Lifestyle / Family

Ezette Oosthuizen
5 minute read
8 Oct 2019
9:00 am

Eating to reduce risk of estrogen-related cancer

Ezette Oosthuizen

Can nutrition affect how you metabolize estrogen?

The answer is yes… But let’s have a quick biology lesson about estrogen.

Estrogen is a collective term used to describe our female hormones which comprise of estradiol, estrone and estriol. Estradiol is the most potent while estrone and estriol are less so. Estrogen plays an important role not only in a women’s reproductive system but also in bone formation & maintenance, cardio-protective effects and last but not least influences behaviour and mood.

Interestingly, estrogen also plays an important role in male tissues such as the prostate & testes.

We produce estrogen through a number of ways such as from cholesterol in the ovaries, from fat cells, skin, bone and other tissues. Estrogen is transported through the body bound to sex hormone-binding globulin (SHBG). Like a bus transporting children to and from school, estrogen will hop off where and when needed. Any changes in SHBG will alter estrogen metabolism by altering the availability of estrogen to target cells.

How do we metabolize and detoxify estrogen?

This happens primarily in the liver with it ultimately leaving the body in our urine and faeces.  When estrogen is metabolized and detoxified it leaves residual metabolites and it is some of these little guys that can increase one’s risk for estrogen-related cancers as the “bad” metabolites have shown estrogenic activity and promote tissue proliferation – which put the body at risk for the development of cancer.

Women who metabolize a larger portion of their estrogen in a particular way versus another may be at elevated risk of breast cancer.

A recent 5-year prospective study of 10786 women found that premenopausal women who developed breast cancer had a decreased “good” metabolites ratio to “bad” metabolites. Women with predominately “good”  were 40% less likely to have developed breast cancer during the 5 years.

Another important note is gastrointestinal health because we excrete some of our estrogens via our stools, if regular stools are not passed some of the estrogens can be reabsorbed in the bloodstream and start circulating the system again.

What are the risk factors for increased estrogen exposure?

We are exposed to estrogens produced by our own bodies called endogenous estrogen and from the outside world called exogenous estrogens.

Factors that increase our estrogens are:

  • Genetic predisposition
  • Obesity, the more fat tissue we have the more estrogen we make
  • Excess insulin can cause increases in testosterone, reducing SHBG (the bus) and increasing levels of free estrogens
  • Alcohol consumption increases estrogen levels, even moderate consumption. Yikes!!!
  • Oral contraceptives
  • Hormone replacement therapy
  • Environmental sources that are structurally similar to estrogen and have the ability to mimic harmful estrogens in the body. For example; Pesticides, herbicides, plastics, refrigerants and industrial solvents
  • The hormones used to fatten livestock and promote milk production
  • Certain drugs like cyclosporin and cimetidine

Fortunately, we can modulate our estrogen metabolism through our diet and supplementation with select nutrients.

It isn’t all doom and gloom… Let’s see what we can do to improve one’s estrogen metabolism:

  • Aim for a better body composition that has less body fat percentage will make a great difference
  • Try and avoid the environmental estrogens by sourcing organic fruit and vegetables or to grow some of your own, hormone-free and antibiotic-free animal products and to opt for glass whenever possible
  • Fibre and lignin found in flaxseeds, the bran layer of grains, beans and seeds can interrupt the reabsorption of estrogen via the stools. It also increases SHBG and therefore decreasing free estrogens
  • Complex carbohydrates from vegetables and whole grains are preferred over simple carbohydrates from cakes, biscuits, cookies, white bread, sugar, etc.
  • Protein is very important for liver detoxification and will this improve estrogen metabolism
  • Cruciferous vegetables such as broccoli, cauliflower, brussels sprouts and cabbage aids in the process of liver detoxification and would have a beneficial outcome towards leaving the “good” metabolites
  • Phytoestrogens have the ability to influence estrogen synthesis & metabolism. Food sources include soy, legumes, alfalfa, clover, liquorice root and kudzu root. It is well known that Japanese women have lower rates or hormone-dependent cancers due to their high intake of soy products

We are living in an amazing day and age with regards to the medical field and knowledge of health and wellness connected to diet, we have the ability to test for these different metabolites and how to shift our body’s metabolism and detoxification of estrogen into the more favourable pathway, which can reduce (not eliminate) one’s risk for developing estrogen-related cancers.

Source: Hall, DC 2001, ’Nutritional influences on Estrogen Metabolism’, Applied Nutritional Science Reports

Ezette-oosthuisen-dieticianEzette Oosthuizen is a Registered Dietitian in Woodmead and Craighall Park in Johannesburg. She started her journey with integrative and functional medicine three years ago, after feeling like she was not making a real difference in her patient’s lives through the conventional dietetic methods she studied.

Ezette especially enjoys working with mothers. As a mother herself, she understands the physical and mental rollercoaster that motherhood can be. She knows that mothers often forget about their own needs and that can often lead to the deterioration of their health. She aims to remind mothers that they need to make themselves a priority and take care of themselves.

Ezette spends her spare time with her husband of nine years, Jacques, her two sons and her recently adopted fur-baby, Levi.

Find her on her site:

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