Oh goody, someone has already looked at protein versus glutamine in endurance athletes:
Effect of glutamine and protein supplementation on exercise-induced decreases in salivary IgA.
Krzywkowski K, Petersen EW, Ostrowski K, Link-Amster H, Boza J, Halkjaer-Kristensen J, Pedersen BK.
The Copenhagen Muscle Research Centre, Rigshospitalet, 2200 Copenhagen, Denmark.
Postexercise immune impairment has been linked to exercise-induced decrease in plasma glutamine concentration. This study examined
the possibility of abolishing the exercise-induced decrease in salivary IgA through glutamine supplementation during and after intense
exercise. Eleven athletes performed cycle ergometer exercise for 2 h at 75% of maximal oxygen uptake on 3 separate days. Glutamine
(a total of 17.5 g), protein (a total of 68.5 g/6.2 g protein-bound glutamine), and placebo supplements were given during and up to 2 h
after exercise. Unstimulated, timed saliva samples were obtained before exercise and 20 min, 140 min, 4 h, and 22 h postexercise. The
exercise protocol induced a decrease in salivary IgA (IgA concentration, IgA output, and IgA relative to total protein). The plasma
concentration of glutamine was decreased by 15% 2 h postexercise in the placebo group, whereas this decline was abolished by both
glutamine and protein supplements. None of the supplements, however, was able to abolish the decline in salivary IgA. This study does
not support that postexercise decrease in salivary IgA is related to plasma glutamine concentrations.
So protein has the same glutamine-sparing effect as straight glutamine. Bodybuilders really need not worry I suspect!
And here's one on carbohydrates:
Carbohydrate supplementation during intense exercise and the immune response of cyclists.
Bacurau RF, Bassit RA, Sawada L, Navarro F, Martins E Jr, Costa Rosa LF.
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Brazil.
OBJECTIVE: To evaluate the effect of carbohydrate supplementation upon some aspects of the immune function in athletes during
intense indoor cycling. METHODS: Twelve male athletes cycled for 20 min at a velocity corresponding to 90% of that obtained at the
anaerobic threshold and rested for 20 min. This protocol was repeated six times. The athletes received, during the trial, water ad
libitum, or a solution of carbohydrate (95% glucose polymers and 5% fructose) at 10% (w/v), 1 g kg h every 20 min, starting at the
10th minute of the first exercise period, plus extra water ad libitum. RESULTS: Exercise induced a reduction in peripheral blood
mononuclear cell proliferation (37%) as well as in the production of cytokines by cultured cells (interleukin-1 (IL-1), interleukin-2
(IL-2), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), by 37%, 35%, 26% and 16%, respectively).
All of these changes were prevented by the ingestion of a carbohydrate drink by the athletes, except that in IFN-gamma production,
which was equally decreased (17%) after the second trial. The concentration of plasma glutamine, an important fuel for immune cells,
was decreased in the placebo group but maintained in the group that received carbohydrate. CONCLUSION: Carbohydrate
supplementation affects positively the immune response of cyclists by avoiding or minimizing changes in plasma glutamine
concentration.
So really, if these silly endurance athletes would just eat properly (by bodybuilding standards anyway), they prolly wouldn't have so many immune probs.........
BCAAs are also 'glutamine sparing'. BCAA supplementation in combination with moderate energy restriction has been shown to induce significant and preferential losses of visceral adipose tissue and to allow maintenance of a high level of performance. Consumption of BCAA before or during endurance exercise may prevent or decrease the net rate of protein degradation, may improve both mental and physical performance and may have a sparing effect on muscle glycogen degradation and depletion of muscle glycogen stores. YMMV, but personally I supplement BCAAs when dieting (as well as glutamine), but otherwise I don't bother. If I were not on a tight budget, I might consider supplementing BCAAs just before and during training sessions.......
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