This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Feeding Healthy Infants and Children, Subject name: Pediatrics
Breast milk contains all except? 
Select and explain. 
A. Lacta globulin, B. Lactoalbumin, C. Whey protein, D. Avidin
D: Avidin
Answer: D: Avidin 
Explanation: Ans. (d) AvidinRef.-.Nelson 18th ed., Chapter 42* Human milk contains a variety of cells, including macrophages, T cells, stem cells, and lymphocytes.* In early lactation, the breastfed infant may consume as many as 1010 maternal leukocytes per day.* About 80% of the cells in early milk are breast milk macrophages, which originate as peripheral blood monocytes that exit the bloodstream and migrate into milk through the mammary epithelium.* The proteins of human milk are divided into the whey and casein fractions or complexes, with each comprising of a remarkable array of specific proteins and peptides.* The most abundant proteins are casein, a-lactalbumin, lactoferrin, secretory immunoglobulin IgA, lysozyme, and serum albumin.