Hair speaks volumes about an individual, revealing ethnic origin, environment, diet and even lifestyle, scientists said on Wednesday.
Although like finger and toe nails the hair itself is dead, it acts like an Arctic ice core, trapping within its physical and chemical structure an accurate record of whatever has been ingested or applied to it externally.
“Your hair tells what you eat, where you live, your lifestyle and habits,” said Emma Freeman from London’s Natural History Museum. “Your hair is what you do.”
It can tell if you smoke, drink or take drugs and, growing at 0.3 to 0.5 millimetres a day, it keeps a record for months if not years -- which is why some people taking illegal substances shave their heads.
Because different races have different hair structures, analysis can also tell ethnic origin -- although it cannot reveal sex.
Starting on Saturday and running through September the museum is opening to the public an exhibition detailing the remarkable story of hair.
“This tells the incredible biology of hair and the place of hair in different cultures,” Freeman said.
The average person has up to 150,000 hairs on the head and a single strand can support 100 grammes in weight.
A whole head of hair could therefore in theory support the weight of two African elephants.
African hair grows more slowly and is more fragile than European hair, but Asian hair grows the fastest and has the greatest elasticity.
Asian people also are ahead when it comes to keeping their hair, with Africans and Europeans more prone to balding.