The quick lowdown on types of fibre
Fibre is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Fibres are diverse and were classically broken into two types; insoluble and soluble. However, with more science and research in the last number of years, they have been categorised based on certain characteristics:
Solubility (the ability to be dissolved, especially in water)
Viscosity (the state of being thick, sticky, and semi-fluid in consistency)
Fermentability (the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms)
Physiological effects (water holding capacity & bulking
(Williams et al., 2019)
Diseases of the Heart
Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in developed countries. CVD is a general term for conditions affecting the heart or blood vessels. Types of CVD include:
Coronary Heart Disease (angina, heart attacks, heart failure)
Strokes
Peripheral Arterial Disease
Aortic Disease
The exact cause of CVD isn’t clear but instead there are several risk factors that can lead to developing CVD; high cholesterol, high blood pressure, smoking, diabetes, inactivity, being overweight/obese, family history, an unhealthy diet and excessive alcohol. Age, gender and ethic background are also factors that can also influence a person's chance of developing CVD. (National Health Service, 2018)
How can fibre actually help my heart?
Intake of dietary fibre lowers plasma lipids. Fibres, particularly soluble ones lower serum total cholesterol and serum low-density lipoprotein cholesterol ('bad cholesterol'). Consequently, the incidence of atherosclerotic heart diseases is lower in those who intake high dietary fibre. People who eat a diet rich in saturated fat and poor in dietary fibre are more prone to develop coronary artery diseases. (Mia et al., 2002)
Research studies have shown that people who eat more fibre in their diet have a lower body weight, lower blood pressure and lower cholesterol which are all great factors for heart health!
The beneficial effects of fibre on cholesterol are well documented. Oats and barley contain a special form of soluble fibre called beta-glucan which has been shown to lower cholesterol. It works by forming a gel in the gut which can bind with cholesterol-rich bile acids and stop them being absorbed into the body. A minimum 3 g dose is recommended for a health benefit (Evans, 2019).
In relation to blood pressure, diets rich in beta-glucans have shown to reduce SBP (systolic blood pressure) by 2.9 mmHg and DBP (diastolic blood pressure) by 1.5 mmHg (Evans et al., 2015). From my research into stroke risk and dietary fibre, more studies need to be carried out. Findings have been inconsistent to date due to the lack of research on stroke and specific fibre types. However, there is evidence that higher total dietary fiber intake is significantly associated with lower risk of first stroke. (Threapleton et al., 2013)
Dietary fiber intake has repeatedly been reported to be beneficial in reducing both serum cholesterol and blood pressure, and so it is believed that a deficiency in dietary fiber might be contributing to the epidemic of cardiovascular disease. (McRae, 2017)
Williams, B.A., Mikkelsen, D., Flanagan, B.M. and Gidley, M.J. (2019). “Dietary fibre”: moving beyond the “soluble/insoluble” classification for monogastric nutrition, with an emphasis on humans and pigs. Journal of Animal Science and Biotechnology, 10(1).
National Health Service (2018). Cardiovascular disease. [online] NHS. Available at: https://www.nhs.uk/conditions/cardiovascular-disease/.
Mia, M.A.R., Siddiqui, M.N.I., Haque, M.S., Islam, M.N., Rukunzzaman, M. and Deb, K. (2002). Dietary fibre and coronary heart disease. Mymensingh medical journal, [online] 11(2), pp.133–135. Available at: https://europepmc.org/article/med/12395688/ [Accessed 31 Jan. 2022].
Evans, C.E.L. (2019). Dietary fibre and cardiovascular health: a review of current evidence and policy. Proceedings of the Nutrition Society, 79(1), pp.61–67.
Evans, C.E.L., Greenwood, D.C., Threapleton, D.E., Cleghorn, C.L., Nykjaer, C., Woodhead, C.E., Gale, C.P. and Burley, V.J. (2015). Effects of dietary fibre type on blood pressure. Journal of Hypertension, 33(5), pp.897–911.
Threapleton, D.E., Greenwood, D.C., Evans, C.E.L., Cleghorn, C.L., Nykjaer, C., Woodhead, C., Cade, J.E., Gale, C.P. and Burley, V.J. (2013). Dietary Fiber Intake and Risk of First Stroke. Stroke, 44(5), pp.1360–1368.
McRae, M.P. (2017). Dietary Fiber Is Beneficial for the Prevention of Cardiovascular Disease: An Umbrella Review of Meta-analyses. Journal of Chiropractic Medicine, 16(4), pp.289–299.
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