Torso of an aged man

Estrogen and Testosterone.

Estrogen is a hormone within the body, more commonly associated with women. However it is true that men also produce a degree of estrogen; the reverse applies to women as they also produce a degree of Testosterone.

Testosterone and estrogen are structurally very similar but their difference in action is vastly different. Testosterone performs ‘masculine’ tasks within the body, such as improving muscle mass and bone density as well as having a significant effect on male libido. There is also some belief that Testosterone can help combat heart and vascular disease as well.

Estrogen is converted from Testosterone by an enzyme called aromatase. This enzyme can be found in many tissues of the body including the liver, muscles, and fat. The last point is the concern in modern society as worldwide population in devloped (and some developing) countries show increasing trends of obesity. Other factors affecting the activity of aromatsde include age, insulin and alcohol – all of which increase activity.

If estrogen levels become too high in men then chronic health problems may follow.

Symptoms/Issues of high estrogen.

1. Gynecomastia/breast growth – is known as gynecomastia and can occur when estrogen levels are too high. But this may sound strange as many believe that men don’t have breasts. However, all men have a small amount of breast tissue which enlarges in the presence of estrogen. Statistics in the UK show that appoximately 1% of newly diagnosed breast cancer cases will involve men.

2. Low sex drive/libido – high estrogen may lead to lower sex drive as well as erectile dysfunction.

3. Sub/infertility – Estrogen is known to lower sperm mobility. If sperm have abnormally low mobility it will be more challenging to achieve fertilisation as the sperm may not meet the egg at the right time or place to allow for fertilisation and implantation.

4. Stroke risk and heart attack – Estrogen also increases the clotting chance of blood. This means that high estrogen increases the risk of blood clots blocking important vessels within the body.

5. Weight gain – this is a bit of a vicious cycle as increased weight leads to higher estrogen which in turn leads to more weight gain. This can be a tough cycle to break.

6. Prostate cancer – some studies show that there may be a link between higher estrogen and prostate cancer.

Methods to reduce estrogen.

1. Weight loss – by losing body fat estrogen levels can be lowered which in turn will also allow for further weight loss – a positive cycle.

2. Reduce alcohol – Alcohol has been shown to increase the amount of estrogen in the body so cutting down can reduce estrogen levels.

3. Avoid foods high in estrogen; the list can be fairly extensive but listed below are some common ones:

  • Flax seeds.
  • Soy products.
  • Legumes (like chick peas), sunflower seeds, sesame seeds.

Certain animal products such as dairy food (cheese and milk) or other foods that have been injected with hormones to aid growth and production.

Foods that inhibit estrogen/aromatase or increase t:

  • Certain fruits such as grapes, pears and pineapples.
  • Vegetables such as broccoli, cauliflower, cabbage, and celery.
  • Certain raw nuts like cashews and almonds.
  • Red wine – although moderation is required.
  • Olive oil
  • White button mushrooms.
  • Oysters
  • Parsley.

Aromatase inhibitors.

These drugs inhibit the action of the enzyme aromatse and help reduce the level of estrogen within the body. Two classes exist; steroidal and non-steroidal.

Steroidal aromatase inhibitors such as formestane and exemestane help to inhibit aromatase by mimicking androstenedione (which is a precursor to testosterone and subsequently estrogen). Since the medication is not converted to estrogen it helps reduce overall estrogen levels by saturating the activity of the aromatase enzyme. The second class (non-steroidal_ includes drugs such as anastrozole and letrozole. This class actively inhibit the aromatase enzyme by binding directly to it and hindering its action.

Anastrozole and lestrozole are the 3rd generation aromatse inhibitors which are believed to produce close to 100% inhibition of aromatase.


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