A fisherman attends for a first appointment before a trip in two days. He complains of burning and dryness of the tongue. Examination shows a pale, atrophic tongue and erythematous, bleeding gingiva. Which nutrient is he most likely deficient in?

Correct answer: C. Ascorbic acid (vitamin C)

• A. B12 deficiency produces a BEEFY RED, atrophic (Hunter/Moeller) glossitis with burning, plus megaloblastic anaemia and subacute combined degeneration of the cord. The pallor here reflects anaemia, but B12 deficiency does not cause haemorrhagic gingivitis.
• B. Riboflavin deficiency gives ANGULAR CHEILITIS, glossitis and a magenta tongue. Note the tongue in riboflavin deficiency is magenta or red, not pale, and gingival bleeding is not a feature.
• C. CORRECT. The occupational history is the deliberate clue — prolonged periods at sea with no fresh fruit or vegetables is the classic setting for SCURVY, historically the sailor's disease. The discriminating finding is SPONTANEOUSLY BLEEDING, swollen, erythematous gingiva. Vitamin C is the cofactor for prolyl and lysyl hydroxylase in collagen synthesis; without it, collagen cannot cross-link, capillaries become fragile and the gingival connective tissue breaks down. Perifollicular haemorrhage, corkscrew hairs, poor wound healing and lassitude complete the picture.
• D. Thiamine deficiency causes beriberi (peripheral neuropathy and high-output cardiac failure) and Wernicke-Korsakoff syndrome in alcoholics. It does not produce bleeding gingiva.

Note: ⚑ Two findings pull in different directions here — a PALE atrophic tongue with burning fits a nutritional anaemia (B12, folate, iron), while BLEEDING gingiva points squarely at vitamin C. Scurvy also causes anaemia (impaired iron absorption and blood loss), which reconciles both. Worth discussing as a group.