What are the effects of Monosodium Glutamate (MSG)?

From the Guidelines

Monosodium glutamate (MSG) is a nonimmune, host-independent food intolerance that can negatively affect certain individuals, and its consumption should be approached with caution, especially for those who experience adverse reactions such as headaches, flushing, or sweating. According to a recent study published in the Annual Review of Nutrition 1, nonimmune, host-independent food intolerances involve chemicals with pharmacological activity in food that affect sensitized individuals, including glutamates like MSG. These substances can cause a range of symptoms, including urticaria, angioedema, asthma, gastrointestinal symptoms, hypotension, headache, and eczema.

Some key points to consider when it comes to MSG consumption include:

• MSG is a flavor enhancer commonly used in cooking and food processing
• It can provide the umami taste, often described as savory or meaty
• Some individuals may experience sensitivity symptoms like headaches, flushing, or sweating after consuming foods with high MSG content
• The typical amount of MSG used in cooking ranges from 0.1-0.8% of the food's weight
• If you're concerned about MSG sensitivity, you can check food labels (where it may be listed as E621) and request no MSG when dining out

It's essential to note that the evidence on MSG sensitivity is not yet fully understood, and more research is needed to determine the exact mechanisms of intolerance and the prevalence of adverse reactions 1. However, for individuals who experience symptoms after consuming MSG, it's crucial to be mindful of their intake and take steps to minimize exposure.

From the Research

Monosodium Glutamate (MSG) Overview

• Monosodium glutamate (MSG) is a food additive used to enhance flavor in foods, with a long history of use and classified as generally recognized as safe (GRAS) by the US Food and Drug Administration 2.
• MSG is a water-soluble salt of glutamate, a non-essential amino acid, normally synthesized in the body and prevalent in protein foods 3.

Health Effects of MSG

• Some studies have suggested that high doses and repeated exposure to MSG may be associated with adverse health outcomes, including embryotoxicity, teratogenicity, obesity, cardiotoxicity, hepatotoxicity, kidney toxicity, neurotoxicity, endothelial dysfunction, reproductive toxicities, and alteration of lipid and glucose metabolism 4.
• However, other studies have found that MSG is safe for all life-cycle stages without respect to ethnic origin or culinary background when consumed at normal dietary levels 3.
• Clinical trials have focused mainly on the effects of MSG on food intake and energy expenditure, with some studies suggesting that MSG enhances salivary secretion and interferes with carbohydrate metabolism 5.

MSG Hypersensitivity and Allergic Reactions

• Reports of MSG hypersensitivity, also known as 'Chinese restaurant syndrome', have been found to have little supporting evidence 5, 6.
• Decades of research have failed to demonstrate a clear and consistent relationship between MSG ingestion and the development of conditions such as asthma, urticaria, angio-oedema, and rhinitis 6.
• Double-blind studies have not been able to consistently elicit reactions in 'sensitive' individuals using MSG or placebo in food 2, 3.

Safety and Regulatory Status

• The European Food Safety Authority (EFSA) has established an acceptable daily intake (ADI) for MSG of 30mg/kg body weight/day, which is not attainable when MSG is consumed at normal dietary levels 3.
• MSG is generally recognized as safe by food safety regulatory agencies, but some studies have questioned its long-term safety 4, 5.