Understanding MSG

Many of us are quite familiar with the three-lettered abbreviation MSG, a well-known food additive that appears in so many of our foods. It is designed to make our food taste better – added artificially to boost less flavoursome foods although it’s found naturally in some foods. But what is it exactly?

Monosodium glutamate (MSG) is a flavour enhancer, originally extracted from seaweed, which is used in a number of foods to make them more palatable.

MSG is the salt form of the common amino acid, glutamic acid. Glutamic acid is naturally present in our bodies, and is naturally found in many food sources of protein such as meat, vegetables (such as tomatoes), cheese and milk. It is also commonly used as a food additive.

The ‘fifth’ taste

Glutamate is perhaps best personified by the word ‘Umami.’ Umami is a Japanese term that translates as ‘pleasant savoury taste’ and has been described as the fifth taste (the other four tastes are – sweet, sour, bitter and salty). Research has shown found this fifth taste in sauces and meat can help us to feel satisfied. The ‘improved flavour’ sensation of eating umami-rich food, such as soy sauce or shellfish, is caused by glutamate.

How else does MSG affect the body?

The glutamate naturally present in food and the glutamate derived from MSG are identical; the body treats both sources of glutamate in the same way. MSG is absorbed very quickly in the gastrointestinal tract as it does not require any enzyme activity to break it down.

It is the speed at which MSG reaches the body that forms the basis of health concerns around MSG. It’s because glutamate is what’s known as an “excitotoxin” – an amino acid that also serves as a neurotransmitter in the brain.

When brain neurons are exposed to these neurotransmitters in too high a dose, they can become very excited and fire their impulses very rapidly until they reach a state of exhaustion. Eating large amounts of foods containing MSG additives such as processed foods can cause these amino acids to reach high levels in the bloodstream – leading to overstimulation.

However, the rate of absorption can be slowed down by eating other foods as this prevents the glutamic acid being so rapidly absorbed, which can impact on levels of glutamate in the blood.

What you should know

A range of foods contain this flavour enhancer and it’s not always easy to keep track of how much you’re consuming as laws in different countries generally do not require manufacturers to declare the amount that is contained on product labelling. MSG can occur naturally in ingredients such as hydrolysed vegetable protein, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts and protein isolate, as well as in vegetable, meat and dairy sources.

Though products containing MSG should be listed on the ingredient panel, the label does not need to specify that it naturally contains MSG.

It’s a good idea to know what to look out for if you’re trying to reduce your intake of MSG-added foods. Other ways food manufacturers can state the inclusion of MSG without using the abbreviation or the wording ‘monosodium glutamate’ are: monopotassium glutamate, glutamic acid, vegetable protein extract, whey protein concentrate, hydrolyzed plant protein, sodium caseinate, calcium caseinate, textured protein. MSG may also be listed under vague terms such as seasoning or flavour enhancers.

On the other hand…

It’s important to note that it’s not all bad news for MSG. The International Glutamate Information Service says although MSG is predominately used in meals to enhance flavour, it can also help to reduce salt intake as it contains only one third of the amount of sodium found in table salt – so might make us less prone to reach for the salt shaker.

Understanding your food

Ultimately, being informed is best – as usual. A little bit of time and research on where MSG (or any additive) is likely to be included in your food goes a long way.

MSG is naturally found in protein foods that can form part of a balanced, healthy diet such as vegetables, lean meat and low fat milk. However, it’s always good to keep a watchful eye on what goes into your shopping trolley. Just because processed foods that contain MSG are appetising, it doesn’t mean eating a steady supply is a good nutritional option.

If you want to reduce your consumption of MSG, the simplest and quickest way to do so is to limit your intake of processed foods, which often contain high levels of glutamic acid. Cooking meals from fresh can be a simple but effective change, and as a bonus, the nutrients within such foods are generally much better preserved.

So don’t worry about enjoying the taste of those naughty MSG-enhanced treats every so often – just be sure to balance it out with a good intake of non-processed foods.