Non-Essential Amino Acids: The Eleven Your Body Makes, and MSG

Non-essential amino acids are the ones your body can build for itself, so no single one of them has to arrive in food. There are eleven: alanine, arginine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine and tyrosine. They are not optional in the body, only in the diet, and in practice they come packaged with every protein food. ICMR-NIN sets no separate requirement for the group; the adult protein allowance of 0.83 g per kg a day covers it. This overview sits in the proteins and amino acids section and points to the single entries.

What are non-essential amino acids?

They are amino acids the body can synthesise in adequate amounts, and therefore need not be supplied by the diet. ICMR-NIN's Dietary Guidelines for Indians, 2024, puts the count plainly: the human body requires only 20 amino acids, and nine of them cannot be synthesised and are termed essential. The remaining eleven are named in a 2015 review in Experimental Biology and Medicine, which adds taurine to its list although taurine is not one of the 20 used to build protein. The nine are covered in the entry on essential amino acids.

The label describes the diet, not the body. Glutamate, cysteine and glycine together form glutathione; arginine and glycine go into creatine; and that review lists roles for the group in digestion, immunity and acid and base balance. An older paper in the Journal of Nutrition makes the point sharply: from a functional perspective all amino acids are essential.

What does conditionally essential mean?

It means the body can make the amino acid, but not always enough of it. The Journal of Nutrition paper defines the class as amino acids whose synthesis can be carried out by mammals but can be limited by a variety of factors, among them the dietary supply of the appropriate precursors and the maturity and health of the individual. Two examples follow from precursors: cysteine is made from methionine and tyrosine from phenylalanine, so a diet short of the parent leaves the child short.

The other examples follow from age and illness. The FAO's 2013 report on protein quality notes that clinical situations such as sepsis impair the normal rate of arginine synthesis. The 2015 review reports a study in which preterm infants could not make enough glutamine, and argues that the body's own output of glycine and proline may lag behind demand. Each has its own entry: arginine, glutamine, the glycine entry, cysteine and tyrosine. Feeding in such conditions is hospital work, not self-care.

How much do you need, and does India set a figure?

India sets no figure for any of the eleven as a group or singly, and neither does the FAO. ICMR-NIN's 2020 recommendations, as printed in its 2024 guidelines, list the nine essential amino acids, with cysteine and tyrosine counted inside two pairs: 22 mg of methionine plus cysteine and 38 mg of phenylalanine plus tyrosine per gram of protein. What the rest need is covered by total protein: an average requirement of 0.66 g per kg a day and an allowance of 0.83 g, which is 54 g for a person weighing 65 kg.

Arithmetic shows how much room that leaves. The FAO's adult scoring pattern adds up to 277 mg of specified amino acids in each gram of protein. The other 723 mg, about 72 per cent, is not specified at all; the report says only that the body's demand is for both the indispensable amino acids and non-essential nitrogen. That nitrogen arrives as the amino acids on this page. NNWA's protein calculator gives your protein figure, and nothing further needs counting.

Non-essential amino acids in Indian foods

Every protein food supplies them, usually as more than half of its protein. The Indian Food Composition Tables 2017 print eight of the group, with cystine in a ninth column, as grams per 100 g of protein. Glutamic acid is the largest single figure in most foods: 29.61 in whole-wheat atta, 21.50 in toor dal, 18.92 in raw milled rice and 17.88 in cow's milk. Added up, the nine columns come to about 66 g per 100 g of protein in atta, 60 g in rice and 56 g in toor dal and milk.

In household terms, the atta for one meal's rotis, about 100 g, holds roughly 3.1 g of glutamic acid bound in its protein, and a katori of toor dal made from 30 g of dal about 1.4 g. Groundnut and chana dal lead for arginine; wheat and paneer for proline; goat meat and groundnut, at about 5.6 g per 100 g of protein, for glycine. For how much protein each food carries, see NNWA's table of protein in Indian foods and the page for paneer in the food tables.

Is MSG safe, and what does FSSAI require on the label?

The international expert bodies regard MSG as safe at the levels used in food, and Indian law permits it with a compulsory warning. Monosodium glutamate is the sodium salt of glutamic acid, used as a flavour enhancer under the number INS 621. JECFA, the joint FAO and WHO expert committee on food additives, gave glutamic acid and its salts a group ADI of not specified, a category it describes as covering substances of low toxicity.

