Archives

  • 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • Based on the molecular weights

    2021-10-11

    Based on the molecular weights of glutamate (147.13 g/mol) and MSG (169.111 g/mol), the amount of free glutamate intake obtained in this study was equivalent to 297 mg MSG/d and 370 mg MSG/d for children and adults, respectively. Several previous studies have assessed population intake of MSG from food additives or seasonings [14], [15], [16], [17], [18]. In the UK, estimated MSG intake by the general population was 580 mg/d, and this value was as high as 4.68 g/d among extreme corticotropin releasing factor [14]. In Asian countries, where MSG is frequently used as a seasoning at home, daily intake of MSG ranged from 0.33 g/d [15] to 3.8 g/d [17] in China, 1.57 g/d in Korea [19], and 2.2 g/d [18] in Vietnam. However, the primary focus of the present research was naturally-occurring free glutamate rather than MSG, which is added to foods during cooking or food processing, whereas the previous studies focused exclusively on MSG [14], [15], [16], [17], [18], [19]. In addition, dietary assessment methods used in the previous studies differ from this study. Thus, we cannot make a direct comparison between our study and the previous ones, limiting our abilities to conclude which study offers more reliable results. All of the studies, including ours, may have underestimated total free glutamate levels as our study did not include values for added free glutamate while previous studies failed to do so for the naturally-occurring one. Major food sources of free glutamate were mixed dishes both among children and adults and its contribution was more than 30%, according to the WWEIA broad food category. Other major contributors included milk and diary, protein foods, fruits, condiments and sauces, and vegetables among children, and vegetables, protein foods, and condiments and sauces among adults. Thus, as we hypothesized, food sources of free glutamate varied, and the contribution of protein foods was not relatively larger than other food categories. Furthermore, when analyzed according to WWEIA specific food categories, we found that major food sources of free glutamate were plant-based foods such as fruits, vegetables, or grain products as well as protein-rich foods such as seafood or meat. Previous studies have shown that animal-based foods serve as the primary source of dietary protein for the US population [44], [45]. The percentages of total protein intake derived from animal-based and plant-based foods were 46% and 30%, respectively, and individual food sources were chicken (7.2%), cheese (4.3%), meat mixed dishes (3.9%), yeast breads (3.9%), cold cuts and cured meats (3.6%), and beef, excludes ground (3.6%) [44]. Consistently, another study showed that the highest-ranked sources of protein were poultry (13.0-15.1%), beef (13.0-14.5%), cheese (7.1-9.3%), milk (6.6-7.4%), and yeast breads and rolls (5.9-7.3%) [45]. However, when the percentage contribution of each food category to free glutamate was calculated according to the USDA food coding scheme [32], plant-based foods such as grains, fruits, and vegetables were included in the primary food sources of free glutamate (for children and adults: milk and milk products (11.5% and 8.7%), meat, poultry, fish and mixtures (21.8% and 25.5%), grain products (31.1% and 23.6%), fruits (12.5% and 8.6%), and vegetables (15.9% and 22.1%)). Given that natural free glutamate is not strongly associated with their protein content, this inconsistency between food sources of protein and those of free glutamate appears to be reasonable [46]. Our study demonstrated statistical differences in free glutamate intakes among different socio-demographic groups, and the food sources of free glutamate were also different between these groups. Although energy-adjusted intake was higher in women than men, the crude free glutamate intake was higher in men than in women. This may be explained by the contribution of low energy-dense foods, such as fruits and vegetables, which were higher among women (fruits = 8.3%, vegetables-excluding potatoes = 16.1%) than men (fruits = 4.6%, vegetables-excluding potatoes = 11.7%).