Oestrogen Metabolism Part 2: Hormone-Driven Cancers

DIETARY changes and the addition of specific nutritional supplements CAN benefit oestrogen metabolism, and as such reduce the risk and incidence of all diseases and conditions in which these oestrogen hormones play a role.

BREAST CANCER is the second largest cause of mortality in women after lung cancer. One in eight women will develop the disease, and it has an enormous negative impact on society and enormous financial implications.

Risk factors:

NOTE:  50% of women who get breast cancer have no obvious risk factors at all. Many healthy women, living healthy lives, get breast cancer.

  • Age.   As women age, so they become at risk for one or another type of cancer. Nearly 80% of breast cancers occur in women older than 50. Women over 50 must screen regularly by having annual mammograms.
  • Family history. 10% of breast and ovarian cancers are inherited. (Note: one does not inherit cancer, but one inherits the risk of developing it). Family history refers to any first-line relative (mother / sister / daughter / father) who may have had breast cancer, especially under the age of 40. Second-line family members (maternal / paternal grandmother) having had it, can also contribute to one having a greater risk of getting it. Development of other hormonally driven cancers such as endometrial cancer can also increase one’s risk for breast cancer as well. 2 genes BRCA1 and BRCA2 are the genes that play a role in preventing breast and ovarian cancers. However a change in these genes (an altered gene having been passed down from a first-line family member) can predispose one to breast cancer (50% increased chance of getting breast cancer), and only usually if there is a trigger.
  • Oestrogen. There is a strong causal relationship between oestrogen and breast cancer. Long exposure (>5 years) to oestrogen and high doses of oestrogen are potential risk factors. Therefore early menarche (starting one’s periods at an early age; late menopause; long-term hormone replacement herapy; late pregnancy; never being pregnant and having dense breast tissue, cause one to have excess or longer exposure to oestrogen – increasing one’s risk to breast cancer.

Other lifestyle factors can also cause one to have more free-flowing oestrogen (unbound): These include being overweight, having an unhealthy diet, lack of exercise, excess levels of blood-insulin, and excessive alcohol consumption.

Remember: unbound oestrogen results in increased oestrogen exposure, and can enter certain tissues in the body, causing tissue changes and potential damage (e.g. endometriosis, and, in extreme cases breast / ovarian cancers).

The ultimate effect of oestrogen depends on how it is metabolised.

Dietary factors can increase SHBG in the body, thus improving oestrogen metabolism and minimising the potential damage caused by excessive oestrogen exposure.

DIETARY changes and addition of specific nutritional supplements CAN benefit oestrogen metabolism, and as such reduce the risk and incidence of all diseases and conditions in which these oestrogen hormones play a role, such as breast, ovarian end endometrial cancers.

The research shows that:

By incorporating dietary changes and using select supplements and functional foods can have profound effects in beneficially influencing oestrogen balance and thus preventing oestrogen-related diseases and conditions.


  1. Manage weight (reducing weight when overweight reduces the production of unbound oestrogen in fat cells, thus facilitating more desirable oestrogen metabolism and excretion).
  2. Reduce fat and increase fibre in the daily diet in order to influence oestrogen metabolism positively.
  3. Increase intake of cruciferous vegetables such as broccoli and cabbage to reduce excess oestrogen exposure.
  4. **Increase intake of phytoestrogen-rich (plant-compounds that improve oestrogen metabolism) foods such as SOY to reduce excess oestrogen exposure, thus reducing the risk of developing breast cancer, amongst other things.
  5. Choose complex carbohydrates (wholegrains, fruits and vegetables) over refined carbohydrates to improve stable blood glucose and thus insulin levels, reducing the negative effects of increased insulin on oestrogen balance.
  6. Use plenty of omega 3 oils to improve oestrogen metabolism.
  7. Ensure adequate but not excessive use of LEAN protein foods (lean meat and chicken, plenty of fish, low fat dairy, eggs, nuts).
  8. Vitamin E (increased levels reduce levels of unbound oestrogen; improves PMS; inhibits growth of breast cancer cells)
  9. Magnesium (improves oestrogen metabolism; promotes oestrogen detoxification;reduces PMS symptoms)
  10. Indole-3-Carbinol (I3C) – occurs naturally in cruciferous vegetables; breaks down oestrogen in a healthy manner; protective to oestrogen-sensitive tissues.
  11. B Vitamins (decreased levels of B Vitamins can disrupt oestrogen detoxification and thus increase levels of circulating estrogens; cancer protective).
  12. Other beneficial Phytonutrients
  • Curcumin (turmeric) and soya isoflavones can reduce levels of unbound oestrogen in the body.
  • Antioxidant nutrients (vitamins E and C, and selenium) can reduce the production of harmful oestrogen metabolites.
  • D-limonene (found in the oils of citrus fruit): promotes the detoxification of oestrogen.


