Saturday 25 Oct 2014

Information and opinions presented here do not always represent the views of the American Heart Association.

Combo of overweight, high sodium intake speeds cell aging in teens

Published: 3:01 pm CDT, March 20, 2014

SAN FRANCISCO — Overweight or obese teenagers who eat lots of salty foods may show signs of faster cell aging.

“Lowering sodium intake, especially if you are overweight or obese, may slow down the cellular aging process that plays an important role in the development of heart disease,” said Haidong Zhu, M.D., Ph.D., lead author of the study presented Thursday and assistant professor of pediatrics at Medical College of Georgia, Georgia Regents University in Augusta, Ga.

Previous research found that protective ends on chromosomes (telomeres) naturally shorten with age, but the process is accelerated by smoking, lack of physical activity and high body fat. The current study is the first to examine the impact of sodium intake on telomere length.

In the study, 766 people 14-18 years old were divided into the lowest or highest half of reported sodium intake. Low-intake teens consumed an average 2,388 mg/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.

After adjusting for several factors that influence telomere length, researchers found:

  • In overweight/obese teens, telomeres were significantly shorter with high-sodium intake (T/S ratio of 1.24 vs. 1.32). T/S ratios are the ratio of the length of the telomere to the length of a single gene.
  • In normal weight teens, telomeres were not significantly different with high-sodium intake (T/S ratio of 1.29 vs. 1.30).

“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.

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.

“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 research presented at the American Heart Association’s Epidemiology & Prevention/Nutrition, Physical Activity & Metabolism Scientific Sessions 2014. The National Heart, Lung, and Blood Institute funded the study.

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  • Zoltán Sándor

    From my article: Entropy and sodium intakes, the wicked problems of health sciences:
    “… Some consequences of high sodium intake; the specialists talk about these rarely or never: Higher energy requirements (energy expenditure) for Na-K pump and kidney. All the rest of our vital processes (functional processes of the cells) receive less energy – because the metabolic rate (speed and capacity of enzyme reactions, oxygen supply, etc.) is limited. And the excess sodium intake do not increase the oxidative pathway. But, a critical surplus switches the anaerobic glycolysis on, in our every cells. This can be named: Sodium-Induced Cellular Anaerobic Glycolysis (SICAG). I think (it is logical) this is a very old anaerobic cellular mechanism, before free oxygen on Earth. We produce lactic acid in our every cells. Consequently, all of our vital processes and organs work worse (our heart, brain, regulating systems, immune system, etc.), and our cells are dying. Remains less energy for the regeneration. We burn the candle on both of his ends (aerobic and anaerobic). The average lifetime of our cells shortens. Soon (faster) the telomeres run out. Our aging accelerates. We get sick often and we will die soon. Logical consequence; the unnecessary sodium increases the incidence of all illnesses. Searching in 12 book set of Dietary Reference Intakes (more than 5000 pages, and about 600 references in the chapter; Sodium and Chloride) no hits for entropy, and the sodium-potassium pump is only some empty phrases. (2) The blind watchmaker learned well the physics first, then the chemistry, and dealt with biochemistry then only. But he never forgot what he learned already once. The optimal Na/K ratio and the ratio between sum of alkaline metals and sum of polyvalent metals, and the ratio between alkaline metals and energy content, etc. is in the human milk. From every viewpoint, the human milk is an evolutionary perfect food, including the minimal energy expenditure of the Na-K pump and kidney of the babies (= possible minimum entropy-transfer into the babies = the baby is growing healthily and with maximal economicalness). Thus, the human milk is the perfect guide to calculate the optimal adult intakes. Unfortunate, that these exist only in traces, in the scientific literature. And in some articles, even the traces are concealed. This is the real wicked problem of health sciences, and this is wronger than malignant neglect. I collected the most important evidences (the traces, and lack of the traces) of the above ones. Let us see it in a logical and nearly chronological order. …”