Preparing for a colonoscopy usually requires a limited diet for the day before the test, or even several days prior to the procedure, to clean out your colon so the doctor can get a good look at any abnormalities. You'll also take a strong laxative. But it's important for diabetics to eat regularly to maintain blood sugar levels. A diabetic will need to make a few adjustments to properly clean out her colon for the test and keep her blood sugar from falling too low.
The Diet
Your doctor will give you instructions for the diet to follow for your colonoscopy prep. Every doctor has a preferred regimen he uses, and he will take your diabetes into account when prescribing the prep. You should follow the diet your doctor prescribes. In general, if you are on a liquid diet, you can help maintain your blood sugar by consuming two cups of regular gelatin, regular soda or juice at mealtimes and one cup of these liquids between meals and at bedtime. Be sure to drink plenty of liquids to avoid becoming dehydrated while you're using the laxative. Avoid sugar-free products and any choices with red food coloring, since the coloring can stain your colon. So stick to lemon, lime or orange gelatin and ginger ale or lemon-lime soda and apple juice or clear sports drinks.
Insulin
If you take insulin to control your diabetes, take half your usual dose the morning you begin your colonoscopy prep, and half at bedtime later that night. If you take an oral medication for diabetes, take half your usual dose in the morning and none that evening. Your doctor may instruct you to take no medication the morning of your colonoscopy. Again, follow your doctor's specific instructions for your medication, which may differ from these guidelines. Every person's situation is different, and general guidelines such as these may not apply.
Blood Sugar Monitoring
Check your blood sugar throughout the day, every four to six hours, while you're preparing for your colonoscopy. Even though you're consuming sugar in the gelatin, sodas and juices, your blood sugar shouldn't rise into the danger zone, since these sugars are replacing carbohydrates you'd normally cosume. If your blood sugar falls too low, have a cup or juice or soda. You can also consume glucose tablets or gels. Contact your doctor if you have any questions or concerns about your blood sugar levels.
Colonoscopy and Diabetes
Having diabetes increases your risk of developing colorectal cancer. Diabetics are 1.4 times more likely to develop colon cancer than people who don't have diabetes, according to Dr. Donald Garrow of the University of South Carolina. Dr. Garrow was part of a research team that surveyed 226,000 people between 1997 and 2003. Colorectal cancer is very curable if caught early, so it's especially important for diabetics to be checked for the disease. The American Cancer Society recommends that all people have a colonoscopy at age 50 to screen for cancer.
