Just how much truth is there in the MSG hype?

With so much being discussed about acceptable levels of mono sodium glutamate (MSG) to be included in packaged foods, it is only fair to give this flavour enhancer a chance and understand its role in the food we eat. But before we do that, let us take a look at the role biochemistry plays in foods consumed by human beings. 

The human body uses a complex mechanism for converting the foods we eat into simpler compounds that provide nutrition. The proteins we eat are broken down into amino acids. Glutamic acid is one such amino acid, derived from proteins. In fact, glutamine is the most abundant amino acid present in the body. 

So what is MSG? Mono sodium glutamate (MSG) is a form of naturally occurring glutamate and is the sodium salt of free glutamic acid. Glutamate is an amino acid our body needs and it is naturally present in food. It is 100 per cent vegetarian and is obtained from carbohydrate sources via a natural fermentation process similar to that used in making cheese and yoghurt.

Free glutamates are virtually present in most natural protein foods like meat, milk, mushrooms and some vegetables like tomatoes, peas and corn.

MSG is a flavour-enhancing food additive which is used primarily in Asian cooking. It is known to enhance the natural flavours of poultry, meat, seafood, snacks and stews due to the heightened perception of the ‘umami’ taste (Japanese word for delicious). Umami is the fifth basic taste in addition to the other four traditional tastes — sweet, sour, salty and bitter. In addition to flavour-enhancing, MSG helps reduce addition of salt to food as it naturally contains sodium but in much lesser amounts than table salt. The amount of glutamate people consume via MSG-processed foods is very similar to the amount of glutamate people consume via natural products. 

It is considered safe to consume by all global and local bodies regarded as safe for general population. The human body metabolises added glutamate in the same manner as it is found digested naturally in many foods. The MSG from a tomato sauce is not differently processed in the body as the glutamate from fresh tomatoes. While MSG has a long track record of being safe, some studies have questioned its safety profile in the public domain. 
There is a broad general consensus, however, in the scientific community and amongst international regulatory bodies such as WHO that MSG when consumed in appropriate amounts is safe for general consumption. These conclusions are based on numerous biochemical, toxicological and medical studies conducted over four decades. A 1979 study found it to be safe even for pregnant mothers and unborn babies. 

MSG was evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1988. They concluded that conventional toxicity studies using dietary administration of MSG in several species did not reveal any specific toxic or carcinogenic effects. Clinical studies in humans have failed to confirm an involvement of MSG in ‘Chinese Restaurant Syndrome’ or other idiosyncratic intolerance and the JECFA allocated an ‘acceptable daily intake (ADI) not specified’, ie, no upper ADI limit is set. No additional risk to infants was indicated. It is important to note that glutamate amounts originating from our foods are still considerably lower than the amounts the body produces. 

The Food Safety Standards Packaging and Labelling Rules (India) says — “Every advertisement for and/or a package of food containing added Mono sodium Glutamate shall carry the following declaration, namely — This package of (name of the food) contains added MONO SODIUM GLUTAMATE. Not recommended for infants below 12 months.

Today, we are buying and using a variety of packaged and processed foods, because they are convenient. Food manufacturers are continuously looking for innovative ways of adding nutritional value and enhancing the health benefits of these foods. As consumers we need to learn more about food safety and quality and rely on scientific and rational evidence in making our choices.

The author is former Director of National Institute of Nutrition, Indian Council of Medical Research