Monosodium glutamate intake is inversely related to the risk of hyperglycemia

Background & aims: In animal studies, monosodium glutamate (MSG) intake at a particular age has been found to increase the risk of insulin resistance and obesity. Inconsistent associations between MSG intake and overweight have been reported in humans. No population study has assessed the association between MSG intake and diabetes risk. This study aims to prospectively examine the association between MSG intake and hyperglycemia in a Chinese population. Methods: We followed 1056 healthy adults aged 20 years and older from 2002 to 2007. Dietary data were collected during home visits using a 3-day food record and a food frequency questionnaire. Fasting blood samples were collected at baseline and follow up. Hyperglycemia was defined as fasting plasma glucose >5.6mmol/l. Results: During the follow-up we identified 125 cases of hyperglycemia. The highest quartile of MSG intake was associated with a lower risk of incident hyperglycemia, even after adjustment for a number of covariates, including dietary patterns. Comparing the highest with the lowest quartiles of MSG intake, the odds ratio (OR) for hyperglycemia was 0.30 (95% CI 0.13-0.66). There was a linear inverse association between MSG intake and change in blood glucose. Conclusion: This cohort study suggests that high MSG intake is associated with a decreased risk of hyperglycemia in Chinese adults.