Glutamine is an amino acid and is essential not just for normal cells to function but for tumour cells too. In fact there is plenty of evidence to suggest that along with glucose, glutamine is one of the preferred fuels for tumour growth and progression. So why suggest taking it? Because, as Steve surmised based on the data that was available to him then, it also has several protective effects and may therefore be of more benefit to the body than to the tumours.
Glutamine has been investigated and used clinically to fight many of the side effects from cancer treatments. And it's still being used this way, even though there is this fear that it's directly feeding tumours. A recent paper in the journal BMC Cancer reports back on a trial in advanced lung cancer patients who were given oral glutamine supplementation.
The result? Here's what the conclusion has to say:
In our study, supplementation with Gln during C-CRT had no detectable negative impact on tumor control and survival outcomes in patients with Stage IIIB NSCLC. Furthermore, Gln appeared to have a beneficial effect with respect to prevention of weight loss and unplanned treatment delays, and reduced the severity and incidence of acute- and late-RIE (radiation induced esophagitis.
There was a small improvement in overall survival reported, but it was a small trial and there's no way to know whether that result was a fluke or something more concrete. In any case, the trial shows that high-dose glutamine in these patients certainly did not make matters worse by feeding the tumours, and may indeed even helped by reducing side effects and the need to stop treatment because of it.
The full paper can be found here: http://www.biomedcentral.com/1471-2407/12/502
Please note, that this is not a randomised controlled trial, so there's a potential bias in the results, but it is at least suggestion and evidence that oral glutamine may not be as bad as a simple reading might suggest.
