Seeking the truth behind MSG hype

With so much being discussed about acceptable levels of mono-sodium glutamate (MSG) to be included in packaged food, 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 food consumed by human beings.

The human body uses a complex mechanism for converting the food we eat into simpler compounds that provide nutrition. The proteins 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? Monosodium 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 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 yogurt. 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 for delicious). Umami is the fifth basic taste in addition to the other four traditional tastes – sweet, sour, salty and bitter.

Also, 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/ pro-cessed foods is very similar to the amount of glutamate people consume via natural products.

It is considered safe for consumption of general population by all global and local bodies. The human body metabolises added glutamate in the same manner as it digests glutamate found naturally in many foods. The MSG from tomato sauce is not differently processed in the body as against 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 scien-tific community and amongst international regulatory bodies such as the WHO, that MSG when consumed in appropriate amounts is safe.

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, while the JECFA has allocated an ‘acceptable daily intake (ADI) not specified’ i.e. no upper ADI limit has been set.

Regulations about MSG

‘E’ numbers are codes for food additives (once the product has been approved as safe) which are approved by the European Food Safety Authority (EFSA). They are commonly found on food labels. MSG has been tested by the EFSA and given the E number 621 for it use. 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.”

Interestingly, although MSG is perceived to contain high levels of sodium, in fact, it contains less than third the amount of sodium we consume as common salt. When MSG is added to a preparation, the dish requires less common salt than normal, reducing the total sodium intake.

Today, we are buying and using a variety of packaged and processed foods, because they are convenient. Food manufacturers are continuously looking at 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 while making our choices.

(The writer is former Director, National Institute of Nutrition, Indian Council of Medical Research)