The nurse is evaluating a 2 month-old baby and their mother at a primary health care clinic. The mother expresses to you that they have been having financial difficulty the past two months, and is working two jobs. The mother has been feeding their baby commercial formula for the first two months of life and reveals to you that they have been watering down the formula for the past couple of weeks due to lack of funds. 

 Based on pediatric developmental disorders, which disorder is the most immediate threat to this infant's health?