Free amino acids in plasma and total protein, albumin, transferrin and retinol-binding protein (RBP) in serum were determined in two groups of healthy adults consisting of 10 female nonusers and 10 female users of monosodium glutamate (MSG). Users or nonusers of MSG were those consuming or not consuming MSG regularly at their homes for at least 1 y. On the bases of body mass index and serum protein concentrations, each of the two groups appeared to have an adequate protein-energy status. Fasting plasma glutamate concentrations in female nonusers and users of MSG were 22.4 Ϯ 3.2 and 21.8 Ϯ 2.0 nmol/mL (means Ϯ SEM), respectively; these values were not significantly different. These findings indicate that there is no glutamate accumulation in the plasma of MSG users and imply the safety of long-term MSG intake. J. Nutr. 130: 1005S-1006S, 2000.Monosodium glutamate (MSG) 4 is widely used as a flavor enhancer in Thai diets. Pothisiri et al. (1983) reported that the average daily intake of MSG in Thai adults was 1.5 g. It has previously been shown in adults that the ingestion of meals containing added MSG (3 g) and the consumption of MSG (2.8 g) with meals for 5 d are not associated with Chinese Restaurant Syndrome 1985). Nonetheless, the public is still concerned about the safety of long-term dietary MSG use. Therefore, we examined plasma glutamate (GLU) concentrations in adult Thais identified on the basis of their chronic use of MSG in the diet. SUBJECTS AND METHODS Subjects.The strict criteria for this study were based on the definition of MSG nonusers as individuals who had not consumed MSG regularly in their homes for at least 1 y, and who refused to take meals outside their homes that contained added MSG. The selection of MSG users was straightforward. Only 10 healthy female Thai adults, aged 20 -53 y, met the nonuser criteria. They were therefore studied with another group of 10 female MSG users. Height and body weight were measured in each subject, and the body mass index (BMI) was calculated (Tanphaichitr 1994).Dietary assessment. Dietary intakes in each subject were obtained for the 3-d period preceding venipuncture. Daily intakes of energy, protein, fat, carbohydrate and amino acids were then calculated for each subject with the use of standard food composition tables (The Nutrient Data Laboratory 1997).Biochemical determinations. Venous blood samples were obtained from each subject in the morning after a 12-to 14-h fast. Plasma was separated from a heparinized sample and used for the determination of amino acids by HPLC (Cohen et al. 1989) within 2 wk after storage at Ϫ70°C. Serum was separated from a clotted sample and used to determine total protein by biuret assay (Bender 1972), albumin by the bromocresol green dye-binding technique (General Diagnostic 1974), transferrin by the immunochemical reaction with a specific antibody (Turbiquant, Behringworke AG, Marburg, Germany), and retinol-binding protein (RBP) by a single radial immunodiffusion technique (LC-Partigen, Behringworke AG).Statisti...

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Although the findings apparently showed higher adipsin levels in the workers, its value as a biomarker for asbestos exposure requires confirmation from studies on a larger group of subjects.