Phytoestrogens

Question 1

Phytoestrogens

Answer 1

Phytoestrogens = naturally-occurring plant compounds structurally similar to 17β-oestradiol (E2).
* Produce a weak anti-oestrogenic effect in the presence of a high endogenous oestrogen. Reduces circulating bioavailable E2.
* Produce a weakly oestrogenic effect in the presence of low endogenous oestrogen.
* Disrupts aromatase — favouring the 2-OH pathway.
* Consider them ‘oestrogen-modulators’.

Question 2

Phytoestrogens: health benefits

Answer 2

Health benefits: Lowered risk of menopausal symptoms,
CVD, obesity, metabolic syndrome, T2DM and breast cancer.

Question 3

Phytoestrogens plant foods:

Answer 3

Flavonoids (isoflavones, genisten, daidzein) — found in soybeans, legumes, lentils, chickpeas.
• Lignans (enterodiol, enterolactone) — found most cereals, linseed, fruit and vegetables.
• Flavones (apigenin) — found in parsley, thyme, celery and chamomile tea.
• There is a concern that phytoestrogens
are contraindicated in oestrogen-sensitive conditions like breast cancer, but their weak oestrogenic effect and selectivity make
them oestrogen antagonists in the presence of oestrogen.

Question 4

The soybean

Answer 4

The soybean = a staple food of Asia for several millennia but has only been introduced into the Americas and Europe in the past 50 years.
• Soybeans are converted using microorganisms to miso and natto (Japan), soy paste (Korea) and tempeh (Indonesia).
• Western consumption of soy products typically
includes soya oil, flour (breads, cake), protein
isolates (textured vegetable protein ‘meat’ products in processed foods), low fat milk and yogurts. Around 1⁄4 of all children in the US receive some soya-based formula (much of which is also GMO).
• If soy products are consumed, they should be fermented.

Question 5

Effectiveness of phytoestrogens

Answer 5

A healthy microbiome is necessary for the fermentation of phytoestrogens by intestinal bacteria.
• This can account for large differences in the effects of phytoestrogens among individuals.
• Any variation from a healthy gut microbiome
will reduce the potential benefits from such foods.
• In these instances, phytoestrogens provided in a non-food forms, such as tinctures or teas may be more appropriate
• Herbs to consider: Black cohosh, Agnus castus, red clover and Dong quai.