Category: Carcinoid syndrome

Carcinoid syndrome, a condition caused by certain neuroendocrine tumors, famously leads to a severe deficiency of niacin, also known as vitamin B3. This happens because the tumors divert the amino acid tryptophan, which is the precursor for both niacin and serotonin, toward producing excessive amounts of serotonin.

Carcinoid tumors can divert up to 70% of the essential amino acid tryptophan away from its normal metabolic pathways. This dramatic metabolic shift is the core reason for the nutritional imbalance, answering the critical question: Why does carcinoid syndrome cause B3 deficiency?.