative and positive is in how it is applied, I mean, one "negative health effect" of Botox is nerve inhibition, which can result in death, but properly applied, it can yield effects that simulate youthfulness in older people. At least call it "potential negative effects". And in the future, it would be a good idea to not assume that every male in the world wants to remain so. --Puellanivis 22:11, 26 July 2006 (UTC)

• This is absolute nonsense. These are not nutritional supplements which a person is free to take or reject. These are part and parcel of all processed foods and fed to the entire population. The large scale results of phytoestrogens are clearly and overwhelmingly negative. 24.200.248.28 23:29, 4 November 2006 (UTC)

• Speaking of absolute nonsense. It's nonsense to make a statement that alludes to "food processing" having anything to do with the fact that foods contain phytoestrogens. Plants contain them naturally and always have. Not just soy. Yes, even organically grown foods contain them naturally. And they aren't "fed to the entire nation" as some sort of trickery or conspiracy as the writer above would have us believe. Every living thing produces hormones as part of its natural chemistry and we eat those living things. Get over it. 75.70.37.61 17:00, 24 June 2007 (UTC)

---

Even for women

how to make people docile conspiracy = xenoestrogens + phytostrogens + fluoride + music brain wave = men ---> women — Preceding unsigned comment added by 81.80.239.162 (talk) 15:26, 5 February 2013 (UTC)

it's not so good , and who cares if some transgenders want to take them because they want to be females.

it doesn't make them a healthy substance.

imagine for example if some flower would have phytoandrogens in it. it would soon find it's way in the same place as cannabis and coca in most countries......... makes you feel like theres a conspiracy to make everyone weak timid and docile , and it's working.

seriously at least wikipedia should warn what phytoestrogens or any substance that binds to the estrogen receptor does. for real.

instead of " lower cholesterol and promote bone health " and lower cholesterol could be bad sometimes...

on another note , why am I wasting my time , wikimedia has this medieval mentality , some hippy registered useer will come and call bullshit with some "study" about cholesterol from soy.com --The preceding unsigned comment was added by 88.155.113.162 (talk) 14:54, 11 April 2007 (UTC).

• I guess there is a reason you want to stay anonymous. Actually, daidzein, a phytoestrogen found in soy and elsewhere, has been described as a phytoandrogen PMID 17252558. There is at least one other phytoandrogen PMID 17261169, and these substances have been implicated in sex-reversal in fish.PMID 12492408 What's your point?Pustelnik 14:02, 13 October 2007 (UTC)

Effect on humans

How much phytoestrogen in a male human being is required to actually begin feminizing him? Doing a web search for such topics brings up many websites claiming eating soy products, for instance, can have such an effect on a man, but these sites cite few reliable sources, if any at all. Can feminization occur even in normal amounts of soy products? I have been a vegetarian (borderline vegan) for the past three years and I've regularly consumed a good amount of soy products, and I have yet to see such effects in myself. In fact, androgenic body hair, which is sensitive to the level of testosterone in the blood, has increased for me. — Sam 01:43, 6 July 2007 (UTC)

==Do you have some proof that phytoestrogens feminize males? According to Crenshaw's Sexual Pharmacology, phytoestrogens may sit in an estrogen receptor site & thus block the affect of estrogen (like beta-sitosterol sitting in a DHT site & blocking that testosterone. BTW, I understand that phytoestrogens are not steroids & not estrogen. (EnochBethany (talk) 06:20, 23 January 2014 (UTC))

• A lot. They are much less potent, on a weight for weight basis, than estradiol, often by a factor of 1000 or even 10,000. Because of the way endocrine receptors work, they can act as "weak agonist-antagonists". This means that they have a little effect by themselves, but prevent a more potent estrogen from working. They can block the effects of estrogens naturally produced by males, and you might end up with a lower total estrogen effect. It is naive to say they "might" have an effect, without quoting a peer-reviewed referrence. Toads might cause warts, too. You need proof, otherwise it is just your point of view, and not neutral. Pustelnik 19:35, 6 October 2007 (UTC)

