The hidden hero of a healthful diet
When it comes to nutrition, certain nutrients often steal the spotlight – protein, omega-3s, caffeine. But one often-overlooked nutrient quietly works wonders behind the scenes. Even though it isn’t essential (meaning we can technically live without it), it does incredible things for our health: fibre.
It’s the Cinderella of nutrients – less glamorous but powerful in ways that extend far beyond digestion. From supporting gut health to balancing blood sugar and improving blood pressure, fibre is a true hero in a healthful diet[1]. And yet, we don’t get enough. Less than 10% of UK adults eat the recommended amount[2]. It’s time to give fibre the limelight it deserves!
What is this fibre?
Dietary fibre is technically a carbohydrate, but it’s one we can’t digest. It’s the part of plant foods that our bodies can’t break down – while other nutrients from food are broken down and absorbed, fibre travels through the gut until our next visit to the loo. But along the way, it interacts with its environment: the gut itself, other nutrients, and the gut microbiota. Different types of fibre have different effects on the body[3]. Some fibres benefit heart health, others support digestion, and some regulate blood sugar. Fibre’s diversity is what makes it so powerful for our health.
The SACN report shows that increasing dietary fibre intake by just 7g per day is associated with a reduced risk of cardiovascular disease, stroke, colorectal cancer, and diabetes[1].
Why fibre variety matters
We often talk about “fibre” as if it’s a single nutrient, but there are hundreds of different types with a wide range of functions, depending on their degree of solubility, viscosity, and fermentability. Fibre plays a part in health in many ways: aiding digestion[4], reducing cholesterol[5], managing blood sugar[6], helping prevent cancer[7] and gut disorders[8]. There is even emerging research suggesting that fibre could improve mood and mental health through the gut-brain axis[9]. This is why eating just wheat bran for breakfast isn’t enough. There is more to fibre than a Weetabix biscuit!
Here’s a focus on specific types of fibre with benefits backed up by science:
Fermentable fibre (e.g., onions, garlic, bananas)
Fermentable fibres act as food for beneficial gut bacteria, which produce short-chain fatty acids that support gut health and modulate the immune system. This process of fermentation is a key element for a balanced microbiome and a good gut barrier function[11].
Beta-glucan (e.g., oats, barley)
This specific type of soluble fibre forms a gel in the gut, which can lower LDL (bad) cholesterol and help manage blood sugar levels. Beta-glucan’s benefits are well-documented, particularly for heart health[12].
Psyllium husk (e.g., found in fibre supplements)
Psyllium is a type of soluble, viscous fibre known for its ability to improve regularity and relieve constipation[13].
Resistant starch (e.g., cooked and cooled potatoes, green bananas, legumes)
Resistant starch is exactly what it says, a starch that resists digestion in the small intestine and instead reaches the colon, where it feeds beneficial bacteria. This fibre type promotes digestive health and may reduce inflammation [11].
Inulin (e.g., chicory roots, garlic, leeks, asparagus, Jerusalem artichokes)
Inulin is a prebiotic, a type of soluble fibre that serves as food (or substrate) for beneficial microorganisms in our gut. It may help regulate blood sugar and improve digestive health[10, 11].
Hemicellulose (e.g., nuts, seeds, whole grains, legumes, some vegetables)
Hemicellulose is a form of mixed soluble and insoluble fibre that helps to regulate digestion and improve stool bulk. It is found in nuts, seeds, and whole grains, contributing to gut health and improved cholesterol metabolism [3, 10].
How much fibre do you need?
In the UK, adults are advised to aim for at least 30 grams of fibre per day [1,3]. However, only about 10% of adults meet this daily target, meaning most of us fall short. The Western diet—high in refined carbs and animal-based protein but low in fruits, vegetables, and whole grains—is notoriously fibre-poor. This may be one reason why ultra-processed foods are linked to poor health outcomes.
Increasing your fibre intake gradually
Hopefully, at this point you are itching to boost your fibre intake. Great, but let’s take it slow! Adding fibre too quickly can cause bloating and gut discomfort. We need to let the gut adapt and get used to this new regime. Let your gut adapt by introducing small amounts at a time, and make sure to drink plenty of water. Hydration is particularly important because some fibre absorbs water to help things move smoothly through your digestive system.
Tips get a variety of fibre in your diet
To get the full spectrum of fibre benefits, aim to include a variety of fibre-rich foods daily:
Whole Grains (e.g., oats, barley, brown rice): These grains provide beta-glucan and other beneficial fibres that support heart health and digestion. They are also protective against certain cancers.
Fruits and Vegetables (e.g., berries, broccoli, carrots): Many fruits and veggies offer both fermentable and resistant fibres (plus they are full of another amazing compound called polyphenols but that is for another time).
Legumes (e.g., lentils, chickpeas, beans): Legumes are packed with fibre that benefits gut health and blood sugar levels. They also bring plenty of protein, and other nutrients and deserve more space on our plates.
