People the world over pay a pretty penny to look young. Many don't realise, however, that staving off wrinkles, age spots and thinning hair has little to do with cosmetic creams and lotions.
Take, for instance, the skin, the body's largest organ. "Twenty to 30% of changes in the skin are attributable to genetics," says Jean Krutmann, director of the Leibniz Research Institute for Environmental Medicine in Dusseldorf, Germany. "The other 70% to 80% are caused by environmental factors, for example ultraviolet radiation and air pollution."
Your skin says a lot about you, too., "Ageing never affects a single organ only – it's always the entire organism that ages," points out Martin Denzel, research group leader at the Cologne-based Max Planck Institute for Biology of Ageing in Germany. "Outward changes are therefore linked to the ageing process as a whole and can be a sign of the body's condition."
A fatty diet, alcohol consumption, smoking and overexposure to the sun subject the body to biological stress. In people young and old, this causes molecular damage in cells – in DNA, for example – a thousand every minute. While a young body can repair the damage quickly, an older one is increasingly unable to.
"Ageing means the body is less and less capable of dealing with stress," Denzel says. "As a result, DNA mutations accumulate in the body's cells, making organs more likely to fail or tumours to develop." Denzel says.
These cell alterations have two visible effects on the skin. "For one thing, pigmentation changes," says Krutmann. "It becomes inhomogeneous, and age spots can form. Secondly, the skin's elasticity decreases, so wrinkles appear. Everyone gets fine wrinkles from ageing. If environmental influences are added, the wrinkles become much deeper. More collagen, a protein in connective tissue, degrades."
Krutmann and his colleagues test the effects of various substances on skin in the laboratory. While the harmful and even carcinogenic impact of ultraviolet radiation and tobacco smoke are already proven, research on air pollutants is still in its early stages. "If you coat skin with airborne particulates, it quickly browns," Krutmann says. "Soot from diesel engines, in particular, has been shown to be harmful."
Along with environmental influences on the skin, a major factor in how old we look is what we ingest.
A recent study by the National Institute of Public Health at the University of South Denmark, published in the London-based Journal Of Epidemiology And Community Health, found that high alcohol consumption and smoking encourage "visible age-related signs" including earlobe creases, yellowish plaques on the upper or lower eyelids, and a greyish-white arc or ring around the cornea.
A harmful lifestyle or environment doesn't affect everyone's health and appearance equally, of course. "People have different genetic makeups. Some live to be well over 100 years old although they smoked and drank alcohol," notes Denzel. "The chronological and biological clocks can be decoupled. A youthful appearance can be a sign that a person has remained biologically young." – dpa