• breast tissue in long term usage, and it also increases the chances of male infertility "http://news.bbc.co.uk/2/hi/uk_news/northern_ireland/3513607.stm" (avoid eating large quantities of soy/tofu as much as possible) Markthemac 01:35, 18 July 2007 (UTC)

• • This is a news article. What have Drs. Anderson and Lewis published in peer-reviewed journals? Have they published any evidence that eating soy causes breast development in males? If so, I can't find it in PubMed. There is a big difference between a news article or a review article and actual research. Only research is considered to be scientific evidence. Pustelnik 22:51, 8 October 2007 (UTC)

• • • They certainly have published something...

http://www.informaworld.com/smpp/content~content=a727272918~db=all

http://www.liebertonline.com/doi/abs/10.1089/10966200152053695

There's (obviously) much more material on male rats, but not from them:

http://www.ingentaconnect.com/content/oup/toxsci/2006/00000091/00000001/art00093

(Effective doses per kg in humans are 10-25x lower than those in rodents btw)

84.50.242.39 (talk) 00:59, 10 February 2008 (UTC)

• • • • Please sign your posts. The first article quoted states an opinion, but does not involve any actual original rerearch by the authors. The second article is an in-vitro study, and the abstracts state that low doses had no effect on sperm. Having no effect on sperm function is a long way from causing breast tissue growth in males, don't you think? If your question is: "Do soy estrogens cause breast development in human males, in quantities that are plausibly ingested in the diet?", the answer must be "There is no published evidence that they do". If you disagree, please quote a peer-reviewd research article that states the contrary. Please state the source of your claim that effective doses are 10-25 X lower in humans. For what chemicals, and in terms of what effects? Pustelnik (talk) 19:42, 10 February 2008 (UTC)

• • • • • I did sign with the IP, I don't have a username. I did not claim the second article is on mammary gland tissue, it's just an example that these two authors do study, and publish articles on, phytoestrogens. I do not care enough to carry out an in-depth search on all their publications and everything published in the field, and record all my sources. I just wanted to point out that safety cannot be assumed, esp. in pregnant women (and was hoping someone else would have the time to go deeper). If it isn't for the estrogenic effect, the anti-thyroid effect is still an obvious reason to avoid at least genistein and daidzein. 82.131.19.119 (talk) 01:29, 14 February 2008 (UTC)

I have done some general editing of the section on females to make the argument clearer and underscore the lack of consensus on the effects of phytoestrogens. Are there more recent studies that have moved the debate forward at all? I am not a scientist or physician, so I hesitate to contribute substantive content. Would an expert please update this section?—and the entire article, as needed. Thanks. KC 21:47, 10 January 2016 (UTC)

See the Dueling meta-analyses section farther down in Talk to realize that even experts are conflicted as to effects on menopause symptoms. David notMD (talk) 11:25, 25 March 2017 (UTC)

Section "Health risks" disputable

Section "Health risks" contains disputable claims:

"Phytoestrogens have the same effect as normal estrogens [...]" This is wrong. So-called "phytoestrogens" have a much lower estrogenic effect than estrogens.

"and in high quantity are known to cause gynecomastia [...], lower androgen levels in men, infertility, early bone maturation [...]" Such claims are highly controversial amongst the endocrinologic community, i.e., they are not "known to".

"and some isoflavones can enlarge the population of estrogen receptors in certain tissues." Like the whole sentence, references are missing.

I have removed all specific unreferenced health risks and simply replaced the section describing infertility etc with unresearched concerns over hormonal imbalances. All of these issues are merely speculation and have no real scientific basis as far as I've managed to find. Halogenated 17:02, 13 September 2007 (UTC)

Please see http://en.wikipedia.org/wiki/Soy#Soy_controversy for comparison.

• I agree, and have tried to clean up the referrences. I can find no published report of gynecomastia due to phytoestrogens. Speculation is not evidence, and most of the adverse claims are not backed up with any study actually showing any adverse effect, but see the "minor effects on serum reproductive hormones" referrence" for an example as to how such claims could be verified.Pustelnik 18:28, 7 October 2007 (UTC)

• • There certainly is abnormal mammary gland development in male rats:

http://www.ingentaconnect.com/content/oup/toxsci/2006/00000091/00000001/art00093

Doing such tests on humans would be complicated, as you can guess...

