Meta-analysis links increased magnesium intake with fasting glucose and insulin reductions
Tuesday, January 29, 2013. The results of a meta-analysis published online on January 23, 2013 in the Journal of Nutrition reveal an association between diets that include higher amounts of magnesium and lower levels of fasting glucose and insulin.
American and European researchers sought to determine the influence of genetic variations associated with glycemic traits or magnesium metabolism on fasting glucose and insulin levels, which are elevated in metabolic syndrome and type 2 diabetes. "Evidence from cross-sectional and longitudinal observational studies suggests that diets higher in magnesium are associated with reduced risk of insulin resistance and type 2 diabetes, whereas in intervention studies, supplemental magnesium improves measures of glucose and insulin metabolism in generally healthy adults, as well as in those with insulin resistance and type 2 diabetes," Adela Hruby and colleagues write. "However, little is known about potential interaction between magnesium intake and genetic variability on glycemic traits, in which genetic variants related to either magnesium transport and homeostasis or glucose and insulin metabolism may modify the pathways through which magnesium exerts its effects."
The researchers analyzed data from up to 52,684 nondiabetic men and women who participated in 15 studies included in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. Dietary questionnaire or interview responses, or food diary entries were analyzed for magnesium content from food and beverages. Participants were genotyped for up to 25 single nucleotide polymorphisms related to fasting glucose, insulin or magnesium.
Average magnesium intake ranged from 224.7 milligrams to 479.7 milligrams per day. Reductions in both fasting glucose and fasting insulin were observed in association with increased magnesium. While a nominal association was found between one of the genetic variants examined in this study and fasting glucose and two variants showed nominal interactions with magnesium intake on fasting glucose and fasting insulin, no significant effects for the variations were observed.
"To our knowledge, this is one of the largest observational studies to investigate magnesium intake's associations with fasting glucose and fasting insulin, and it is the largest meta-analysis investigating interactions between magnesium intake and risk loci on fasting glucose and fasting insulin," the authors announce.
"Our results indicate that higher dietary magnesium intake is inversely associated with fasting glucose and fasting insulin in individuals free of diabetes, generally irrespective of genetic variation at glycemia- and magnesium-related loci investigated," they conclude.