Sugars

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September 2016

Sugars are the basic building blocks of carbohydrates found in nature; they can be found in milk, tree saps and many fruits and vegetables. The most common sugars found in foods are the monosaccharides glucose, fructose and galactose and the disaccharides sucrose, lactose and maltose.

Sugars provide many functions in foods not only sweetness but also texture, colour and flavour formation, freezing point depression, different physical forms – amorphous and glassy (vitreous), preservation and sugars can also be fermented. Thus they provide a range of versatile, multifunctional ingredients.

Because of the recent, growing negative health perceptions of sugar(s) many terms have been coined in an attempt to differentiate between them and their potential health impacts.  Up until 2015 the terms Intrinsic and Non-Milk Extrinsic Sugars were used in the UK to differentiate between sugars within the cell matrix of plants and those released from the cells (i.e. extrinsic). The Scientific Advisory Committee on Nutrition (the UK Government’s advisory group, commonly known as SACN) have recommended that the definition for ‘free sugars’ be adopted in the UK. Free sugars are defined as all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices. Under this definition lactose when naturally present in milk and milk products is excluded. It should be noted that it is not possible analytically to distinguish between intrinsic and extrinsic (free) sugars and estimates are based on the best available information.

In a nutrition declaration or nutrition labelling the information required in the EU is specified in Regulation (EC) No 1169/2011 on the provision of food information to consumers. The regulation states that labelling should be ‘carbohydrate - of which sugars’ and defines sugars as “all monosaccharides and disaccharides present in food, but excludes polyols”. The regulation provides energy values for components in foods – for carbohydrate (including sugars) the figures to be used in labelling are 17 kJ/g and 4 kcal/g. Reference Intakes for (total) sugars is 90 g/day based on a total energy intake of 8400 kJ/2000 kcal.

The body of scientific evidence on sugars and their impact on health has been the subject of many  extensive reviews by expert committees. The main concerns raised by the reviews have been on obesity and dental health; more recent reviews have raised an additional concern, based on prospective cohort studies that indicate a greater consumption of sugars sweetened beverages is associated with an increased risk of type 2 diabetes.

Dietary and food surveys indicate a reduction of intake of both total sugars and free sugars over recent years, however most intakes are above the reference intakes and committee recommendations. The recent SACN report has recommended that free sugars intake should not exceed 5 % of energy intake.

There is no universal single sugars replacer that can replace all the many functions of sugars in every application. Therefore different ingredients must be used to deliver a particular functionality in a specific application. 

In many reformulated products there may be an increase in the number of ingredients used to replicate the many functions of sugars; this may also require additional labelling and consumer warnings about the presence of these alternative ingredients.  In many instances even large reductions of sugars may not result in a significant reduction in calories due to other changes that are made to maintain the taste and physical attributes of the product.

Background

Sugars are natural carbohydrates found widely in nature for example in milk, tree saps and many fruits and vegetables. Sugar is very topical at present and scientific reviews (1) have called for reductions in the consumption of ‘free sugars’ as a means of tackling increasing obesity and dental health issues. This Information Statement will provide detailed technical information on dietary sugars.

Terminology

Sugars are the basic building blocks of carbohydrates. They are classified chemically according to how many sugar units they contain (2, 3). The term ‘sugars’ is conventionally used to describe the mono- and disaccharides in foods (also known as total sugars).

The three most common monosaccharides (single units) found in foods are glucose, fructose and galactose. Where two of these monosaccharides combine they form a disaccharide (two units) – the main disaccharides in foods are sucrose (glucose & fructose); maltose (glucose & glucose) and lactose (glucose and galactose). If three or more sugars are combined they produce oligo-saccharides (3 – 10 monosaccharide units) and polysaccharides (more than 10 monosaccharide units) See IFST Information Statement on Carbohydrates [in preparation].

Sugars can also be hydrogenated to produce polyols which can be used as food additives. The polyol’s name typically follows the root of the sugar name e.g. xylose is hydrogenated to produce xylitol; maltose to produce maltitol. Polyols are classified as carbohydrates, but not sugars (see labelling and IFST information statement on carbohydrates [in preparation]).

