Pellagra from niacin deficiency can occur even with adequate dietary tryptophan in populations consuming a staple diet of which cereal, due to the presence of bound (unabsorbable) niacin?
- A Rice
- B Wheat
- C Maize (corn) ✓
- D Sorghum (jowar)
Explanation
In maize (corn), niacin is bound in a form called niacytin (niacin–polysaccharide complex), which is not bioavailable to humans unless treated with alkali (nixtamalization — lime/calcium hydroxide treatment used in traditional Mexican cooking). Populations that rely on untreated maize as a staple (e.g., parts of South Africa and southern India) develop pellagra despite the presence of niacin in the grain. Sorghum has high leucine content, which antagonizes tryptophan-to-niacin conversion, causing pellagra through a different mechanism. Wheat and rice do not cause pellagra through bound niacin.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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