Let’s look at how dietary and lifestyle changes that can assist with fighting breast cancer. In order to do this, the target is to control estrogen exposure and estrogen metabolism. We will focus on foods that help detoxify the body of the type of estrogen that is associated with breast cancer.
Beneficial versus harmful estrogen metabolites:
It is important to be aware that certain products that we consume can negatively or positively affect how we handle the estrogen we naturally produce in our bodies. Some metabolites (break-down products) of estrogen pose a risk, whereas others protect against breast cancer.
Estrogen can be metabolised (broken down) in your body into one or more of the following products (metabolites):
- 2-hydroxyestrone / 2-hydroxyestradiol (2-OHE)
- 4-hydroxyestrone / 4-hydroxyestradiol (4-OHE2)
- 16α-hydroxyestrone (16α-OHE1)
2-OHE has very weak estrogenic activity and is actually protective against breast cancer, whereas 4-OHE and 16α-OHE1 both have full estrogenic activity and turn on the estrogen receptor that is involved in breast cancer (estrogen receptor alpha). Both 4-OHE and 16α OHE1 increase the risk for breast cancer.
I offer my patients specialised testing to assess the ratio of their estrogen metabolite and this can be used to monitor how a person responds to beneficial dietary changes.
Foods that can help improve the ratio of the estrogen metabolites:
Soya foods
Not only does consumption of soya improve the ratio of 2OH:16OH and 2OH:4OH estrogen metabolites, but the phytochemicals (plant chemicals) in soya foods also have a predominant affinity for estrogen receptor (ER)-βeta. This makes it protective, since substances that activate ER-βeta are protective against breast cancer. Only the estrogen receptor (ER)- αlpha is associated with an increased risk of breast cancer.
The phytochemicals in soya foods bind to estrogen receptors to protect them from more potent stimulation from estrogen, 4-OHE, 16α-OHE1 and chemical estrogens from pesticides and plastics. Research shows that eating soy foods can lower breast cancer risk by 20%. Research also shows that the higher the intake of soya food in the diet the lower the rate of death due to and recurrence of breast cancer.
Interestingly, people that adopt a vegetarian diet benefit more from soya products than omnivores do due to the specific probiotic gut bacteria that naturally establishes in the gut as a result of the vegetarian diet. These specific probiotic bacteria ensure that the soya is broken down into the most beneficial plant chemicals that confer the greatest anticancer properties. However, using a specific prebiotic high in fructooligosaccharides (FOS) supplement can confer the soya benefit of a vegetarian diet.
Omega 3 from eating fish or taking a fish oil supplement
This improves the ratio of 2OH:16OH and 2OH:4OH estrogen metabolites. However, please limit the consumption of large fish (e.g. tuna), as they are known to have higher mercury levels. Also try to avoid tinned fish since the tins are lined with BPA. Rather consume fresh fish whenever possible.
Cruciferous vegetables (e.g. broccoli, cabbage, cauliflower, brussel sprouts, turnips, kale)
1. They improve the ratio of 2OH:16OH and 2OH:4OH
estrogen metabolites.
2. Has anti-estrogenic effects.
3. Inhibits breast cancer cell growth.
Following a low fat diet, especially low saturated fat (most saturated fat come from animal sources; please limit intake)
1. Improves the ratio of 2OH:16OH and 2OH:4OH estrogen metabolites.
2. Good research evidence for its role in reducing the risk of breast cancer.
3. Research shows that higher animal fat intake results in a higher tumour proliferative index.
High fibre diet (from grains, fruit, vegetables, and beans)
1. Improves the ratio of 2OH:16OH and 2OH:4OH estrogen metabolites.
2. Improves intestinal transit of estrogen in the gut, which is beneficial. Women who suffer from constipation will have higher blood levels of estrogen. Research shows that increased dietary fibre reduces the risk of breast cancer via estrogen and non-estrogen pathways.
Ground flax seeds – at least 10g consumed two to three times daily
1. Improves the ratio of 2OH:16OH and 2OH:4OH estrogen metabolites.
2. Inhibits aromatase activity, thereby reducing estrogen production.
3. Reduces breast tumour initiation.
4. Inhibits growth of human breast tumour cells.
These dietary recommendations are valid while undergoing treatment for breast cancer and when you have been cleared in order to minimise the possibility of reoccurrence. Always keep in mind that prevention is better than cure.
Written by Dr Cornelia Botha