Menopause Flashcards
What are phytoestrogens
Naturally occurring chemical compounds found in plants
Antifungal agent
Structured similarly to mammalian oestrogen
Phytoestrogen structure
Phenol rings
Hydroxyl group
Distance between two structures
May exert oestrogenic properties
Phytoestrogens Definition
Any plant substance or metabolite that induces biological responses in vertebrates and can mimic or modulate the action of endogenous oestrogen usually by binding to oestrogen receptors
Phytoestrogens sub-group
Flavonoids
Non-flavonoids
Flavonoids sub-group
Isoflavones
Coumestans
Prenyl flavonoids
Isoflavones
Richest source is soyabean
Legumes
Lentils
Chickpeas
Coumestans
Similar physical and chemical properties to isoflavones
Less well studied
Coumestrol – most common coumestan found in food
Young sprouting legumes
Clover
Alfalfa sprouts
Prenylated Flavonoids
Structural similarity to isoflavones
Prenyl group rather than hydroxyl group
Found in high concentration in some beers
Hops
Lignans
Flaxseed is most concentrated source of lignans – rarely consumes
Common consumption through cereal and whole grain products
o Rye
o Barley
o Wheat
Other sources – Sesame, fruits and veg
What determines Phytoestrogen Concentration
Natural Variation Influenced by: Genetics Crop year Environment Harvesting and Processing
Consumers of Phytoestrogens
Vegetarians and Vegans (Isoflavones and lignin’s)
Japanese/Chinese (isoflavones)
Soy based food consumers (isoflavones)
Phytoestrogen dietary supplement consumers
Cancer
- Multi-factorial – genetics, lifestyle, diet
- Hormone dependent – Breast, prostate, female reproductive tract
- Lower in Asia
- Support of migrant studies
Bioavailability Definition
The fraction of ingested nutrient utilized for normal physiological function
Non-nutrients definition
Effectiveness of a chemical in eliciting response in a target tissue
Menopause
Ovarian failure 51+ Peri-menopausal - 1-5yrs Irregular periods Hot flushes Fatigue Body changes Headaches Memory problems Joint and muscle stiffness Bladder weakness Psychological changes Vaginal dryness
Menopause south east asia
Report few and differing symptoms to western world
Thought it might be due to diet difference
Cardiovascular disease and Menopause
Major cause of morbidity
Risk increases after menopause
Idea oestrogen is protective
Hormone supplementation helps reduce risk in women
Hormone supplementation and Cardiovascular disease
Oestrogen decrease atherosclerosis
Improve lipid profile
Enhanced vascular reactivity
However,
Heart and Estrogen/Progestin intervention trial
- increased early CVD
- Hypertriglyceridemia
- Hypercoagulable state
South east Asia and Cardiovascular disease
CHD mortality rates lower in Eastern Population
Beaglehole (1990)
Could phytoestrogens play a role?
Osteoporosis
Disease characterised by bone mass loss and microarchitectural deterioration of bone
Bone remodelling
Continuous process
Renewal of bone - deuteriation, Redistributing of matrix where there is stress
Bone formation occurring after bone resorption
Must be tightly controlled
Controlled by hormones and growth factors
Oestrogen
Critical importance of oestrogen - prevent bone resorption and promote increased bone density
Menopause - significant reduction in circulating levels
Hip fractures in japan
Lower levels in post-menopause women
Eat more soy
220 per 100/000 in oxford
90 in japan
Could phytoestrogens offer a solution to bone mass loss post-menopause
Current use HRT but that increase chance of breast cancer
Phytoestrogen mimic oestrogen to inhibit bone resorption and may stimulate bone formation
May absorb more calcium
Phytoestrogen and calcium
High animal protein intake increases calcium loss via urine
Replacing animal with soy reduce this loss
Research study Methods
- Can animal studies be considered representative of humans
- Are phytoestrogens consumed from diet or supplements
- Quantity consumed
- Length of consumption
- Double blind?
- Can people remember their historical dietary consumption
- How much influence does historical dietary consumption
- Objective or subjective improvement
- How long does the effect last
- In cross-over studies, is there a wash-out period
Observation in humans and synthetic oestrogen
Diethylstilboestrol
Drug to prevent miscarriage used in 1940s
Abnormal reproductive development during puberty
Vaginal adenocarcinoma
What are the critical periods of sexual development and reproduction
Embryo Foetus Neonatal period Puberty Adulthood
Human and Animal studies on phytoestrogens
Effect of phytoestrogen on reproduction or sexual development unethical in humans
Use animal but:
-reproductive and sexual development different
-Route of administration
-Exposure per kg
Foetal exposure to phytoestrogens
Lower birth weight and delayed sexual maturation in rats when mother exposed to genistein
Female offspring of mice exposed to genistein had early mammary gland development
Perinatal exposure - irregular oestrogen cycle in rat but irregularity found similar in normal rats and so found to not impact
Weaning exposure to phytoestrogen
Advanced puberty
Longer oestrogen cycles and abnormalities in reproductive tissue in female mice but did bot effect fertility
Human studies and phytoestrogen
• More abnormal menstrual cycle for those working with hops
• Increased rate of male hypospadias in vegetarian mothers
• Longer and more painful periods for those who fed soy as a child
• Consumption of soy infant formula associated with premature thelarche
• However, males supplemented with isoflavones showed no difference in sex hormone concentration or semen quality
• Infants – greater risk to infants fed on soy-based infant formula
o Asian countries - <1mg/kg body weight
o 4 month infant exclusive fed soya formula - <5mg/kg body weight
Menopause and Cardiovascular disease
Oestrogen increases storage of peripheral fat
Post menopause less oestrogen so more fat around organs
Muscle mass decrease
Lower BMR
Blood pressure with age
UCLP
Step 1 - mindset
Step 2 - Healthy swap
Step 3 - Introduce 4 UCLP foods a day
