Health Watch: Glutamine is more than just an amino acid

[Guest guest]

Health Watch: Glutamine is more than just an amino acid

HONG KONG, Oct. 16

United Press International, Asia - Hong Kong,China

DR. PRADNYA KULKARNI

http://www.upiasiaonline.com/society_culture/2007/10/16/health_watch_

glutamine_is_more_than_just_an_amino_acid/

Column: Doc Talk

Recent studies have shown a strong correlation between levels of

a " non-essential " amino acid called " glutamine " in the human body

and the survival of patients in intensive care units. Glutamine is

one of the 20 amino acids present in the human body and is labeled

as non-essential because it can be easily synthesized in our body.

Dr. Griffiths of the University of Liverpool in Britain

was the first to publish trials on the intravenous use of glutamine

in ICU patients. He studied a group of critically ill patients fed

by parentral nutrition -- a process where nutritional formulas

containing salts, glucose, amino acids, lipids, and vitamins are

directly injected into the patient's blood through tubes, bypassing

the usual process of eating. Patients were divided into two groups --

one received glutamine in their nutrition while the other did not.

Patients were monitored for a period of 6 months even after

discharge. Griffiths noted fewer deaths in the group that had

received glutamine versus those who had not. None of the glutamine

recipients died from multiple organ failure and few suffered fungal

infections. The findings surprised ICU specialists and intensivists.

According to Griffiths, an ICU admission is a state of great

stress, which has serious consequences on the patient's health. His

study proved that including parenteral glutamine in the nutritional

management had positive outcomes on the recovery of such patients.

Dr. Christiane Goeters from the department of Anaesthiology and

Intensive Care at the University of Munster in Germany conducted a

similar study on a larger group of ICU patients and re-asserted the

importance of glutamine and its role in the reduction of deaths in

critically ill patients.

Glutamine is manufactured abundantly in the human body where

muscles tend to be its most important source. However, glutamine

levels diminish following major surgeries, trauma, or sepsis.

Studies have shown that there is a high turnover of blood glutamine

in ICU patients and the demand for this amino acid increases during

stress.

Historically, glutamine was not considered important in

parenteral nutrition, as its behavior was not extensively studied.

In addition, pharmaceutical problems in making a glutamine solution,

as it neither soluble in water nor stable in a solution, made

manufacturing it for intravenous use difficult.

In order to fight infections that ICU patients generally

develop, like pneumonias and organ failures or those caused by

severe burns and accident injuries, the body needs a healthy army of

fighter immune cells, comprising white blood cells called

lymphocytes, monocytes, and neutrophils. Researchers believe that

glutamine is a major fuel for these cells. Studies by Dr. Rudolf

Oehler from Surgical Research Laboratories in Vienna and Griffiths

have proved that during stress, like an infection, glutamine is

necessary for the optimal response of the immune cells.

Dr. Wischmeyer from the University of Colorado Health

Sciences Center in Denver has suggested that glutamine helps immune

cells manufacture certain protective proteins, called heat shock

proteins. Armed with these HSP's, lymphocytes are able to protect

themselves from destructive chemicals produced during life

threatening infections.

Burn patients are most susceptible to infections as they lack a

very important protective barrier, the skin. Wischmeyer found that

adding glutamine in their therapy reduced infections, making

recovery faster. Retrospective studies have also shown that

glutamine supplements reduce infections and deaths in surgical

patients besides those in ICU's.

Severely ill patients also suffer from decreased responses to

insulin. The resulting high blood sugar or hyperglycemia often worry

physicians, as it is an additional risk for bacterial and fungal

infections and an important cause of death in ICU patients. Besides,

administering increased levels of insulin has its own risks. Studies

by Dr. Soh Iwashita from Iowa State University and Dr. M. J. Borel

from the Department of Surgery in Nashville showed that parenteral

glutamine supplements increased responsiveness to insulin and

therefore reduced its need. As a result, fewer infective

complications and deaths occurred.

ICU patients also suffer from multiple organ failure where

several toxic chemicals called free radicals are produced. These

accentuate damage by promoting the release of more toxic substances.

The body usually reacts to such situations by producing anti-

oxidants, which are scavengers of free radicals. Glutathione is one

such major anti-oxidant and plays a vital role in maintaining the

levels of glutathione during stress. This was evident in a study on

surgical patients, carried out by Dr. Jan Werneman at the Karolinska

Institute in Sweden. Glutamine thus indirectly protects our body

from oxidative damage.

Research says that the effects of glutamine are best when given

in large doses, evident in patients who recovered faster than those

who received lesser doses. In addition, those who received it early

in their treatment and for longer periods fared better than those

who did not. This proves that the body at war for longer periods

needs generous doses of glutamine.

Despite understanding the role of glutamine in immune function,

cell protection, DNA synthesis, and other complex metabolic

processes, scientists do not yet know, how precisely glutamine works

and the mechanism of its action is still a mystery.

Fortunately, this amino acid has no side effects. Dr. Ravinder

Reddy, a gastro-intestinal surgeon from India, noted a very amusing

side effect when his ICU patients on ventilators demanded food -- a

behavior not associated with ICU patients due to their drastically

reduced appetite. Therefore, hunger seems to be one favorable side

effect of this supplement.

However, glutamine taken through the mouth is not as effective

in ICU patients as it has been when given intravenously. The reason

is physiological as intestinal cells use most of it to manufacture

other amino acids and for producing energy. In addition, glutamine

is flushed as a natural process by the liver. Hence, for best

results, glutamine is injected parenterally. However, studies are

under way to manufacture an equally effective glutamine product that

can be taken orally by ICU patients who can eat.

As muscles produce glutamine, it is easy to understand why they

are such an important immune organ of our body. It also explains why

elderly persons with reduced muscle mass are more prone to

infections.

Glutamine supplementation is an additional expense to patients.

However, benefits in terms of improved survival, fewer

complications, fewer antibiotics, and reduced hospital stays are

manifold compared to the price. Mauren Macburney, Director of

Nutrition Support Service at the Brigham and Women's Hospital in

Boston did a cost evaluation study on bone marrow transplant

patients. Of 43 patients, 22 received glutamine supplements at an

extra cost of about US$1300 per patient. However, each patient saved

almost US$21,000 in hospital stays, medication, laboratory, and

radiology expenses.

Though technical difficulties of producing a glutamine solution

were resolved two decades ago, its usage as an indispensible amino

acid supplement in critically ill patients has been accepted only

recently. While its levels are high in the healthy body, they fall

markedly during stress. Correcting this deficiency seems to be a

powerful tool in reducing ICU related morbidities and mortalities.

--

(Dr. Pradnya Kulkarni is a clinical pathologist. She worked as a

consultant pathologist in a private laboratory in Pune before moving

to Hong Kong with her husband and young daughter. She is also a

freelance writer, focusing on medical issues of public concern.