Oestrogen and health

During my long series about nutrition, I occasionally strayed into discussions of the hormonal effects of food/

I mentioned in my post about water that both tap water and mineral water have oestrogenic compounds in them, that are carcinogenic.  However, I didn’t really present a full case, which I hope to here.

Please note that this article is based on desktop research for interest purposes only and if you want detailed and specific information about cancer, I would start with Cancer Research UK.

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Oestrogen can cause cancer

Let’s start here, because there seems to be a good consensus in the medical research community that oestrogen and oestrogenic compounds can cause cancer under certain circumstances.  However, the average man and woman in the street probably haven’t really taken this on board.

Here are just a couple of examples:

• Oestrogen appears to cause head and neck cancer in young women, by causing pre-cancerous cells to move and divide by triggering the activity of an enzyme (BBC)
• Exposure of the mother during pregnancy to exogenous oestrogen seems to increase the risk of her sons of getting:
  • Testicular cancer (Estrogen exposure during gestation and risk of testicular cancer, Depue, R H, Pike, M C, Henderson, B E, PubMed), and
  • Prostate cancer (Early Estrogen Exposure Leads To Later Prostate Cancer Risk, Gail Prins, Shuk-Mei Ho, Science Daily)

It’s a grim picture, especially when you come to look at oestrogenic compounds and how common they are…

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Oestrogenic compounds are everywhere

There also seems to be a reasonably strong consensus that we are exposed to a number of oestrogenic compounds that cause cancer in Western society, including:

• BPA – Bisphenol A (BPA) is a compound that has been used to make food containers since the 1960′s and yet has been known to be oestrogenic since the 1930′s (Wikipedia).  The FDA currently holds that ”recent studies provide reason for some concern about the potential effects of BPA on the brain, behavior, and prostate gland of fetuses, infants and children” (FDA).
• Other plastics – Other plastics also cause oestrogenic effects (Endocrine disruptors in bottled mineral water: total estrogenic burden and migration from plastic bottles, Martin Wagner and Jörg Oehlmann, Science Daily, SpringerLink)
• Soy – Soy also contains oestrogenic compounds, Soy and soy-derived products contain isoflavones that mimic the actions of oestrogens and may exert adverse effects on male fertility (Soy, phyto-oestrogens and male reproductive function: a review, PubMed)
• Drinking water – in 2008, the US Geological Survey reported that there were 85 man-made chemicals in the water supply, including birth control hormones (mainly oestrogen) and pharmaceuticals.  The recommendation is that we use reverse-osmosis filters to remove such contaminants to protect our health (Scientific American).
• Artificial hormones - using oestrogen replacement therapy seems to be risky from a cancer point of view (A meta-analysis of the effect of Oestrogen Replacement Therapy on breast cancer risk, JAMA)

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So how does oestrogen cause cancer?

I find it interesting that despite the consensus that oestrogen causes cancer (Cancer Research UK), there is no generally accepted mechanism by which this works.   This reminds me of the lipid hypothesis of heart disease, which also has no accepted mechanism, as Dr Malcolm Kendrick makes clear. 

However, unlike the lipid hypothesis, there are one or two contenders for a sensible mechanism:

• Cell division theory – some researchers think that oestrogen encourages certain cell types to divide more often and that more cell divisions means a greater likelihood of cancer-causing mistakes
• Gene activation theory – other researchers think that oestrogen turns on certain genes inside cells at the wrong time and that this encourages cancer
• DNA damage theory – there is some laboratory evidence that oestrogen can directly bind to, and damage, DNA (PubMed)
• Somatic hypermutation theory – somatic hypermutation is the mutation mechanism by which the immune system adapts to new threats.  Oestrogen switches on the gene that activates the mutation in immune cells and it has been linked to the formation of certain cancers, also via mutation (JEM) 
• Trophoblast theory - one of the more wacky theories of oestrogen causing cancer is the trophoblast theory, which you can read in detail about in my article about William Donald Kelley.  Tropoblast cells are placental cells, which are said to be activated by oestrogen. 

I think that the somatic hypermutation theory has a lot of internal coherence, speaking purely as a lay person, but I have to say that I find the trophoblast theory a much simpler, more all-encompassing and therefore more exciting.  That obviously has no bearing on whether it is true or not…

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How to avoid exposing yourself to too much oestrogen

Since the mechanism by which oestrogen causes cancer has not been determined,  it is difficult for people to give firm recommedations about how to manipulate exposure in order to reduce the likelihood of developing cancer.

However, many sources have proposed ways to decrease excess oestrogen and avoid oestrogenic compounds as follows:

• Avoid oestrogenic plastics – avoiding eating food that has come into contact with BPA or other plastics is a good way to avoid inadvertently consuming oestrogenic compounds.
• Don’t eat soy – just don’t eat it, OK?  And remember, they try to stick it into almost everything these days, so be sure to read the label.  Hang on, scratch that.  Just don’t eat anything that comes in a packet or has a label on it and you’ll be fine.
• Improve your digestive health - in my post about the digestive system, I noted that excess oestrogen is excreted by the body via the large intestine.   However, some bacteria that live in the gut can cause the oestrogen to be reabsorbed, increasing the oestrogenic effect on the body (Effect of milk and lactobacillus feeding on human intestinal bacterial enzyme activity, Goldin BR, Gorbach SL, PubMed)
• Get a reverse osmosis water filter – this is something I am looking into at the moment so watch out for a review in due course.

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 That’s all folks.