Answer:
Glutamine boosts immune system which decreases the risks of infections
Explanation:
Glutamine is an important amino acid for the human body. It has various functions including improvement in the immune system of body. It serves as a critical fuel for the immune cells. Researchers have found that glutamine supplements can improve health and reduce infections. By boosting the immune response it makes a person resistant towards many bacteria and viruses.
In the question, it has been said that the runner is taking glutamine supplement because she has upper respiratory tract infections. This is biologically plausible because glutamine reduces infections.