Endocrine Disruptors and Phytoestrogens

Question 1

Endocrine disrupting chemicals (EDCs)

Answer 1

Exogenous agents that interfere with the production, release, transport, metabolism, binding, action or elimination of bodily hormones.

Question 2

EDC: Examples

Answer 2

BPA
PCBs
Phthalates (e.g., beauty products)
Heavy metals
Pesticides and herbicides,
PBDEs: Fire retardants
Dioxins
Drugs
Tap water

Question 3

EDC: Mechanisms

Answer 3

‒ Alter hormone receptor signalling and sex hormone production, secretion and metabolism.
‒ Induce oxidative stress, mitochondrial damage and epigenetic alterations (DNA damage and chromosome alterations).

Question 4

EDC: Adverse Health Effects

Answer 4

Increased risk of cancer, hormonal disorders such as PCOS, early puberty and gynaecomastia; infertility, cognitive deficits and obesity.
* Critical window of susceptibility: In utero, neonatally, in childhood and puberty.

Question 5

Xenoestrogens

Answer 5

A sub category of EDC that are structurally similar to oestrogen and can bind to oestrogen receptor sites with potentially hazardous outcomes.

Question 6

Xenoestrogens: Examples

Answer 6

Pesticides and herbicides, dioxins, parabens, BPAs, phthalates, preservatives.
Tap water

Question 7

Dairy

Answer 7

Commercial milk is mostly derived from pregnant cows, with increased hormone concentrations in the third trimester.
* E1, E2 and E3 steroid hormones are found in all milks, with a higher concentration in whole milk. Choosing raw or organic milk will make little difference to hormone content.
* Dairy products also contain other hormones, including IGF, PCBs, dioxins, insecticides, bovine growth hormone (use of growth hormones is banned in EU / UK).
* Whilst amounts are deemed safe, they add to the overall oestrogen load and, therefore, should be avoided in hormonal imbalances.

Question 8

Phytoestrogens

Answer 8

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

Question 9

Natural Phytoestrogens

Answer 9

• 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.