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While diet is a key factor in maintaining a healthy gut, don’t count on a one-off gut cleanse or short-term diet to have long-lasting effects.Thinkstock/Getty Images/iStockphoto

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD

Should you ‘cleanse’ or ‘reset’ your gut? What the science says

After the indulgences of the holiday season you might be tempted to “cleanse” your colon or follow a “gut reset” diet. Doing so, proponents say, can improve digestion, kick-start weight loss, enhance mental focus, ease joint pain, even improve fertility.

Sounds enticing, especially now when many of us are highly focused on personal health and wellness goals.

While diet is a key factor in maintaining a healthy gut, don’t count on a one-off gut cleanse or short-term diet to have long-lasting effects. Here’s what to know.

Colon cleanses, detoxes

A colon cleanse involves flushing out the large intestine. The practice is based on the ancient theory of autointoxication, based on the idea that toxins from stagnant materials in the large intestine can build up and cause symptoms such as fatigue, headache, high blood pressure, arthritis and weight gain. Eliminating these toxins is necessary to improve health.

Various methods are touted to “cleanse” your colon. At home, you might follow a special diet, use herbal extracts and teas and/or take certain nutrition supplements, for example.

Or you can consult a practitioner trained to perform colonic irrigations. This procedure involves irrigating the colon with a large amount of water (about 60 litres) through a small tube inserted in the rectum. Gentle abdominal massage is used to help release waste and trapped gas.

Research on colon cleansing is incredibly sparse; no studies have been done to show that colon cleansing delivers its claimed benefits. Colonic irrigation can, however, provide temporary relief to those with severe constipation.

Consider also that a healthy human body is highly efficient at removing or neutralizing toxic substances. Our liver, gastrointestinal tract, kidneys and lungs are exquisitely designed to do so.

Colon cleanses have potential side effects including dehydration, electrolyte imbalances, abdominal pain and cramping, nausea and vomiting.

Colonic irrigation may result in a perforation (tear) of the rectum. People with diverticulitis, inflammatory bowel disease, kidney disease or heart disease should avoid colonic irrigation.

‘Gut reset’ diets explained

The goal of a gut reset diet is to increase the number of beneficial bacteria that live inside your large intestine. (Some gut reset diets also aim to improve gut detoxification.)

The active community of gut microbes, collectively known as the gut microbiome, influences our metabolism, body weight, immunity and inflammation, as well as susceptibility to allergies, asthma, type 2 diabetes, heart disease, certain cancers and Alzheimer’s disease.

Having a diverse population of gut microbes has been linked to better health.

Gut reset diets, lasting three to 30 days, are plentiful on the internet. Some programs also sell microbiome tests, colon cleanse kits and various nutrition and probiotic supplements.

Many gut reset plans offer evidence-based dietary advice such as increasing intake of fibre, probiotic- and prebiotic-containing foods and plant protein while, at the same time, eliminating or limiting foods that can disrupt the microbiome (e.g., alcohol, added sugars, highly processed foods, too many animal foods).

Some of these programs also provide sound guidance around sleep, exercise and stress management, other lifestyle factors that influence the makeup of your gut microbiome.

All good advice.

Research has shown that making a big shift in what you eat can alter your gut microbiome rapidly, in just three to four days.

Here’s the problem. While short-term dietary change may bolster your microbiome, there’s no evidence that doing so has health benefits, or even what those health benefits might be.

What’s more, once you stop following a gut-friendly diet and resume your usual food intake, your microbiome returns to its original composition (ditto for discontinuing probiotic supplements).

How to nourish your gut

Eat a diet that’s high in nutrient- and fibre-rich fruits and vegetables, whole grains, beans and lentils and nuts and seeds.

Include probiotic-containing fermented foods in your daily diet – kefir, yogurt, kombucha, kimchi, unpasteurized sauerkraut and vegetable brine. Probiotics are beneficial microbes that can increase the population and diversity of gut microbes.

Eat prebiotic foods, too. Oats, barley, whole grain rye bread, white beans, lentils, apples, artichokes, asparagus, garlic, onion, banana and Jerusalem artichokes contain fermentable carbohydrates that fuel the growth of beneficial gut bacteria.

Polyphenol-rich foods – berries, red grapes, pomegranate seeds, green tea, cocoa powder, onions, kale, broccoli, citrus fruit, celery, parsley, soybeans – also support your microbiome. So do leafy greens.

Instead of approaching gut health with a quick-fix diet (or cleanse), adopt a long-term eating plan to build and maintain a richer and more diverse microbiome.

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