What Causes Premature Hair Graying?
Genes Responsible for Early Loss of Hair Pigmentation
Sep 27, 2009
Greying hair is a normal part of the aging process, but is sometimes seen in younger adults, teenagers and even children.
Why Does Hair Turn Grey?
Hair owes its colour to melanin, a pigment that is also responsible for the colour of the skin and eyes. Melanin is produced by specialized cells called melanocytes. In hair, melanocytes are located in the follicles from which individual hairs develop. The melanin passes into each hair shaft as it grows and remains there until it falls out, which may be as many as three or more years.
There are two types of melanin – phaeomelanin, which has a yellowish-red tone, and eumelanin, which is brown-black. The amounts and relative proportions of phaeomelanin and eumelanin produced in the follicles account for the whole range of hair colour shades seen in humans, from the palest blonde to black.
Hair loses its colour when the melanocytes stop producing melanin and new hairs grow without pigment. A hair with no melanin is transparent; ‘grey hair’ is actually a mixture of colourless hairs and hairs of the person’s original shade. When every hair on the head is melanin-free, the hair appears pure white.
Causes of Premature Grey Hair
The age at which hair greying begins varies between individuals and with skin colour – lighter-skinned people tend to go grey earlier than darker-skinned people. Greying that begins in the 30s or 40s is a normal part of the aging process; earlier greying may be considered premature.
In most cases, the cause of premature greying is simply genetic. People whose parents and grandparents showed premature greying are likely to go grey early themselves.
Premature greying has also been associated with medical conditions such as anaemia, vitamin B12 deficiency and vitiligo (in which the body’s own immune system attacks the melanocytes, causing patchy loss of hair and skin colour).
It is commonly believed that stress can cause grey hair, but there is no scientific evidence for this – or for people ‘going grey overnight’. Such tales may have arisen from cases of alopecia areata in which pigmented hair has fallen out rapidly, leaving grey hair unaffected.
Is There Any Way to Prevent or Reverse Grey Hair?
As with other aspects of aging, there is currently no known way to stop the degeneration of melanocytes. However, people with premature greying can take comfort from the fact that there is no link between early grey hair and premature aging of the rest of the body. As Dr Leo M Cooney, Professor and Chief of Geriatrics at Yale University School of Medicine explains, “People with premature graying of the hair don’t die any sooner than anybody else… gray hair has something to with your genetics and very little to do with premature aging.”
References
Dawber RPR. Integumentary Associations of Pernicious Anaemia. Br J Dermatol 2006; 82(3): 221–3.
Juangbhanit C et al. Vitamin B12 Deficiency: Report of a Childhood Case. J Med Assoc Thai 1991; 74(6): 348–54.
Parker-Pope T. Unlocking the Secrets of Gray Hair. The New York Times, 10 March 2009.
WebMD. The ABCs of Premature Graying. Accessed 27-09-09
Disclaimer
The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
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