Dietary fibre

Updated September 2023

Executive summary

Why is Dietary Fibre (DF) important?

Diets low in DF may underlie the development of many characteristically western diseases such as bowel cancer and heart disease.

What is DF?

DF consists of carbohydrate polymers or oligomers that are neither digested nor absorbed in the human small intestine. More detailed definitions are given below from Codex Alimentarius and European labelling law.

Food labelling:

Fibre must be declared on pre-packed labelling if a claim is made (e.g. ‘high in fibre’) and is part of voluntary European nutrition labelling.

How is DF measured?

Either ‘empirical’ (AOAC), ‘rational’ (Englyst) or their hybrids can be used. Each starts with dispersion and enzymatic hydrolysis of starch, but they differ in the analytical ‘finish’. For foods not containing resistant starch any of the methods can be employed with broadly similar results. The main exceptions are raw flours and foods that contain non-digestible oligosaccharides.

How much DF should I eat?

The value for the average population intake of DF for adults should be 30g per day, measured using the AOAC methods.

This Information Statement is intended to be read with separate Information Statements on ‘Sugars’.

Key glossary

DF:                  Dietary Fibre

CHD:               Coronary heart disease

GI:                   Glycaemic index

SACN:            Scientific Advisory Committee on Nutrition

Essential reading

  1. Carbohydrates and Health, Scientific Advisory Committee on Nutrition 2015 https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report
  2. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre. EFSA Journal 2010; 8(3):1462  http://www.efsa.europa.eu/en/efsajournal/pub/1462 
  3. Summary of advice for competent authorities for the control of compliance with legislation requiring analysis for determination of the fibre content declared on a label https://ec.europa.eu/food/system/files/2016-10/labelling_legislation_guidance_methods_2012_en.pdf
  4. Stephen, A.M., Champ, M.M.J., Cloran, S.J., Fleith, M., Van Lieshout, L., Mejborn, H. and Burley, V.J., 2017. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health. Nutrition research reviews, 30(2), pp.149-190. https://www.cambridge.org/core/journals/nutrition-research-reviews/article/dietary-fibre-in-europe-current-state-of-knowledge-on-definitions-sources-recommendations-intakes-and-relationships-to-health/B263D1D7B3440DC9D6F68E23C2B4212F
  5. Codex Alimentarius Guidelines on Nutrition Labelling, CAC/GL 2-1985, last revised 2017, https://www.fao.org/3/y2770e/y2770e06.htm
  6. IGD ‘Reformulating with fibre’  https://www.igd.com/charitable-impact/healthy-eating/reformulation/reformulating-with-fibre   
  7. Action on Fibre, FDF 2023 https://www.fdf.org.uk/fdf/what-we-do/diet-and-health/action-on-fibre/
Introduction

This IFST Information Statement:

  • introduces the concept of dietary fibre (DF)
  • explains why it is important in terms of its health benefits
  • gives some background to, and the current definition of, DF
  • discusses the main components of DF
  • briefly discusses analysis for DF
  • describes labelling for DF.

DF is part of the carbohydrate fraction of food. Carbohydrates can be considered in two broad categories: (a) those digested and absorbed in the human small intestine, termed ‘available’ or ‘glycaemic’ carbohydrates and (b) those passing undigested into the large intestine, termed ‘non-digestible’, ‘unavailable’ carbohydrates, or ‘dietary fibre’; also ‘fibre’ or ‘fiber’ (USA).

The term dietary fibre stems from research suggesting relationships between diets low in DF and the development of many characteristically western diseases such as poor bowel function, cancer, type 2 diabetes and coronary heart disease. Obesity is an independent risk factor for both type 2 diabetes and coronary heart disease and numerous studies have linked higher intake of dietary fibre to improved management of body weight.

