Glutamine is one of the amino acids which are described as ?non-essential?, but this should not in any way be taken as implying that it is unimportant. In this context the term ?non-essential? simply means that the amino acid in question can be synthesised within the body and therefore need not necessarily be obtained from food sources. Along with the other twenty or so amino acids which have been identified, glutamine is required for the formation of the thousands of proteins which are vital to the health of the body. The enzymes which govern the body's countless biochemical reactions are largely formed from protein, as are the antibodies that fight disease. Skin, hair and nails are also made of proteins, as is the collagen which binds the body's cells together and, of course, the muscles.



Considerable quantities of glutamine are required by the body for it to play its part in maintaining the health of all these structures and compounds. But glutamine also has a number of important, more specific, functions including the maintenance of normal blood sugar and energy levels, the transmission of messages between brain cells and as an anti-depressant. Glutamine is also involved in the production of essential genetic material within rapidly reproducing cells such as red blood cells, those in the immune system and those lining the intestines.

Although it is normally manufactured in the body in sufficient quantities to maintain health, levels of glutamine can become depleted following illness, injury, or even particularly intense or prolonged exercise. Ordinarily, individual amino acids are released into the body by the breaking down of dietary protein obtained from food during the process of digestion. But unfortunately glutamine in food is made inactive by cooking, so that the best dietary sources ? eggs, meat and chicken are effectively ruled out on grounds of both safety and palatability. Grains and fruits in the diet may provide a small amount of dietary glutamine, but probably not in sufficient quantities to derive much benefit.

Fortunately, however, there is some evidence that taking individual amino acids directly, in the form of dietary supplements, may be beneficial in some circumstances.

And in the case of glutamine these benefits are considerable. Some nutritionists and alternative practitioners believe that glutamine supplements may help build muscle while reducing body fat and boosting levels of growth hormone, which otherwise decline inexorably as the body ages. Not surprisingly, these possibilities have aroused great interest amongst the athletic (particularly bodybuilding) communities, and those looking for ways to slow down the ageing process.

But more important, perhaps, is the effect of glutamine on the immune system. A number of studies have shown that both intensive exercise and endurance events may reduce blood glutamine levels by up to 50% and also have a marked effect on the balance of the immune system. While the apparent link between these effects is not definitively established, it is known that intensely training athletes are more prone to infections than the general population, and research has suggested that glutamine supplementation at the level of 5mg a day may help significantly in reducing colds and other low level but debilitating infections. Put simply, it is sometimes said that glutamine can best be understood as the energy source which fuels the immune system, and that the harder the immune system is being asked to work the more glutamine it will require. Some practitioners therefore recommend as much as 20 or even 40 g a day when recovering from serious illness, wounds or surgery.

However, supplements of glutamine are more usually taken in doses of between 500 and 2,000 mg (0.5g ?2g) a day; although some athletes have been known to take as much as 3,000 mg following particularly intensive workouts as there is evidence that this may help replenish depleted supplies of glycogen, the muscles? principal energy source. Weightlifters, bodybuilders and other strength and power athletes looking for rapid gains in muscle mass may find this effect of glutamine particularly beneficial in speeding recovery between workouts and maintaining training intensity.

Single amino acid supplementation should not be continued indefinitely, however, because of the risk of creating imbalances, and glutamine supplementation, in particular, should be avoided by diabetics and those suffering from kidney problems. Moreover, it should be stressed as always that the body functions holistically, and amino acids are no different from any other supplements in that they will function best in the presence of adequate amounts of all the nutrients needed by the body.

So if taking glutamine supplements, you should make sure that you also obtain plenty of high quality protein from your diet, as well as a good supply of the full range of essential vitamins and minerals.