15c - Men's health Flashcards
What is testosterone and what glands control it?
A steroid sex hormone under hypothalamic and pituitary gland control.
Testosterone plays a crucial role in male sexual development and reproductive function.
Where is testosterone primarily produced in men?
In men, >95% from the testes by Leydig cells, with the remainder mostly from the adrenals.
Leydig cells are located in the testes and are responsible for the production of testosterone.
What are the main functions of testosterone? (5)
- Male characteristics (facial hair, deep voice, penis development)
- Skeletal muscle growth
- Libido
- Sperm production
- Bone density
Male sexual characteristics include facial hair, deepening of voice, development of penis and testes, libido, and sperm production.
How is testosterone circulated in the blood?
~60% is weakly bound to albumin
~40% tightly bound to SHBG
~1-2%. is “free testosterone”
SHBG stands for Sex Hormone-Binding Globulin, which plays a key role in regulating the availability of testosterone.
What is ‘bioavailable testosterone’?
Free + albumin-bound testosterone.
Bioavailable testosterone refers to the fraction of testosterone that is readily available for use by the body.
What are signs & symptoms of low testosterone? (10)
- Central weight gain
- Low energy
- Low libido
- Erectile dysfunction
- Infertility / low sperm
count / motility - Osteoporosis
- Hair loss
- Fatigue
- Loss of muscle bulk and strength
- Mood changes
What are some causes of low testosterone? (9)
- Ageing — testosterone declines with age after 40 years by ~1% each year. Associated with the ‘andropause’.
- Chronic stress — cortisol and epinephrine have inhibitory effects on testosterone release.
- Elevated SHBG― binding too much testosterone, e.g.,
medications (metformin, tamoxifen); liver disease and dysfunction ― impaired SHBG detoxification; anorexic states and overtraining. - Thyroid dysfunction ― likely through its effects on SHBG.
- Zinc deficiency ― it supports testosterone production.
- Increased aromatase activity (conversion of androgens to oestrogens - e.g., from obesity, insulin resistance, excess alcohol, inflammation)
- Environmental toxins ― e.g., BPA can bind to androgen receptors.
- Sleep deprivation ― testosterone is made mostly during sleep.
- Medications― e.g., opioids (inhibit GnRH).
What are the diet and lifestyle approaches to addressing low testosterone? (7)
- CNM Naturopathic Diet with low GI foods, healthy dietary fats (pregnenolone synthesis), zinc-rich foods (testosterone synthesis).
- Address the cause, e.g., stress support , weight loss, thyroid support
- Exercise― resistance training (e.g., weights) and HIIT ↑ testosterone.
- Sleep hygiene;
- Avoid xenoestrogens
- Support liver detox and balance gut microbiome (oestrobolome) to ↓ SHBG and oestrogens
- Mitochondrial support (e.g., B vitamins, CoQ10, alpha-lipoic acid, Se, glutathione, etc.,) ― pregnenolone is formed in mitochondria.
What nutritional supplements can be used to support low testosterone? Give dose and mode of action. (5)
- Zinc ( 15‒30 mg / day) - Supports testosterone production and promotes spermatogenesis.
- Vitamin D (Optimise levels) Increases Leydig cell testosterone production and
supports a healthy testosterone / oestradiol ratio.
- Vitamin D (Optimise levels) Increases Leydig cell testosterone production and
- Magnesium (200‒400 mg / day) In combination with zinc and B6 shown to improve testosterone levels in athletes.
- D-chiro-inositol (600 mcg x 2 / day) Modulates aromatase: ↓conversion to oestrogens. Also supports cell insulin sensitivity.
- B complex ( 50‒150 mg / day) Mitochondrial support (for pregnenolone synthesis).
Methylation support (↓homocysteine and CVD risk).
What herbs can be used to support low testosterone? Give dose and mode of action. (4)
- Ashwagandha (2‒5 g powder/ day) Increases testosterone (and DHEA) by stimulating GnRH production. Might also inhibit aromatase activity.
- Mucuna pruriens (Up to 100 mg / day) ↑ Leydig cell production of testosterone, likely through ↑ dopamine
- Tribulus terrestris (500–650mg / day) ↑libido,
- Shatavari (Up to 3 g powder / day) Its steroidal glycosides exert testosterone-like effects.