Most sugars in nature are D- isomers however some do exist as L-isomers, notably L-arabinose, L-rhamnose (6-deoxy L -mannose) and L-fucose (6-deoxy L-galactose). These L-sugars are found in plant cell wall polysaccharides (Non starch polysaccharides NSP; hemicelluloses).

Sugars can exist in different forms – they are built up of a carbon backbone with several hydroxyl groups attached, they can be present as aldehydes or ketones and change between different acyclic (straight chain) form and ring forms 5 atom (furan) and 6 atom (pyran) rings. The proportion of the different anomers is dependent on the stereo chemistry and the most thermodynamically stable form will be present in the highest abundance e.g. in D-glucose which is an aldo-hexose (i.e. aldehyde form; 6 carbons). It’s most stable form is β-D-glucopyranose (present at 64 %) in an equilibrium with the other anomers. This interchange of different forms is known as mutarotation (4). The 6 carbon sugars notably glucose, fructose and galactose are present in mono-, di- and polysaccharides. The 5 carbon sugars e.g. xylose and arabinose are found mostly in polysaccharides e.g. hemicelluloses and pectins, whereas ribose and in particular deoxy ribose (also 5 carbon sugars) are the backbone sugars in RNA and DNA.

Sugars can also be classified according to their chemical reactions e.g. reducing and non-reducing sugars. The carbon 1 on the ring form of carbohydrates can be reduced to form other compounds e.g. hydrogenated to produce polyols (see below). If blocked or linked to another sugar in for example the di-saccharide sucrose the C1 is not available for reaction and the sugar is known as a non-reducing sugar.  This reactivity is important in food manufacture – reducing sugars can react with other ingredients e.g. amino groups in proteins to form more complex compounds e.g. Maillard reaction products which deliver characteristic colour and flavour to products. Non-reducing sugars cannot react and typically will hydrolyse to their component mono-saccharides (reducing sugars) before they take part in the Maillard reaction. Sucrose in particular reacts to produce glucose and fructose (the reaction is known as inversion from the change in optical rotation in a polarimeter) which then react to give colour and flavour. This reactivity of sugars is fundamental to the range of properties that sugars can deliver and can change the properties e.g. sweetness, freezing point depression and other colligative properties where the number of molecules present is important.

Occurrence

Sugars occur in nature in many forms and combinations:

Glucose, fructose and sucrose are present in many fruits and vegetables e.g. an apple contains 11.6 g sugars/100 g edible matter; 2.1 g glucose; 6.7 g fructose and 2.8 g sucrose; carrots(old, raw) contain 7.2 g sugars/100 g edible matter; 1.1 g glucose, 1.1 g fructose and 5.0 g sucrose (5).

Glucose and fructose are present in honey and lactose is found in milk. Sucrose is the sugar that can be extracted from sugar beet or sugar cane on an industrial scale and is the sugar that is present as granulated sugar in many kitchen cupboards and is widely used in the food, pharmaceutical, fermentation and industrial sectors. Glucose and maltose are derived from the hydrolysis of starch and glucose syrups are used in confectionery and bakery applications. Glucose syrups (commonly called corn syrups in the USA) are widely used in food and fermentation being produced by the hydrolysis of starch and deliver a mixture of glucose, maltose and glucose oligomers. They are defined by their dextrose equivalent or DE, this is the number of reducing ends (C1) present in the mixture. The higher the DE the more free glucose is present e.g. fully hydrolysed starch or pure glucose would have a DE of 100. The standard glucose syrups produced are 95DE, used as a fermentation feedstock, 63DE used in confectionery and bakery where more reducing sugar is required to generate flavour and colour and 42DE used in confectionery applications where glass-forming properties and viscosity are required. Glucose can be isomerised to fructose to produce mixtures of the two sugars – where glucose is present at the higher proportion they are known as glucose-fructose syrups and vice-versa if fructose is present at the higher amount they are known as fructose-glucose syrups. The equilibrium mixture obtained after treatment with glucose isomerase contains 42 % fructose and is known as iso-glucose. Iso-glucose is converted into high fructose corn syrup (HFCS) by separating the glucose from the fructose by large scale chromatography and adding the separated fructose back to iso-glucose to give a higher proportion of fructose (55 %). This is known as HFCS F55 and is equi-sweet  with sugar and can thus be used interchangeably in products.