In 2009 agreement was reached in the Codex Alimentarius Commission on a definition of DF (see Box 1 below page 6). The European Commission largely adopted the Codex definition and the Food Information to Consumers Regulation 1169/2011 now sets a definition of ‘fibre’ as “‘fibre’ means carbohydrate polymers with three or more monomeric units, which are neither digested nor absorbed in the human small intestine and belong to the following categories:

  • edible carbohydrate polymers naturally occurring in the food as consumed,
  • edible carbohydrate polymers which have been obtained from food raw material by physical, enzymatic or chemical means and which have a beneficial physiological effect demonstrated by generally accepted scientific evidence,
  • edible synthetic carbohydrate polymers which have a beneficial physiological effect demonstrated by generally accepted scientific evidence.”
Health effects

Although work on crude fibre, and available and unavailable carbohydrates began much earlier, DF as a concept to describe a heterogeneous complex of components relating diet to disease is generally considered to have been coined by Hipsley in 1953. In the 1960s and 1970s Cleave, Burkitt[1] and others[2] took diet/disease research further. A series of papers proposed relationships between diets low in fibre and the development of many characteristically western diseases, including bowel cancer and heart disease. Trowell contributed definitions and in a very readable paper[3] described the history of the concept of DF in human nutrition. Much research was stimulated but challenges remain, as summarised by Southgate et al.[4] in 1990 and still worth bearing in mind:

  • DF is a complex and naturally variable mixture of components;
  • How do DF structures and physicochemical properties relate to their physiological effects?
  • What conceptual framework links dietary intake to indicators of health and disease?

Cleave and Burkitt’s ideas have been developed, refined and in some cases vindicated; their simplicity made them understandable and thus they continue to drive research relating deficiencies in DF intakes to disease. A review, drawn upon in the following section, published by Kendall et al.[5] in 2010 summarised the position and a recent review of Burkitt’s contribution makes interesting reading[6]. One by Mathers collates recent research in this area and is a good summary of current thinking[7].

DF and cancer prevention

International studies have consistently shown that traditional high fibre diets are associated with decreased prevalence of cancer, particularly cancers of the colon and breast. However, population cohort studies, randomised controlled trials and case control studies have been inconsistent in their findings. These inconsistencies may in part be explained by inherent problems in these studies and complications when determining the actual fibre intake. Because of the age and genetic dependency of cancer, other factors, such as type of subjects, ethnicity and stage in life may play a significant role in explaining the inconsistencies. However, published[8] results of the European Prospective Investigation into Cancer and Nutrition (EPIC) strengthen the evidence for the role of high dietary fibre intake in colorectal cancer prevention.

DF, glycaemic index (GI) and type 2 diabetes

Authoritative nutritional recommendations include increasing dietary fibre intake in individuals with type-2 diabetes[9] and the intake of low GI diets. In general, most medium and low GI foods (i.e. those low in non-resistant starch, maltodextrins, sucrose, glucose and fructose) are those that are used as sources of fibre such as all-bran, oats and legumes. Therefore, undertaking a diet that is composed of many low GI foods essentially results in a diet that is high in fibre.

DF and weight management

Obesity is an independent risk factor for both type 2 diabetes and coronary heart disease and numerous studies have linked higher intake of dietary fibre to improved management of body weight. The clinical evidence suggests that the optimal results for high fibre diets are attained in a low GI context which may even exceed outcomes for low fat diets. One proposed mechanism of action for the effect is through increased satiety.

DF and prevention of coronary heart disease (CHD)

By reducing the risk of type-2 diabetes, controlling body weight and targeting elevated serum LDL-cholesterol there is overwhelming evidence that diets rich in low GI foods and DF can effectively lower CHD risk.

DF and bowel function

EFSA considered the role of dietary fibre in bowel function was considered the most suitable criterion for establishing an adequate intake.[10]

Summary of health effects

In summary therefore, there is evidence for beneficial effects for a given dietary fibre intake in

  • normal laxation (bowel function) in adults,
  • colorectal cancer prevention,
  • better management of type 2 diabetes
  • effectively lowering the risk of coronary heart disease by
    • improved management of body weight and
    • targeting elevated serum LDL-cholesterol.

A 2017 review paper by Stephen et al. supports the above conclusions.[11]

What is Dietary Fibre?

