Glutamate is found in many foods in a natural protein-bound form. It is high in flavoursome foods like tomatoes, aged cheese and mushrooms, and most notably found in a Japanese seaweed sauce from which MSG was extracted. Glutamate is the most common neurotransmitter in the brain; that is, it is responsible for transporting chemical signals from neuron to neuron. However, if the level of glutamates is too high, neurons can misfire, causing physical and psychological problems., and may contribute to central sensitisation and pain hypersensitivity (e.g. allodynia, hyperalgesia).
A 2020 review notes that too much dietary glutamate may contribute to certain psychiatric conditions, such as anxiety, depression, and psychosis. According to the review, it is possible that reducing added glutamate in the diet may improve mental health in certain cases. However, further high quality clinical trials are necessary to determine whether this is the case.
While MSG and natural glutamate are generally tolerated at reasonable levels, some people can be more sensitive to these genetically and for some other reasons including low gaba,
Specific menu planning guidelines for a low glutamate diet
https://aci.health.nsw.gov.au/projects/diet-specifications/adult/allergy/glutamate-low
| Allowed | Not allowed | |
|---|---|---|
| Hot main dishes | All plain cooked meat, poultry, fish, eggs and legumes | Casserole dishes made with commercial stocks and flavour enhancers, or tomato pasteDishes containing tomato, mushrooms, spinach or peas |
| Sauces, gravies | Plain white sauce | Soy sauce, fish sauce, oyster sauce, tomato saucesCheese sauces and black bean sauceGravies made with stock cubes |
| Starchy vegetables / pasta / rice | All potato, pasta, plain rice, noodles, couscous, quinoa, semolina | Commercial flavoured noodles and savoury rice |
| Vegetables | All others | Spinach, tomato, mushrooms or peasPickled vegetables |
| Soups | All others – check label | Commercial condensed soupsSoups with mushroom, tomato or peas |
| Sandwiches | All others | Tomatoes |
| Salads, dressings | Most salad ingredientsPlain salad dressing (oil and vinegar) and mayonnaise – check labels | Tomatoes, mushrooms, parmesan cheeseCommercial salad dressings |
| Breads, cereals | All others | Breads and cereals containing dried fruit |
| Spreads | Jam, honey, peanut butter | Yeast spread, pickles and chutney |
| Hot breakfast choices | All others | Mushrooms, tomatoes, canned spaghetti, baked beansAny dishes made with tomato or peas (e.g. savoury mince) |
| Fruit | All others | Plums, grapes and dried fruit |
| Yoghurt | All | – |
| Desserts | Cakes and desserts containing allowed ingredients | All others, e.g. cakes and desserts containing dried fruit |
| Milk and cheese | All milksMost mild cheeses | Hard aged cheese, e.g. parmesanCamembert, blue vein cheese, Brie and Gruyere |
| Beverages | All others | Vegetable juice |
| Biscuits | Biscuits and crackers containing allowed ingredients | All others, e.g. biscuits and crackers containing dried fruit or parmesan cheese |
| Miscellaneous | Salt, pepper, sweetener, sugar, cream, nuts | Miso |
References
- Royal Prince Alfred Hospital Allergy Unit. RPAH Food Intolerance Handbook, Volume I: Diagnostic elimination diet. Sydney: RPAH 2016.
- Royal Prince Alfred Hospital Allergy Unit. RPAH Food Intolerance Handbook, Volume II: Challenges, liberalizing and maintenance. Sydney: RPAH 2016.
- Swain AR, Soutter VL, Loblay RH. Friendly food: the complete guide to avoiding allergies, additives and problem chemicals. Sydney: Murdoch Books; 2004.
- Food Standards Australia New Zealand. Monosodium glutamate: a safety assessment. Technical Report Series No 20. Canberra: FSANZ; 2003.