84.50.242.39 (talk) 00:51, 10 February 2008 (UTC)

Cleaned Up

I merged a couple of sections, removed a number of unreferenced and unsubstantiated comments and generally clean a few parts up. It's not great, but at least it is more accurate. Halogenated 17:14, 13 September 2007 (UTC)

Good Work

This article is really starting to come along! When I first stumbled across it I found myself compelled to try and edit out some of the obvious flawed assertions and claims without causing too much fuss, as my area of expertise is far from here! I'm glad to see the interest taken up by Pustelnik and Jennylee who evidently are much better versed on the topic. Cheers! Halogenated 03:57, 13 October 2007 (UTC)

Sometimes a keen interest and steady contributions as you have done and continue doing is as important as knowledge on the topic. Keep up the good work! Jenny^Len* 06:16, 13 October 2007 (UTC)

Yeah! Thanks to the folks cleaning up the urban legend stuff from this article. Came here looking to see if there was real research to back up claims that Yoruban Nigerians have a high rate of twins, and that it's caused by phytoestrogens in the yams they eat. Didn't find any; don't think there is any. -Anon. --Preceding unsigned comment added by 71.191.16.16 (talk) 03:59, 17 February 2008 (UTC)

Not NPOV

This article is not NPOV. Research which hasn't reached positive conclusions (even after funding from the Soy industry) is combined with positively framed sentencing such that we are led to beleive the debate on phytoestrogens is conclusively positive. Has ANY reasearch regarding phytoestrogens reached a positive CONCLUSION? Whereas anything negative is framed with words such as speculate. Talk to an endocrinologist or toxicologist and you'll get a very different story. I quote toxicologist Professor Ian Shaw from University of Canterbury Alumni Magazine Vol6 No1 Winter 2009 - "Natural plant estrogens are found in some foods, such as soy. Soy contains the chemical genisten, which is an estrogen-mimic and soy is widely used in New Zealand. But, as these estrogens are naturally occuring, there is not much we can do about them - except reduce consumption of the foods which contain them." Thats just info I currently have on hand. My father was colleages with an endocrinologist at Lincoln University who was also concerned about dietary consumption of phytoestrogens particularly in infants. I know medical lecturers who advise limiting phytoestrogen consumption for women due to breast cancer risk. Scientific articles on wikipedia are frankly becoming rubbish because a lot of people aren't scientifically critical enough of their sources... —Preceding unsigned comment added by 118.92.175.235 (talk) 10:41, 6 January 2010 (UTC)

My reading of the current version of the article and in particular the section on phytoestrogens in females is that the article is balanced and maintains a neutral point of view. This article states that the evidence that phytoestrogens prevent breast cancer is mixed and provides reliable sources to back up this claim. On the other hand, the section on phytoestrogens in infant formula may need to be reworded slightly. The present version seems to go too far in down playing the potential risks. Boghog (talk) 11:28, 6 January 2010 (UTC)

I am a Pediatric endocrinologist, and I consider the section on infant formula to be balanced. Speculation that something might be harmful is not "evidence" that it is harmful. Actual epidemiologic studies in human women quoted in the article suggest that phytoestrogens prevent breast cancer, and probably prevent prostate cancer in men as well as well. Articles in Pediatrics or the Journal of Clinical Endocrinology and Metabolism should carry much more weight than the University of Canturbury Alumni Magazine. Looking at "pro" and "Con" articles, consider the source.Pustelnik (talk) 01:12, 7 January 2010 (UTC)

Plant Defense Against Herbivores

A sentence in the first paragraph refers to plants using phytoestrogen to protect themselves against herbivores. But the citation is a single, brief, poorly argued scientific paper. I would delete it, accept the issue of soy "feminizing" people is a hot-button hysterical issue, so I assume a paranoid person will just put the sentence back again. I encourage everyone to read the article, it's brief and not too difficult, and you might be able to spot all of the fallacious presumptions and logical flaws.96.246.13.91 (talk) 00:08, 14 April 2011 (UTC)

