In brief

• Dietary fibres are non-digestible carbohydrates primarily found in whole-grains, pulses, nuts, seeds, fruits and vegetables
• A daily diet high in fibre is associated with extensive health benefits such as 
  • enhancing blood sugar and insulin control,
  • supporting weight/fat loss,
  • improving digestive function,
  • strengthening immune defence,
  • providing protection against several lifestyle-related diseases
• Intakes of 25 g per day or more of dietary fibre is required to maintain good digestive health, which is most easily achieved by consuming a fibre-rich diet, in conjunction with a high-quality dietary fibre supplement
• ROS Nutrition provides a variety of options to supplement your diet with fibre, and also includes added fibre in a range of our powder formulations

Background

It was first observed over half a century ago that populations of countries with high intakes of dietary fibre had lower disease incidence rates compared to countries with more “Westernised” diets, where the intake of refined, low fibre carbohydrates predominated¹.  Disease states attributed to inadequate dietary fibre intake included constipation, diverticular disease, appendicitis, haemorrhoids, cancer (particularly of the colon and rectum), type 2 diabetes, cardiovascular disease and obesity^1,2.

The digestion process starts in the mouth, with the majority of macronutrients (i.e. carbohydrates, fats and protein) being digested and absorbed in the stomach and small intestine. Carbohydrates are long chains of carbon, hydrogen and oxygen molecules of various lengths, of which the most basic are monosaccharides (single sugar molecules). Dietary fibres are edible carbohydrates comprised of chains of sugar units of a few (oligosaccharides) or multiple monosaccharide units (polysaccharides), but are not digested by the human small intestine³. However, some (fermentable) dietary fibre (i.e. Fructooligosaccharides or FOS) can be broken down and converted into short-chain fatty acids (SCFAs) in the large intestine by resident “good” bacteria. These SCFAs are associated with numerous health benefits.

Types of dietary fibre

Meeting the recommended intakes of dietary fibre (>25 g per day) is associated with numerous health-related benefits^1-4.There are various types of dietary fibre including cellulose, hemicelluloses, pectins, gums (i.e. β-glucan), resistant starch, oligosaccharides (including FOS), dextrins and lignin. Dietary fibres can be characterised as being soluble or insoluble. Most foods contain a mixture of both soluble and insoluble fibres, but the potential benefits vary depending on the characteristics of the type of dietary fibre consumed. Soluble fibres dissolve water and form a gel-like substance (i.e. gums). This slows down the digestion process, which may help promote a sense of fullness and help control blood sugar and insulin (a hormone that regulates fat and blood sugar levels) levels. The main benefit associated with insoluble dietary fibres is the ability to act as a bulking agent, helping to increase stool bulk and relieve constipation by promoting a more rapid transit of food (and consequently, stools) through the intestines.

Two types of fibre that have recently received a considerable amount of attention are FOS (also known as fructans, oligofructose, inulin-type fructans and inulin) and β-glucan, due to their well-described health benefits. For instance, supplementing your diet with FOS and/or β-glucan is associated with enhanced body composition (decreased body weight and fat)^5-7, enhanced blood sugar and insulin control^5,8-10, enhanced bowel function^11-13, strengthened immunity^14-16, and also protection against several disease states^{4-6,8-10,16-20}. Furthermore, FOS also acts to promote digestive function^16,21,22, while the main benefit associated with β-glucan is for its ability to reduce blood cholesterol levels^19,20.

What does the research say?

Most individuals can benefit from increasing their daily fibre intake. Although the key focus for athletes is often on enhancing performance and recovery from training, promoting general good health is also paramount. Ensuring good digestive health is important to facilitate the absorption of other essential nutrients (i.e. vitamins, minerals, amino acids) that are crucial to promote performance and recovery gains. Likewise, supporting immune function is also vital to limit training days lost due to illness. Due to the numerous health benefits associated with dietary fibre intake, ensuring to meet recommended intakes of dietary fibre is therefore not only essential to support general health and well-being but is also important to maximise sports performance.

