Looking beyond overnutrition for causes of epidemic metabolic disease

Abstract

In 1500 B.C., when the author of the Egyptian papyrus Ebers first described an obscure illness that later became known as diabetes mellitus (from Greek diabetes meaning siphon and Latin or Greek mel meaning honey) (1), he could hardly have envisioned the pandemic of metabolic disease that would take place at the end of the 20th century through the beginning of the 21st century. According to the International Diabetes Federation, diabetes affects ∼366 million people worldwide (2). This number is projected to rise to 552 million by 2030 (2). Additionally, there were 280 million people with impaired glucose tolerance in 2011 (2); this number is projected to increase to 398 million in 2030 (2). Thus, by 2030, close to 1 billion people are expected to have abnormal glucose tolerance. The epidemic of diabetes is accompanied by epidemics of obesity and atherosclerotic heart disease and may have at its roots an insulin-resistant state called the metabolic syndrome (3). Why is this epidemic of metabolic disease taking place now? In PNAS, Cai et al. (4) propose one possible explanation.