A team of scientists have discovered that tiny chemical differences in how our skin reacts to ultraviolet light could explain why red heads are more likely to suffer skin cancer.
The team from Duke University, North Carolina, believe, the clue is in the skin and hair pigment melanin, and people with ginger hair have pigment that is chemically different from that of people with darker hair.
This difference they say might explain why people with red hair burn easily and are prone to sun damage.
Professor John Simon along with colleagues from the Fujita Health University in Japan, used a special microscope and an ultraviolet (UV) laser to see what was happening to the pigment-containing structures in hair, called melanosomes, from redheads and black-haired people.
The study has shown that chemicals are likely to activate oxygen by taking up electrons, and such changes are known to be linked to cell damage and cancer.
Their work found that the red melanosomes were much more reactive than the black melanosomes and this suggests that it takes less of a trigger, in the form of UV rays in sunlight, to make potentially harmful cellular changes in people with red hair.
Professor Simon explains that activating oxygen can produce compounds called radicals that put oxidative stress on cells.
Such stress could ultimately lead to cancer and other diseases.
According to Simon not only do people with red hair have less protective pigment than people with darker hair, but the pigment they have appears to be more likely to react and produce harmful agents associated with cancer.
Dr Steven Rotter of the U.S. Skin Cancer Foundation says they measured something called the oxidation potential of the red and black melanosomes, and this has helped to clarify at a molecular level knowledge they have had for years.
Ed Yong, science information officer for Cancer Research UK, says although it is well known that red or fair-haired people have a higher risk of skin cancer, this study provides a possible explanation for it.
Yong advises people with red hair and fair skin to take particular care to avoid sunburn and to protect their skin by avoiding the sun in the middle of the day, seeking shade and covering up with a T-shirt and sunglasses and using sunscreen of at least factor 15.
Professor John Simon from Duke University will present the findings at the 230th national meeting of the American Chemical Society in Washington DC at the end of August.