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The most plentiful amino acid

Non-essential amino acid glutamate appears to be on the cross-roads of all key metabolic process; it is synthetized in our organs and present in our food. We do not really know what makes glutamate so special. But, since it is a part of every single protein, nature has selected glutamate to become the signal molecule for protein digestion (www.ncbi.nlm.nih.gov/pubmed/23463402).

Due to importance of protein for both growth and maintenance, mammals have developed ability to sense and to like glutamate taste (umami) and also to recognize it after the digestion – in the intestines (www.ncbi.nlm.nih.gov/pubmed/26247011). Already our first food experience, mother milk, is very rich in glutamate (and infants like it, http://www.ncbi.nlm.nih.gov/pubmed/23660363 ). This is most linked to glutamate’s protective role against infections of the intestinal tract. Glutamate is so precious for all higher mammals that we have perfected compartmentalization of its uses. This means that glutamate from one bodily “pool” (for example brain) is not affected by glutamate from other “pools” (periphery) and vice versa.

Considering all the above-written; it is not surprising that as soon as production technologies were in place during early 20th century, inventive people came to an idea to purify glutamate, make it stable, dry, easy-to-use … and sell it as a taste substance. It was much easier to use purified glutamate to enhance flavor than to use various glutamate-rich savory sauces, cheeses, yeast extracts or vegetables. Of course, a similar point can be made when comparing the use of salt (sodium chloride) and that of anchovies. Sodium chloride is cheaper, easier to use and much more stable. The key difference is that we call “salt” salt and not “sodium chloride”, and also that pure salt has 1,000s years of history, while glutamate has only 100.

Since the most stable form of glutamate turned to be the sodium form (MSG); it is the glutamate most of us know. It had been used widely for some 60 years until someone speculated in late 1969 that MSG might be the reason for headache-like feelings after eating unknown foods. Because scientific knowledge on amino acids was practically zero and because late 1960 was the first time when people started to question modern food industry, the accusations against MSG found a fertile ground.

Between 1970 and 2015, MSG has been the most widely studied food ingredient in the human history. All the toxicological science which was thrown at the substance only reiterated its safety. Even better, sometime around year 2000, scientists documented that there were glutamate receptors on our tongues, which proved beyond doubt that MSG had a long evolutionary role in food digestion. Other projects have illustrated benefits of MSG, such as stimulation of intestinal contraction (www.ncbi.nlm.nih.gov/pubmed/10736365) or salivation – both very important for proper digestion. Scientifically speaking, there is very little to add to the impressive story of food-added glutamates. It took 45 years; but MSG has been shown to be not only a safe but also a beneficial food substance.

Finally, glutamate is not alone among those amino acids that can be used as flavors. Since free amino acids have taste properties, fourteen of them have been recognized as flavor substances in the USA and elsewhere. Luckily for them; none of those amino acids have reached notoriety of that single form of glutamate known as MSG.