What is Gut Health and Why is it Important?
The gut contains 70-80% of the body’s immune system (2), so it’s important we look after it. The gut microbiome also affects physical health, mental health, and the brain. Eating a gut-friendly diet has the potential to improve your mood, power your brain performance, improve your long-term brain health, reduce anxiety, stress, and depression, and support your immune system - the benefits are endless!
An imbalance of gut microbiota (known as gut dysbiosis) is associated with a higher risk and incidence of central nervous disorders (i.e., anxiety, depression) as well as functional gastrointestinal disorders (e.g. constipation, Irritable Bowel Syndrome (IBS))(8). The gut is now being referred to as our ‘second brain’. So that age-old saying about having a “gut feeling” about something makes a lot of sense when you see how much is actually going on in your gut. The gut has its own nervous system, and it contains more neurotransmitters than the brain itself! Metabolites produced by the microbiome can act as signalling molecules to the brain (4). In terms of diet and lifestyle factors – what’s good for gut health is good for the brain!
How Can You Improve Your Gut Health?
Environmental considerations such as diet and the people you live with have major, and real-time influence on the composition and function of the gut microbiota (6). Dietary diversity leads to microbial diversity and more positive health outcomes. Some beneficial microbes can ferment plant fibres to produce important short-chain fatty acids (SCFAs) such as butyrate (6). Butyrate is a powerful anti-inflammatory inside the gut and provides your colon cells with energy (7). The best way of improving butyrate in your body is to increase your intake of dietary fibres – think vegetables, fruits, nuts, seeds, legumes, and wholegrains.
Diet is considered one of the primary drivers in shaping the gut microbiota across the lifetime. A ‘gut-friendly’ diet is personal to the individual (e.g. dairy-free, gluten-free, supplements), however, there are some basics that are often missed:
1. Variety is the Spice of Life!
- Aim for 30+ plant foods each week for good gut health (9).
- Consume 5 servings of vegetables each day. Try to have as many different colours here as possible. E.g. broccoli, yellow pepper, tomato, carrot, mushrooms – eat the rainbow! Rotate your sources of each colour too. If your green vegetable today is broccoli, tomorrow make it peas. If you’re having a yellow pepper today, have sweetcorn tomorrow as your yellow vegetable. Mix it up and have fun tasting the rainbow!
- Choose wholefoods and minimally processed foods. Avoid ultra-processed foods.
2. Fibre Diversity
- The World Health Organisation (WHO) recommends adults have 30g of fibre each day. Fibre feeds our gut bacteria, so it’s important we consume enough.
- Fibre diversity is also key! Your gut bacteria require a complex mix of fibres to thrive. Increased fibre allows your gut to produce more butyrate (7), which reduces inflammation.
- Consume meals that are complex to digest.
- Aim for 3 wholegrain foods each day. An increase in just 3 serves/day of wholegrains has been shown to reduce mortality by all causes by 17%, from cardiovascular disease by 25%, and from all types of cancer combined by 10% (even more so for bowel cancer) (3)! Wholegrain intake is associated with less inflammation and better cognitive health, particularly as we get older (5).
- Eat legumes/pulses at least 3 times a week.
- Nuts and seeds are great sources of prebiotics (plant fibres that feed the good bacteria). Aim for ~30g most days.
- Ensure you drink lots of water to allow the fibre to do its job properly and avoid dehydration.
3. Probiotics & Fermented Foods
- Taking a daily probiotic such as kefir can actively support your digestion, skin, and immune system, particularly when combined with prebiotics and a high-fibre diet. Both probiotics and prebiotics have been shown to reduce levels of anxiety, stress, and depression (12).
- Your gut loves fermented foods e.g. kefir, kimchi, sauerkraut, tempeh, kombucha, miso, probiotic yoghurt.
- Including both probiotics and fermented foods in your diet will hugely benefit you in boosting your levels of some of the most beneficial good bacteria in your gut!
