Dietary free glutamate comes from a variety of food products in the United States

Abstract Glutamate is naturally present in various foods, such as many savory foods. Therefore, we hypothesized that dietary free glutamate comes from a variety of foods in the United States. The aims of this study were to develop a naturally-occurring free glutamate composition database, in addition to further estimate dietary intake and identify major food sources of free glutamate in US children and adults. The composition database of free glutamate was developed based on analytical values obtained from food analysis and available literature. This database was applied to dietary data obtained from a 24-h dietary recall among 8597 children (2-19 y) and 13 969 adults (≥20 y) in the National Health and Nutrition Examination Survey (2009-2014) to estimate dietary intake and major food sources of free glutamate. Mean intake of free glutamate for children and adults was 258 mg/d (136 mg/1000 kcal) and 322 mg/d (155 mg/1000 kcal), respectively. According to the What We Eat in America category, major food sources of free glutamate were fruits (9.3%), condiments and sauces (9.0%), and mixed dishes-grain based (8.1%) for children and vegetables-excluding potatoes (13.6%), mixed dishes-meat, poultry, seafood (8.5%), and condiments and sauces (7.8%) for adults. For both children and adults, the top food sources included watermelon, raw; tomato catsup; tomatoes, raw; and roll, white, soft. To our knowledge, this is the first study to provide valuable data regarding intake of naturally-occurring free glutamate in foods. We found that dietary free glutamate comes from various foods in the US population, not exclusively from protein-rich foods.