Eunuchs do not go bald, observed Hippocrates 2,500 years ago, and while few have gone down the castration route to avoid hair loss, they have tried almost everything else. Queen Victoria was so worried about her thinning locks that she took a concoction made from silver birch sap. However, there is now a new remedy for hair loss that looks more promising.
Equol is a form of oestrogen that is made when bacteria in the gut breaks down oestrogen-mimicking chemicals, known as "isoflavones", chemicals found naturally in soya beans and some other plants. The results of a study published last month in Biology of Reproduction indicated that equol effectively blocks a particularly potent form of testosterone, dihydrotestosterone (DHT), linked with both male pattern baldness and an increased risk of prostate cancer.
DHT can be kept in check with Propecia (finasteride), which targets the enzyme that turns testosterone into DHT, and stops hair loss in about 80 per cent of cases and stimulates new growth in 30 per cent. However, benefits are lost when you stop taking the medication, and side-effects can include temporary impotence.
Equol, when injected into mice, did not stop DHT being made, but put it in "handcuffs", stopping it from attaching to the male hormone receptors in the prostate and hair follicles and preventing hair growth. It is a kinder solution than castration.
"Directly binding and inactivating DHT without influencing testosterone gives equol the ability to reduce many harmful effects of androgens without affecting the beneficial ones," says Professor Robert Handa, an endocrinologist at Colorado State College of Veterinary Medicine, the senior author of the latest study.
So could boosting equol intake via diet help prevent hair loss? Should baldies binge on soya and tofu burgers? Certainly far fewer Japanese men go bald or develop prostate cancer and they eat ten times more soya than we do. But there is a catch -can your body make equol?
According to a paper published last December in Ob/Gyn Clinical Alert, only about 30 per cent of the population produces it in their guts (another characteristic distinguishing us from other mammals, all of which churn out equol effortlessly - hair loss is an almost exclusively human affliction). At first sight, hair loss appears a depressingly localised affliction. With an estimated five million hairs on our bodies, most incredibly fine, why should the 100,000 or so thickest on the top of the head go into retreat as we age?
In fact research shows that the reason receding hair is so difficult to treat is because it is intimately connected not just with testosterone and its action on the prostate, but also with foetal development.
Last year it was reported that scientists were working on molecules to target a gene called Sonic Hedgehog which controls such vital steps in the foetus's development as making sure that the baby has two eyes, that the brain forms two hemispheres, and that hair follicles are created. This gene is also active in adults, which is why in October a company patented a drug that turns on the Hedgehog signalling pathway to kick-start hair growth.
Meanwhile, researchers at the Howard Hughes Medical Institute at Rockefeller University in New York are studying two other genes, "wht" and "noggin", which are involved in altering stem cells in the skin so that instead of producing more skin, they become hair follicles. But the spectre of cancer looms over such approaches; wht and noggin have both been implicated in the changes involved in colon and breast tumours.
Meanwhile, you could try saw palmetto berries (available in health-food shops) which a controlled trial two years ago found can inhibit DHT: the subjects were given 400mg a day in the form of two capsules. Silver birch sap probably is not advisable, as herbalists today use it for rheumatism and bladder problems.
By Jerome Burne, Times of London, 04-14-2004