The USMLE frequently touches on the concept of pellagra pathogenesis and an understanding of the biochemical causation and the full list is required to answer related questions.
Niacin is also called Vitamin B3 is important for the formation of NAD which in turn is needed in several intermediary biochemical reactions.
Niacin can be endogenously synthesized from Tryptophan via a reaction that needs vitamin B6 as a cofactor.
Causes of deficiency (Pellagra):
Niacin is also called Vitamin B3 is important for the formation of NAD which in turn is needed in several intermediary biochemical reactions.
Niacin can be endogenously synthesized from Tryptophan via a reaction that needs vitamin B6 as a cofactor.
Causes of deficiency (Pellagra):
- Dietary deficiency mainly arise in geographic areas where consumption of corn is the main source of staple rather than wheat. Niacin in corn in nonabsorbable. This is specially seen in African countries.
- Hartnup disease, because Tryptophan being a large neutral amino acid will be deficient and thence Niacin will also be deficient.
- Isoniazid treatment as it inhibits vitamin B6 needed for endogenous synthesis as mentioned above.
- Alcoholics as the over active dehydrogenases will consume all the NAD available.
- HIV patients