The citation in question (see PMID 3203635) is to a high quality, well researched review article that has been published in a respected peer reviewed journal (Environmental Health Perspectives) by an author who is an expert in the field. Citations don't get much better than this. Why would you delete it? Boghog (talk) 13:35, 22 July 2012 (UTC)

It’s now in the second paragraph. The author of that paper offers no evidence that the effect has been sufficient to result in selection pressure. There is not even an argument to indicate why one might expect the effect to be sufficient to result in selection pressure. The paper refers to the “classic example” of “clover disease” in sheep. Formononetin is ruminally metabolized to equol, with effects on reproduction that can be economically significant for sheep production on pastures with considerable red or subterranean clover, but given the fact that forage stands with substantial representation by such legume species do not tend to exist naturally, the amount of formononetin ingested in nature would be expected to be far too small for this to have a noticeable effect on reproduction and to result in selection pressure. Distribution of the biochemical pathway for formononetin production among related plant taxa indicates evolution of this long before managed stands with large components of these species were prevalent. So the paper’s suggestion on this seems to be nothing more than superficial speculation. The author is an expert on endocrinology, but his publications do not indicate specialization in evolution of plant biochemical pathways. And although the journal involved has a pretty good record in terms of peer-review on health-related matters, its track record is quite spotty when it comes to peer review with environmental science expertise. Finally, the cited paper explicitly focuses on effects on female, not male, reproductive physiology, while the Wikipedia article for some reason makes a claim about effects on male fertility. So the cited paper provides no support at all for the article's claim. Schafhirt (talk) 05:07, 11 August 2015 (UTC)

Estrogen positive breast cancers

This article will attract those seeking information on which foods are best avoided by people with estrogen positive breast cancer. It could provide clearer information or links to such. 124.148.165.158 (talk) 02:58, 14 January 2012 (UTC)

It is not at all clear whether phytoestrogens promote or protect against breast cancer. The available evidence is mixed. There is even less data on the effect of phytoestrogens in patients that have breast cancer. The following advice seems sound:

• ER+ patients should avoid phytoestrogens? Answer: phytoestrogens consumed as part of a normal diet should not be a concern.

Also, please keep in mind WP:MEDICAL. Boghog (talk) 15:16, 22 July 2012 (UTC)

Plant Based Sources Only vs. Plastics Sources

A simple web search on 'phytoestrogens plastic' shows many claims that plastics can leech phytoestrogens. But this article starts by saying the are plant based only. What is correct? Can a short line be added to the article to clarify any misinformation? Dcsutherland

The statement in this article is true. By definition, phytoestrogens are produced by plants and are not normally found in plastics. Plastics contain synthetic man made materials such as plasticizers that can leech out of the plastic. Furthermore some of these plasticizers are estrogenic (i.e., xenoestrogens). Phytoestrogens are a type of xenoestrogen but not all xenoestrogens are phytoestrogens. In short, plastics leech synthetic xenoestrogens, not but plant produced phytoestrogens. Boghog (talk) 14:06, 22 July 2012 (UTC)

Xenoestrogenes = novel, man made

• Click: Links to page xenoestrogenes.

First paragraph on that page says: They can be either' synthetic or natural chemical compounds. — Preceding unsigned comment added by 24.202.208.89 (talk) 12:11, 13 April 2013 (UTC)

Health risks section skewed to only listing positive benefits

there's no mention of the adverse effects of phytoestrogen on the thyroid, the brain (shrinkage, parkinsons, alzheimers, dementia, ect). This section needs to be more balanced.

• Higdon J (2006-01-01). "Soy Isoflavones: Cognitive Decline". Micronutrient Information Center. Linus Pauling Institute at Oregon State University. Retrieved 2013-07-18.
• MacArthur JD. "The Trouble With Tofu - Soy and the Brain". Rense.com. Retrieved 2013-07-18.
• Patisaul HB, Jefferson W (2010). "The pros and cons of phytoestrogens". Front Neuroendocrinol. 31 (4): 400–19. doi:10.1016/j.yfrne.2010.03.003. PMC 3074428. PMID 20347861. {{cite journal}}: Unknown parameter |month= ignored (help) – review
• Shomon M (2012-06-12). "Soy and the Thyroid: A Look at the Controversy Over Soy and Thyroid Health". Health: Thyroid disease. About.com. Retrieved 2013-07-18.

