This Australian group, supported by the Australian Sports Medicine Foundation, set out to compare the glutamine status of CFS subjects to matched controls and to test the effect of L-glutamine supplements on CFS symptoms. This was a randomized, double blind, placebo-controlled trial of 26 weeks, although the study group was small, just 16 patients.
The study found that while plasma concentrations of glutamine (and to a lesser degree, muscle concentrations) were lower in CFS subjects than in controls, raising those concentrations had no effect on CFS symptoms. (Six patients did show improvement, but four were in the placebo group.) The researchers said their data suggested that low levels of glutamine in plasma might not be directly related to the symptoms.
They said further studies could investigate whether glutamine levels are a secondary observation, resulting from some central dysfunction in CFS, or whether low plasma glutamine might indicate susceptibility to CFS.
Rowbottom, D., Keast, D., Pervan, Z., et. al. (1998). The role of glutamine in the aetiology of the chronic fatigue syndrome: A prospective study. Journal of Chronic Fatigue Syndrome, 4:2, 3–22.