All About Glutamine

by Ryan
Andrews
, July 13th, 2009.

What is glutamine?

l_glutamine-300x300Glutamine is the most abundant free amino acid in the
human body, making up about 60% of the skeletal muscle amino acid pool. (For
more on amino acids, see All About BCAAs and
All About
Protein
.)
Glutamine is a conditionally essential amino acid, which means that normally
our bodies don’t need it from our diet. Exogeneous glutamine (in other words,
glutamine we supplement or consume in food) is essential only under certain
conditions, which include stress, trauma, muscular dystrophy, and illness, which
can decrease glutamine levels by up to 50% (in severe cases). Because glutamine
is a precursor for the structural unit of DNA and RNA, rapidly dividing cells
are most likely to suffer from a shortage.
When we aren’t experiencing stress, trauma, muscular dystrophy or illness,
our body produces enough glutamine on its own to supply our needs. The major
part of endogenously produced (in other words, stuff our body makes) glutamine
comes from skeletal muscle. Vitamin B3 and B6 are necessary for the production
of glutamine from glutamic acid.

Why is glutamine so important?

Glutamine is a vital fuel source for the intestines and immune system that
helps to keep defenses up against microbes. By nourishing these cells, it
maintains the integrity of the GI tract.
Since the immune system is necessary for recovery from stress, glutamine may
help during intense bouts of training. It may play a role in:
  • Normalizing growth hormone
  • Promoting glucose uptake after workouts
  • Enhancing the hydration state of a muscle
  • Reducing acid buildup with exercise (more on acid-base
    balance
    )
Yet it doesn’t seem that exercise decreases glutamine concentrations enough
to compromise regular immune functions. This makes sense, since those who
consume adequate energy from their diet tend to have a high glutamine intake.
However, some people whose training and diet causes physical stress may benefit,
e.g. people who are eating less food than necessary to modify body composition
(in other words, dieting) or people whose training is extremely strenuous (such
as elite athletes).

What you should know about glutamine

red and green cabbage

Where to find it

Cabbage and beets contain high concentrations of glutamine. (Eastern European
grandmothers everywhere, rejoice! You have one more reason to encourage your
“too skinny” grandchildren to eat the buraczki, borscht and
holubtsi!) Other food sources include fish, beans and dairy.

Glutamine supplementation and dose

Typically, the consumption of any solo amino acid in high doses may hinder
the assimilation of other amino acids. High doses of single amino acids can also
result in bloating and diarrhea since they have osmotic properties. Yet
glutamine supplements appear to be absorbed adequately and don’t create GI
distress.
Glutamine supplementation has become routine to promote gut health in those
with GI disorders, or those with HIV/AIDS, cancer, and other severe illnesses.
Because glutamine has a rapid turnover rate, even high amounts (up to 30 grams
each day) can be given without side effects. Most people will have a normalized
plasma glutamine concentration by adding 20-25 grams over a 24 hour period.
In studies, glutamine supplement dosages have varied, including:
  • 18 to 30 grams per day, by mouth
  • 10 grams three times per day, by mouth
  • 0.6 grams per kg of body weight per day (thus a 100 kg/220 lb person would
    consume 60 g daily)
  • 14 grams of glutamine per day in combination with arginine and HMB for up to
    24 weeks

Glutamine side effects and long-term use

There is little data regarding long-term usage (more than a few weeks) of
glutamine supplements. No reported adverse effects have been attributed to
short-term supplementation at less than 30 grams per day. Still, in some studies
using high-dose intravenous administration of glutamine, patients developed
elevated liver enzymes (indicating liver stress).
Other groups at risk:
  • Those with diabetes should use caution when supplementing with
    glutamine because they tend to metabolize glutamine abnormally.
  • Those who are sensitive to MSG (monosodium glutamate) may want to
    avoid glutamine supplements, due to glutamate inter-conversion.
  • Those with epilepsy or bipolar disorder should be extremely
    cautious if considering glutamine and discuss it with their doctor first. Many
    anti-seizure medications work to block glutamate stimulation in the brain. And
    since the body metabolizes glutamine to glutamate, glutamine may interact
    negatively with anti-seizure medication.

Summary and recommendations

Will adding glutamine make a difference to your body if you are healthy?
Probably not.
Will it harm you in doses of less than 30 grams per day? Probably not.
If all of your bases are covered with nutrition, exercise and recovery, and
you have the money to spend each month on more supplements, then adding
glutamine is fine. If you are undergoing a period of food restriction, then
glutamine supplementation may improve nitrogen retention, decrease infection,
and promote recovery from illness. Other situations that may benefit from
glutamine supplementation include GI disorders, HIV/AIDS, and cancer.
For healthy individuals, the suggested reasons for taking glutamine
supplements have received little support from well-controlled studies in
healthy, well-nourished humans.
I contacted Dr. Michael Gleeson, a glutamine guru at the School of Sport and
Exercise Sciences, Loughborough University, Loughborough England. His response
was short and sweet:
Dear Ryan,
I do not see any point in supplementing glutamine for the healthy
athlete/exerciser.

Regards,
Mike

For extra credit

Glutamine is a precursor for arginine.
A supplement blend containing glutamine has been shown to lower body fat,
increase muscle mass, and increase strength when combined with 12 weeks of
resistance training.