Considered an aphrodisiac.
What is Dihydrotestosterone (DHT) produced from and by what?
Produced from testosterone by 5α-reductase
DHT is a metabolite of testosterone that plays a key role in androgenic activity.
How does the potency of DHT compare to testosterone?
DHT is approximately 2–5 times stronger than testosterone
DHT binds more strongly to androgen receptors.
What are key characteristics of DHT regarding binding and aromatization?
DHT binds more strongly to androgen receptors. It does not aromatise into oestrogen
This characteristic distinguishes it from testosterone.
Where is 5a-reductase located in the human body?
Located in the gonads, skin, hair, and nervous system
5a-reductase is essential for converting testosterone into DHT.
What conditions are associated with increased levels of DHT?
Associated with acne, male pattern baldness, mood (anger), prostate disorders
These conditions highlight the impact of DHT on various bodily functions.
What are some causes of increased 5α-reductase activity?
Causes include:
* Inflammation (e.g., poor diet, gut health)
* Increased insulin
* Obesity
* Low zinc status
* Pesticides
* SRD5A2 SNP (steroid 5-alpha reductase type 2)
Understanding these causes can help in managing conditions related to DHT.
How do you reduce DHT levels? (Main principle & 4 methods to do this)
By inhibiting 5α-reductase
* Address inflammation
* Stabilise blood glucose levels and support insulin sensitivity
* Reduce adiposity
* Eat organic.
What nutrients and herbs can be used to reduce DHT levels? Give dose & function (3)
- Zinc (15–30 mg / day) ↓5α-reductase activity, stabilising DHT levels.
- Saw palmetto (500–1000 mg) Its high levels of beta-sitosterol
inhibit 5α-reductase and DHT
binding to androgen receptors. - Stinging nettle root (300–600 mg) Inhibits 5α-reductase and aromatase (reducing DHT and oestrogen); binds to SHBG, increases testosterone.
What are the causes & risk factors for erectile dysfunction? (8)
- Low testosterone
- Stress, anxiety ― increases sympathetic NS activity; noradrenaline is the primary ‘anti-erectile’ neurotransmitter.
- Dietary - low antioxidants and low nitric oxide. E.g. from low whole-grain foods, legumes, vegetables, fruits. High red meats, refined sugars and dairy products.
- Diabetes mellitus — associated with ↑ AGEs, ↑ free radicals, impaired nitric oxide synthesis and neuropathic damage.
- Medication induced — e.g., β-blockers, anti-depressants, opiates.
- CVD—atherosclerosis results in arterial insufficiency.
- Low NO synthesis (e.g., low arginine, vitamin D etc.)
- Neurogenic — deficit in nerve signalling to the corpora cavernosa. E.g., lumbar disc herniation, MS, Parkinson’s.
What are diet and lifestyle approaches to addressing erectile dysfunction? (5)
- CNM Naturopathic Diet with the focus on phytonutrient-rich
plant foods, alcohol elimination and healthy weight management. - Address the cause, e.g., Diabetes mellitus, low testosterone
- Moderate exercise including both cardio and calming
exercise (yoga, tai chi) to reduce stress and aid circulation. - Stress reduction
- Support CV health to support penile blood flow. Include circulatory stimulants, e.g., ginger, rosemary, cayenne.
What nutritional supplements (including herbs/powders) can be used to address erectile dysfunction? Give dose & mechanism (5)
- Ashwagandha 2‒5 g powder/ day) to increase testosterone.
- Siberian ginseng (100–300 mg x 2/day) Promotes NO release for vasodilation.
- Arginine (1500–5000 mg / day) Promotes NO release for vasodilation.
- Vitamin D (Optimise levels) Regulates NO synthesis. Protects vascular endothelium.
- Ginkgo biloba (60‒120 mg x 2 / day) Improves blood circulation
What does Benign Prostatic Hyperplasia (BPH) refer to?
Enlargement of the prostate without the presence of malignancy.
List the signs and symptoms of BPH.
- Urinary frequency
- Urgency
- Hesitancy
- Nocturia
- Incomplete evacuation
- Terminal dribbling
What are the diagnostics used for prostate evaluation?
- Digital rectal examination (DRE)
- Prostate specific antigen (PSA) blood test
- Ultrasound
- Biopsy