Some history will help in appreciation of the modern definition of DF. Hipsley[3] included lignin, cellulose and the hemicelluloses in his consideration of DF in 1953 and in the 1970’s Trowell introduced definitions such as “that portion of food which is derived from cellular walls of plants which are digested very poorly by human beings”[12], or ‘in terms of physiology as the remnants of plant cells resistant to hydrolysis by the alimentary enzymes’[3]. Trowell also noted that gastroenterologists considered that storage polysaccharides (often water soluble), pectic substances, plant gums, and mucilages should be included in a definition of DF. Carbohydrate quickly featured in a basic definition of DF, ‘fibre’ or ‘fiber’[13] as carbohydrate polymer which is neither digested nor absorbed in the human small intestine thus bulking the faeces. This led to Trowell et al. defining DF as: “the plant polysaccharides and lignin which are resistant to hydrolysis by digestive enzymes of man. This defines a macro constituent of foods which includes cellulose, hemicellulose, lignin, gums, modified celluloses, mucilages, oligosaccharides, pectins and associated minor substances such as waxes, cutin, and suberin.[14] Others have included seaweed polysaccharides, resistant starch and inulin.[15] It was assumed that Non-Starch Polysaccharides NSP were the principal substrates resistant to digestion. However, there was indirect evidence in the 1980s (e.g. from breath H2 measurements) that some starch escapes digestion in the small intestine, passing into the large intestine. It was also clear that NSP alone could not meet the substrate requirements of resident microorganisms. It was then shown by direct intubation of the human small intestine that some forms of starch, termed resistant starch, RS, could make its way into the human large intestine where it is partially or completely fermented by gut microorganisms.

The current Codex Alimentarius definition of DF, which has global significance is shown in Box 1[16]:

Box 1 -- The Codex Alimentarius definition of DF as of 2013

Dietary fibre means carbohydrate polymers* with ten or more monomeric units** , which are not hydrolysed by the endogenous enzymes in the small intestine of humans and belong to the following categories:

  • Edible carbohydrate polymers naturally occurring in the food as consumed,
  • carbohydrate polymers, which have been obtained from food raw material by physical, enzymatic or chemical means and which have been shown to have a physiological effect of benefit to health as demonstrated by generally accepted scientific evidence to competent authorities,
  • synthetic carbohydrate polymers which have been shown to have a physiological effect of benefit to health as demonstrated by generally accepted scientific evidence to competent authorities.

 

*When derived from a plant origin, dietary fibre may include fractions of lignin and/or other compounds associated with polysaccharides in the plant cell walls.

These compounds also may be measured by certain analytical method(s) for dietary fibre. However, such compounds are not included in the definition of dietary fibre if extracted and re-introduced into a food.

**[The] decision on whether to include carbohydrates from 3 to 9 monomeric units should be left to national authorities.

In Europe ‘fibre’ is defined by the Food Information Regulation[17], Regulation (EU) No. 1169/2011 on the provision of food information to consumers, Annex I, see box 2. The European definition closely parallels that of Codex except in that carbohydrate polymers with three or more monomeric units are included. and fractions of lignin and/or other compounds associated with polysaccharides in the plant cell walls are not excluded if extracted and re-introduced into a food.

Box 2 – Definition of ‘fibre’, Regulation (EU) No. 1169/2011 on the provision of food information to consumers

‘fibre’ means carbohydrate polymers with three or more monomeric units, which are neither digested nor absorbed in the human small intestine and belong to the following categories:

  •  edible carbohydrate polymers naturally occurring in the food as consumed,
  •  edible carbohydrate polymers which have been obtained from food raw material by physical, enzymatic or chemical means and which have a beneficial physiological effect demonstrated by generally accepted scientific evidence,
  •  edible synthetic carbohydrate polymers which have a beneficial physiological effect demonstrated by generally accepted scientific evidence,

A class of carbohydrate that can be characterised as neither digested nor absorbed in the human small intestine clearly implies that solubility is a key consideration. Indeed, while insoluble fibre is important, soluble fractions have also been shown to have physiological effects. An understanding of the components of DF is aided by a brief excursion into carbohydrate chemistry. The chemical classification of carbohydrates is usually based on molecular size and monomeric composition, thus: monosaccharides and disaccharides are self-defined; oligosaccharides are broadly defined as consisting of 3–9 monomers; and polysaccharides are composed of 10 or more monomers.[18] See also the IFST Information Statements on ‘Sugars’[19]. Table 1 shows the main components of DF. Westenbrink[20] has produced a useful schematic overview of carbohydrates including dietary fibre.

Lee describes the evolution of the DF definition from an interesting socio-technical perspective in terms of ‘knowledge claims’ and governance techniques[21].

How do humans digest carbohydrates?

