What Is Monosodium Glutamate (MSG) Allergy

Overview

Do you experience headaches, flushing, or nausea after a meal? If so, you might be dealing with what is known as the monosodium glutamate (MSG) symptom complex. The MSG symptom complex is a set of symptoms that some individuals may experience when consuming foods containing MSG, a common food additive.

Initially, the term ‘Chinese Restaurant Syndrome’ was used to describe these symptoms, particularly after reported incidents following the consumption of Chinese food.^1,2 However, due to the lack of strong evidence to prove a causal relationship between the symptoms and Chinese food and the negative connotation associated with the term, it has been replaced by a less pejorative and more neutral term, namely the ‘MSG Symptom Complex’.²

If you are curious about how to identify and manage this problem, you have come to the right place. We are here to provide you with clear and concise information to help you better understand this condition.

What is MSG?

MSG is a common food additive used to enhance the flavour of many processed and restaurant dishes. Think of it as a natural flavour enhancer, similar to how salt or sugar can make food more palatable. MSG gives food a more umami flavour; thus, it is commonly found in savoury dishes like soups, snacks, canned food, and some restaurant dishes, as it makes food more savoury and satisfying.²

Foods that contain MSG

MSG is found in natural foods such as tomatoes, cheese, and mushrooms. However, it can be found in a variety of processed foods, including:³

• Restaurant meals and fast food: Many restaurants add MSG to their dishes, including many Chinese dishes and fried chicken for its umami flavour
• Processed meats: Some processed meats such as sausages, hot dogs, pepperoni, and ham slices contain MSG to preserve their taste and freshness
• Snack foods: Snack foods like potato chips, flavoured crackers, and popcorn often use MSG to make them more savoury and appealing
• Canned soups and broths: Some canned soups and broths, including chicken and beef broths, may contain MSG
• Prepackaged and frozen meals: Frozen dinners, instant noodles, and prepackaged meals can contain MSG for flavour enhancement
• Seasoning mixes: Some spice blends, seasoning mixes, and bouillon cubes contain MSG to boost flavour
• Salad dressings: Certain salad dressings and condiments such as soy sauce, barbeque sauce, ketchup, and mayonnaise may use MSG to enhance their taste
• Milk products: Some studies suggest the use of MSG in milk products, such as mozzarella and cream cheese, to enhance flavour

Safe levels of MSG consumption

The Food and Drug Administration (FDA) classifies MSG as “generally recognised as safe”. This designation implies that it is considered safe for most people when consumed at typical levels found in foods. The FDA has not established a specific daily intake limit for MSG.

The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) have also evaluated MSG and concluded that it is safe for consumption within acceptable daily intake levels.

While MSG is generally safe, a small percentage of individuals may report an allergy to it, leading to symptoms such as headaches, sweating, or nausea. This condition is commonly referred to as the "MSG Symptom Complex" and has been reported in individuals who have consumed 3 grams or more of MSG without food, though this is highly unlikely since a typical serving of food contains no more than 0.5 grams of MSG.

Causes of MSG allergy

The definite mechanism or cause of why some people are allergic to MSG is still not fully understood. Ongoing studies have not found a direct link between MSG and its adverse effects. However, researchers have identified a few possible factors:

• Dose and timing: Consuming large amounts of MSG or ingesting it on an empty stomach may result in the development of MSG allergy⁴
• Interaction with other food components: It's possible that your meal contains high quantities of salt, fat, and other processed foods, which may be triggering the allergy

Additionally, some studies suggest that headaches or sweating might be solely linked to exceptionally high amounts of salt and fat added to meals prepared at fast-food and other restaurants.⁵

Symptoms of MSG allergy

People who are allergic to MSG may experience the following symptoms 15 to 20 minutes after eating foods containing MSG. The symptoms may last up to 48 hours.^6,7

• Headache
• Face flushing
• Tightening feeling in the temples and face
• Increased heart rate and palpitations
• Excessive sweating
• Numbness/burning sensation that starts at the back of the neck and spreads to the arm, down the spine, and sometimes toward the chest
• Fatigue and dizziness
• Nausea 
• Chest pain
• Difficulty breathing observed in people suffering from asthma 

It is important to note that these symptoms vary in severity and may not be observed in all individuals consuming foods containing MSG. Additionally, scientific research has not yet established a direct link between MSG and these symptoms in the general population. If you suspect an allergy to MSG or experience any of these symptoms, it's advisable to consult a healthcare professional for proper evaluation and diagnosis. 

