In July I talked about how dietary change can lower cancer risk. This was in response to the latest statistics which show 40% of Britons are expected to get cancer in their lifetime. In the second part of my blog I focus on how hormone disruption and exposure to environmental oestrogens may also pose a cancer threat and what you can do to help reduce your risk.

Oestrogen-related cancers

The sex hormone oestrogen serves many functions in the body. In women, it makes the lining of the womb grow each month ready to receive a fertilised egg in the event of pregnancy.  It also stimulates the growth of breast tissue and reduces the breakdown of bone. Oestrogen is not just a female hormone. Men have this hormone too, but in smaller quantities.

However, oestrogen has been linked to a number of cancers including breast cancer and cancers of the womb and ovaries.  It may also be involved in prostate cancer.

There are different theories as to how oestrogen can increase cancer risk. These include:

1.    Causing DNA mutations due to its effect on the immune system.
2.    Encouraging certain cells to divide more often.  The more cell divisions the greater the chance of faulty
       cells being made.
3.    Turning on specific genes when they are not supposed to be turned on.  This could, for example,
       prevent damaged cells from dying thereby encouraging cancer.

It is important to bear in mind that oestrogen is a necessary hormone.  However, in women, levels must be balanced with another sex hormone called progesterone.  Oestrogen and progesterone have opposite actions in the body, serving to balance one another.  For example, oestrogen promotes uterine cancer by building excessive uterine lining.  Progesterone prevents uterine cancer by promoting shedding of the uterine lining.  When progesterone and oestrogen are not correctly balanced this can lead to a condition known as oestrogen dominance.  (Sometimes women have excess progesterone but this is far rarer than excess oestrogen.)

We also see that women who are on HRT or who have been on the pill for a long time have increased risk of oestrogen-related cancers.  This is because these drugs add to the body’s normal levels of oestrogen.**

Signs of oestrogen dominance in women include:

•    Weight gain
•    Water retention
•    Breast tenderness
•    PMS
•    Mood swings
•    Depression
•    Loss of libido
•    Heavy or irregular periods
•    Fibroids

However, oestrogen dominance can also occur without these symptoms.

Men can have excessively high levels of oestrogen too. Signs of this include:

•    Prostate problems  
•    Growth of “man breasts”
•    Impotency  
•    Male patterned baldness
•    Weight gain
•    Low libido

Xenoestrogens

The body can also be exposed to environmental oestrogens called ‘xenoestrogens’. These are chemicals that can exert an oestrogenic effect although they differ chemically from our own natural oestrogens.  

Xenoestrogens are found in chemicals such as PCB, BPA and phthalates which can be found in plastics such as those used to make drink bottles, food containers and cling film.  Xenoestrogens are also found in pesticides and fungicides, household cleaning products and toiletries (such as those containing parabens).

As xenoestrogens are stored in fat it means overweight people can have higher levels.

It is recognised that exposure to xenoestrogens plays a role in the induction of breast, testicular, and prostate cancers.  In fact the Endocrine Society in the USA “actively engages in lobbying for regulation seeking to decrease human exposure to the many endocrine-disrupting agents.”

What can you do?

Some of the things you can do to reduce your risk of oestrogen-related cancers include:

1.    Maintain a healthy weight

Although oestrogen is primarily synthesised in the ovaries, fat cells also produce it. This is why overweight men can often develop ‘male breasts’.

2.    Eat phytoestrogens

These are plant oestrogens which are structurally similar to human oestrogens.  This means that they can exert either a mild oestrogenic or anti-oestrogenic effect by binding to oestrogen receptors.  Phytoestrogens can have a balancing effect on oestrogen – they can increase oestrogen levels when they are low and decrease the effects on cells when oestrogen is high. This means they are useful to add to the diet in order to block the action of excess oestrogens.

Phytoestrogens also help to stimulate the production of Sex Hormone Binding Globulin (SHBG).  This is a protein which circulates in the body and binds hormones such as oestrogen and testosterone.  Bound hormones don’t exert influence on the body.

Phytoestrogens can be founding most fruit and vegetables. Particularly rich sources are legumes, beans, flaxseeds, oats, red peppers, red clover sprouts, hummus, and fermented soya.

3.  Reduce your exposure to xenoestrogens.  

•    If you can, choose organic.  If not, be sure to wash all your fruit and vegetables thoroughly.  
•    Avoid food and drinks wrapped in plastic or in plastic containers.  Consider investing in a stainless steel
     drinking bottle and filling it with filtered water instead of buying plastic bottled water.
•    Do not heat foods in plastic (including in the microwave) – heat causes chemicals from the plastic to leech
     into the food. Avoid drinking out of plastic bottles that have been in the sun or a hot car.
•    Filter tap water.
•    Choose natural household products and toiletries.

4.  Eat fibre and drink sufficient water.

Old oestrogens are excreted in the stool. If they are not eliminated through regular stool movements then they can be reabsorbed back into the body. It is therefore important to have a bowel movement at least once a day.  Fibre (found in legumes, flaxseeds, fruit, vegetables and wholegrains) and sufficient water can help prevent constipation.

6.  Reduce alcohol

Alcohol can increase levels of oestrogen.  Studies have shown that moderate alcohol intake increases breast cancer risk.

**If your are on HRT or the pill and are concerned then speak to your GP. Do not stop taking prescribed medication.

References

http://scienceblog.cancerresearchuk.org/2009/01/12/oestrogen-causes-dna-mutations-%E2%80%93-is-this-how-it-fuels-cancer/

Crisp et al. Environmental endocrine disruption: an effects assessment and analysis. Environ Health Perspect. 1998 February; 106(Suppl 1): 11–56.

Diamanti-Kandarakis E., et al. Endocrine-disrupting chemicals: an Endocrine Society scientific statement. Endocr. Rev. 2009. 30 (4): 293–342.

Yildiz, Fatih (2005). Phytoestrogens in Functional Foods. Taylor & Francis Ltd. pp. 3–5, 210–211.

http://info.cancerresearchuk.org/healthyliving/alcohol/howdoweknow/

Darbre P. et al. Paraben esters: review of recent studies of endocrinetoxicity, absorption, esterase and human exposure, and discussion of potential human health risks J. Appl. Toxicol. 2008.  Published online in Wiley InterScience.  http://www.theorganicpharmacy.com/downloads/Files/fact_sheets/7.pdf