Human digestive enzymes, e.g. amylases, hydrolyse starch and its breakdown products in the mouth, stomach and, mainly, the small intestine (duodenum, jejunum and ileum).[22] Starches that escape digestion higher in the gastrointestinal (GI) tract, non-starch polysaccharides (NSP), and oligosaccharides pass into the large intestine (caecum, colon, rectum and anal canal) where a variable amount of fermentation by resident microorganisms can take place. The fermentation end-products include short chain fatty acids (SCFA), mainly acetate, propionate and butyrate, with a range of physiological benefits. The attributed benefits include lowering of pH which inhibits absorption of toxic and carcinogenic bases by reducing their dissociation, other antineoplastic benefits, raising muscular tone and improving nutrient transport. It has also been suggested that an inability to digest starch higher in the GI tract results in a slower delivery of glucose potentially resulting in a lowered insulin response, improved access to stored fat, reduction of physiological hunger, and promotion of weight management. Undigested and unfermented material increases faecal bulk giving a mild laxative effect.[23][24]

 

What are resistant starches

Cooking causes a variable amount of starch gelatinisation, which in turn facilitates enzyme hydrolysis. However, it has been shown by experiments on human subjects that some starch, resistant starch (RS) escapes digestion up to and including in the human small intestine. RS is defined as ‘the sum of starch and starch degradation products that, on average, reach the human large intestine’.[25] RS occurs naturally, can be formed during food processing, or can be added as a functional additive. There are four main reasons why starch may not be completely digested before entry into the large intestine, giving rise to classifications of RS as Types 1 – 4.

RS1 represents starch that is physical inaccessible to enzymes because it is in unmilled or partially milled grains, and seeds. The degree of milling, particle size, chewing and transit time to the large intestine all influence the extent to which this form of RS is eventually made accessible to microorganisms in the large intestine.

RS2 is starch physically inaccessible to enzymes because it is in raw or ungelatinised starch granules which, as any food microscopist knows, are plentiful in cooked and baked starchy foods. The degree of cooking, chewing, particle size and transit time to the large intestine all influence the extent to which this form of RS is eventually made accessible to microorganisms in the large intestine.

RS3 is retrograded starch formed after gelatinisation. The starch gels, and during subsequent cooling it re-associates and the amylose and linear regions of amylopectin partially crystallise. Water can be exuded from the gel and the associated/crystallised structures resist enzyme attack. Examples include cooked starch (e.g. pasta and potato salad) and the phenomenon contributes to the staling of bread. Cooking, the starch amylose: amylopectin ratio, other components of the matrix and additives influence the extent of RS3 formation.

RS4 is chemically modified starch used in processed food and contains ether, ester and other cross-linked bonds.

Individual physiological factors influence the extent of formation of RS and it is thus difficult chemically to mimic these physiological processes; hence the amount of RS measured in baked beans or brown rice vary dependent on the analytical procedure employed. It is generally assumed that approximately 10% of ingested starch may enter the colon. RS has been advocated as a prebiotic, one of the best known being fructo-oligosaccharide (FOS). While starch and NSP have been regarded as unlikely prebiotics, it appears likely that starch fermentation in both the mouth and the large bowel can be modulated so as to lower disease risk. In the mouth, slower starch breakdown can protect teeth. In the colon, fermentation can promote SCFA production so as to optimise physiological function and manage and prevent important pathologies.

Synthetic oligosaccharides based on galactose, glucose and other sugars, so-called resistant oligosaccharides, and polydextrose would, under the recent proposed Codex definition be classified as DF.

Various terminologies have been employed in defining DF, such as low molecular weight dietary fibre (LMWDF), also termed non-digestible oligosaccharides (NDO) or soluble dietary fibre that remains soluble in the presence of 80% ethanol (SDFS). High molecular weight dietary fibre (HMWDF) includes insoluble dietary fibre (IDF) and soluble dietary fibre that precipitates in the presence of 80% ethanol (SDFP). The terms SDFS and SDFP were introduced to link dietary fibre fractions to the process used to obtain them.

Solubility does not always predict physiological effects. Therefore, FAO/WHO proposed the distinction between soluble and insoluble fibre should be phased out.

Table 1 Non-exhaustive examples of the main components of dietary fibre

Compound class and classification

Origin

Typical chemistry, water solubility and classification

Cellulose

 

An essential component of plant cell walls, e.g. cotton is almost pure cellulose

 

A water insoluble linear polysaccharide of 3000 or more β1,4 linked glucopyranose units, a non-starch polysaccharide (NSP)

 

Derivatised celluloses, e.g. carboxymethyl cellulose (CMC) [E466, E469] used as a thickener in foods

Resistant starch, RS, (any starch not digested in the small intestine and passes to the large bowel).

