Researchers are studying the case of a 27-year-old woman who developed a vitamin deficiency after failing to take multivitamins post- gastric bypass surgery. After two months of an uncomplicated surgery for weight loss at the University College Hospital, London she suffered from dizziness, vomiting and low-appetite. Also, prescribed lansoprazole (drug for prevention of acid production in stomach), the patient was found to be deficient in these medications. Only after physicians administered thiamine (Vitamin B1), the patient recovered.