Sugar: Little Known Effects on Gut Microbiota

Sugar: Little Known Effects on Gut Microbiota

  • Gut Health

  • By Andréanne Martin, Bachelor's degree in nutrition

    There are various times during the year when holiday traditions mean lots of sugary treats around the house to indulge our sweet tooth. These chocolates and candies are a delight to our taste buds, but to our gut bacteria, pancreas and liver, it's a bit of a different story, especially when consumed in excess.


    The Impact of Sugar on Our Gut

    Sugar is ever-present in North American diets, thanks in large to the prevalence of ultra-processed foods which contain poor-quality ingredients like glucose-fructose, high-fructose corn syrup and artificial sweeteners.1 

    The overconsumption of sugar negatively impacts the community of our gut bacteria, and in turn our overall gut health. It has been well documented that high intakes of sugar can result in slower bowel transit times and alter the gut microbiome, leading to a state of gut dysbiosis and an increase in the production of endotoxins.2,3

    When our gut bacteria becomes unbalanced, it can also alter the gut mucosa, the layer of our gut that plays a critical role in the barrier function of our intestine.4 When our gut mucosa is altered, it results in increased gut permeability (aka ‘leaky gut syndrome’). Over time, this may lead to issues rooted in chronic inflammation like poor weight management, cardiovascular disease, type II diabetes, obesity, metabolic syndrome, hepatic steatosis (fatty liver), irritable bowel syndrome (to name a few).


    What About Artificial Sweeteners?

    In an attempt to choose 'healthier' options for a leaky gut diet, many people reach for foods or beverages that claim to have 'no-added sugars' without checking the labels to see if there are sweeteners or sugar substitutes listed. While there is still more research to be done on this topic (especially in human studies), evidence is mounting that long-term consumption of artificial sweeteners may disrupt the balance and diversity of our gut bacteria, and in turn increase the risk for developing type II diabetes.5


    Make Good Decisions About Sugar

    Understanding the impact that sugar has on your gut microbes means taking a different approach to how you indulge your sweet tooth. To keep your gut bacteria happy, here are a few pieces of advice to limit the negative effects of sugars and sugar substitutes:


    1. When at the supermarket, leave behind any food that contains the following ingredients: glucose-fructose, high-fructose corn syrup, agave nectar, sucralose, aspartame, sorbitol and xylitol.

    2. Choose foods with ingredients lists that are as short as possible, and minimally processed. For example, dark chocolate, with no added or processed sugar, will have a less damaging effect on gut microbes and contains other healthy compounds like flavonoids.

    3. Don't skip your fibre: vegetables, legumes, whole grains, berries and colourful fruits. Getting these into every meal and snack helps your body absorb carbohydrates more slowly (reducing the sugar spike) and nourishes good families of bacteria.

    4. Consume a high-quality probiotic daily, like Bio-K+. It contains three strains of probiotic bacteria that work synergistically with our resident bacteria to balance our good bacteria, lower intestinal permeability and improve immune function.

    5. When eating treats, choose the best quality you can and consume in smaller amounts, rather than a large quantity over just a few days.

    6. Save sugar for your treats! Cook your food at home to decrease your consumption of processed foods (which are notoriously high in sugar) or replace the sugar in your recipes with less processed options like date or sweet potato paste.


    Enjoying the sweet food you love can be done with a minimized impact to your health when you incorporate healthy lifestyle habits that include physical activity, restorative sleep and staying hydrated. Feeling healthy should be sweeter than any chocolate or treat!


    Do you have more questions about gut health? Let us know in comments below! For more information on probiotics, Bio-K+ and digestive health, join our community. Click here to find the closest point of sale. Contact us or find us on Facebook and Instagram.




    1. Steele et. al Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study (2015)


    1. Kruis et. al Effect of diets low and high in refined sugars on gut transit, bile acid metabolism, and bacterial fermentation. (1991)


    1. Tomasello et al. Nutrition, oxidative stress and intestinal dysbiosis: Influence of diet on gut microbiota in inflammatory bowel diseases (2016)


    1. Desai et. al. A dietary fiber-deprived gut microbiota degrades the colonic mucus barrier and enhances pathogen susceptibility. (2016)


    1. Nettleton et al. Reshaping the gut microbiota: Impact of low calorie sweeteners and the link to insulin resistance? (2016)


    • Flint et coll. Links between diet, gut microbiota composition and gut metabolism. Proceedings of the Nutrition Society (2015)


    • Payne et coll. Gut microbial adaptation to dietary consumption of fructose, artificial sweeteners and sugar alcohols: implications for host–microbe interactions contributing to obesity. Etiology and Pathophysiologyobr_ (2012)


    • Spencer et collArtificial Sweeteners: A Systematic Review and Primer for Gastroenterologists. Journal of Neurogastroenterology and Motility (2016)


    • Burke, M. V. et Small, D. M. (2015) Physiological mechanisms by which non-nutritive sweeteners may impact body weight and metabolism. Physiology & Behavior, 152, 381-388.

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    Andréanne Martin Bachelor's degree in nutrition
    About the author
    Andréanne Martin is a dietitian and nutritionist who drives projects that enable her to promote healthy lifestyles in order to help as many people as possible to feel better.
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