RS1 grains or seeds

RS2 Resistant granules e.g. raw potato, green banana, some legumes and high amylose starches

RS3 Retrograded starch

RS4 Chemically modified starches – used in processed food

 

High molecular weight homo polysaccharides

RS1 starch physically inaccessible to enzymes in whole or partly milled grains or seeds

RS2 starch physically inaccessible to enzymes in raw and non-gelatinised granules

RS3 Retrograded starch – e.g. cooked

then cooled potato, rice or pasta, cornflakes;

RS4 Chemically modified starches – do

not occur naturally but are created

to be resistant to digestion, etherised, esterified or cross-linked starches [26]

 

Hemicellulose

 

Vegetable leaves and stem

Sparingly soluble, NSP, natural hetero polysaccharides, the chemistry of these components is less known

Cereal, especially. seed coats

Xylans – sparingly soluble, NSP, linear polysaccharide of β1,4 linked xylopyranose units with single L-arabino fructose and D-glucopyranosyluronic acid residues as side units.

Mannans – sparingly soluble, NSP, linear polysaccharides of β1,4 linked mainly mannose units & glucomannans – as above but backbone contains in addition β1,4 linked glucose

Galactans – sparingly soluble, NSP, polysaccharides of 1,3, 1,4, 1,6, α- and β-bonded D-galactopyranoses usually found as part of the pectic complex, and

Arabinogalactans - Sparingly soluble, NSP, β1,4-linked D-galactan with branches of α1,5 arabinose

β-Glucans

 

Oats, barley, baker's yeast, mushrooms

Water soluble (in cereals) NSP - linear polysaccharides of β1,3 and β1,4 linked glucose units, form viscous aqueous solutions. Commission Regulation 1160/2011[27] permits the claim ‘Oat beta-glucan has been shown to lower/reduce blood cholesterol. High cholesterol is a risk factor in the development of coronary heart disease’. Information must be given to the consumer that the beneficial effect is obtained with a daily intake of 3 g of oat beta-glucan. The claim can be used for foods which provide at least 1 g of oat beta glucan per quantified portion.

β glucans from yeasts and moulds are not water soluble

 

Pectins

 

Major component of plant cell walls and parenchyma of soft fruit & fleshy roots

Water soluble NSP. Essentially regarded as linear polymers of α-D-galacturonic acid, an oversimplification and based on the material extracted from plants, the in-situ structure is uncertain. In the structure opposite (a) is a repeating segment of pectin molecule with (b) – (d) functional groups: (b) carboxyl; (c) ester; (d) amide in pectin chain.

Also, non-water-soluble pectin

 

Pentosans

 

Soluble and insoluble neutral hetero polysaccharides composed mainly of pentose sugars e.g. arabinoxylans

 

Gums

 

Plant non-cereal seed exudates, such as gum tragacanth and guar gum, and bacterial secretions, such as xanthan gum and gellan

 

Essentially water soluble NSP. Some examples are extensively branched D-galacturonic acid residue polymers with occasional insertions of L-rhamnose (e.g. in tragacanth). Guar gum consists of a linear 1,4-b-D-mannan backbone which is substituted by single a-linked D-galactosyl residues. Xanthan gum and gellan are more complex bacterial exo-polysaccharides. Carrageenan and alginate are seaweed polysaccharides

Inulin, occurs in chicory and Jerusalem artichoke

Water soluble NSP fructan, a small polysaccharide of β2,1 fructofuranose units with sucrose terminus

Chitin

Chitosan

Cell walls of fungi, exoskeletons of

crustaceans and insects

 

Long-chain polymer of a N-acetylglucosamine ((C8H13O5N)n)

Lignin

Lignin occurs in the xylem tracheids, vessel elements and sclereids of plant cell walls cells. It is covalently linked to hemicellulose and, therefore, crosslinks different plant polysaccharides, conferring mechanical strength to the cell wall and by extension the plant as a whole

 

Lignin is a cross-linked racemic macromolecule with molecular masses in excess of 10,000 u. It is relatively hydrophobic and aromatic in nature. The degree of polymerisation in nature is difficult to measure, since it is fragmented during extraction and the molecule consists of various types of substructures that appear to repeat in a haphazard manner. Different types of lignin have been described depending on the means of isolation. [17]

 

There are three monolignol monomers, methoxylated to various degrees: p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. These lignols are incorporated into lignin in the form of the phenylpropanoids p-hydroxyphenyl, guaiacyl, and syringyl, respectively.