— Preceding unsigned comment added by Normana400 (talk • contribs) 06:46, 18 July 2013 (UTC)

Thanks for pointing out the problem and for the references (I hope you don't mind, but I have reformatted them for eventual inclusion in the article). I agree that the section is not balanced. Furthermore the section is too reliant on primary sources. Per WP:MEDRS, high quality review articles should be used instead. The Patisaul & Jefferson (2010) article certainly qualifies. I will work on this as I find time. Boghog (talk) 07:41, 18 July 2013 (UTC)

See also the "reliable sources" banner at the top of this talk page for links to high quality secondary sources. Boghog (talk) 07:47, 18 July 2013 (UTC)

Here is another high quality review:

• Jefferson WN, Patisaul HB, Williams CJ (2012). "Reproductive consequences of developmental phytoestrogen exposure". Reproduction. 143 (3): 247–60. doi:10.1530/REP-11-0369. PMC 3443604. PMID 22223686. information gathered from the published human studies combined with the large number of animal studies already available clearly demonstrates that phytoestrogens have the ability to permanently reprogram adult tissue responses after a developmental exposure, and that these altered tissue responses are important for reproductive health {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

Boghog (talk) 21:04, 24 July 2013 (UTC)

Regarding the "brain shrinkage"-study from Indonesia I just found the following information considerable:

(copied and pasted from site: http://www.veganhealth.org/articles/soy_wth )

• "Tofu and Tempeh Study, Indonesia (2008 & 2010)

A 2008 study from Indonesia found that among people aged 52 to 98, tempeh intake was associated with slightly better memory scores (9). The authors suggested that tempeh might be good for memory because the bacteria used in the tempeh starter, Rhizopus oligosporus, produce folate which is thought to protect memory.

However, increased tofu consumption was linked to slightly worse memory scores (-0.18, p = .05). The authors state that, "According to the Departments of Public Health at the Universities of Jakarta and Yogyakarta, formaldehyde is often added to tofu (but not tempeh) to preserve its freshness. Formaldehyde can induce oxidative damage to the frontal cortex and hippocampal tissue...." As of January 2011, the Indonesian government was still trying to end the practice of adding formaldehyde to tofu (43).

In 2010, this research group published a follow-up paper (42). It was a cross-sectional study of 151 men and women (most from the previous report) over the age of 56. Both immediate and delayed recall were tested. Median and mean tempeh and tofu consumption was seven times a week, ranging from never to three times a day. Before adjusting for age, sex, and education, tempeh and tofu were associated with better immediate recall; after adjusting, the associations were no longer significant. In the group younger than 73 years, higher tofu consumption was significantly associated with better immediate recall even after the adjustments." 41.189.161.43 (talk) 10:31, 5 April 2014 (UTC)

Balance to "Effects on Human" section

In contrast to PMID 19524224 cited in the article I have also found PMID 19919579 and PMID 16234205 (the latter mentioned previously in this Talk page). I do not have access to the full text of the PMID 19919579 but it appears to be a review done in 2010 like PMID 19524224. Its abstract indicates there is doubt on any firm conclusion and that more investigation is needed but that caution would suggest reduced infant consumption would be wise. Stan3 (talk) 17:07, 9 May 2015 (UTC)

