This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: vitamins, Subject name: Biochemistry
[{'content': 'Major functions of Vitamin E in the body \nSelect and explain. \nA. Regulation of energy metabolism, B. Carboxylation reaction, C. Blood clotting, D. Protection of biological membrane from free radical damage', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The primary function of vitamin E is as an antioxidant in prevention of the nonenzymic oxidation of cell components, for example, polyunsaturated fatty acids, by molecular oxygen and free radicals. Vitamin E deficiency is almost entirely restricted to premature infants. When observed in adults, it is usually associated with defective lipid absorption or transpo. The signs of human vitamin E deficiency include sensitivity of erythrocytes to peroxide and the appearance of abnormal cellular membranes. Reference: Lippincott Textbook of Biochemistry pg no. 391', 'role': 'assistant'}]