 

Lignin is more properly included as DF when it is chemically bound to polysaccharides

 

Other, mainly lower molecular weight, non-available oligosaccharides

 

Fructo-oligosaccharides (FOS) including kestose and nystose.

Galacto-oligosaccharides (GOS) derived from lactose by transglycosylation.

Polydextrose

Resistant maltodextrin

Galactosyl-sucrose oligosaccharides including stachyose and verbascose

 
How do I analyse for Dietary Fibre?

The concept of DF as a food component resistant to digestion in the small and large intestine has proved difficult to translate into straightforward analytical chemistry. Nevertheless, driven by the need to quantify DF for epidemiological purposes, inform the public, and assess nutrition claims efforts have been made towards analytically meaningful interpretations. The complex and naturally variable components that make up DF require correspondingly complex analytical chemistry and different analytical approaches have evolved:

  • ‘empirical’ AOAC[28]
  •  methods that measure unspecified intact components gravimetrically and by size exclusion liquid chromatography,
  • ‘rational’ methods first described by Hans Englyst, in 1981 that chemically determine specific components of DF as their monosaccharide constituents
  • hybrid approaches articulated in various AOAC methods.  

Either ‘empirical’ (AOAC Methods 985.29 etc.[29]), ‘rational’ (Englyst [30] ) or hybrid (AOAC Methods 2009.01 and 2017.16[31], [32]) methods can be used. Each employs dispersion and enzymatic hydrolysis of starch but in the AOAC methods, starch that is not hydrolysed under the assay conditions employed (resistant starch; RS) is considered to be dietary fibre and is measured. AOAC methods measure dietary fibre gravimetrically[29] and by HPLC (methods 2009.01 and 2017.16). Englyst methods measure fibre chemically. For foods not containing resistant starch, any of the methods can be employed with broadly similar results. The main exceptions are raw flours and foods that contain non-digestible oligosaccharides. AOAC Method 2017.16 accurately measures all components of dietary fibre as defined by Codex Alimentarius, including resistant starch and non-digestible oligosaccharides.

The Englyst method generally gives lower data than the AOAC method since lignin and resistant starch (that which escapes from digestion in the small intestine) are not included. Englyst DF data were traditionally used by the food industry in the UK and in UK food composition databases. Other European Member States and the USA use AOAC methods, which are now also recommended by the Scientific Advisory Committee on Nutrition, SACN,[33] and the EU and the UK government.

Stephen et al., 2017[11] give a brief summary of various analytical methods.

Label claims

European regulations on nutrition and health claims state that a product claiming to be a ‘source’ of fibre should contain at least 3g of fibre per 100g or at least 1.5g of fibre per 100 kcal.  A product claiming to be ‘high fibre’ should contain at least 6g of fibre per 100g or at least 3g of fibre per 100 kcal. [34]

Regulation 1169/2011 on the provision of food information to consumers (EU FIC) [35], includes mandatory nutrition information for the majority of prepacked food and a consistent format for its presentation. Fibre is included in voluntary nutrition declaration but must comply with the nutrition labelling provisions of EU FIC. Declared values must be average values based on one of the following: (a) the manufacturer’s analysis of the food, (b) a calculation from the known or actual average values of the ingredients used or (c) a calculation from generally established and accepted data such as McCance & Widdowson’s The Composition of Foods. The term ‘average value’ is defined and tolerances, including analytical measurement uncertainty, MU, are given for legislated nutrients including DF are available.[36]

Table 2 reproduces the tolerance data for DF [37] :

Table 2: Tolerances including MU for label declared values of DF

Fibre content of food

Tolerance

<10 g per 100 g

 

± 2 g

 

10-40 g per 100 g

 

± 20 %

 

>40 g per 100 g

± 8 g

 

The Scientific Advisory Committee on Nutrition (SACN)[33] recommend that the dietary reference value for the average population intake of DF for adults should be 30g/day measured using the AOAC methods. The previous dietary reference value of 18g/day of non-starch polysaccharides defined by the Englyst method, equates to about 23-24 g/day of dietary fibre if analysed using these AOAC methods, thus the new recommendation represents an increase from this current value. Government accepted the SACN recommendations and detailed data including for those aged 1 – 18 years are available.[38] A summary of advice for competent authorities for the control of compliance with legislation requiring analysis for determination of the fibre content declared on a label is available.[39]

National dietary survey data reviewed by Stephen et al.11 showed that intakes do not reach recommendations and very few countries provide guidance on the types of fibre that are preferable to achieve recommended intakes. Ideas were suggested to provide information for more detailed advice to the public about specific food sources that should be consumed to achieve health benefits.