(i) Body composition Increasing daily dietary fibre intake through supplementing with FOS and/or β-glucansupports weight loss (and body fat loss) goals^5-7, particularly for individuals following calorie-controlled diets. Dietary fibre helps to reduce food intake by positively affecting the hormonal response to food intake (decreasing feelings of hunger and/or increasing feelings of fullness)^5,17. Furthermore, fibre may also promote increased excretion of dietary fats⁶, which may also aid weight loss. Supplementing a diet with FOS has also been shown to enhance insulin sensitivity and blood glucose control^5,8. This is important because improving insulin sensitivity enhances energy metabolism (promoting carbohydrate uptake and use by muscles) and reduces the preferential storage of carbohydrates as body fat. Insulin sensitivity is also a key marker of health as insulin resistance is associated with a range of lifestyle-related diseases such as obesity, type 2 diabetes and cardiovascular disease. Furthermore, increased intakes of dietary fibre may help to reduce visceral fat (fat that surrounds body organs) accumulation, which is associated with increased risk of these chronic disease states⁶.

(ii) Digestive health & immunity One of the key roles of dietary fibre is for it’s ability to enhance bowel function by facilitating more frequent bowel movements and preventing constipation, which is often observed in a low-fibre diet¹¹. Increasing stool bulk helps to create stools that are transported more easily and rapidly through the colon. Dietary fibres that have a high water-binding capacity (i.e. β-glucan)¹² have the greatest ability to create softer stools and increase stool bulk, while fermentable dietary fibres (i.e. FOS)¹³ help to increase bacterial mass, which also creates some bulking effect.
Dietary fibre, particularly fermentable dietary fibre (the most central of which is FOS) stimulates the production of short chain fatty acids (SCFAs) in the gut¹⁴. These SCFAs provide an energy source for “good” bacteria in the gut, known as pro-biotics (i.e. Lactic acid bacteria and Bifidobacterium) and may also help reduce the number of harmful microorganisms (substances) present in the gut, promoting gut health and immune defence¹⁴. Fermentable dietary fibres (including FOS) may also help to increase the absorption of various minerals including calcium²¹, magnesium, zinc and iron²², which are important for immune health and general well-being. SCFAs are also the main source of energy for the gut wall¹⁵. An inadequate intake of dietary fibre may be detrimental to gut health as bacteria (both “good” and “bad”) may break down the lining of the gut wall to meet energy demands, which may damage the digestive and immunoprotective ability of the gut. Furthermore, ensuring an adequate intake of dietary fibre also helps to reduce levels of inflammation¹⁶, which may also help to protect against the onset of irritable bowel disease (IBD) and other inflammatory-related disease states.

(iii) Metabolic disease One of the primary benefits associated with elevated dietary fibre intake is for it’s associated benefit to protect against numerous disease states. A high intake of highly-processed, refined carbohydrates (i.e. white rice/bread/pasta; pastries; highly-processed sugar-rich breakfast cereals; carbonated beverages; sweets) and/or a poor intake of dietary fibre are associated with increased risk of developing type 2 diabetes mellitus⁹. Conversely, ingesting approximately 4 g of dietary fibre (preferably in the form of β-glucan) for every 30-80 g of dietary carbohydrate enhances blood glucose and insulin control¹⁰, enhancing the control of and/or reducing the risk of developing type 2 diabetes.
Meeting recommended daily intakes of dietary fibre may also help to decrease triglyceride¹⁸ and total- and LDL- cholesterol (“bad” fats) levels¹⁹. The European Food Safety Authority (EFSA) advises to consume at least 3 g of β-glucan per day to help reduce LDL-cholesterol levels²⁰. Additionally, the aforementioned effects of dietary fibre on appetite^5,17, fat around internal body organs⁶; and inflammation¹⁶ is critical for reducing the risk of chronic lifestyle-related disease states such as cardiovascular disease and obesity.

(iv) Gut function and cancer risk Finally, health benefits are also observed by helping reduce the risk of developing and/or the growth of cancerous tumours, particularly of the colon and rectum via a variety of different mechanisms including decreased gut pH²³, the supply of energy (SCFAs) to resident gut bacteria¹⁴, dilution and more rapid movement of toxic substances through the gut facilitated by increased faecal bulk¹² (which reduces the contact time between the gut wall and potentially toxic substances), and decreased absorption of bile acids²⁴, therefore reducing the potential to convert primary to secondary bile acids, which has been associated with increased cancer risk. Ensuring to meet (or even better, exceed) the recommended daily intakes of dietary fibre is important as increased stool weight has been associated with decreased risk of intestinal disorders including colon cancer⁴.

