Our bodies naturally produce cholesterol to help it function and carry out normal processes. But too much cholesterol from dietary foods (eg animal fats, which are high in saturated fats) can impact heart health. High levels of low-density lipoprotein (LDL) cholesterol (sometimes referred to as bad cholesterol) can increase the risk of heart disease.
Eating fibre sourced from vegetables and fruit can lower LDL levels, but if increasing your fibre intake proves challenging from dietary sources, then an alternative solution could be using supplementation.
· A review of clinical studies showed increasing fibre intake using soluble fibre supplementation to be an effective way of lowering the risk of heart disease.
· The findings were based on an analysis of 181 randomised controlled trials and included people with hyperlipidaemia, type 2 diabetes, and those who were obese or overweight.
· Researchers concluded taking just 5 grams of water-soluble fibre supplements on a daily basis could lower ‘bad’ cholesterol levels.
Delve into the full science
Cholesterol is a type of fat, often referred to as lipids, which travels through your bloodstream in tiny molecules wrapped inside proteins called lipoproteins. Dietary fibre, particularly water-soluble fibres, has demonstrated efficacy in lipid management. Dietary fibres are either insoluble or soluble forms. Insoluble fibre has a faecal bulking effect and passes through the digestive tract intact. Soluble fibre is the edible part of plants, such as vegetables, fruits, beans and oats, that are resistant to digestion and can improve cardiovascular health by lowering blood pressure, inflammatory markers, blood glucose, and lipids levels. Despite the known benefits of dietary fibre, less than 5% of the general population meets the recommended daily intake.
Earlier this year, Ghavami et al published a systematic review and meta-analysis, consisting of 181 randomised controlled trials, investigating the beneficial effects that soluble fibre has on serum lipid profiles. Amongst the 181 trials, 26% of studies included participants with hyperlipidaemia, 20% included participants with type 2 diabetes mellitus, 15% included participants who were obese or overweight, 13% included healthy participants, 5.5% included participants with a metabolic syndrome, and the remaining 20% included other diseases (1).
The meta-analysis highlighted that soluble fibre supplementation had an overall benefit by improving serum triglycerides, total cholesterol, LDL cholesterol, and apolipoprotein-B concentrations; however, it did not affect serum HDL cholesterol and Apolipoprotein-A levels. It demonstrated that soluble fibre supplementation significantly reduced triglycerides levels when compared with the placebo group by 5.55mg/d; significantly reduced total cholesterol levels after soluble fibre supplementation compared with the control group by 10.82 mg/d; significantly reduced LDL cholesterol, bad cholesterol, compared with placebo by 8.28mg/d; and significantly reduced Apolipoprotein-B, a protein that binds lipids to for lipoprotein, by 44.99mg/l. Finally, the dose-response meta-analyses indicated that taking a 5g soluble fibre supplement daily could reduce total cholesterol by 6.11 mg/dL, LDL cholesterol by 5.57 mg/d and Apolipoprotein-B by 16.37 mg/L.
The improvement that soluble fibre has for lipid markers suggests that soluble fibre, especially sticky fibres from fruits and vegetables, can help decrease gastric emptying time and delay the absorption of dietary cholesterol. As a result, delayed gastric emptying restricts glucose response after eating a main meal, improves insulin resistance and increases cholesterol synthesis (2 & 3). Therefore, those diagnosed with type 2 diabetes mellitus or metabolic syndrome may benefit from a soluble fibre supplement to help decrease cholesterol levels by insulin resistance-related mechanisms.
Based on the findings, increasing fibre intake using soluble fibre supplementation could be an effective intervention to prevent cardiovascular diseases.
Author: Katy Grieshaber is a Nutrition Advisor at Viridian Nutrition. She holds a BSc (Hons), in Food, Nutrition and Health and a Masters’ degree in Public Health.
References:
1. Ghavami A, Ziaei R, Talebi S, Barghchi H, Nattagh-Eshtivani E, Moradi S, et al. Soluble fiber supplementation and Serum Lipid Profile: A systematic review and dose-response meta-analysis of randomized controlled trials. Advances in Nutrition. 2023Jan13;
2. Wolever TMS, Tosh SM, Spruill SE, Jenkins AL, Ezatagha A, Duss R, et al. Increasing oat β-glucan viscosity in a breakfast meal slows gastric emptying and reduces glycemic and insulinemic responses but has no effect on appetite, food intake, or plasma ghrelin and PYY responses in healthy humans: A randomized, placebo-controlled, crossover trial. The American Journal of Clinical Nutrition. 2020;111(2):319–28.
3. Hoenig MR, Sellke FW. Insulin resistance is associated with increased cholesterol synthesis, decreased cholesterol absorption and enhanced lipid response to statin therapy. Atherosclerosis. 2010;211(1):260–5.
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