The aim of this analysis was to determine the relationship between monosodium glutamate (MSG) intake and change in hemoglobin (Hb) levels and the risk of anemia over 5 years in 1197 Chinese men and women who participated in the Jiangsu Nutrition Study (JIN). MSG intake and Hb were quantitatively assessed in 2002 and followed up in 2007. Diet and lifestyle factors were assessed at both time points. There was a positive association between MSG intake and increase in Hb among men but not women. In the multivariate model adjusting for demographic and lifestyle factors as well as baseline dietary pattern, the beta values and 95% confidence interval for Hb changes across quartiles of MSG intake were 0, 0.67(0.04-1.29), 0.99(0.38-1.60), 0.73(0.13-1.34) among men (p for trend 0.091); 0, -0.01(-0.45-0.43), 0.23(-0.25-0.71), and -0.45(-0.96-0.05) among women (p for trend 0.087). Among anemic participants at baseline, there was a significant inverse association between MSG intake and the risk of anemia at follow-up. Comparing extreme quartiles of MSG intake among those anemic at baseline, the relative risk for persistent anemia at follow-up was 0.49 (95% CI: 0.28-0.86, p < 0.01). The association was independent of dietary patterns and lifestyle factors. A dose-response relationship between MSG intake and increase in Hb levels among anemic participants was seen. MSG intake may have independent Hb-increasing effects, especially among men and those anemic at baseline.