Functionality and Properties

The multi-functionality of sugars provide versatile, traditional ingredients that deliver different properties to many food products, illustrated in the table below: 

Table 1 Sugars Functionality in Food Products (after 6)

Food Products

Functionality delivered by sugars

Soft Drinks

Sweetness, mouthfeel, flavour enhancement

Confectionery

Sweetness, bulk, preservative, humectancy, colour & flavour formation, solubility, flavour release, crystal and glass formation

Baked Goods

Sweetness, bulk, humectancy, colour & flavour formation, texture modification, coating, glazing, fermentation substrate

Dairy

Sweetness, mouthfeel, flavour enhancement

Breakfast Cereals

Sweetness, bulk, colour & flavour formation, texture modification, structure forming, bowl life

Jams & preserves

Sweetness, bulk, flavour enhancement, colour & flavour formation, preservative synergy with other ingredients

Frozen Desserts

Sweetness, bulk, flavour enhancement, freezing point depression, mouthfeel

Properties of sugars

Sweetness

The sweetness of sucrose is seen as the principal standard of sweetness. All sugars and sweeteners are compared to sucrose with respect to sweetness intensity usually at a defined concentration (either 5 % or 10 % w/v) - see Table 2. The sugars each have a different sweetness intensity and sweetness quality – for example fructose has a very clean, fast onset of sweetness which is quickly cleared from the palate and complements citrus flavours. Glucose has a slower onset of sweetness with a greater linger and complements caramel flavours. The sweetness intensity can also be affected by the temperature and pH of the test solution. In acid solution sucrose is hydrolysed to its component mono-saccharides, glucose and fructose (inversion). This can also change the sweetness intensity as there is sweetness synergy between sucrose and fructose giving an increased sweetness at different concentrations.

Table 2 Sweetness of Sugars (adapted from 7)

Sugar

Sweetness

(10 % w/v solution)

Sucrose

1.0

Fructose

1.2 – 1.5 (depending on temperature)

Glucose

0.6

Maltose

0.25

Lactose

0.35

Texture

Sugars also provide texture to foods e.g. in confectionery where the crystalline texture is provided by small sucrose crystals. Sugars also interact with other ingredients e.g. proteins and carbohydrates to provide structure and texture. Sucrose increases the starch gelatinisation temperature in baking and therefore starch gels set at a higher temperature and provide excellent texture to cakes (8). In addition the dissolved sucrose competes with the gluten protein to provide a more tender crumb texture. Sucrose also provides the snap to biscuits and in 1985 Doescher and Hoseney (9) reported that only sucrose would deliver the snap and surface crazing in dough biscuits and that glucose and fructose were not as effective. The particle size of sugar can also have an impact on the dough characteristics in biscuit manufacture. Coarser sugar crystals dissolve more slowly in the dough and give a more compact biscuit whereas finer crystals dissolve rapidly and give greater dough spread (8).

Colour & Flavour formation

Sugars play a major role in the development of characteristic colours and flavours in food products. There are two principal reactions where sugars deliver flavour and colour. These are caramelisation and the Maillard reaction. These are known as non-enzymatic browning as they do not require enzymes to deliver their products and are wholly chemical. Enzymatic browning involves enzymes, principally polyphenol oxidase, and is the route to producing brown discolouration when an apple is cut.

Caramelisation typically occurs in high sugar systems with low nitrogen and is accelerated by the addition of alkali (pH >9) or acid (pH<3). It is essentially decomposition of the sugar molecules and is a removal of water followed by isomerisation, condensation and polymerisation giving a mixture of low and high molecular weight compounds. (10)

The Maillard reaction is a cascade of reactions starting with the reaction of the carbonyl group of a reducing sugar with the amino group of an amino acid followed by Amadori rearrangements (isomerisations) and formation of dehydration, fission and Strecker degradation products producing a mixture of low and high molecular weight heterocyclic nitrogen compounds (melanoidins) similar to those produced by caramelisation. (11)

Many different factors can influence the route and rate of the two reactions that result in characteristic flavours and colours e.g. pH, type of amino acid and sugar(s), temperature, time and other ingredients. For example, fructose (keto hexose) reacts very quickly to give characteristic caramel, treacle flavours and rapid colour formation. Ribose and Xylose (aldo-pentoses) react more slowly to give meaty flavours which are used widely in the snack food industry. Sucrose as a non-reducing sugar must hydrolyse to glucose and fructose before taking part in either of the two reactions.