Estrogenic effect of red clover ingestion by sheep

The article states “In the 1940s, it was noticed for the first time that red clover (a plant which is rich in the phytoestrogen coumestrol[6]) pastures had effects on the fecundity of grazing sheep.” The phrase in parentheses is misleading, implying that coumestrol was responsible, while failing to mention any other substances, notably formononetin. However, Adams (1995. J. Anim. Sci.), Shutt et al. (1970. Austral. J. Agric. Res.) and numerous other sources implicate red clover’s formononetin, which is metabolized to the more estrogenic equol in the sheep (Shutt and Braden 1968. Austral. J. Agric. Res.), particularly in rumen fluid (Nilsson et al. 1967. Biochim. Biophys. Acta). As much as 20 g formononetin may be ingested (by a sheep) per day on some red clover pastures (Lindsay and Kelly 1970. Austral. Vet. J.) This is consistent with data of Dedio and Clark (1967. Can. J. Plant Sci.). The source cited in parentheses in the Wikipedia article gives phytoestrogen contents of foods, but with regard to red clover, it does not identify the plant parts analyzed. Several references specify red clover flowers as food, whereas foliage and stems are the principal plant parts grazed as forages. Formononetin concentration in red clover varies greatly with plant parts, and also with cultivar, season, growing conditions, and hay-making (Kelly et al. 1979. N. Z. J. Exp. Agric.; Booth et al. 2006. J. Agric. Food Chem.; Dedio and Clark. 1967; Sivesind and Seguin 2005. J. Agric. Food Chem.; Rumball et al. 1997. N. Z. J. Agric. Sci.; Saviranta et al. 2008. J. Sci. Food Agric.). Similarly, very wide within-species variations in coumestrol content of forages have been noted. Consequently, the Wikipedia article’s reference citation is not clearly relevant to “clover disease” of sheep. The recognized importance of formononetin with regard to forage is indicated by the effort made to develop low-formononetin red clover cultivars, e.g. ‘Grasslands G27’ in New Zealand. With removal of the parenthetical phrase and re-insertion of the deleted “(a phytoestrogens-rich plant)” in its place, the Wikipedia statement will not be misleading. Schafhirt (talk) 00:08, 11 August 2015 (UTC)

Unsupported claim regarding male fertility

Recent deletion of a claim in the article’s introduction was promptly reverted. Apparently the claim needs discussion beyond what can be contained in an edit summary.

The claim is “It has been proposed that plants use phytoestrogens as part of their natural defence against the overpopulation of herbivore animals by controlling male fertility.” The citations given in ostensible support of this are Hughes (1988. Environ. Health Perspectives 78: 171-174) and Bentley and Mascie-Taylor (2000. Infertility in the modern world: present and future. pp. 99-100), with the latter reference’s authorship order inverted in the Wikipedia citation. However, neither reference makes such a proposal regarding male fertility. Moreover, Hughes explicitly suggests that effective defence using phytoestrogens against herbivores would operate by effects on female, rather than male fertility. [See Hughes’s comments listed for (i) on the second page of his paper.]

The problem with the actual proposals of the cited sources is that they are worded as generalizations regarding how plants use phytoestrogens, not recognizing that many plants possess them at concentrations and in forms with estrogenicity levels too low to suggest a discernible effect on populations of their herbivores, not recognizing that evidence of effective natural defence against herbivores is extremely limited, not considering that in some cases plants might be using phytoestrogens as a defence against pathogens rather than herbivores, etc.

Adverse effects on fertility of various herbivore species are noted by Hughes, but most of those are not evidence to support his proposal that phytoestrogens are “produced by plants to modulate the fertility of herbivores.” He invokes sheep and cattle. However, insofar as cases involving domestic ruminants have occurred under unnatural dietary conditions (greatly elevated phytoestrogen intake imposed by monoculture or near-monoculture of certain forages, far exceeding intakes to be expected in nature)(Bennetts et al. 1946. Austral. Vet. J. 22: 2-12; Schutt et al. 1970. Austral. J. Agric. Res. 21: 713-722; Adler and Trainin. 1960. Refuah Veterinarith 17: 58-67; Kallela et al. 1983. Nordisk Veterinærmed. 36: 124-129; Adams. 1995. J. Anim. Sci. 73: 1509-1515; etc.) they are not evidence of phytoestrogens being produced to modulate animal fertility, any more than are the cases of reduced fertility in captive cheetahs fed an unnatural high-phytoestrogen diet containing considerable soy, described by Setchell et al. (1987. Gastroenterology 93: 225-233). While Hughes indicates reduced fertility in mice with the 15 and 30 percent ladino clover diets administered by Leavitt and Wright (1963. Reprod. Fertil. 6: 115-123), he does not mention that in their study, at 30 percent, estrus and fertile matings reappeared after 18 days, or that with 15 percent second-growth (in contrast to pre-bloom) ladino clover, estrus persistence and frequency were somewhat increased, rather than reduced, relative to normal estrus. Of all the examples listed by Hughes, the best case for a possible adaptive natural plant defence against herbivore fertility would appear to be in the California quail study of Leopold et al. (1976. Science 191: 98-100), which is briefly described in the Wikipedia article’s “Avian studies” section). [With regard to avian species, see also the paper by Rochester and Millam (2009. Comp. Bioch. Physiol. A. Molec. Integr. Physiol. 154: 279-288).]