References

Wernerman J. Clinical use of glutamine supplementation. J Nutr
2008;138:2040S-2044S.
Choi SH et al. Glutamine on the luminal microbial environment after massive
small bowel resection. J Korean Med Sci 2002;17:778-783.
Darmaun D. Role of glutamine depletion in severe illness. Diabetes Nutr Metab
2000;13:25-30.
Goodman MJ, et al. Abnormalities in the apparently normal bowel mucosa in
Crohn’s disease. Lancet 1976;7:275-278.
Bertolo RF & Burrin DG.
Comparative aspects of tissue glutamine and proline metabolism. J Nutr
2008;138:2032S-2039S.
Roth E. Nonnutritive effects of glutamine. J Nutr 2008;138:2025S-2031S.
Carvalho-Peixoto J, et al. Glutamine and carbohydrate supplements reduce
ammonemia increase during endurance field exercise. Appl Physiol Nutr Metab
2007;32:1186-1190.
Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West
Publishing Company, New York, 1995.
Institute of Medicine. The Role of Protein and Amino Acids in Sustaining and
Enhancing Performance. National Academy Press: Washington DC, 1999.
Mack G. Glutamine synthetase isoenzymes, oligomers and subunits from hairy
roots of Beta Vulgaris L. var. lutea. Planta 1998;205:113-20.
DiPasquale M. Amino Acids and Proteins for the Athlete: The Anabolic Edge.
CRC Press: Boca Raton, FL, 1997.
Lohaus G. & Moellers C. Phloem transport of amino acids in two Brassica
napus L. genotypes and one B. carinata genotype in relation to their seed
protein content. Planta 2000;211:833-840.
Ziegler TR, et al. Glutamine and the gastrointestinal tract. Curr Opin Clin
Nutr Metab Care 2000;3:355-362.
Ochs G. Complexity and expression of the
glutamine synthetase multigene family in the amphidiploid crop Brassica napus.
Plant Mol Biol 1999;39:395-405.
Labow BI & Souba WW. Glutamine. World J Surg 2000;24:1503-1513.
Gleeson M. Dosing and efficacy of glutamine supplementation in human exercise
and sport training. J Nutr 2008;138:2045S-2049S.
Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima
Health, Rocklin, CA, 2000.
Mahan K, Escott-Stump S. Krause’s Food, Nutrition,
and Diet Therapy. WB Saunders Company; Philadelphia, 2004.
Iwashita S, et al. Impact of glutamine supplementation on glucose homeostasis
during and after exercise. J Appl Physiol 2005;99:1858-1865.
Scarpignato C, Pelosini I. Management of irritable bowel syndrome: novel
approaches to the pharmacology of gut motility. Can J Gastroenterol 1999;13 Supp
A:50A-65A.
Medina MA. Glutamine and cancer. J Nutr 2001;131:2539S-2542S.
Mithieux G. New data and concepts on glutamine and glucose metabolism in the
gut. Curr Opin Clin Nutr Metab Care 2001;4:267-271.
Noyer CM, et al. A double-blind placebo-controlled pilot study of glutamine
therapy for abnormal intestintal permeability in patients with AIDS. Am J
Gastroenterol 1998;93:972–975.
Shabert JK, Wilmore DW. Glutamine deficiency as a cause of human
immunodeficiency virus wasting. Med Hypotheses 1996;46:252–256.
Reeds PJ, Burrin DG. Glutamine and the bowel. J Nutr
2001;131:2505S-2508S.
Melis GC, et al. Glutamine: recent developments in research on the clinical
significance of glutamine. Curr Opin Clin Nutr Metab Care 2004;7:59-70.
Vardimon L. Neuroprotection by glutamine synthetase. Isr Med Assoc J 2000;2
Supp:46-51.
Kraemer WJ, et al. Effects of amino acids supplement on physiological
adaptations to resistance training. Med Sci Sports Exerc 2009 Apr 3 [Epub ahead
of print]
Hankard R, et al. Is glutamine a ‘conditionally essential; amino acid in
Duchenne muscular dystrophy? Clin Nutr 1999;18:365-369.
Stumvoll M, et al. Glutamine and alanine metabolism in NIDDM. Diabetes
1996;45:863-868.
Ligthart-Melis GC, et al. Glutamine is an important precursor for de novo
synthesis of arginine in humans. Am J Clin Nutr 2008;87:1282-1289.
<!–
–>

About dkpilates

Pilates Instructor, Yoga Instructor, Personnel trainer and Group Fitness Instructor. Don teaches Contemporary and the Authentic forms of Pilates, in the later 90's, Don began his study of Yoga. His study of Yoga includes the Hatha, Iyengar, Bikram, and Astanga disciplines. His other areas of interest in fitness include Martial Arts, Spin, Boot Camp Training, and Weight Training. Don has extensive training and certifications from AFFA, IDEA, MadDog, B-Fit and Polestar. Don Continues his of Pilates education with Michelle Larson in Santa Fe New Mexico. His personal philosophy related to fitness is to aid students in a personalized balance of strength, stamina and flexibility. He is dedicated to design a program specifically for his students independent of the season of their life to create functional movement and help them reach their fitness goals.
This entry was posted in LIFE. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s