On Nutrition by Ed Blonz

Colonoscopy Prep No Fun, But Important

DEAR DR. BLONZ: I will be having a routine colonoscopy next month and just received the preparation instructions. It says that in the week before the test, I should avoid seeds and even corn (one of my favorite foods). What defines a seed? What about fruits and nuts? -- F.S., Des Moines, Iowa

DEAR F.S.: A colonoscopy is a test in which a specialist, usually a gastroenterologist, uses a device that provides a view of the lining of the large intestine. It is a method used both for routine screening and for patients with symptoms that require a closer look. The preparation during the days before the test is no fun, but this is a very important procedure that can be a lifesaver. For your practitioner to get the needed view, it is essential that the surface inside your colon be as clean as possible. Once the procedure is over, you can begin to resume your regular menu, comforted that you have taken an important step to assess this aspect of your health.

Medical practices can have different methods of preparation before the test. Our doctor’s office had us on a very low-fiber diet for three days, and then on the day before the colonoscopy, nothing but clear liquids, such as flavored gelatin (any color but red), clear juices and soups. There were no fruits, vegetables or fiber-rich foods during any of the four days. My menu during the three days consisted of cream of wheat, eggs, cheese, meat, juices (no pulp), white rice, and English muffins with butter. I read labels to make sure nothing contained more than 1 gram of fiber per serving.

A key period of the preparation is the day before the test, and the use of medications that empty out your digestive tract. I used magnesium citrate, which I found to be a bit more palatable than the sodium phosphate product that was also an option. Some physicians rely on a PEG (polyethylene glycol) solution to be consumed throughout the day. There is no real culinary joy with any of these; it is something we have to endure, with the knowledge that in a short time, it will be over. Most instructions say that you should drink lots of water that last day. Please rely on your doctor’s office and the specific instructions they provide.

As for the specifics of your question: Fruits, nuts and seeds are higher in fiber, so they might be a problem, especially on the three “modified diet” days before the test. The day before, of course, they are out of the question.

Again, good preparation is the key to a good reading, so toe that line as best you can. An inadequate preparation might make it impossible for your doctor to see what needs to be seen and draw medical conclusions. Your preparation can affect how long you are allowed to wait before your next test, so there is a benefit to doing it right! Best wishes for a clean test.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.