This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and health, Subject name: Social & Preventive Medicine
[{'content': 'One mg. of Niacin is produced by _______ mg. of Trytophan - \nSelect and explain. \nA. 22, B. 37, C. 55, D. 60', 'role': 'user'}, {'content': "Answer: D \nExplanation: p> - niacin is essential for the metabolism of carbohydrate, fat and protein. It is also essential for the normal functioning of skin , intestinal and nervous system. - it differs from other other B complex vitamins that an essential amino acid tryptophan serves as its precursor. - about 60 mg of tryptophan is required to result in 1 mg of niacin Reference : Park's textbook of preventive and social medicine, 23rd edition, pg no:619 <\\p>", 'role': 'assistant'}]