The European Food Safety Authority looked again in 2017 and set a group acceptable daily intake of 30 mg per kg of body weight a day, expressed as glutamic acid, derived from an animal study with an uncertainty factor of 100. In India, the Food Safety and Standards (Labelling and Display) Regulations, 2020, require a pack with added MSG to declare it and to state that it is not recommended for infants below 12 months and pregnant women. ICMR-NIN's guidelines add a different caution: MSG is one more source of sodium in processed food.

Can you run short of an amino acid your body makes?

A healthy adult eating enough protein does not, and this entry found no Indian survey figure for any of these amino acids. The body builds the eleven from other amino acids and from carbohydrate, provided it has enough total nitrogen and enough energy. ICMR-NIN's guidelines make the energy point directly: without adequate carbohydrate and fat, dietary protein is not used efficiently for its own functions. A very low protein intake, or a crash diet, is the realistic route to a shortfall.

The exceptions are the conditional cases already described: preterm babies, and adults with serious illness, injury or infection, where demand rises or synthesis falls. Those are managed in hospital with feeds a doctor prescribes. In everyday Indian diets the quality problem lies elsewhere, with lysine in cereal-heavy plates, which is explained in the entry on lysine and the cereal and pulse ratio and in the one on protein quality.

What does the evidence say?

First, the dividing line is less firm than the two lists suggest. The Journal of Nutrition paper compares three ways of sorting amino acids and finds they disagree: by strict metabolism only lysine, threonine and tryptophan are indispensable and only glutamate and serine fully dispensable. It also notes that growth responses to a lack of dispensable amino acids can be found in the literature. This is expert reasoning from metabolic studies, not trial evidence.

Second, the 2015 review argues that these amino acids may be needed in the diet for the best growth and health. Much of its supporting work is in animals, and the authors themselves present it as an emerging concept. It is not evidence that a healthy adult benefits from buying single amino acids.

Third, on MSG the human challenge studies are the strongest evidence available. The review that reported the 130-person trial concluded that surveys and clinical challenges in the general population reveal no evidence of untoward effects. EFSA, for its part, found the human data unsuitable for setting a limit because they lacked dose and response information, and noted that some groups' estimated exposure exceeded its new figure.

A worked example: glutamate in a day's meals beside the limit for added MSG

This is an illustrative case, not a real person. Take a 30-year-old vegetarian bank employee in Kolkata who weighs 60 kg and worries about the MSG in a packet of instant noodles. Her ordinary day includes rotis from 150 g of atta, 100 g of rice, 60 g of toor dal and 300 g of milk and curd. Using IFCT 2017, those four foods supply 46.6 g of protein, and about 10.7 g of it, 23 per cent, is glutamic acid bound in protein.

EFSA's limit for glutamates added to food is 30 mg per kg a day, which for 60 kg is 1,800 mg, or 1.8 g. Her meals therefore carry about six times that amount as a normal part of protein. The two figures are not the same thing: the limit applies to free glutamate added as an additive, and JECFA's earlier limit was explicitly additional to glutamate from ordinary food. The sodium and the processed food around the MSG are the better reasons to limit the noodles.

Common mistakes about non-essential amino acids

The first mistake is reading non-essential as unimportant. The second is the opposite: assuming that because glutamine, arginine or glycine do useful things in the body, more of them in a tub must do more. A day of ordinary Indian meals already supplies grams of each. A third is to judge a protein powder by a long amino acid list; the figure that separates good protein from poor is its essential amino acid pattern, not the eleven it shares with every dal.

Supplements: safety, and when to see a doctor

FSSAI's health supplements regulations permit several of the group as ingredients: Schedule II lists L-glutamine, glycine, L-proline, L-serine, L-alanine, L-arginine, L-tyrosine and L-cysteine among others. Permitted is not the same as needed. The 2024 dietary guidelines from ICMR-NIN say that protein supplement powders in high amounts are not advisable and that no single nutrient should be overdone in supplement form. This entry gives no dose for any amino acid; related products are covered under collagen and creatine.

See a doctor for weight or muscle loss you cannot explain, for wounds that are slow to heal, or if a baby or child is not feeding or growing as expected. If you believe a food with MSG makes you unwell, tell your doctor what you ate and when instead of guessing. Never stop or alter a prescribed medicine on the strength of a supplement.

Learning protein and amino acids at NNWA

How proteins are built, what makes one better than another and how to read a supplement label are taught at NNWA, a private skill academy in Kolkata that holds its classes online in English and Hindi. The Diploma in Nutrition and the Sports Nutrition course are two of the places this is covered, and both train people to coach healthy clients and send medical cases to a doctor. None of them is a degree or a dietitian qualification.