THE SECRETS YOUR HAIR TELLS

So you keep to a good diet but who would know what you have really eaten?

 Someone may know more than you think. 

 The secrets of ancient civilisations are coming to the fore with research by Stephen Macko, professor of environmental science at the University of Virginia.

 He says, "You are what you eat, and clues to what people ate thousands of years ago are stored in their hair."

 First-time studies of ancient human hair are bringing new insights to old questions about the diet and nutrition of ancient civilisations.

 "Ancient hair is chemically little different from the hair that's swept up each day from the barbershop floor," Macko says. "Unlike bones and flesh which decay and change chemically, hair seems to stay the same. It is a terrific archive of information about the nutrition of ancient peoples."

 He has analysed hair clippings from the Neolithic Ice Man of the Oetztaler Alps; the Coptics of Egypt; the Late Middle Kingdom mummies of Egypt; and the Chinchorro mummies of Chile.

 He has found that the Ice Man -- thought by some to be a hunter -- was probably a very strict vegetarian at the time of his death. "There's little indication of meat consumption," Macko says. The Coptics of Egypt, like the Chinchorro of Chile, ate a wide variety of vegetables, grains, meats, seafood and dairy products, " The Late Middle Kingdom Egyptians, on the other hand, appear to have eaten a somewhat restricted diet with more animal products. "It seems that the upper-class of the time, perhaps for some sociological reason, had a much less diverse diet than was available to them," Macko says.

 “As geochemists, we are providing a different perspective for the archaeologists. We are using sophisticated laboratory techniques to analyse hair, which may be the best preserved part of the human body."

 Professor Macko obtains his data by measuring the isotopes in organic materials. By observing changes in abundances of carbon, nitrogen or sulfur, he can differentiate source materials, whether plant or animal and terrestrial or marine.

 "We cannot tell what kind of bread a person ate, but we can determine if they ate grains, or meat or fish or vegetables. There is a great deal we can explain about a person's diet through hair. Nature has done the work for us by storing this information in the material. We simply measure it. This is basically a forensic technique, performed on ancient people."

 "It is fascinating to speculate on their lives based on what we are learning about their diets."

 He gives the Chinchorro of Chile as an example. "We have found a strong marine component in the diet of a population that lived well inland in the Atacama desert," he says. "This indicated a level of interaction between the coastal and inland populations that previously was not recognised. We also have indications that Egyptian Late Middle Kingdom royalty ate a fairly constrained diet. This is new information for the archaeologists to use in their study of ancient peoples."

 So make sure you have a good relationship with the barber because all your secrets may be at the mercy of the hairdresser and their broom.