Exploratory analysis of the associations between urinary phytoestrogens and thyroid hormones among adolescents and adults in the USA

[helvella]

First, this is a bit of an oddity - a paper from China about health in the USA. Second, a paper from China in part about the impact of soy. After all, there is a widespread belief that vast quantities of soy are consumed in China.

There have been many posts here in which soy and soy products have been discussed. Unlike some foods, it isn't the interactions between the food and levothyroxine in the stomach that is the issue, but the effects within the blood and body.

Environ Sci Pollut Res Int. 2021 Aug 12.

doi: 10.1007/s11356-021-14553-7. Online ahead of print.

Exploratory analysis of the associations between urinary phytoestrogens and thyroid hormones among adolescents and adults in the United States: National Health and Nutrition Examination Survey 2007-2010

Yun Fan # 1 2 , Hong Qian # 1 2 , Zhuo Wu # 3 , Zhi Li 1 2 , Xiuzhu Li 4 , Yan Zhang 5 , Qiaoqiao Xu 1 2 , Chuncheng Lu 6 7 , Xinru Wang 8 9

• PMID: 34383217

• DOI: 10.1007/s11356-021-14553-7

Abstract

Phytoestrogens are naturally plant-derived compounds that could bind to estrogen receptors and mimic estrogenic effects. Previous studies showed a positive association between phytoestrogens and hypothyroidism; however, little is known on phytoestrogens and thyroid hormones. This study was designed to investigate the associations between urinary phytoestrogens and thyroid hormone levels. Based on the US National Health and Nutrition Examination Survey (NHANES) 2007-2010, 4103 participants were recruited in this cross-sectional study. Linear regression models and multiple linear regressions models were applied to examine the relationships between urinary phytoestrogens and thyroid hormone levels. Urinary O-desmethylangolensin (O-DMA) was found to be correlated with serum FT4 levels in the female 20-60-year-of-age group (β=0.018, 95% CI: 0.006, 0.031). Higher enterolactone (ENT) levels were significantly positively associated with TSH levels in the 12-19-year-of-age female group (β=0.196, 95% CI: 0.081, 0.311). In the male group, enterodiol (END) was significantly positively correlated with TSH and TT3 in the 12-19-year-of-age group, respectively (TT3: β=3.444, 95% CI: 0.150, 6.737; TSH: β=0.104, 95% CI: 0.005, 0.203). However, equol (EQU) levels were negatively associated with TT4 (12-19-year-of-age: β=- 0.166, 95% CI: - 0.279, - 0.034; 20-60-year-of-age: β=- 0.132, 95% CI: - 0.230, - 0.034). Our study provided epidemiological evidence that urinary phytoestrogens were powerfully associated with thyroid hormone levels. The results also supported that phytoestrogens acted as endocrine disruptors. It is imperative and important to pay attention to the intake of phytoestrogens.

Keywords: Adolescents; Adults; Cross-sectional study; National Health and Nutrition Examination Survey; Phytoestrogen; Thyroid hormone.

pubmed.ncbi.nlm.nih.gov/343...

O-Desmethylangolensin

O-Desmethylangolensin (O-DMA) is a phytoestrogen. It is an intestinal bacterial metabolite of the soy phytoestrogen daidzein.

en.wikipedia.org/wiki/O-Des...

Enterolactone

Enterolactone is a organic compound classified as an enterolignan. It is formed by the action of intestinal bacteria on plant lignan precursors present in the diet.

en.wikipedia.org/wiki/Enter...

Enterodiol

It is formed by the action of intestinal bacteria on lignan precursors.

en.wikipedia.org/wiki/Enter...

[janeroar]

Thanks helvella So I wonder what this means for people with Hashi’s and also on HRT like me. I take a form of oestrogen (as well as progesterone) called estradiol.

[helvella Administrator Thyroid UK in reply to janeroar]

A very reasonable question. However, I think the direction this was taking was about unknown, unexpected, effects of phytoestrogens. Although it might end up that HRT has similar or identical effects, it isn't something from the diet but a medicine. Therefore, the prescriber should know about effects, including side effects and factor that into their prescribing practices.

We all know that all too often prescribers simply do not have sufficient in-depth understanding. So I'd not be holding my breath hoping they do recognise the issues. But, unless you consume phytoestrogens, especially if you increase your intake, I don't think this changes where you are.

[janeroar in reply to helvella]

It’s been a real roller coaster ride for soya. At one time (about 30 yrs ago!) it was being hailed as a super food and the reason why Japanese women live to 120 and don’t get menopausal symptoms. Now we are being told it’s a deadly substance and can cause cancer. I believe fermented soya - eg tempeh - doesn’t have the same negative impact. Probably organic will be better but who knows.

[helvella Administrator Thyroid UK in reply to janeroar]

Also, there has been much disagreement over the years about quite how much people consume. At one point, it seemed to be assumed that Chinese and Japanese diets contained vast quantities of soy. Then, that virtually no Chinese or Japanese diets would contain as much as many western diets - especially as people went for non-dairy, vegetarian, vegan, etc., products.

I really don't know where we are at present. But I do know that I have a very modest intake. Not zero - but I can only think of one product I regularly consume with significant soy in it.

[janeroar in reply to helvella]

I used to solely consume soya milk because it was supposed to be healthy. Maybe that contributed to my Hashimotos!! Japanese and Chinese tend to eat smaller portions of everything and maybe that’s the key, well to a lot of dietary issues. Everything’s ok in moderation.

[Hidden in reply to janeroar]

Hi yes Asian countries use Fermented Soy where as US/UK use Non the Fermented removes Phytoestrogens.

They don't have much tolerance to wheat one reason they often struggle with Beer.

A lot has changed over the years as many exposed to many substances as the world changes.

But was something i learned many years back.

Phytoestrogens are in many things though one being plasticisers including was found in Children's toys!

[helvella Administrator Thyroid UK in reply to Hidden]

However, beancurd/tofu is not fermented but is wiedely considered an Asian food consumed in significant quantities.

And there are now many wheat-free beers. I have some in my refrigerator! 🍺🍻

[Hidden in reply to helvella]

EFES turkish beer is said to be brewed via rice?

From what i remember as a long time back they fermented it to remove most likely Phytoestrogens!

[Hidden in reply to helvella]

If i remember right Tofu is also not that great for you think is it's very high in Sugars like a lot of veggie foods.

Trouble with a lot of Vegetarian foods high in sugars and oils plus Purines which link to gout.

A lot of it i can't have anyway as Can't really have Green things ie Vit K as on Warfarin along with NO Cranberry & Grapefruit!

[LindaC]

Fascinating, helvella - thank you, once more!