Nuts and Seeds (e.g., almonds, chia seeds, flaxseeds): Nuts and seeds contain a mix of fibres, healthy fats, and protein, helping with satiety and nutrient intake.
When fibre doesn’t sit right with you
While most of us would benefit from more fibre, people with Irritable Bowel Syndrome (IBS) may find certain fibres trigger bloating, gas, or discomfort[14]. Some highly fermentable fibres (in some fruits, vegetables, and legumes) can cause these issues.
Because IBS varies from person to person, finding the right fibre balance often requires personalised support. A registered nutrition professional can help identify which fibres to limit while keeping your diet as varied as possible.
And don’t feel like you have to eat the same way for life. Interestingly, gradually reintroducing certain fibres may help the body adjust over time.
A Fibre-boosting tip: pair for power!
To get the best variety, try combining foods from different groups in one meal. For instance, add a handful of berries and chia seeds to your morning oats, or toss chickpeas into a vegetable salad, sprinkle some seeds onto your roasted veggies. This way, you’re getting a mix of different fibres in a single meal, working together to support your health.
Incorporating more fibre into your diet is a great start, but remember that variety is the key to unlocking its full potential. Just like Cinderella, fibre may seem unassuming, but it has the power to make a big impact. By adding a diverse range of fibre-rich foods to your meals, you’re setting up your body for success – from supporting your gut microbiome to protecting heart health.
And the benefits go beyond personal health – eating more plant-based, fibre-rich foods is also a step towards a more sustainable diet that’s better for the planet. So, next time you’re planning a meal, think about how you can include this hidden hero. Your body, your health, and the environment will thank you!
Hello, my name is Clem.
I’m an award-winning, evidence-based nutritionist (MSc, RNutr) and workplace wellbeing specialist.
I help organisations and individuals make sense of nutrition so they can nurture their health and wellbeing with confidence.
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References
[1] Scientific Advisory Committee on Nutrition (SACN). Carbohydrates and health. Public Health England (2015). https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report
[2] Public Health England. NDNS: Results from years 9 to 11 (combined) – Statistical summary (2019). https://www.gov.uk/government/statistics/ndns-results-from-years-9-to-11-2016-to-2017-and-2018-to-2019
[3] Stephen, A. M. et al. Dietary fibre in Europe: Definitions, sources, recommendations, intakes and health effects. Nutr. Res. Rev. 30, 149–190 (2017). https://doi.org/10.1017/S095442241700004X
[4] Frame, L. A. et al. Nutrition and the gut microbiome: A comprehensive review. Nutr. Rev. 78, 798-812 (2020). https://doi.org/10.1093/nutrit/nuz106
[5] Fu, L. et al. Dietary fibre intake and cardiovascular risk factors: An umbrella review. Front. Nutr. 9, 972399 (2022). https://doi.org/10.3389/fnut.2022.972399
[6] Reynolds, A. et al. Carbohydrate quality and human health: Systematic reviews and meta-analyses. Lancet 393, 434–445 (2019). https://doi.org/10.1016/S0140-6736(18)31809-9
[7] Hu, J. et al. Dietary fibres and cancer risk: An umbrella review. Nutrients 15, 2545 (2023). https://doi.org/10.3390/nu15112545
[8] Gill, S. K. et al. Dietary fibre in gastrointestinal health and disease. Nat. Rev. Gastroenterol. Hepatol. 18, 101-116 (2021). https://doi.org/10.1038/s41575-020-00375-4
[9] Saghafian, F. et al. Dietary fibre intake, depression, and anxiety: A systematic review and meta-analysis. Nutr. Neurosci.26, 108-126 (2023). https://doi.org/10.1080/1028415X.2021.2020403
[10] Deehan, E. C. et al. Effects of dietary fibre on metabolic health and obesity. Nat. Rev. Gastroenterol. Hepatol. 21, 301–318 (2024). https://doi.org/10.1038/s41575-023-00891-z
[11] Slavin, J. Dietary fibre and its many benefits. Nutr. Today 48, 189-195 (2013). https://doi.org/10.1097/NT.0b013e3182a40a0d
[12] Ho, H. V. et al. The effect of oat β-glucan on LDL-cholesterol: A systematic review. Br. J. Nutr. 116, 1369-1382 (2016). https://doi.org/10.1017/S000711451600341X
[13] van der Schoot, A. et al. Fibre supplementation and chronic constipation: A systematic review. Am. J. Clin. Nutr. 116, 953–969 (2022). https://doi.org/10.1093/ajcn/nqac184
[14] Whelan, K. & Martin, L. D. Dietary management of irritable bowel syndrome. Lancet Gastroenterol. Hepatol. 8, 234–245 (2023). https://doi.org/10.1016/S2468-1253(22)00377-0
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