A 60-year-old woman comes to the office with intermittent flatulence, crampy abdominal pain, and watery diarrhea. Her symptoms started 2 months ago after she recovered from an episode of acute gastroenteritis associated with nausea, vomiting, and diarrhea. The patient's symptoms are worse after drinking 'too much milk.' She usually has 1 or 2 glasses of wine every evening with dinner. Physical examination is unremarkable. Initial laboratory evaluation, including serum chemistries, blood counts, stool cultures, and studies for ova and parasites, is negative. Which of the following is most likely decreased in this patient?
1) breath hydrogen content
2) Fecal fat
3) Pancreatic enzymes
4) Stool osmolality
5) Stool pH