Don’t mess up your colonoscopy prep by eating the wrong stuff. In this guide, Dr. Akintomiwa explains which foods to avoid pre colonoscopy, and why, to ensure your procedure runs smoothly.

As of today, colonoscopy is the gold standard investigation in the screening, diagnosis, and management of colorectal cancer, one of the top 5 cancers in the world.

Routine colonoscopy enables doctors to identify colorectal polyps (these are typically benign but may become cancerous, e.g., adenomatous polyps) as well as malignant lesions in their early stages. This early detection gives room for prompt therapeutic interventions and, as a result, lower mortality rates. Also, when patients present with symptoms that are suggestive of colonic pathologies at whatever stage, a colonoscopy may be done to confirm the provisional diagnosis.

Proper bowel preparation plays a huge role in the effectiveness of a colonoscopy. Bowel preparation is the thorough cleansing of fecal matter and residue of the colon using mechanical, pharmacological, and dietary measures. Inadequate intestinal preparation can limit the procedure’s accuracy, resulting in missed lesions and the need for repeat colonoscopy sessions. One crucial dietary aspect of bowel preparation is avoiding certain foods that can hinder the process. This article discusses the need to avoid certain foods, provides a detailed list of such foods, and explains why they are excluded.

WHY ARE THERE CERTAIN FOODS TO AVOID PRE COLONOSCOPY?

First of all, we must establish the fact that there are some foods to avoid pre colonoscopy. This is because, as previously stated, the primary objective of bowel preparation before a colonoscopy is to achieve optimal cleanliness of the colon, which in turn aids visibility and navigation of the colon during the procedure.

However, certain foods can hinder proper bowel preparation by slowing down digestion and the clearance of fecal matter. Some foods also leave behind a lot of residue in the colon after digestion. Therefore, it is critical to understand what foods to avoid pre colonoscopy in a bid to increase the efficacy of bowel preparation and, ultimately, the effectiveness of the colonoscopy. It also reduces the chances of missing lesions during the procedure. Furthermore, adhering to recommended dietary restrictions increases your safety and comfort during colonoscopy, improving your overall experience.

LIST OF FOODS TO AVOID PRE COLONOSCOPY

Dietary Fiber Should be Avoided

Dietary fibre is one of the most important foods to avoid pre colonoscopy.

Dietary fiber, which is also known as roughage or bulk, refers to the components of plant-based foods that the body cannot digest or absorb. Fiber, unlike other components of food such as lipids, proteins, or carbohydrates, is not digested and absorbed by the body. Instead, it travels – mostly intact – through the stomach, small intestine, and into the colon, from where it is passed out in feces.

Dietary fiber increases the weight and size of stool and softens it. It makes stool well-formed and bulky, ready to be passed. While bulky stool is good for excretion, it obstructs the easy passage of the colonoscope during colonoscopy. On the other hand, foods with low fiber content result in loose, watery stools that are passed out with the aid of laxatives and enemas in preparation for a colonoscopy.

Examples of Specific Foods to Avoid Pre Colonoscopy

For a more practical discussion, some examples of foods to avoid on a low-fiber diet when preparing for a colonoscopy include:

Whole Grain Foods

Grains are the seeds of edible grasses and are also known as cereals. Common examples of grains include wheat, barley, oats, and rice. Whole grains, as opposed to refined grains, contain all the components of a grain, including considerable amounts of fiber. Products such as flour may be whole grain if derived from whole-grain sources. Hence, foods like whole-grain bread should also be avoided.

An alternative to this is the refined grain. Refined grains have parts of their components known as the germ and the bran removed. The process of refining takes out most of the fiber, thereby making it more easily digestible with low residue left in the colon. Therefore, foods made from refined grains, for example, white rice, white bread, and pastries may be consumed.

Nuts

Nuts are seed kernels enclosed in hard shells that are commonly eaten as a snack. They are also used in cooking a variety of dishes. Examples of nuts are groundnuts, cashew nuts, macadamia nuts, hazelnuts, etc. Nuts are nutrient-dense foods rich in fats, minerals, vitamins, protein, and fiber. The high fiber content makes it unsuitable for consumption when preparing for a colonoscopy.

Legumes

Legumes are foods derived from plants of the same name. They are also commonly regarded as members of the bean family. Aside from cereals (grains), legumes are arguably the most consumed and most important group of foods worldwide. Examples of legumes include beans, peas, lentils, chickpeas, soybeans, etc. Legumes are very nutritious. They are good sources of protein, vitamins, and minerals. However, they are also high in fiber, and that is why you are to avoid them when preparing for a colonoscopy.

