WHEN the rain comes, can diarrhea be far behind? Of course, there are the other illnesses, mostly respiratory in nature, but with all the water carrying all the garbage, dirt and effluents full with all sorts of microbes- name it virus, bacteria, fungi, protozoa- it is expected that there is a dramatic increase in gastro intestinal problems with diarrhea as the main symptom.

At this juncture, a brief review of gastroenterology is in order. The adult alimentary tract or digestive system measures, from mouth to anus, 26-28 feet- with a tube-like shape lined with mucous membrane.

For normal, healthy active persons, the transit time or how long it takes for food from the mouth to reach the rectum and eventually the anus is from 18-24 hours, and that explains why we should- at least for most of us- go to the toilet - comfort room or rest room - every morning and hopefully come out of it, smiling, because, the defecation was successful. There are three movements of the digestive tract; segmental is a churning mixing movement, there is also the pendular, almost swinging movement which is also mixing in function and there is the peristaltic motion, which is propulsive, that is it is the force that drives the chyme-partially digested food aboral- away from the mouth. The stomach has the most number of contraction- normally 12-15 contractions per minute- with the rate decreasing in the other organs from thereof. Most of the absorption of nutrients is done in the jejunum, with the exception of bile salts, bile acids and vitamin B12 or cobalamin, which are absorbed in the last portion of the small intestines, ileum. The term " colon" applies to the large intestines- cecum whose underside contains the appendix, ascending colon, transverse colon, descending colon, sigmoid colon- parts where only water is reabsorbed which explains why, at the rectum, we have a solid stool ready to be defecated.

Diarrhea is also called loose bowel movement or in layman's parlance, watery stool. Why watery? Because water was not absorbed in the colon. And why was water not absorbed in the colon? Because the colon was contracting extremely fast thus there was not enough time to reabsorbed water, so water is in the stool.

There are many reasons why the colon would be hyperactive that is, contracting too fast. Very common among us Filipinos, and also Asians where lactose intolerance rate is almost 20-25 %, every time we enjoy our halo-halo, or eat cheese or take our yoghurt, we might find ourselves in the toilet after one hour with diarrhea. Of course, there is also the so-called “empatso” or a bad case of indigestion, which is commonly observed among our adolescents who love to eat different unrelated foods altogether or in immediate sequence as exemplified by raw mango with bagoong alamang, then ice cream or halo-halo or any dairy product. Lest you forget, there is also the stress diarrhea, seen among persons waiting for the chance to be interviewed, students grappling with failing grades as they take their final exams or an employee told to see the boss urgently. Although rare among us Filipinos and Asians, there are metabolic diseases whose symptoms include diarrhea like Crohn's disease, Irritable bowel syndrome and allergy to gluten, a protein found in most complex carbohydrates like rice, wheat, barley

Next Week: Infectious diarrhea and its complications