A while ago I documented literature that demonstrated glutamine did not appear to be absorbed effectively when ingested with other amino acids. The scientists behind this research commented “free form glutamine appears to compete poorly with other amino acids for intestinal absorption” (Keohane PP, et al. Gut.26:907-913. 1985; Grimble GK et al. Clin.Sci.71:65-69, 1986).
Based on this, I cautioned athletes to ensure they obtain the most from their GL3 L-Glutamine supplement by consuming their serving 15-minutes before a protein meal.
This research is in fact 25 years old and I now suspect due to the inferior tracer techniques used to “follow” amino acids back then, the scientists could not accurately take into account the splenic extraction of glutamine from the intestinal tract. This may have produced a “false” reading in terms of what was happening to the glutamine.
More recent work has demonstrated that when glutamine is taken with other proteins such as VP2 Whey Isolate, a greater improvement in cellular anabolism occurs. This research was performed on rats, so its results need to be interpreted with caution. However, so far all current research points toward the fact glutamine absorption is not affected by other proteins. Therefore, based on the limited research available on the subject, it seems okay to take free-form glutamine supplements such as GL3 with other proteins.
AST will always provide you with the most accurate information available, so I’ll continue to keep a close eye on the research on this subject.