The claim by Bentley and Mascie-Taylor is that “Development of these phytoestrogens is presumably adaptive in that potential plant predators may suffer from reduced fertility as a result of ingesting sufficient quantities of the plant in question.” There is nothing about male fertility in this statement, and no accompanying math or evidence or analysis to assess whether, under natural conditions, ingestion by herbivores would have been sufficient to justify inference of an adaptive effect involving them. No evidence is invoked to justify presumption that development of phytoestrogens across numerous plant taxa generally has been adaptive due to herbivory. A more recent consideration of possible adaptive effects would presumably acknowledge the demonstrated relationships of some phytoestrogens in certain plant pathogenic infections, arbuscular mycorrhizae, and nitrogen-fixing root nodule symbioses, several of which would be expected to exert far more effective selection pressure than would be expected with herbivory. Bentley and Mascie-Taylor cite Hughes. Neither reference considers invertebrate herbivores. Of the few herbivorous arthropod studies conducted and reviewed by Karowe and Radi (2011. J. Chem. Ecol. 37: 830-837), none found adverse fertility effects of phytoestrogens at intake levels that would seem realistic in nature.

So while some avian examples, in particular, would support suggesting that an adaptive natural defence against herbivore overpopulation, attributable to phytoestrogens, may (or might) occur in some instances, there is not evidence or analysis to justify proposing that in general, plants use phytoestrogens in this way, and it is misleading to buttress a claim that “It has been proposed...” about male fertility with citations that do not support that claim, especially when one of the cited references explicitly argues against natural defence through effects on male fertility. Schafhirt (talk) 04:59, 18 August 2015 (UTC)

Thanks for discussing this here and above. After re-reading the sources, it is clear that they more strongly support the hypothesis that phytoestrogens are synthesized by plants to reduce female and not male herbivore fertility. Perhaps this was a typo by the editor who originally added this sentence. In addition, it would be more accurate to describe this as a hypothesis (a suggested explanation) than a well-tested theory. While the evidence for this hypothesis is far from conclusive, it at least provides a plausible explanation for why plants synthesize these substances and this hypothesis is supported by reliable secondary sources. I have therefore replaced "male" with "female" and "proposed" with ""hypothesized". I hope this is adequate. Boghog (talk) 11:15, 18 August 2015 (UTC)

Dueling meta-analyses for female health

The text cites a 2007 Cochrane systemic review (Lethaby) about phytoestrogens and menopause symptoms, with a note that a citation update would be appropriate. And herein the problem: Lethaby co-authored a Cochrane review in 2013 (PMID 24323914). There was a data exclusion process that in my opinion verged on bias: the review identified 43 randomized controlled trials (RCTs) but included only five (all with a red clover extract) in a meta-analysis. The RESULTS section states that trials with soy genestein had symptom benefits, but then the authors' conclusion was "No conclusive evidence...." Other options for updating the referencing are: Chen et al. meta-analysis and systemic review in 2015, pooling 15 RCTS: "Phytoestrogens appear to reduce the frequency of hot flushes..." (PMID 25263312), and Franco et al, in JAMA 2016, published a systemic review and meta-analysis incorporating 62 clinical trials with conclusions that hot flashes and vaginal dryness improved, but not night sweats (PMID 27327802). If anyone wishes to tackle this - good luck. David notMD (talk) 18:51, 24 March 2017 (UTC)

