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Melatonin and Mealtime: Common Genetic Difference Could Put Some at Greater Risk of Diabetes

October 6, 2015



By carefully studying healthy subjects, researchers were able to chart the effect of melatonin supplements on blood sugar control. Their results, reported in Metabolism, suggest that taking melatonin close to mealtimes may put people with a common genetic variant more at risk. Read the paper, titled “Common Type 2 diabetes-risk variant in MTNR1B worsens the deleterious effect of melatonin on glucose tolerance in humans.”, here.

“Our work is the first to show that a person’s genetic profile could impact their ability to tolerate glucose when they take melatonin,” said co-corresponding author Frank A.J.L. Scheer, PhD, Associate Professor of Medicine at Harvard Medical School and the Director of the Medical Chronobiology Program at the Harvard Medical School Division of Sleep Medicine.

“Our results suggest that we may need to exert caution when taking melatonin close to meal times, especially in carriers of the risk variant,” said co-corresponding author Marta Garaulet, PhD, a full professor of Physiology at the University of Murcia. As many as 50 percent of people of European ancestry carry this genetic variation in MTNR1B, a gene that encodes a melatonin receptor. Previous studies have found that this mutation increases a person’s risk of diabetes, but exactly how and why it influences blood sugar control has remained poorly understood and has mostly been studied during the daytime, when naturally occurring melatonin concentrations are very low.

Other researchers who contributed to this study include Purificación Gómez-Abellán, Patricia Rubio-Sastre, Juan A. Madrid and Richa Saxena.

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