Milk and Dairy Products

When preparing for a colonoscopy, milk is to be avoided. Milk is naturally produced by the mammary glands of mammals, including humans. Aside from human milk that is fed to our infants, cow milk is arguably the most common source of milk consumed by humans. Other common animal sources of milk consumed by humans include goats, sheep, camels, and buffaloes. Milk may also be obtained from plants. Some examples of plant-based milk are coconut milk, almond milk, soy milk, hazelnut milk, and so on.

Milk is highly nutritious as it is an excellent source of protein, vitamins, and some minerals like calcium, potassium, and phosphorus. Dairy products such as yogurt are also nutritious.

However, milk should not be consumed before a colonoscopy due to a number of reasons. First, the digestion of milk leaves undigested lactose to travel into the colon, where it may cause symptoms of lactose intolerance in some people, making a colonoscopy more distressing and uncomfortable than it ought to be. Secondly, traces of milk in the colon can distort and hide the appearance of lesions and polyps, thereby reducing the reliability of results and requiring a repeat procedure at a later date.

Alcohol

Alcohol should not be consumed before a colonoscopy. This is because alcohol induces diuresis, which is the exception of body fluids through urine. It suppresses a hormone known as Vasopressin, which regulates fluid levels in the body. The suppression of Vasopressin allows water to move out of the cells into the kidneys, from where it travels to the bladder and is eventually excreted as urine. The excess excretion of water as urine causes dehydration.

Alcohol may also slow down digestion and passage of stool. Additionally, it may negatively interact with the anesthetic agents used during the colonoscopy. Because of the undesirable effects that alcohol consumption may have in this procedure, it is best avoided completely for a few days before the colonoscopy.

Red, Blue, and Purple Beverages

Blue, red, and purple beverages should be avoided when preparing for a colonoscopy. This is because, as explained in the American Journal of Gastroenterology, red coloring may mimic blood in the colon. Furthermore, blue and purple coloring may also stain the walls of the colon and create false appearances of abnormalities in the colon.

Fruits with Their Skins and Seeds

Fruits like apples and pears have high fiber content and should not be consumed when preparing for a colonoscopy. If you must eat these fruits, you must peel and cook them before eating so as to reduce their fiber content. Skins of fruits like mangoes and kiwis are fiber-dense and must be peeled before consumption. Fruits with seeds, such as watermelon, raspberries, and strawberries, should be avoided or wholly deseeded before eating.

Vegetables

Raw vegetables should be avoided. Only vegetables like cucumbers that have been peeled and thoroughly deseeded can be consumed raw.

How Long Should These Foods Be Avoided Pre Colonoscopy?

It is also important to note that the foods to avoid pre colonoscopy increase as you approach the day of your procedure. This is because you are expected to transition from a low-fiber diet to a clear liquid diet when you have about 24 hours left to your colonoscopy. Hence, some of the foods permitted in a low-fiber diet will not be allowed into your clear liquid diet plan.

As a rule of thumb, all foods that are not permissible on a low-fiber diet are strictly off limits on a clear liquid diet. However – as the name implies – only liquids are allowed in a clear liquid diet. So, when it is time to make the switch, you will need to avoid solid foods, even though they are low in fiber content.

Hence, white rice, white bread, pastries, and other foods made from refined grains must be avoided when on a pre-colonoscopy clear liquid diet. Similarly, fruits and vegetables, even when peeled and cooked, are off the menu for once you have 24 hours or less to your procedure.

FOODS TO AVOID PRE COLONOSCOPY – FINAL WORDS OF ADVICE

Complying with dietary rules and recommendations when preparing for a colonoscopy is critical to its success. Failure to comply with set dos and don’ts can result in poor colon cleansing, which in turn can cause unsatisfactory colon visibility and increased procedural discomfort and risks. A specific risk that comes to mind and is often mitigated by proper colon cleansing is a post-procedural bacterial infection due to exposure to a high bacterial load in feces.

Moreover, inadequate bowel preparation may lead to unreliable results, thereby warranting a need for a repeat procedure. Consequences of multiple colonoscopies include prolonged procedural discomfort, emotional stress, and increased healthcare costs. Hence, it is advisable to adhere to the given instructions when preparing for a colonoscopy and ask for clarifications when unsure of foods and drinks to eat and drink.

Conclusion

In conclusion, adequate bowel preparation – and especially dietary changes – is vital to the success of colonoscopy because it allows for better visualization and detection of colorectal abnormalities.

Being mindful of which foods to avoid pre colonoscopy, and understanding how they can interfere with bowel cleansing, is critical for improving the accuracy and effectiveness of your colonoscopy. When preparing for a colonoscopy, it is crucial to strictly adhere to dietary rules such as avoiding a high-fiber foods like whole grains, nuts, and legumes, abstaining from alcohol, and ceasing intake of colored fluids. Doing so helps achieve optimal bowel preparation and reduce procedural risks.