The characteristic colour and flavour of brown sugars is produced in the sugar manufacturing process and will also contain many colour and flavour precursors (products part way down the colour/flavour cascade) and so can provide additional colour and flavour to food products with less processing or cooking.

More recently the Maillard reaction has been recognised as a route to production of acrylamide in food products (12). This route is usually associated with the presence of the amino acid asparagine found in potatoes and some cereal products.  See IFST Information Statement on Acrylamide.

Amorphous and Glass formation

Sugars are highly soluble and when they reach saturation point they will crystallise. This is important in some food products e.g. fudge or set honey, where the sucrose (fudge) and glucose (honey) provide the characteristic texture of the product. In relatively pure solutions the concentration at which crystallisation occurs is governed by the solubility product and saturation point of the specific sugar. However if other sugars are present they act as a ‘sugar doctor’ which prevents/delays the crystallisation and typically results in a super-cooled liquid or glass. This mechanism is the basis for many confectionery products e.g. high boil sweets where sucrose is combined with 42 DE glucose syrup and boiled to a constant temperature before cooling. The sugars inhibit each other and produce a characteristic glass which combined with colours and flavours give the range of sugar confectionery products (13).

Under certain conditions sugars can also exist in an amorphous state. However, it is very unstable and the preferred state is crystalline (14). The sugar amorphous phase is very important in certain food products e.g. chocolate. During the refining stages of chocolate manufacture sucrose is subjected to very high physical pressure and amorphous sugar is produced in situ. The amorphous sugar is highly absorptive and changes the flavour and flow properties of the liquid chocolate. The change of physical state of the sugar is fundamental to the taste, texture and shelf life of chocolate (15) and other food products (14).

Preservation

Water is ubiquitous in foods and the amount and availability determine the shelf life of many products. Sugars are highly soluble and thus influence the water activity aw in many systems.  The ability to retain water and in some cases even attract water (hygroscopicity) can also influence the texture of many foods. Traditionally sugars have been used to preserve foods providing nutritious and safe foods outside the usual harvest season e.g. jams, preserves, chutneys. The ability of sugars to deliver humectancy is a colligative property i.e. the number of molecules influence the effect rather than the amount or molecular weight. Therefore glucose and fructose (invert) have a greater humectant effect than sucrose and are widely used as humectants in bakery products (16).  Problems can occur if sugars are reduced or replaced in food products and a well-documented outbreak of botulism in 1989 was associated with the replacement of sugar with aspartame in hazelnut puree products. Sugar was providing the microbiological hurdle in the processing and replacement with aspartame changed the aw and allowed the microbial growth of Clostridium botulinum in the product (17).

Fermentation

Sugars are readily broken down by yeasts, bacteria and moulds. In many food products this is undesirable hence the need for preservation (see above). However in some products the fermentation of sugars is essential to deliver the desired characteristics e.g. in bread production the formation of carbon dioxide is fundamental to the texture of a dough. On an industrial scale sugars are widely used to produced alcoholic beverages, yeast, citric acid, xanthan gum, enzymes, antibiotics and more recently to produce bioethanol for fuel use (18).

The functionality of sugars and their impact on health have been reviewed by Clemens et al (19)

Other terms for sugars

Because of the recent increasing, negative perception of sugar(s) and their impact on health many terms have been coined to try to differentiate between sugars naturally present in foods and those added during food preparation. The terms are based on the origin of the sugars and attempt to differentiate between them and their potential impact on health. Brouns reviews the terms for sugars and carbohydrates and suggests better definitions of carbohydrates and sugars would lead to less confusion (20).

Total Sugars or Sugars

This is the term used to categorise all sugars in a product and is the one that appears on a nutritional declaration on a food label in the EU (21) usually as ‘carbohydrate’ – ‘of which sugars’. In this context sugars refers to all monosaccharides and disaccharides present in the food, but excludes polyols; carbohydrate means any carbohydrate which is metabolised by humans, and includes polyols (but it does not include dietary fibre (fibre) which is defined additionally).

