Giving supplements of the amino acid glutamine in intravenous fluids was
linked to a nearly 30% increase in the risk of death, according to the
study. The researchers also found that replacing antioxidants didn't appear to
lower the risk of death or organ failure.
"When you get sick, your body has [internal] mechanisms to help you get
better. Levels of glutamine and antioxidants get depleted, and we thought giving
them back would be beneficial. So, we picked the sickest patients - critically
ill patients with multi-organ failure - and gave them back high doses,"
explained study author Dr Daren Heyland, a professor of medicine at Queens
University in Kingston, Ontario.
"We were totally surprised to find that glutamine was harmful. There was no
prior indication in the literature that it could be harmful. Antioxidants were
neutral. They weren't positive or negative. It's likely that we gave too little
antioxidants and [didn't give them quickly enough]," Heyland said.
As to why glutamine was linked to an increased risk of death, Heyland said
the researchers aren't sure how that happened. "Perhaps the changes that occur
because of sickness are adaptive rather than maladaptive," he said. The author of an accompanying editorial, Dr Greet Van den Berghe, head of
intensive care medicine at University Hospitals Leuven, in Belgium, agreed that
low glutamine levels may be an adaptive response.
"If patients show low glutamine levels acutely in response to severe illness,
it certainly looks like one should not correct this with the dose used in this
study," Van den Berghe said.
But, she added that more research should be done because the average
glutamine levels weren't especially low in this study, and she suggested that
the dose of replacement glutamine given might have been too high, or it might
have been given too early in the course of the illness.
How the study was done
Overall, she said, this study shows that glutamine may have the potential to
cause harm. "I think this study, given its power and quality and showing a
substantial rise in the risk of death with the treatment, strongly advises
against infusing glutamine in severely ill patients with multiple organ failure
in the ICU. The outcome of this study forms a solid basis for changing clinical
practice guidelines," she said.
Heyland's study included 1 223 critically ill patients treated in 40
intensive care units in Canada, the United States and Europe. All of the
patients had multi-organ failure and were on mechanical ventilation to
The patients were randomly assigned to receive glutamine, antioxidants, both
or a placebo treatment within 24 hours of admission to the intensive care
The results showed a "trend" in the association between receiving glutamine
and a higher death rate. 32% of those who received glutamine died
within 28 days, compared with 27% of those who weren't given glutamine. The risk
of dying if given glutamine was 28% higher than for patients who weren't given
In a stronger finding deemed statistically significant, in-hospital deaths
and deaths within six months were also higher for those given glutamine,
according to the study.
Heyland said it's important to note that this study's finding only apply to
the critically ill patients with multi-organ failure. Glutamine is often used
beneficially in patients who aren't so sick, he said.
"Overall, there was no suggestion that glutamine supplementation was harmful
until this report," said Dr Rafael Barrera, director of the surgical intensive
care unit at Long Island Jewish Medical Center in New Hyde Park, NY.
"It now appears that the low glutamine levels are an adaptive response to
inflammation and probably a protective pathway to down-regulate the stressed
Barrera said glutamine supplementation hasn't been widely adopted in the
United States and he expects that the results of the latest study will cause a
further decrease in the use of glutamine in the care of critically ill
Learn more about how antioxidants affect general health at the US
National Center for Complementary and Alternative Medicine.
(Copyright © 2013 HealthDay. All rights