Secrets of the Silver Fox - Grey hair (the facts!)
May 2011
Consultant Trichologist Iain Sallis is the only hospital based
trichologist in the UK and has a network of clinics across the UK –
currently in Leeds, Hull, Lincoln, Sheffield, Manchester,
Nottingham, Harrogate, Huddersfield and London.
Most problems seen by trichologists involve either excessive loss of
hair, thinning hair, patches of baldness, hair breakage, scaling
problems or excessive oiliness and itching of the scalp. Conditions
range from psoriasis, hair loss, alopecia and baldness.
Here – Iain talks about the science behind greying hair and the
individuals who are most susceptible.
Melanocytes are the cells in a human body which gives us our colour
(hair, eyes, and skin) and so; are arguably to blame for more wars
and upset in human history than any other cell, it also gives the
human body some of the most noted signs of where we come from and
how old we are?
Hair colour shows signs of age-related changes only one of which is the well known reduction of melanocytes in hair. There is a 10-20% reduction of pigment producing melanocytes for every decade after 30 years of age (in Caucasian).
Though it’s gradual in the skin, it can be quite sudden in the hair follicle. The predominant factor of this appears to be heredity.
The mechanisms for these two types of
reductions in both hair and skin are unclear and there is no
convincing explanation the reason why one population in the skin
dies gradually and its neighbour disappears suddenly.
There is a ‘free radical’ theory of why hairs lose their colour,
which postulates that the accumulative action of ‘oxidative damage’
is an important element in the rate of ageing.
Damage to the DNA through ‘environmental’ issues (diet, stress, and genetics) can lead to mutations which in turn can induce oxidative stress and thereby trigger destruction of the colour producing cells.
Grey Hair
The onset and progression of greying hair correlates closely with
ageing and affects every human to some degree (regardless of gender
or race), the age of onset is genetically controlled and inherited:
Average age for Caucasians – mid thirties,
Asians – late thirties
Africans- Mid Forties.
Hair is only said to be prematurely grey if it occurs before the age
of:
20 in Caucasians,
25 in Asians, and
30 in Africans.
Although not formally tested the rule of thumb is that by 50 years,
50% of people will have 50% grey hair. Of course this is more
predominant and noticeable on people with darker hair..and is
usually not grey either, rather interplay of the white hair and the
darker ones surrounding it.
Greying hair is often coarser, wirer and more ‘unmanageable’ than
pigmented hair, this would reflect a change in chemical and physical
properties before/after pigmentation of the hair, in addition grey
hair is often unable to hold a ‘set’ and is more resistant to
incorporating hair dyes,
Conclusion
The reason that the science of greying hair has been stalled for so
long is that the melanocytes are basically individual
sub-populations which up until now have been impossible to isolate
and therefore study,
There is no upward trend in early greying hair
in men or women, though there is most definitely more people who
notice their hair more and that includes the ‘natural’ colour of it.
Professor Tobin and co-workers have developed novel methods to study
these cells outside the body (i.e.: in vitro) and are aiming to
unlock the mysteries of the melanocytes and greying hair that this
review has only gleamed!
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