Teens eating high amounts of salt speed aging

Overweight or obese teenagers who eat lots of salty foods may show signs of faster cell aging, researchers in the United States say. Lead author Dr. Haidong Zhu, an assistant professor of pediatrics at Medical College of Georgia, Georgia Regents University in Augusta, Ga., and colleagues said previous research found the protective ends on chromosomes -- telomeres -- naturally shorten with age, but the process is accelerated by smoking, lack of physical activity and high body fat. This study was the first to examine the impact of sodium intake on telomere length, Zhu said. The study involved 766 people ages 14-18 divided into the lowest or highest half of reported sodium intake. Low-salt intake teens consumed an average 2,388 milligrams/day, compared with 4,142 mg/day in the high-intake group. Both groups consumed far more than the 1,500 mg/day maximum -- about 2/3 teaspoon of salt -- recommended by the American Heart Association, Zhu said. After adjusting for several factors that influence telomere length, the study found: -- In overweight/obese teens, telomeres were significantly shorter with high-sodium intake. -- In normal weight teens, telomeres were not significantly different with high-sodium intake. "Even in these relatively healthy young people, we can already see the effect of high sodium intake, suggesting that high sodium intake and obesity may act synergistically to accelerate cellular aging," Zhu said in a statement. Obesity is associated with high levels of inflammation, which also hastens telomere shortening, and increases sensitivity to salt, which may help explain why higher sodium intake had a greater effect in that group, Zhu said. "Lowering sodium intake may be an easier first step than losing weight for overweight young people who want to lower their risk of heart disease," Zhu said. "The majority of sodium in the diet comes from processed foods, so parents can help by cooking fresh meals more often and by offering fresh fruit rather than potato chips for a snack." The findings were presented at the American Heart Association's Epidemiology & Prevention/Nutrition, Physical Activity & Metabolism Scientific Sessions in San Francisco.