5 ways sugar can harm your health

We all know sugar can make us fat, but did you know it also has a damaging effect on gut health?

Our gastrointestinal system, or gut for short, is responsible for a multitude of functions including digestion of food, absorption of nutrients, mental health, immunity, and more. (1) Our gut microbiota is made up of microbes that colonise our entire gastrointestinal system. These microbes include bacteria, viruses, fungi, and other organisms. (1) Many things in life affect the health and balance of our microbiota such as antibiotic use, diet, and even the way we are born! (1) There is currently lots of research surrounding the importance of seeding the gut during birth and its impact on the health of an infant. (1–3)

Gut health and sugar

What is gut flora?

Part of our gut flora are the healthy bacteria that makes up our internal microbiome, however our microbiota is made up of lots of different types of microbes. (1) The majority of microorganisms in the gut live in harmony and symbiotically with one another, (1) it’s when there is a disruption balance between ‘good’ microbes and ‘bad’ microbes that dysfunction, disease, and/or disorder occurs. (4)

We have approximately 1,000,000,000,000,000 different microbes residing in our gut! (2,4,5) Or 1014put more simply. (2,4,5) This is ten times the amount of human cells that we have inside of us. (2,4,5) From about the age of one to three the gut of a young child will start to more closely resemble that of an adult. (4,5)

What are gap junctions?

The lining of the small intestine plays a role in absorption of nutrients but also acts as a barrier to stop large particles from leaking from the gut and causing dysfunction within the body, called dysbiosis (‘leaky gut’). (6) The lining of the gut wall is made up of lots of cells that are tightly packed together, these are called tight junctions. (6) The tight junctions work to prevent large molecules such as microbes or xenobiotics from passing through. (6) Conversely, the tight junctions also help to regulate flow of other fluids and absorption of nutrients that need to pass through the gut wall. (6) When the tight junctions are open, this can lead to a number of diseases and disorders within the body. (6) This can include irritable bowel disease (IBD), irritable bowel syndrome (IBS), obesity, type 2 diabetes, and even affect immunity. (2,6)

What does your gut do for you?

Your gut plays a major role in taking care of your immune system, (1) communicating with your brain for optimal mental health – also known as the gut-brain axis, (7) and even influences the presentation of skin conditions. (8)

Western diets are high in added sugars and can cause an imbalance of good and bad gut flora. (9) It’s this overgrowth of bad bacteria that can cause other ill-health effects like type 2 diabetes, IBD, and have an impact on immune system regulation. (2,6,9)

Gut health and sugar

Photo credit: Rod Long

5 ways sugar can harm your health.

  1. Immune function is affected by sugar. (2,5) High sugar diets also increase the risk of other diseases such as non-alcoholic fatty liver disease. (10)
  2. Glucose levels spike and plummet. (11) When glucose levels spike it can cause us to feel a wide range of symptoms from increased thirst, headaches, and even nauseous if we have too much glucose in one meal. (12)
  3. Fatigue, headaches, mood swings. (5,12) Diets high in sugar like the Western diet can have negative effects on your mental health. (13)
  4. Linked to acne. (8) Sugar exacerbates acne development because it causes the increased secretion of insulin leading to higher levels of circulating androgens, which increases sebum production in acne. (14)
  5. Increases risk of type 2 diabetes, amongst other life-long diseases. (2,6,9)

How to be good to your gut.

  • Eat a balanced diet with plenty of fibre, pro and prebiotics, and amino acids that are good for the gut and improve the integrity of the gut lining. (15)
  • Don’t drink too much alcohol or smoke as both of these adversely affect gut health and they create an imbalance of good and bad gut flora. (2)
  • Take some time to de-stress every day. Stress has a massive impact on the gut-brain axis and can sometimes be an instigator for IBS. (2)

Gut health and sugar

Photo credit: Alisha Hieb

3 things you can do every day to make your gut smile.

  1. Add fermented foods to one meal a day. Start small with about a teaspoon of a fermented food such as kimchi, sauerkraut, or kombucha. If you notice any gut symptoms, take a couple of days off before reintroducing. We all have different tolerances of introducing fermented foods into our diets, so it is always best to start small and work your way up.
  2. Eat lots of veg and fruit for nutrients good for your gut. Lots of fibrous fruits and vegetables like carrots, beetroots, celery, pumpkin, and berries also have high levels of gut-friendly nutrients.
  3. Drink plenty of water to help with moving bowels. Having healthy looking bowel movements that sink (sinking stools means you are eating plenty of fibre) every day is reflective of a happy gut.

