Stress Condition on a Restricted Sodium Diet Using Umami Substance (L-Glutamate) in a Pilot Randomized Cross-Over Study.

Hypertensive patients who adopt a sodium-restricted diet have difficulty maintaining this change, and this could increase stress. On the other hand, soup rich in umami substances (dashi) was reported to reduce indexes of anxiety and stress. The objective of this study was to measure mood and physiological stress indexes during administration of a sodium-restricted diet with and without an umami substance (free L-glutamate) by a cross-over randomized, single-blind, placebo-controlled trial in Japanese female university students. The baseline was measured for 5 days followed by a sodium-restricted diet intervention phase that lasted for 10 days. The Profile of Mood States questionnaire was administered, a stress marker in saliva (chromogranin-A) was measured, and the amount of sodium intake was confirmed from 24 h urine collection samples. Results showed that the sodium reduction was verified by 24 h urine excretion. The percentage of change in the stress marker from the baseline showed that the stress level in group without the umami substance was significantly higher than that in the group with the umami substance (p = 0.013) after receiving a sodium-reduced diet for 6 or more days, indicating that stress was alleviated. This study suggested that umami substances might help to ameliorate stress during a sodium-reduced diet, especially in the initial phase.

Monosodium glutamate is not associated with overweight in Vietnamese adults.

OBJECTIVE: To determine the prevalence of and associated factors for overweight, especially to determine the relationship between the intake of monosodium glutamate (MSG) as a seasoning and overweight in Vietnam. DESIGN: A cross-sectional survey was conducted of Vietnamese adults aged ≥20 years in 2008. Dietary intake was assessed by the 24 h recall method for 3 d. MSG intake was evaluated by the weighing method on three consecutive days. Physical activity was assessed based on the Global Physical Activity Questionnaire recommended by the WHO. Overweight was defined as BMI ≥ 23·0 kg/m2. Other characteristics such as age and lifelong occupation were determined by a structured questionnaire. SETTING: Some rural and urban areas of Hanoi, Thua Thien Hue Province and Ho Chi Minh City, Vietnam. SUBJECTS: A total of 1528 adults living in surveyed areas were randomly selected by the multistage cluster sampling method. RESULTS: The prevalence of overweight was 27·9 %, and 81·0 % of participants were MSG users. Average MSG intake was 2·2 (sd 1·8) g/d. Multiple logistic regression analysis revealed that factors associated with overweight were age, region of residence, lifelong occupation, physical activity and intakes of energy, carbohydrates, saturated fat and animal protein. There was no significant association between MSG intake and overweight. CONCLUSIONS: The study demonstrated that overweight was not associated with MSG intake in Vietnamese adults. Further longitudinal studies should be done in different populations to determine the relationship between MSG and overweight.