FIBRE

You probably already know that fibre is essential for good digestive function and a healthy gut microbiome, but did you know that fibre can also influence your metabolism, immune function, hormones, vitamin synthesis and brain health? 

Fibre is emerging as a fundamental factor in overall health following studies into the gut microbiome in the fields of neuroscience, metabolism and healthy ageing. 

Fibre is actually a form of carbohydrate found only in plant foods. We can’t digest it so when we eat, the fibre travels to the large intestine where it acts as ‘food’ for our beneficial bacteria, activating reactions that influence wide- ranging health benefits, from lowering cholesterol by reducing absorption in the gut, to reducing constipation, diverticular disease and colorectal cancer. Fibre also helps maintain a healthy weight, playing a role in satiety signalling, and buffering blood glucose levels.  

World and UK health organisations have identified that in the UK we should be eating 30g fibre per day - the current average being 17g-19g per day.  Children and the over 50’s need a bit less. 

Here are some examples of how much fibre is in common foods: 

1. 3g fibre = 1 medium (underripe) banana, carrot, or orange, or 1 small apple, or 10 brazil nuts, 0r 30 raspberries
2. 4g fibre = 2 Slices Wholemeal bread or a medium baked potato (with skin) , or 40g serving of oats, or a tablespoon of flaxseeds
3. 6g fibre= 2 kiwi fruits, or 160g tofu 
4. 8g fibre = 75g of wholewheat spaghetti, or 100g beans, lentils or bulghur wheat, or 2 tablespoons of chia seeds

Fibre is found in all plant foods (non-starch polysaccharides are part of the cell wall) but there are different forms, with different benefits.

Soluble fibre forms a gel in the gut and can lower high cholesterol, and blood glucose. It’s found in all fruits (especially apples and citrus), flaxseed (also known as linseeds), vegetables, beans and pulses . Ground flaxseeds (or linseeds), chia seeds, and psyllium husk are very high in soluble fibre, so start slowly if you’re incorporating these into your diet.  Beta-glucans are a superhero sub-group of soluble fibre, proven to reduce cholesterol and are found in oats, barley, mushrooms, rye bread, nutritional yeast and seaweed. 

Insoluble fibre acts like a brush for our intestine. It’s best for constipation (softening the stool and speeding transit time), and it buffers glucose absorption. Fruits with small seeds like strawberries, raspberry, and kiwi, wheat and oat bran, rye bread, barley, and wholemeal cereals are good sources. Some foods like vegetables, beans and pulses contain both soluble and insoluble fibre. 

Prebiotics and resistant starches can be considered as types of fibre, because they act on our gut microbes. Prebiotics are a specific group of plant foods useful for balancing blood glucose, and feeding the beneficial bacteria in the gut. Prebiotic foods include Jerusalem artichokes, underripe bananas, tomatoes, leeks, onions, garlic, chicory root, legumes, nuts & seeds.

Resistant starches are a type of starch that also feeds beneficial bacteria, found in green banana, coarse corn (maize) flour, cooked and cooled potatoes and rice (potato salad, russian salad, sushi rice, rice salad) or cooked, cooled and reheated pasta.

Tips  for including fibre in your diet: 

• Try to get most of your fibre from soluble fibre, as it has wider gut benefits.  
• Increase hydration when you eat more fibre, to avoid gas and bloating!
• Some forms of fibre, like prebiotics may trigger symptoms in IBS, so add foods individually to track any symptoms.

Here are some practical ways to add fibre-rich foods to everyday meals:

Fibre Quiz https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/fibre/fibre-quiz

References

1. https://www.fdf.org.uk/globalassets/final---fibre-feb-webinar.pdf
2. European Journal of Clinical Nutrition: "A systematic review and meta-analysis of randomized controlled trials of the effect of barley β-glucan on LDL-C, non-HDL-C and apoB for cardiovascular disease risk reduction"
3. Journal of Nutrition and Metabolism: "Beta Glucan: Health Benefits in Obesity and Metabolic Syndrome"
4. https://zoe.com/learn/vegetables-high-in-fiber, https://badgut.org/information-centre/health-nutrition/dietary-fibre/, https://www.bda.uk.com/resource/fibre.html
5. https://innovixlabs.com/blogs/insights/prebiotic-fiber-supplement
6. https://gutscharity.org.uk/advice-and-information/health-and-lifestyle/prebiotics-probiotics/
7. https://badgut.org/information-centre/health-nutrition/dietary-fibre/
8. https://www.monashfodmap.com/blog/getting-enough-fibre/