Conclusions

Understanding dietary fibre and using it in product formulation has an important part to play in reformulating foods to address public health issues. Moreover, dietary fibre has key functional properties in foods. Measuring dietary fibre for product quality control and to ensure accurate labelling as part of nutrition information is also necessary for a wide range of food. We trust this Information Statement, read with that on Sugars[20] will assist the food industry, regulators and enforcement personnel to innovate and to provide consumers with attractive foods contributing to healthy eating objectives.

References
  1. Jon A. Story, David Kritchevsky, 1994, Denis Parsons Burkitt (1911-1993), Nutr. 124: 1551-1554.
  2. J H Cummings 1973, Progress Report Dietary Fibre, Gut, 14, 69
  3. H Trowell, 1978, The development of the concept of dietary fibre in human nutrition, Am. J. Clin. Nutr., 31, S3 – S11
  4. D A T Southgate, K W Waldron, I T Johnson and G R Fenwick, 1990, Proceedings, Fibre 90, Dietary Fibre: Chemical and Biological Aspects, Food Chemistry Group Royal Society of Chemistry, 17 – 20 April 1990, RSC Special Publication No. 83, ISBN 0-85186-667-0, Preface
  5. Cyril WC Kendall, Amin Esfahani, David JA Jenkins, 2010, The link between dietary fibre and human health, Food Hydrocolloids, 24: 42–48
  6. Cummings, J.H. and Engineer, A., 2018. Denis Burkitt and the origins of the dietary fibre hypothesis. Nutrition research reviews, 31(1), pp.1-15
  7. J C Mathers, 2023, Dietary fibre and health: the story so far, Proceedings of the Nutrition Society, 82(2), 120-129. doi:10.1017/S0029665123002215, https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/dietary-fibre-and-health-the-story-so-far/FEEDAFA7E6866D717566FDF4D03C4A66
  8. Murphy N, Norat T, Ferrari P, Jenab M, Bueno-de-Mesquita B, et al. (2012) Dietary Fibre Intake and Risks of Cancers of the Colon and Rectum in the European Prospective Investigation into Cancer and Nutrition (EPIC). PLoS ONE 7(6): e39361. doi:10.1371/journal.pone.0039361
  9. NHS https://www.nhs.uk/conditions/diabetes/ Accessed 01 December 2021.
  10. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre. EFSA Journal 2010; 8(3):1462 [77 pp.]. Available at http://www.efsa.europa.eu/en/efsajournal/pub/1462.htm  accessed 04.01.2014
  11. Stephen, A.M., Champ, M.M.J., Cloran, S.J., Fleith, M., Van Lieshout, L., Mejborn, H. and Burley, V.J., 2017. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health. Nutrition research reviews, 30(2), pp.149-190.
  12. H Trowell, 1972, Fiber: a natural hypocholesteremic agent, Am. J. Clin. Nutr., 25, 464-465.
  13. DeVries, Jonathan W., 2004, Dietary Fiber: The Influence of Definition on Analysis and Regulation, J AOAC Int., 87: 682-706 
  14. McCleary, Barry V; De Vries, Jonathan W; Rader, Jeanne I; Cohen, Gerald; Prosky, Leon; Mugford, David C; Champ, Martine; Okuma, Kazuhiro, 2010, Determination of Total Dietary Fiber (CODEX Definition) by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study, J AOAC Int, 93, 221-233
  15. Tom Coultate, Food: The Chemistry of its components, 5th Ed., 2009, RSC Publishing, p72
  16. Codex Alimentarius, 2017, Guidelines on Nutrition Labelling, CAC/GL 2-1985, Adopted 1985. Revisions 1993 and 2011. Annex adopted 2011, last amendment and revision (to date) in 2017
  17. Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers,…OJ L304/18 22.11.2011 available at: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:02011R1169-20180101&from=EN
  18. R J Simmonds, Chemistry of Biomolecules, an introduction, RSC 1992
  19. https://www.ifst.org/resources/information-statements/sugars
  20. Susanne Westenbrink, Kommer Brunt, Jan-Willem van der Kamp, 2013, Dietary fibre: Challenges in production and use of food composition data, Food Chemistry 140, 562–567
  21. Lee, R.P., 2012. Knowledge claims and the governance of agri-food innovation. Agriculture and human values, 29(1), pp.79-91.