The pros and cons of phytoestrogens

@Zefr: I dispute that PMID 20347861 is a low quality review with a weak conclusions. Its overall conclusions are consistent with the older PMID 19919579 (Further investigation is needed before a firm conclusion can be drawn). Both review the available animal and human data. Also characterizing the edits as sloppy is not accurate. There was one word that was misspelled. You need to be more careful with your edit summaries. Boghog (talk) 15:36, 3 November 2017 (UTC)

PMID 20347861 is not only 7.5 years old, outdated by MEDRS standards, but its conclusions are soft and subjective, such as "the question of whether or not phytoestrogens are beneficial or harmful to human health remains unresolved", i.e., not clear information for an encyclopedia. Even more recent reviews, PMID 25160742 (2014), remain vague. My edit details are obvious from the copyediting done. --Zefr (talk) 16:16, 3 November 2017 (UTC)

"the question of whether or not phytoestrogens are beneficial or harmful to human health remains unresolved" – if that is the current state of knowledge (this is frequently the case of science), that is not at all subjective, it is an accurate statement of fact, and therefore encyclopedic. Boghog (talk) 17:30, 3 November 2017 (UTC)

@Zefr: Can you explain to me what's more "unencyclopedic" in the researches I cited, in comparison to the ones currently in the article? If the scientific consensus is that this is a vague subject (which it is), than this is the stand that should be taken by the article. It seems to me like you are cherry-picking scientific data that fits your own agenda. Haha01haha01 (talk) 22:42, 3 November 2017 (UTC)

Also, the strongest citation supporting the current text is "A 2010 meta-analysis". Therefore, if you claim that my citations are outdated thus invalid, then so is the entire section. Haha01haha01 (talk) 22:48, 3 November 2017 (UTC)

It's true the literature on phytoestrogen effects does not facilitate clear description. The version I edited here removed 2005 and 2008 studies and content which added little value and can be seen as unencyclopedic when one considers WP:NOTJOURNAL, #7. We can replace older literature with more recent reviews, which I have entered with subsequent edits. --Zefr (talk) 03:18, 4 November 2017 (UTC)

Your subsequent edits were to the Females section. We were discussing the Males section. The Males section contains two 2010 reviews (PMID 19524224, 19919579). You removed a third 2010 review (PMID 20347861) that is slightly more up-to-date than the first two. Removing the third review while leaving in place the first two makes absolutely no sense. As often is the case in science, the available evidence that phytoestrogens affect male fertility is insufficient to draw a firm conclusion. This is a very clear statement that is encyclopedic. The passages in WP:NOTJOURNAL that are relevant to this discussion are:

• The purpose of Wikipedia is to present facts, not to teach subject matter. – Nothing is being taught here, just a simple statement of fact that current knowledge is insufficient to draw a conclusion.
• article[s] should be written in plain terms and concepts that can be understood by any literate reader. – Any literate reader can understand the conclusion is that the evidence is inconclusive.

Hence WP:NOTJOURNAL does not apply here. WP:MEDRS does. Boghog (talk) 05:53, 4 November 2017 (UTC)

PMID 27723080 is a 2017 review that concludes that a definite conclusion on possible beneficial health effects of phytoestrogens cannot be made. This is a very clear, encyclopedic statement that can be understood by any literate reader. Boghog (talk) 06:23, 4 November 2017 (UTC)

Requested move 8 August 2018

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Moved  — Amakuru (talk) 17:44, 17 August 2018 (UTC)

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Phytoestrogens → Phytoestrogen – Per WP:SINGULAR and the recent move request at Talk:Isoflavone#Requested move 30 July 2018. Please note that there is significant edit history at the target, which was previously merged here. Dekimasuよ! 19:11, 8 August 2018 (UTC)

• Support. Even though WP:SINGULAR and WP:PLURAL have an exception to the general rule for singular titles for classes of objects, and arguably these chemicals are classes of objects, most article titles of this sort seem to be singular, so per WP:CONSISTENCY this one probably should be also. Rreagan007 (talk) 01:14, 9 August 2018 (UTC)
• Support. Echoing Rreagan007's rationale. Rap Chart Mike (talk) 19:18, 9 August 2018 (UTC)
• Support. Rreagan007 said it all. Chhandama (talk) 10:43, 17 August 2018 (UTC)

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The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.