Phytoestrogens are plant compounds that can improve oestrogen metabolism through a variety of mechanisms, and are currently being extensively investigated as a potential alternative therapy for a range of conditions associated with oestrogen imbalance (including menopausal symptoms, PMS, endometriosis, prevention of breast and prostate cancer, and protection against cardiovascular disease and osteoporosis).

There are 2 types of phytoestrogens: ISOFLAVONES and LIGNANS.


Found in Soy (most common food source of isoflavones), legumes, alfalfa, clover, licorice root and kudzu root.

Higher intakes of soy isoflavones (as is found in traditional Japanese diets) is associated with low rates of hormone-dependant cancers.    THE AVERAGE DAILY ISOFLAVONE INTAKE OF JAPANESE WOMEN is 20-80mg; WHILE THAT OF AMERICAN WOMEN is  1-3mg.

Soy Isoflavones are antioxidants, and are the active components in the soy bean accounting for +/-  75% of the beneficial effects of soy-based foods in human health.

Soy isoflavones have a potentially important role to play in minimising risk of developing breast cancer:

  • When oestrogen levels are high in the body, isoflavones block the more potent forms of oestrogen produced by the body. In this way they may help to prevent hormone-driven diseases, such as breast and prostate cancer.


  • In women with low SHBG levels: 69mg of isoflavones/day obtained from soymilk powder increased their SHBG concentrations, thus improving oestrogen metabolism.
  • In research done in China (Anticancer Research 2000 Jul-Aug; 20(4): 2409-16.) : “Genistein, a natural flavone found in soy has been postulated to be responsible for lowering the rate of breast cancer in Asian women. Our previous studies have shown that genistein exerts multiple suppressive effects on both estrogen receptor positive (ER+) as well as estrogen receptor negative (ER-) human breast carcinoma lines suggesting that the mechanisms of these effects may be independent of ER pathways. Our observations resurrect the hypothesis that genistein functions as a “good estrogen” in ER+ breast carcinomas. Since chemopreventive effects of genistein would be targeted to normal ER-positive ductal-lobular cells of the breast, this “good estrogen” action of genistein is most relevant to our understanding of chemoprevention.”
  • In Cancer Epidemiology Biomarkers, 2000; 9(8):781-786.: Isoflavones are soy phytoestrogens that have been suggested to be anticarcinogenic. Their data suggest that both isoflavones and other soy constituents may exert cancer-preventive effects in postmenopausal women by altering estrogen metabolism away from genotoxic metabolites toward inactive metabolites.
  • Further findings presented in the Journal of Cancer Research and Clinical Oncology 2000; 126(8):448-454. Indicate that  Dietary intake of genistein in combination with EPA may be beneficial for breast cancer control.

Most experts say that one should obtain the soy isoflavones required from food (not capsules).

1-2 servings a day will most likely provide adequate soya isoflavones:

1 serving = 1 cup soya milk OR ½ cup (50g) soya porridge.


  • Found in fibre-rich foods and, through intestinal fermentation is converted into lignans with excellent health effects in the body.
  • Lignans are found in flaxseed, other oil seeds, wholegrains, legumes including soya and vegetables.
  • They stimulate the production of SHBG in the liver thus reducing levels of free estrogen circulation.
  • They directly decrease the conversion of testosterone to oestrogens in fat and breast cells.


CHOOSE FROM THE SOYA LIFE RANGE: obtain your DAILY DOSE OF ISOFLAVONES AND LIGNANS and improve oestrogen metabolism in the body!

  1. Soya Life Soya Milk
  2. Soya Life Meal Replacement Shake
  3. Soya Life Breakfast Porridge
  4. Soya Life Premium Porridge
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