Free Sugars

Free Sugars was a term traditionally used to refer to any sugars in a food that were free and not bound (22) and included all monosaccharides and disaccharides present in a food including lactose. Analytically the term was used to describe the sugars liberated when a food was hydrolysed and the sugars detected by HPLC, other chromatographic means or colorimetric methods (23). More recently the terms ‘free sugars’ has been used to refer to sugars added by the manufacturer, cook and consumer and includes other sugar containing materials. The WHO/FAO expert consultation in 2003 defined ‘free sugars’ as all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and fruit juices (24). In the UK prior to 2015 the term Non-Milk Extrinsic Sugars (NMES – see below) was the equivalent of free sugars, however the report Carbohydrates and Health (1) by the Scientific Advisory Committee on Nutrition (the UK Government’s advisory group commonly known as SACN)  recommended that the definition for ‘free sugars’ be adopted in the UK. This comprises all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices. Under this definition lactose when naturally present in milk and milk products is excluded. 

Added Sugars

In the EU, EFSA defines the term added sugars as sucrose, fructose, glucose and starch hydrolysates (glucose syrup, high fructose syrup, and isoglucose) and other isolated sugar preparations used as such, or added during food preparation and manufacturing (25). In the USA dietary reference intakes are set for ‘added sugars’, which are defined as sugars and syrups that are added to foods during processing and preparation. Added sugars do not include naturally occurring sugars such as lactose in milk or fructose in fruits (26).

Intrinsic Sugars

Intrinsic sugars are those naturally incorporated into the cellular structure of foods e.g. fruit and vegetables (27).

Extrinsic Sugars

Extrinsic sugars are those sugars not contained within the cellular structure of a food (27).

Non- Milk Extrinsic Sugars

In 1989 the UK Committee on Medical Aspects of Food Policy (COMA) presented a report on dietary sugars (27). In the report they coined two new terms ‘intrinsic sugars’ (see above) and non-milk extrinsic sugars (NMES) to describe the sugar content of foods in the human diet. The distinction between the sugars was based on the assumption that they exhibit different physiological and metabolic characteristics and in particular that the extrinsic sugars were the most available and the main dietary cause of dental caries. NMES were defined as all sugars in fruit juices, table sugar, honey, sucrose, glucose and glucose syrups added to food plus 50% of the sugars in canned, stewed, dried or preserved fruits and preserves e.g. jam.

In all instances it is not possible analytically to differentiate between sugars from different sources so the terms above (with the exception of sugars or total sugars) cannot be confirmed by analysis and the most important determinant of physiological response is the chemical composition of the carbohydrate (sugar) digested (28).  In the latest edition of McCance & Widdowson’s (5) it is stated that ‘it is not analytically possible to distinguish between intrinsic and extrinsic sugars. Instead values are estimated based on available information about sources of sugars in processed foods, but there is no definitive method for this.’

Regulations & Labelling

Sugars are one of the few food ingredients that are specified under regulations which define their characteristics (purity, moisture and non-sugar composition and colour) and also provide reserved descriptions which must be used in labelling. In the EU, Directive 2001/111/EC relating to certain sugars intended for human consumption (29) outlines the products, characteristics and analysis. The Directive is implemented separately in each of the home countries of the UK, for example Statutory Instrument 2003 No 1563; The Specified Sugar Products (England) Regulations 2003, (30).  The regulations cover sucrose derived products e.g. sugar, sugar solution, invert sugar syrup etc., glucose derived products e.g.  glucose syrup, dried glucose syrup, dextrose monohydrate etc. and also fructose. For iso-glucose where the percentage of glucose is higher than fructose it should be labelled as glucose-fructose syrup and where fructose is present at a higher percentage e.g. in HFCS it must be labelled as fructose-glucose syrup. Sugar is a reserved description and legally should only be used when referring to a purified and crystallised sucrose with specific characteristics (including colour). Internationally the same definitions and terms are used in the Codex standard for sugars (31).

