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Fibre. Thought by most as so completely unsexy and unexciting.

But old mate fibre – the original super functional food (well, it’s a part of foods) – has not been given credit where credit is due.

Why?

Cleaning up
First, fibre helps us clear out endogenous and exogenous chemicals, toxins, unhelpful microbes, and any other waste products, encouraging clearer skin, brighter eyes, balancing hormones, and reducing risk factors for conditions like heart disease.

Not to mention getting your bowels moving regularly and happily. If you have ever been the subject of persistent constipation or diarrhoea, you will understand the good time that is a good poo.

Feeding gut bugs
Second, it supports a healthy intestinal microbiome. Why do we care about the microbiome?

Well, it pretty much influences every aspect of health – mood, inflammation, weight, and conditions such as type 2 diabetes, cardiovascular disease, a myriad of gastrointestinal issues – the list goes on.

Humans cannot digest fibre – but fermentable fibres are the fav food of the microbes of the intestinal tract. These are generally the ‘soluble’ fibre, found in whole foods like beans, legumes, veg, and oats, and resistant starch, found in unripe bananas, plantains, and cooked and cooled rice, legumes, or potatoes.

When these are digested by the gut bugs short-chain fatty acids butyrate, propionate and acetate, are produced.

Short-chain fatty acids feed the cells of the colon, lower inflammation, and are helpful in conditions such as inflammatory bowel and Crohn’s disease.

Butyrate is also believed to be brain-protective, encouraging neuroplasticity and regeneration, and may be of use as part of treatment for a variety of brain disorders, as suggested below.1

Image: Bourassa et. al 2016.

Image: Bourassa et. al 2016.

Essentially, if we can keep the good gut bugs happy with some soluble fibre and resistant starch, we are helping ourselves in a number of ways.

Protective
Third, fibre is delivered in whole foods that offer an array of other nutrients that can exert health protective and anti-inflammatory benefits. Think veg, leafy greens, fruit, nuts, seeds, beans, and some whole grain like oats and brown rice.

Diets higher in fibre have been associated with reduced risk for:2-4

  • cardiovascular disease
  • type 2 diabetes
  • inflammatory bowel and other gastrointestinal conditions
  • some cancers.

Such benefits may also be – at least in part – due to fibre’s benefit to the health of the microbiome, or the action of the butyrate produced by the gut bugs.

Resistant starch, specifically, may improve insulin sensitivity.5

Fibre also slows the absorption of simple sugars into the bloodstream, avoiding post-food spikes and crashes of blood glucose and insulin (and your energy),as well as an onslaught of fructose to the liver. Hence why naturally occurring sugars in whole foods are often not a problem, but can of soft drink is.

This combined with beneficial effect on the gut microbe populations may be why there is a positive association between adequate dietary fibre intake and reduced risk of overweight and insulin resistance.4

Fuel up on fibre!
If you are eating mostly real whole foods, including an abundance of vegetables, you are likely already meeting the recommended 25-30 grams daily intake.

Some sources believe that on average our hunter-gatherer ancestors were chomping down on up to 100 grams a day, which is a lot of food – but it was provided in simple whole foods like leaves, berries, and roots.

We aren’t saying going overboard on the stuff! But when seeking fibrous foods, take some ancestral inspiration and enjoy good quality real, whole foods, over the packaged stuff ‘fortified’ with added fibre (like high sugar cereal products).

Within that 25-30 grams, aim to get some resistant starch, and ensure a mix of soluble (the type that soaks up water and prevents constipation) and insoluble (the type that adds bulk to stools, helping them pass) fibre. Each plant food will have a different ratio of soluble to insoluble fibre.

So, go on – fuel up on the original super functional food. Because you, and your gut bugs, are worth it.

By Angela Johnson (BHSc Nut. Med.)

 

References:

  1. Bourassa, MW, Alim, I, Bultman, SJ, & Ratan, RR 2016, ‘Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health?’, Neuroscience Letters, p. 56.
  2. Anderson, JW, Baird, P, Davis, RH, Ferreri, S, Knudtson, M, Koraym, A, Waters, V, & Williams, CL 2009, ‘Health benefits of dietary fiber’, Nutrition Reviews, vol. 67, no. 4, pp. 188-205
  3. Kim, Y, & Je, Y 2016, ‘Dietary fibre intake and mortality from cardiovascular disease and all cancers: A meta-analysis of prospective cohort studies’, Archives Of Cardiovascular Diseases, vol. 109, no. 1, pp. 39-54.
  4. Weickert, MO, & Pfeiffer, AH 2008, ‘Metabolic effects of dietary fiber consumption and prevention of diabetes’, The Journal Of Nutrition, vol. 138, no. 3, pp. 439-442.
  5. Johnston, KL, Thomas, EL, Bell, JD, Frost, GS, & Robertson, MD 2010, ‘Resistant starch improves insulin sensitivity in metabolic syndrome’, Diabetic Medicine: A Journal Of The British Diabetic Association, vol. 27, no. 4, pp. 391-397.