What does the research say?

Recommended daily intakes of 25 g of dietary fibre are based on amounts adequate to ensure regular bowel function³. However, achieving fibre intakes as high as 30-40g/day may further enhance bowel movements and/or stool weight²⁵. While sources of dietary fibre are plentiful (whole-grain food choices (bread, rice, pasta), minimally-processed cereals (all bran/bran flakes, porridge oats), legumes, pulses, nuts, seeds, fruits and vegetables), reported intakes of fibre in the Irish population have been shown to reach only approximately 20.2 g/day (23.2 g and 17.4 g per day for males and females, respectively)²⁶. This reportedly poor intake of fibre is most likely due to the high intake of refined (rather than whole-grain) carbohydrates, and the oft-reported inadequate intake of fruits and vegetables.

To this end, consuming dietary fibre in supplement form as an adjunct to a healthy, whole foods-based diet is likely to offer the following benefits:

• Weight loss diets: promote adherence to weight/fat loss diets by reducing feelings of hunger and increasing feelings of fullness
• Training: helps control blood sugar and insulin levels, enhancing energy metabolism and decreasing the storage of carbohydrate as body fat
• Illness: strengthens immunity by increasing “good” gut bacteria and decreasing “bad” bacteria in the gut and may help to promote the absorption of minerals important for immune function, therefore helping to reduce potential training days lost due to illness
• Bowel function: protects against constipation and promotes increased regularity
• Disease prevention: help protect against numerous disease states

Dietary Fibre supplements at ROS Nutrition

The health benefits achieved from dietary fibre intake are dependent on the type of dietary fibre consumed. Furthermore, these benefits are mainly achieved with high intakes of dietary fibre that are often not achieved through diet alone²⁶. Here at ROS Nutrition we provide convenient, high-quality sources of β-glucan and FOS, which are the two key types of dietary fibre associated with numerous health-promoting benefits. Our OAT FIBRE® product provides a concentrated source of the health-promoting fibre β-glucan, derived from the bran of oats. Similarly, our ACTILIGHT® supplement provides a concentrated source of FOS, derived from beet sugar. ACTILIGHT® can be used to reduce the calorie content of meals (by bulking up the appearance of the meal) and/or as a healthy and natural sweetener to replace sugar while also providing potential health benefits. OAT FIBRE® and ACTILIGHT® should not replace a healthy, balanced diet, but can be consumed as directed as part of a healthy diet and lifestyle plan. In addition, our meal replacement (FEMME SHAPE®, FEMME MEAL®) and all-in-one muscle gain formulations (META MUSCLE®, ALPHA MASS®) include added fibre to ensure that you obtain a balanced and beneficial nutrient intake to maintain good digestive health while helping to achieve your body composition goals.

