Why fibre is now the most fashionable thing on your plate
Celery juice cleanses and alkaline diets are so 2019 (and nutribollocks). Time to pay attention to the real player in bettering your health, backed by a tonne of real evidence and research.
When I was younger, I only really knew of fibre from the unappetising box of bran cereal in my nan’s kitchen. It was known for keeping your bowel movements regular and supporting your digestive system but as research has evolved and interest in the microbiome has boomed, fibre is really taking centre stage.
You may think fibre as pretty simple, its own entity. However, as nutrition professionals know, fibre is simply an umbrella term for a huge range of compounds each with differing physiochemical properties. Academics for years have argued over the actual definition of fibre and there are still varying classifications depending on which country you live in.
So let’s break it down, all dietary fibres are able to avoid being digested in your small intestine, however they can differ in their solubility (ability to dissolve in water), viscosity (its ‘thickness’) and fermentability. These 3 traits are incredibly important in determining the subsequent health benefits from fibre consumption. The varying types of fibre are found in differing ratios within whole foods therefore it’s so important to eat a wide variety in order to maximise all the benefits of fibre.
So what can fibre do for you? Well….
Reduce your blood cholesterol
Lower your glucose response to a meal
Lower your blood pressure
Improve your number 2’s!
Associated with reduction in cardiovascular disease, type 2 diabetes, metabolic syndrome, cancer, weight maintenance and gastrointestinal issues like IBS
Nourish and support your microbiota
Produce anti-inflammatory compounds and reduce gut inflammation
Importance of fermentability and your gut health
Poorly fermentable fibres are present in things like grains ie wheat, rye, barley and psyllium supplements. These can bind to water, increasing faecal bulk, and reducing transit time thus are key in aiding with constipation. Fibres such as cellulose and lignin (found in cell walls of vegetables or woody plants and seeds) are also poorly fermented fibres. For those with IBS, soluble poorly fermentable fibres have shown to help alleviate gas, however this is limited to soluble fibre, as insoluble fibre poorly fermented (e.g., wheat bran) can cause bloating and abdominal discomfort. Complex, I know!
Fermentable fibres are found in fruits, vegetables, nuts and oats and act as a fuel supply for bacteria. Think of this ‘eating for 2’, encouraging consumption of foods which help support a healthy gut microflora. These types of fibres are what we call ‘prebiotics’. Some fermentable fibres such as beta glucan found in oats have other health benefits such as helping maintain healthy cholesterol levels and benefiting blood glucose levels. Those with IBS symptoms, reducing these highly fermentable fibres ie FODMAP foods has been found to relieve abdominal pain/discomfort, abdominal bloating/distension, and flatulence.
Fermentation of fibre results in the formation of short-chain fatty acids (SCFA) which are incredibly important compounds, called propionate, acetate and butyrate. A few studies have suggested anti-obesogenic and anti-diabetic effects of SCFA produced from fibre fermentation. Butyrate has been a key interest, as its acts as an energy source for your cells in the gut, a powerful antioxidant, and possesses anti-inflammatory properties. I will do a separate post on Butyrate as it deserves it!
Remember, there is no single answer for achieving optimum health. Associations between high fibre diets and reductions in disease often look at fibre rich whole foods, but there are plenty of other nutrients and phytochemicals which will also be having a positive impact on your body.
Eat real and eat whole! For example, flaxseeds, oats, legumes, nuts, fruit, and vegetables are good sources of soluble viscous and non viscous fibre. Wheat bran, brown rice, barley, cabbage, celery, and whole grains are rich sources of insoluble fibre. Diversity in your diet is so important to make sure you are getting all of the different fibre types. The current recommended fibre intake for adults is 30g per day, how much are you having?