Male-pattern baldness (androgenic alopecia) is the most prominent type of hair disorder affecting, to varying degrees, half of all men over 50 years of age.
The current theory about holds that in males who are genetically predisposed to baldness, certain areas of scalp tissue start to produce an enzyme called 5-alpha reductase. This enzyme converts the male hormone testosterone circulating in the blood into dihydrotestosterone or just simply DHT. Men who are prone to baldness, areas of scalp tissue (and these are the areas that become characteristically bald) start to produce 5-alpha reductase, which grabs testosterone from the blood and converts it into the potent DHT.
DHT is the culprit. DHT has an adverse affect on the hair follicles. High concentrations of DHT in the follicles cause them to spend less time in the growing stage and more time in the resting stage of the hair cycle.
Hirsutism: male-pattern hair growth affecting eight percent of adult women comes about due to hormonal disorders. Other symptoms include irregular menstruation, lack of ovulation, acne, deepening of voice, balding, and genital abnormalities. Usually caused by excess of androgen (steroid hormone that stimulates development of male sex organs and secondary sexual characteristics). This overproduction of androgen could result from certain drugs or conditions.
Hair shaft disorders: usually hereditary abnormalities or due to inflammation and infection. Hair shaft disorders involve split ends, and hair that is dry, brittle, and coarse, as well as skin and other abnormalities. Causes include over processed hair (colouring, permanent waves, excessive heating) or certain diseases.
People with the following conditions or characteristics are at risk for developing hair disorders:
Noticeable diffuse thinning in women usually starts after menopause when the production of the female hormone estrogen slows down dramatically or stops altogether. Before menopause when production of estrogens is high, this hormone has a protective effect against the small amount of testosterone that women also produce.
The enzyme 5-alpha reductase in scalp tissue converts circulating (free) testosterone into DHT. The hormone DHT (dihydrotestosterone) can harm hair follicles by making them shrink or causing them to enter prematurely into the resting stage of the hair cycle. Before menopause the estrogens in a woman's body counteracts the small amount of testosterone she produces and makes it less available to conversion into DHT.
The result is usually the characteristic U-shaped pattern of hair loss. Women very rarely have this kind of hair loss. The hair loss in women is more diffuse and there are seldom any bald spots. The frontal hairline is also spared in most cases. None the less it can be devastating aesthetically.
About fifteen percent of women are afflicted with a degree of hair loss that is depressingly evident. This hair loss happens at a slower rate than in men and it happens at a much later time in life.
It is a proven scientific fact that a diet that weighs in at less than 1,200 calories a day can trigger sudden hair loss known as "Telogen effluvium".
Note: Telogen effluvium (TE) is not the same as Anagen effluvium (AE) with is sudden hair loss from chemotherapy or radiation treatments.
The type of hair loss known as TE is more common in women than in men. It Is due to many hairs entering the telogen or resting stage of the hair cycle at one time. The profuse shedding that occurs during TE can seem overwhelming to women experiencing it. The condition is often brought on by crash dieting (losing more than two pounds a week), prolonged emotional or physical stress, post-pregnancy hormone changes, and severe illness. When these triggering factors are removed, TE hair loss usually ceases.
The recovery of the lost hair, however, may take six months to a year. Recovery of this kind of hair loss is probable even without treatment.
A diet high in fat, especially fat from animal products, is thought to reduce the amount of sex hormone binding globulin (SHBG), a protein that binds to testosterone circulating in the bloodstream. This binding by the protein keeps the testosterone unavailable for conversion into DHT. With high fat diets, the amount of circulating SHBG is reduced and hence more testosterone will be available to be converted into DHT.
The body will often react to the physical stress of severely reduced calories or necessary nutrients by falling out in clumps. Diets that are especially low in protein are most suspect.
When the body is deprived of sufficient protein, through dieting or other abnormal food consumption, it will shut down all production of hair in order to divert all of its energies towards conserving vital body organs. The body will save protein by shifting healthy hairs that are in a normal growth phase (anagen) into a sudden resting phase.
Telogen effluvium does not usually cause bald patches but it does prematurely force a much larger percentage of scalp hair into a sudden resting phase. Hair that is forced into an early resting period will almost always react by thinning and falling out.
If you are experiencing symptoms associated with a hair disorder that fit into the categories mentioned above, you should see your health care provider or naturopathic doctor, in order to identify what exactly is the root cause of your symptoms.