4. Mind your Mind
- Prolonged stress is almost always felt in our digestion thanks to our gut: brain axis. Being under stress reduces the number and diversity of microbiota and can lead to digestive issues (10). Incorporating stress-relieving practices into daily life can protect against negative effects on gut health (11). This is particularly important as poor gut health can amplify mental health symptoms. Include practices such as exercise, yoga, meditation, deep breathing, and time in nature.
Whilst it can feel like an effort to implement these things into your daily diet at the start, it feels a lot easier than facing the negative health outcomes that often come with poor gut health. Once you feel the benefits of good gut health, you will not want to look back! Start slow and challenge yourself to include 2-3 new plant foods in your food shop each week and have fun incorporating these into your meals. In a world where we’re constantly being pushed on diets that focus on removing food groups, treats, etc., it can be easy to feel negative feelings towards the word ‘diet’. The great thing about a gut-healthy diet is that it's all about adding more! How can I add more colour to my plate? How can I add more fibre or diversity? So have fun with it!
- Raes, J., 2012. The gut flora: You and your 100 trillion friends: Jeroen Raes at TEDxBrussels. [online] Youtube.com. Available at: https://www.youtube.com/watch?v=Af5qUxl1ktI [Accessed 7 November 2021].
- Furness, J., Kunze, W. and Clerc, N., 1999. II. The intestine as a sensory organ: neural, endocrine, and immune responses | American Journal of Physiology-Gastrointestinal and Liver Physiology. [online] American Journal of Physiology-Gastrointestinal and Liver Physiology. Available at: https://journals.physiology.org/doi/full/10.1152/ajpgi.1999.277.5.g922 [Accessed 7 November 2021].
- Audible Australia Pty Ltd, 2020. Gutfull: What to Eat for a Happy Gut
- Valles-Colomer, M., Falony, G., Darzi, Y. et al. The neuroactive potential of the human gut microbiota in quality of life and depression. Nat Microbiol 4, 623–632 (2019). https://doi.org/10.1038/s41564-018-0337-x
- Schmidt, K., Cowen, P., Harmer, C., Tzortzis, G., Errington, S. and Burnet, P., 2014. Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers. Psychopharmacology, 232(10), pp.1793-1801.
- Hills RD Jr, Pontefract BA, Mishcon HR, Black CA, Sutton SC, Theberge CR. Gut Microbiome: Profound Implications for Diet and Disease. Nutrients. 2019 Jul 16;11(7):1613. doi: 10.3390/nu11071613. PMID: 31315227; PMCID: PMC6682904.
- Eyvazzadeh, A., 2019. Butyric Acid: What Is It, and What Are the Benefits?. [online] Healthline. Available at: https://www.healthline.com/health/butyric-acid [Accessed 30 July 2022].
- Vijay, A. and Valdes, A., 2022. Role of the gut microbiome in chronic diseases: a narrative review. European Journal of Clinical Nutrition, 76(4), pp.489-501.
- The Irish Nutrition and Dietetic Institute (INDI), 2022. The 30 Different Plant Based Foods Per Week Challenge - INDI. [online] Indi.ie. Available at: https://www.indi.ie/11-news/1458-the-30-different-plant-based-foods-per-week-challenge.html [Accessed 30 July 2022].
- Geng, S., Yang, L., Cheng, F., Zhang, Z., Li, J., Liu, W., Li, Y., Chen, Y., Bao, Y., Chen, L., Fei, Z., Li, X., Hou, J., Lin, Y., Liu, Z., Zhang, S., Wang, H., Zhang, Q., Wang, H., Wang, X. and Zhang, J., 2020. Gut Microbiota Are Associated With Psychological Stress-Induced Defections in Intestinal and Blood–Brain Barriers. Frontiers in Microbiology, 10.
- Carver-Carter, R., 2022. How Stress Impacts The Microbiome And Gut Health. [online] Atlas Biomed blog | Take control of your health with no-nonsense news on lifestyle, gut microbes and genetics. Available at: https://atlasbiomed.com/blog/how-stress-impacts-the-gut-via-the-gut-brain-axis/ [Accessed 30 July 2022].
- Liu, R., Walsh, R. and Sheehan, A., 2019. Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials. Neuroscience & Biobehavioral Reviews, 102, pp.13-23.