FIGURE 2.

Conceptual description of the impact of increasing amino acid intakes and risk of toxicity. With amino acid intakes above the requirement, amino acid oxidative pathways continue to dispose of the additional amino acids. With intakes above the UL, oxidative pathways are saturated, and metabolites from amino acid catabolic pathways start to accumulate and increase risk of adverse events. AA, amino acid; LOAEL, lowest-observed-adverse-effect-level; NOAEL, no-observed-adverse-effect-level; UL, tolerable upper intake level. Adapted from reference [42] with permission.