Tag: Tryptophan depletion

Carcinoid tumors can divert up to 70% of the body's tryptophan toward serotonin production, drastically reducing the amount available for other metabolic processes. This metabolic shift is the direct cause of the most prominent vitamin deficiency that is common in carcinoid symptoms: niacin, or vitamin B3.

Research in both animals and humans demonstrates that diets enriched with certain amino acids can decrease brain serotonin levels by inhibiting the transport of its precursor, tryptophan. Understanding what amino acid lowers serotonin involves examining the critical competitive process at the blood-brain barrier.