Have you been training super-hard, with all-out aerobic exercise, in addition to push-to-the-max weight training? If so, a crucial amino acid called glutamine could be de-pleted from your body. The most abundant amino acid in your body, glutamine is stored mostly in your muscles, although rather significant amounts are found in your brain, lungs, blood, and liver. This important amino acid serves as a building block for proteins, nucleotides (structural units of RNA and DNA), and other amino acids and is the principle fuel source for cells that make up your immune system. Glutamine is also one of the amino acids found in our Ultimate Amino Formula™.Under certain conditions – including injury and intense exercise – the body’s tissues demand more glutamine than the normal amount supplied by diet (which is five to 10 grams a day) and more than can be synthe-sized normally by your body. 1During intense exercise, for instance, your muscles release glutamine into the blood-stream . This can deplete muscle glutamine reserves by as much as 34 percent. Such a shortfall can be problematic, since a defi-ciency of glutamine promotes the breakdown and wasting of muscle tissue. But if ample glutamine is available, muscle loss can be prevented.2Glutamine is the amino of the moment; that is, it has been in the nutritional spotlight because of its amazing versatility. There was a time when glutamine was thought to be a non-essential amino acid, but now it has been re-christened “conditionally essential.”
If you are highly active, glutamine should be a part of your supplement program, for reasons described below.Glutamine is an immunonutrient.Glutamine is the favored fuel of your im-mune cells. This means you need it when you’re ill, stressed, or recovering from surgery. During such times, the demand for glutamine exceeds its production and the body’s nitrogen stores become rapidly de-pleted — a sign that muscle protein is being broken down. This is a problem since glutamine is required for healing internal tissues and manufacturing muscle protein. Patients hospitalized for surgery, trauma, or infec-tion often receive supplemental glutamine in their feeding solutions.Researchers have also discovered that many athletes are deficient in glutamine – a shortage that makes them more vulnerable to infections.
One group of investigators mea-sured plasma levels of glutamine in runners following their participation in a marathon. For about an hour after the event, glutamine levels declined, but slowly returned to nor-mal within about 16 hours of the race. But during this period, the runners’ lymphocyte (white blood cell) count declined. Interest-ingly, lymphocytes rely on glutamine for growth.3 In a separate study by the same group of researchers, athletes supplemented with 5 grams of glutamine right after exercise and again two hours later. Only 19 percent of the glutamine-supplemented athletes reported infections during the next week, while 51 percent of those who took a placebo got a cold or other infection.4Studies like this one have led researchers to believe that the increased incidence of colds, infections and other illnesses among athletes after intense exercise sessions may have something to do with the glutamine/lymphocyte connection . Thus, supplement-ing with glutamine may fend off infections that can sideline your training .5Glutamine stimulates the synthesis of muscle glycogen.
Glutamine is technically described as a “glucogenic,” meaning that it assists your body in manufacturing glycogen, the chief muscle fuel. In a study involving subjects who cycled for 90 minutes, intravenous glutamine, administered during a two-hour period following exercise, doubled the concentration of glycogen in the muscles. It’s not clear exactly how glutamine works in this regard, though . Scientists speculate either that glutamine itself can be converted into muscle glycogen or that it may inhibit the breakdown of glycogen.6Glutamine may enhance muscle growth.Also, supplemental glutamine has been shown to elevate growth hormone (GH) lev-els, theoretically influencing muscle growth. Physiologically, GH is the most important hormone in the body for exercisers and bodybuilders because it acts as a powerful stimulus for muscle growth and fat loss. Growth hormone is a substance that makes cells multiply faster. Among other func-tions, growth hormone helps mobilize fat from storage and makes more fat available for energy.
It also promotes the transport of certain essential amino acids inside muscle cells to stimulate muscle growth. Many of the effects of exercise in increasing muscle mass and decreasing body fat are mediated by growth hormone. In a study at Louisiana State University College of Medicine in Shreveport, research-ers found that oral supplementation with glutamine dramatically elevated growth hormone levels. Nine healthy volunteers (ages 32 to 64) were given 2 grams of glu-tamine over a 20-minute period, 45 minutes following breakfast. Blood samples taken every half hour over 90 minutes revealed a 430 percent hike in growth hormone levels. Theoretically, supplementing with glutamine may help you build and maintain muscle tissue, particularly if you exercise regularly. The research into the glutamine/growth hormone connection is preliminary, but promising nonetheless.7Glutamine may aid in fat loss.Some research hints that supplementing with glutamine can curb the desire for sug-ary foods — an excess of which leads to fat gain . For these reasons, glutamine may turn out to be an important amino acids dieters and exercisers who need to curb their desire for fat-forming sweets.
Between 200 mg and one gram of glutamine can be taken with water 30 minutes before meals to lessen the desire for sugary foods.8 Supplementing with glutamine.Clearly, glutamine has numerous benefits for any athlete who wants to maximize performance, muscle repair, and immunity. Generally, a protein-rich training diet such as that recommended by the Parrillo Nutrition Program™ should prevent your glutamine levels from dipping too low. However, supplemental glutamine provides extra insur-ance, plus a windfall of other benefits. What’s more, if you’re the victim of frequent colds or infections, consider supplementing with this amino acid . Each capsule in our Ultimate Amino Formula™ contains 103 milligrams of glu-tamine. We recommend that you take two or more capsules of this supplement with each meal . That should supply a gram or more daily – which is appropriate for athletes and active individuals. We also add extra glutamine to our Hi-Protein™ powder and Optimized Whey™ protein powders. Both heat and acid destroy glutamine, so you should not take it with hot or acidic foods, such as vinegar.Glutamine supplementation is well toler-ated. Glutamine safety studies have been conducted using healthy volunteers who took doses of 0.75 gram per 2.2 (1 kilogram) of body weight. No side effects occurred at those doses .People with liver or kidney disease should not supplement with glutamine, however, because it can aggravate these conditions and interfere with their treatment .
1 .Miller, A .L . 1999 . Therapeutic con-siderations of l-glutamine: a review of the literature. Alternative Medicine Review 4: 239-248; Antonio, J, et al.1999. Glutamine: a potentially useful supplement for athletes. Canadian Journal of Applied Physiology 24: 1-14 .
2. Walsh, NP, et al. 1998. Glutamine, ex-ercise and immune function. Sports Medicine 26: 177-191 .
3 . Tuttle, D . 1997 . Glutamine: athletic benefits times three. Let’s Live, September, 71-73 .
4 . Tuttle, D . 1997 . Glutamine: athletic benefits times three. Let’s Live, September, 71-73 .
5. Castell, LM. 1996. Does glutamine have a role in reducing infections in athletes?” European Journal of Applied Physiology 73: 488-490 .
6. Varnier, M, et al. 1995. Stimulatory ef-fect of glutamine on glycogen accumulation in human skeletal muscle. American Journal of Physiology 269: E309-E315.
7. Welbourne, T. 1995. Increased plasma bicarbonate and growth hormone after an oral glutamine load. American Journal of Clinical Nutrition 61: 1058-1061.
8. Greenwood-Robinson, M. 1998. Natural Weight Loss Miracles. New York: Perigee Books.9 . Editor . 1994 . Glutamine: the essential non-essential amino acid. Executive Health’s Good Health Report, July, 1-2.