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Our sports doctor Emil Hodzovic explains more about exogenous oestrogens and the problems they can cause in men.
While the role of testosterone in men is widely recognised and understood, oestrogens role in male health and wellbeing is far less clear. It’s highly likely that the small amount of natural oestrogen produced in men is required for normal sexual functioning including fertility and libido [1,2] and although low oestrogen can possibly cause issues, the more common concern is related to high levels of oestrogen.
Oestrogen is the collective term for a group of hormones that promote and maintain female characteristics within the body and conditions such as gynecomastia (breast tissue in males) and fertility problems, often associated with high levels of oestrogen, are generally not desirable. High oestrogen levels can also affect liver function and insulin response  and the other main concern is that high levels of oestrogen can negatively affect testosterone levels through negative feedback in the brain – basically the brain thinks that you have too much testosterone and reduces production when this is not the case!
Both high and low oestrogen levels are relatively rare in normal healthy males and apart from certain testosterone boosting supplements and medications, it’s highly unlikely to even be on your radar. But it is now seen more and more in the media the issue of ‘exogenous oestrogens’ [4,5] and a quick search on Google for “high oestrogen in men” brings up over a million hits.
In short, exogenous oestrogens are those that originate from outside the body and apart from doctor prescribed medications such as female contraception and hormone replacement therapy, there are 3 main sources
• Oestrogen-like compounds from plastics (e.g BPA, phthalates)
• Phytoestrogen’s from foods such as soy
• Increased oestrogen conversion within the body by alcohol and drugs (the oestrogen here isn’t technically from outside the body but the substance that is responsible for it is).
You may have heard whispers about the oestrogenic effects of certain plastics and you may even have seen the ‘BPA free’ label on plastic bottles and this is the reason for it. Not all plastics cause issues and the potentially harmful ones can be found in food and drink tins and cans, reusable water bottles and food containers as well as a few unexpected sources including fast food, doughnuts and even till receipts. 
Research in this area is ongoing but there are many studies showing fertility issues in both animals  and humans [8,9] and there have been studies showing significant increases in oestrogen in the blood due to plastics along with measurable changes in physiological markers .
Overall, the evidence is mounting and although there isn’t conclusive evidence yet, we may not uncover the full extent for years to come. It is probably unrealistic to suddenly stop using all plastic but avoiding exposure where possible is probably wise. Consuming less canned food and drink is one way to avoid BPA and avoiding plastic in drink bottles and food containers (especially in ones that you are heating) will likely help.
Phytoestrogens found in foods are another source of exogenous oestrogen that may or may not cause issues and there has been a debate back and forth regarding their safety for many years. These oestrogen-like compounds are mainly found in soy products (but also foods such as doughnuts and pastries ) and have been in Asian cuisine for many years with no apparent ill effects but there are still a lot of unknowns surrounding their consumption .
A recent fact sheet by the British Dietetics Association sheds some light on this and supports their safety, concluding that: “Studies consistently show that eating soya foods does not raise oestrogen levels, upset hormonal balance or reduce testosterone concentrations in men. The few cases where negative effects have been shown were associated with large doses of soy food in those following unbalanced diets.” 
In short, there is likely nothing to worry about with moderate consumption of soy as part of a healthy and balanced diet and I personally eat tofu and tempeh on occasion. That said, these compounds are undeniably oestrogenic and do show to have effects within both human and animal models so if you are concerned then avoiding them altogether shouldn’t cause a problem either.
The final piece of the oestrogen jigsaw is alcohol and drugs. These can have a significant effect on oestrogen levels in men and misused anabolic steroids are the main culprit. Medically prescribed drugs can occasionally affect hormone levels but will often have a greater purpose (such as controlling blood pressure) so it is unwise to mess around with these without your doctors’ advice [17,18].
There are things that you can do if you are taking prescribed medications and these centre around making improvements in lifestyle. This can reduce or even remove the need for certain medications, but this should always be done in conjunction with your prescribing doctor. Amongst the many negative health effects associated with alcohol excess, it’s effect on hormones can be profound, decreasing testosterone [19,20,21] and promoting the conversion of testosterone to oestrogen .
On top of this, alcohol can contribute to increased body fat both via the increased calories associated with the drink itself but also the eating behaviours often surrounding alcohol consumption (midnight kebab anyone?). This beer belly can also contribute to the conversion of testosterone to oestrogen for a double whammy effect. 
Beer is possibly one of the worst sources when it comes to the effect of alcoholic beverages on hormones as the hops used to produce it also contain phytoestrogens. As seen previously, these may not be an issue on their own but in conjunction with everything else may start to add up . Apart from the usual lifestyle advice (drink less alcohol, exercise more and eat a healthier diet), the main thing you can do is to consider the plastics that you are using day to day. This is probably not a bad idea in general as it will be beneficial for the environment as well as for your health and hormone levels.
If you are concerned, then testing for hormone levels is an excellent option to find out more. If you are suffering symptoms then I recommend that you see your GP for a comprehensive history, examination and further investigation as required.
9. https://www.ncbi.nlm.nih.gov/pubmed/25121464 - phthalates and low test