Find Dietary Fibre at ROS Nutrition

Further reading

• Burkitt DP (1973) Epidemiology of large bowel disease: the role of fibre. Proc Nutr Soc, 32, 145-149.
• Trowell H (1976) Definition of dietary fiber and hypotheses that it is a protective factor in certain diseases. Amer J Clin Nutr, 29, 417-427.
• EFSA (2010) Scientific opinion on dietary reference values for carbohydrates and dietary fibre. EFSA J, 8 (3), 1-77.
• Cummings JH, Bingham SA, Heaton KW & Eastwood MA (1992) Fecal weight, colon cancer risk, and dietary intake of nonstarch polysaccharides (dietary fiber). Gastroenterology, 103, 1783-1789.
• Parnell JA & Reimer RA (2009) Weight loss during oligofructose supplementation is associated with decreased ghrelin and increased peptide YY in overweight and obese adults. Amer J Clin Nutr, 89, 1751-1759.
• Nakamura Y, Natsume M, Yasuda A, Ishizaka M, Kawahata K & Koga J (epub ahead of print) Fructooligosaccharides suppress high-fat diet-induced fat accumulation in C57BL/6J mice. Biofactors.
• Chang HC, Huang CN, Yeh DM, Wang SJ, Peng CH & Wang CJ (2013) Oat prevents obesity and abdominal fat distribution, and improves liver function in humans. Plant Foods Hum Nutr, 68 (1), 18-23.
• Haber GB, Heaton KW, Murphy D & Burroughs LF (1977) Depletion and disruption of dietary fibre. Effects on satiety, plasma-glucose, and serum-insulin. Lancet, 2 (8040), 679-682.
• Salmerón J, Ascherio A, Rimm EB, Colditz GA, Spiegelman D, Jenkins DJ, Stampfer MJ, Wing AL & Willett WC (1997) Dietary fiber, glycaemic load, and risk of NIDDM in men. Diabetes Care, 20 (4), 545-550.
• 10 Tosh SM (epub ahead of print) Review of human studies investigating the post-prandial blood-glucose lowering ability of oat and barley food products. Eur J Clin Nutr.
• Institute of Medicine (IoM; 2005) Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. National Academies Press: Washington DC.
• Kim HJ & White PJ (epub ahead of print) Impact of molecular weight, viscosity, and solubility of β-glucan on in vitro oat starch digestibility. J Agric Food Chem.
• 13 Nordlund E, Aura AM, Mattila I, Kössö T, Rouau X & Poutanen K (2012) Formation of phenolic microbial metabolites and short-chain fatty acids from rye, wheat, and oat bran and their fractions in the metabolical in vitro colon model. J Agric Food Chem, 60 (33), 8134-8145.
• van Zanten GC, Knudsen A, Röytiö H, Forssten S, Lawther M, Blennow A, Lahtinen SJ, Jakobsen M, Svensson B & Jespersen L (2012) The effect of selected synbiotics on microbial composition and short-chain fatty acid production in a model system of the human colon. Plos One, 7 (10), 1-11.
• 15 Roediger WEW (1980) Role of anaerobic bacteria in the metabolic welfare of the colonic mucosa in man. Gut, 21, 793-798.
• Cani PD, Joly E, Horsmans Y & Delzenne NM (2006) Oligofructose promotes satiety in healthy human: a pilot study. Eur J Clin Nutr, 60, 567-572.
• Piche T, des Varannes SB, Sacher-Huvelin S, Holst JJ, Cuber JC & Galmiche JP (2003) Colonic fermentation influences lower oesophageal sphincter function in gastroesophageal reflux disease.  Gastroenterology, 124 (4), 894-902.
• Chandalia M, Garg A, Lutiohann D, von Bergmann K, Grundy SM & Brinkley LJ (2000) Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus. N Engl J Med, 342, 1392-1398.
• 19 Goff LM, Cowland DE, Hooper L & Frost GS (2013) Low glycaemic index diets and blood lipids: A systemic review and meta-analysis of randomised controlled trials. Nutr Metab Cardiovasc Dis, 23 (1), 1-10.
• European Food Safety Authority (EFSA; 2011) Scientific opinion on the substantiation of a health claim related to barley beta-glucans and lowering of blood cholesterol and reduced risk of (coronary) heart disease pursuant to article 14 of regulation (EC) no 1924/2006. EFSA J, 9 (12), 1-13.
• Trinidad TP, Wolever TMS & Thompson LU (1999) Effects of calcium concentration, acetate, and proprionate on calcium absorption in the human distal colon. Nutr, 15 (7-8), 529-533.
• Delzenne N, Aertssens J, Verplaetse H, Roccaro M & Robertfroid M (1995) Effect of fermentable fructo-oligosaccharides on mineral, nitrogen and energy digestive balance in the rat. Life Sci, 57 (17), 1579-1587.
• Campbell JM, Fahey GC & Wolf BW (1997) Selected indigestible oligosaccharides affect large bowel mass, cecal and fecal short-chain fatty acids, pH and microflora in rats. J Nutr, 127, 130-136.
• Rondanelli M, Opizzi A & Monteferrario F (2009) The biological activity of beta-glucans. Minerva Med, 100 (3), 237-245.
• Haack VS, Chesters JG, Vollendorf NW, Story JA & Marlett JA (1998) Increasing amounts of dietary fiber provided by foods normalizes physiologic response of the large bowel without altering calcium balance or fecal steroid excretion. Amer J Clin Nutr, 68, 615-622.
• Galvin MA, Kiely M, Harrington KE, Robson PJ, Moore R & Flynn A (2001) The north/south Ireland food consumption survey: the dietary fibre intake of Irish adults. Public Health Nutr, 4 (5A), 1061-1068.