Gut health and sugar

Photo credit: Heather Ford


  1. Jandhyala SM, Talukdar R, Subramanyam C, Vuyyuru H, Sasikala M, Reddy DN. Role of the normal gut microbiota. World J Gastroenterol [Internet]. 2015;21(29):8836–47. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528021/pdf/WJG-21-8787.pdf
  2. Conlon MA, Bird AR. The impact of diet and lifestyle on gut microbiota and human health. Nutrients [Internet]. 2015;7(1):17–44. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303825/pdf/nutrients-07-00017.pdf
  3. Wampach L, Heintz-Buschart A, Fritz J V., Ramiro-Garcia J, Habier J, Herold M, et al. Birth mode is associated with earliest strain-conferred gut microbiome functions and immunostimulatory potential. Nat Commun [Internet]. 2018;9(1). Available from: http://dx.doi.org/10.1038/s41467-018-07631-x
  4. Zhang YJ, Li S, Gan RY, Zhou T, Xu DP, Li H Bin. Impacts of gut bacteria on human health and diseases. Int J Mol Sci. 2015;16(4):7493–519.
  5. Wang H, Wei CX, Min L, Zhu LY. Good or bad: gut bacteria in human health and diseases. Biotechnol Biotechnol Equip [Internet]. 2018;32(5):1075–80. Available from: https://www.tandfonline.com/doi/pdf/10.1080/13102818.2018.1481350?needAccess=true
  6. Lee B, Moon KM, Kim CY. Tight junction in the intestinal epithelium: Its association with diseases and regulation by phytochemicals. J Immunol Res [Internet]. 2018;2018(Figure 2). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6311762/pdf/JIR2018-2645465.pdf
  7. Carabotti M, Scirocco A, Maselli MA, Severi C. The gut-brain axis: Interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol [Internet]. 2015;28(2):203–9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/pdf/AnnGastroenterol-28-203.pdf
  8. Salem I, Ramser A, Isham N, Ghannoum MA. The gut microbiome as a major regulator of the gut-skin axis. Front Microbiol [Internet]. 2018;9(JUL):1–14. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6048199/pdf/fmicb-09-01459.pdf
  9. Hills RD, Pontefract BA, Mishcon HR, Black CA, Sutton SC, Theberge CR. Gut microbiome: Profound implications for diet and disease. Nutrients [Internet]. 2019;11(7):1–40. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682904/pdf/nutrients-11-01613.pdf
  10. Jensen T, Abdelmalek MF, Sullivan S, Nadeau KJ, Green M, Roncal C, et al. Fructose and Sugar: A Major Mediator of Nonalcoholic Fatty Liver Disease. J Hepatol [Internet]. 2018;68(5):1063–75. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893377/pdf/nihms942365.pdf
  11. Leahy J (Jack) L, Aleppo G, Fonseca VA, Garg SK, Hirsch IB, McCall AL, et al. Optimizing Postprandial Glucose Management in Adults With Insulin-Requiring Diabetes: Report and Recommendations. J Endocr Soc [Internet]. 2019;3(October):1942–57. Available from: https://academic.oup.com/jes/article/3/10/1942/5581189
  12. O’Keefe Osborn C. How to Recognize and Manage a Blood Sugar Spike [Internet]. 2018 [cited 2019 Nov 25]. Available from: https://www.healthline.com/health/blood-sugar-spike
  13. Sack D. 4 Ways Sugar Could Be Harming Your Mental Health [Internet]. 2013 [cited 2019 Nov 25]. Available from: https://www.psychologytoday.com/au/blog/where-science-meets-the-steps/201309/4-ways-sugar-could-be-harming-your-mental-health
  14. Kucharska A, Szmurło A, Sinska B. Significance of diet in treated and untreated acne vulgaris. Postep Dermatologii i Alergol [Internet]. 2016;33(2):81–6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4884775/pdf/PDIA-33-27313.pdf
  15. Singh RK, Chang HW, Yan D, Lee KM, Ucmak D, Wong K, et al. Influence of diet on the gut microbiome and implications for human health. J Transl Med. 2017;15(1):1–17.

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