Diagnosis of MSG allergy

Medical evaluation

Medical history

The first step in diagnosing MSG allergy is a detailed medical history. Your healthcare professional will ask about your symptoms, when they occur, and whether they are linked to specific foods.

Elimination diet

Your healthcare professional will advise you to temporarily avoid foods containing MSG to check whether the symptoms resolve. If they do, this may indicate an allergy to MSG.

Symptom tracking

Keeping a food diary can help you track your symptoms and identify potential patterns related to MSG consumption.

Allergy testing

Since MSG sensitivity has not been scientifically proven to be a true allergy, there is no specific test available for diagnosing it.⁶

Treatment and management

The symptoms of MSG allergy are mild and typically resolve within a few hours without any treatment. Doctors recommend taking over-the-counter (OTC) medications, such as painkillers, to relieve headaches and suggest keeping your body well-hydrated for a prompt recovery.

However, seek immediate medical attention if you experience any of the following severe symptoms, as they can be life-threatening:⁶

• Difficulty breathing
• Swelling in the mouth
• Swelling in the throat
• Difficulty swallowing
• Palpitations or rapid heartbeat 

Your doctor may give you a dose of epinephrine and prescribe anti-allergic medication for the next few days.

Prevention

The best practice to prevent such episodes from occurring in the future is to look out for products containing MSG and avoid them. Here’s how you can do that.

Reading food labels

Read the ingredient lists on the back of food products during your grocery shopping. Keep in mind that processed foods containing ingredients with naturally occurring MSG may not explicitly state the addition of MSG. If processed foods contain any of these naturally occurring ingredients, it includes MSG:⁸

• Monosodium glutamate (MSG)
• Autolysed yeast
• Hydrolysed yeast
• Yeast extract/ yeast food
• Soy sauce/ soy isolate
• Ingredients listed as hydrolysed, protein-fortified, ultra-pasteurised, or enzyme-modified
• Hydrolysed vegetable protein

Dining out tips

While some restaurants now promote themselves as MSG-free, most do not. However, you don't have to avoid dining out. Always ask your server about the presence of MSG in the food you order. Look for meals that contain fewer processed foods and more whole foods. It's advisable to avoid condiments and salad dressings. Additionally, considering a distance from Chinese cuisine could be beneficial.

Cooking at home

• Make sure your pantry contains minimal ingredients with MSG
• Include whole foods into your meals and season them with natural herbs and spices to get delicious flavours without adding additives
• Avoid cooking frozen or processed meats. Use fresh poultry instead

Pro tip: A good homemade beef broth not only delivers the desired umami effect but also provides essential nutrition for your body!

FAQs

Is MSG the same as salt?

No, salt is sodium chloride, giving a salty flavour to your food, while MSG is a combination of sodium and glutamic acid, providing a meaty, umami flavour to dishes. 

How do I know if there is MSG in my food? 

Although MSG has been declared safe to use, it remains a controversial additive. Hence, the FDA requires manufacturers to list it in their ingredient panels.

Are there substitutes for MSG? 

Yes, you can use various herbs and spices to enhance the flavour of your food. Additionally, consider using lemon juice, vinegar, homemade broth, and seasoning blends.

Is MSG harmful to consume?

The FDA considers MSG to be “generally recognised as safe” as an additive. Therefore, it is safe to consume at the typical levels found in food. However, some sensitive individuals might experience adverse reactions.

Is MSG allergy a true allergy?

Since no scientific evidence has been found to prove a direct link between MSG and allergic symptoms, it cannot be defined as a true allergy yet. 

Summary

Monosodium glutamate (MSG) is an additive used to enhance the flavour of food and is generally safe for most people to consume. Some sensitive individuals may experience unpleasant symptoms after consuming it, possibly due to various factors. It's crucial to emphasise that, as of now, there's no established direct link between MSG and allergic symptoms. However, if you believe you're allergic to MSG, it's essential to avoid it.