  22. R M H McMinn, R T Hutchings and B M Logan, Concise Handbook of Human Anatomy, 1998, Manson Publishing Ltd, London
  23. Bird, A. R.; Brown, I. L.; Topping, D. L., 2000,  Starches, resistant starches, the gut microflora and human health, Current Issues in Intestinal Microbiology, 1, 25-37, https://www.caister.com/backlist/ciim/v/v1/03.pdf accessed 18.01.2014
  24. Tapsell LC, 2004, Diet and metabolic syndrome: where does resistant starch fit in? J AOAC Int,. 87, 756-60
  25. Englyst HN, Kingman SM, Cummings JH (1992). Classification and measurement of nutritionally important starch fractions. Eur J Clin Nutr 46, S33–S50
  26. Anthony R Bird, Ian L Brown and David L Topping, 2000, Starches, Resistant Starches, the Gut Microflora and Human Health, Curr. Issues Intest. Microbiol., 1, 25-37. https://www.caister.com/backlist/ciim/v/v1/03.pdf   
  27. Commission Regulation (EU) No 1160/2011 of 14 November 2011 on the authorisation and refusal of authorisation of certain health claims made on foods and referring to the reduction of disease risk, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2011:296:0026:0028:EN:PDF accessed 19.01.2014
  28. Association of Analytical Communities http://www.aoac.org/ 
  29. Official Methods of Analysis of AOAC International, 19th Ed. 2012, Methods 925.10, 985.29, 991.42, 991.43, 993.19, 994.13, 996.01, 2001.03, 2002.01, 2002.02, 2009.01, and 2011.25. AOAC International, Rockville, Maryland, USA.
  30. Englyst, H. N., Cummings, J. H. An improved method for the measurement of dietary fiber as non-starch polysaccharides in plant foods. J. AOAC International 1988, 71, 808-814.
  31. McCleary, B. V., Sloane, N. and Draga, A. (2015) Determination of total dietary fibre and available carbohydrates: A rapid integrated procedure that simulates in vivo digestion. Starch/Starke 67, 860-883
  32. McCleary, B.V., 2019. Total Dietary Fiber (CODEX Definition) in Foods and Food Ingredients by a Rapid Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study, First Action 2017.16. Journal of AOAC International, 102(1), pp.196-207.
  33. SACN Report Carbohydrates & Health Scientific Advisory Committee on Nutrition 2015 https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report
  34. Annex of Regulation (EC) No 1924/2006 of the European Parliament and of the Council of 20 December 2006 on nutrition and health claims made on foods – see EUR-Lex for latest version https://ec.europa.eu/food/safety/labelling-and-nutrition/nutrition-and-health-claims_en
  35. Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers
  36. https://ec.europa.eu/food/system/files/2016-10/labelling_nutrition-vitamins_minerals-guidance_tolerances_1212_en.pdf
  37. http://ec.europa.eu/food/safety/labelling_nutrition/labelling_legislation_en
  38. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf
  39. https://food.ec.europa.eu/system/files/2016-10/labelling_legislation_guidance_methods_2012_en.pdf

Institute of Food Science & Technology has authorised the publication of the following updated Information Statement on Dietary Fibre dated September 2023, replacing that of February 2019.  

This Information Statement has been updated by Michael Walker FIFST and Julian Cooper FIFST, and peer reviewed by professional members of IFST and approved by the IFST Scientific Committee. 

The Institute takes every possible care in compiling, preparing and issuing the information contained in Information Statements, but can accept no liability whatsoever in connection with them. Nothing in them should be construed as absolving anyone from complying with legal requirements. They are provided for general information and guidance and to express expert professional interpretation and opinion, on important food-related issues.

Keywords: 
Dietary Fibre
Health and Nutrition
Information Statement