Monosodium glutamate (MSG) intake is associated with the prevalence of metabolic syndrome in a rural Thai population

Background: Epidemiology and animal models suggest that dietary monosodium glutamate (MSG) may contribute to the onset of obesity and the metabolic syndrome. Methods: Families (n = 324) from a rural area of Thailand were selected and provided MSG as the sole source for the use in meal preparation for 10 days. Three hundred forty-nine subjects aged 35-55 years completed the study and were evaluated for energy and nutrient intake, physical activity, and tobacco smoking. The prevalence of overweight and obesity (BMI >= 25 kg/m(2)), insulin resistance (HOMA-IR > 3), and the metabolic syndrome (ATP III criteria) were evaluated according to the daily MSG intake. Results: The prevalence of the metabolic syndrome was significantly higher in the tertile with the highest MSG intake. Further, every 1 g increase in MSG intake significantly increased the risk of having the metabolic syndrome (odds ratio 1.14, 95% confidence interval-CI- 1.12 - 1.28) or being overweight (odds ratio 1.16, 95% CI 1.04 - 1.29), independent of the total energy intake and the level of physical activity. Conclusion: Higher amounts of individual MSG consumption are associated with the risk of having the metabolic syndrome and being overweight independent of other major determinants.