In a nutrition declaration or nutrition labelling the information required is specified in EU Regulation 1169/2011 on the provision of food information to consumers (21). The regulation outlines the expression and presentation of nutrition declaration in Annex XV and states that labelling should be ‘carbohydrate - of which sugars’ and defines sugars in Annex I  ‘sugars’ means all monosaccharides and disaccharides in food but excludes polyols. In Annex XIV the regulation provides energy values for components in foods – for carbohydrate (including sugars) the figures to be used in labelling are 17 kJ/g and 4 kcal/g. Reference Intakes for sugars are also specified in Annex XIII – based on a total energy intake of 8400 kJ/2000 kcal the reference intake for sugars is 90 g/day. 

Analysis

The separation and quantitative analysis of sugars is challenging for several reasons – sugars are hydrophilic and have an array of hydroxyl groups with only minor differences between sugars, their structures do not contain any chromophores and the use of UV-Vis spectrometry is not possible. Thus detection is very difficult. Early quantitative analysis was very laborious and usually entailed derivatisation followed by gas chromatography (GC) or liquid chromatography with detection and quantification by refractive index or mass spectrometry with poor sensitivities. For a simple estimatesin solution e.g. juices or fruit extracts refractometry can be used, expressed as degrees Brix (g/100g solution; % w/w). However the scale is based on pure sucrose solutions at 20°C and the other sugars will have different refractive indices. Therefore a Brix reading is in most cases an approximation and not a quantitative measure(32). The method most commonly used for quantitative analysis is High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD) (32, 33). Sugars are typically extracted from the food matrix using mixtures of ethanol and water (note mono and disaccharides are soluble in relatively high concentrations of ethanol but polysaccharides are precipitated).

For nutritional tables carbohydrates are usually expressed as monosaccharide equivalents. Therefore the values for disaccharides e.g. sucrose, maltose and lactose may exceed 100g/100g of food because on hydrolysis 100 g of disaccharide will yield 105 g of monosaccharide (5).

Nutrition

The body of scientific evidence on sugars and their impact on health has been the subject of many extensive reviews by expert committees in recent years (1, 26, 27, 34, and 35). The main concerns raised by the reviews have been on obesity and dental health (see below); the more recent reviews (1, 34) have raised additional concerns about over-consumption of sugar-sweetened beverages. All have presented recommendations on the intakes of sugars in relation to energy intake. These recommendations are summarised in Table 3.

Table 3 Sugars Intake – recommendations from Expert Committees

Expert Committee

Sugars

Recommendations

SACN 2015 (1)

Free Sugars

Average population intake of free sugars should not exceed 5 % of total energy

WHO 2015 (35)

Free Sugars

Strong recommendation- reducing the intake of free sugars to less than 10% of total energy intake

Conditional recommendation – a further reduction of the intake of free sugars to below 5 % of total energy intake

EFSA 2010 (34)

Added Sugars

No limit set

Institute of Medicine, US (26)

Added Sugars

No limit set*

COMA 1989 (27)

NMES

No more than 10 % of total dietary energy

*a maximum level of intake of 25 % of energy or less due to decreased intakes of certain micronutrients observed at these consumption levels was suggested.

Calories & Obesity

The SACN review (1) reported that randomised control trials conducted in adults indicate that increasing or decreasing the percentage of total dietary energy as sugars when consuming an ad libitum diet leads to a corresponding increase or decrease in energy intake.  Similarly the WHO Guidelines (35) report, a meta-analysis of randomised controlled trials in adults, suggests an association between reduction of free sugars intake and reduced body weight. Increased intake of free sugars was associated with a comparable increase in body weight.  However the EFSA expert panel (34) found that the evidence relating high intakes of sugars (mainly added sugars), compared to high intakes of starch (i.e. the same calories), to weight gain is inconsistent for solid foods. However they concluded there is some evidence that high intakes of sugars in the form of sugar-sweetened beverages might contribute to weight gain. EFSA concluded that the available evidence was insufficient to set an upper limit for the intake of added sugars based on the effect on body weight.

Dental Health

The SACN Committee (1) reported that prospective cohort studies indicated that higher consumption of sugars and sugars-containing foods and beverages, but not total sugars, was associated with a greater risk of dental caries. EFSA in 2010 (34) reported that frequent consumption of sugar-containing foods can increase the risk of dental caries, especially when oral hygiene and fluoride prophylaxis are insufficient. However the available data did not allow the setting of an upper limit for intake of added sugars on the basis of a risk reduction for dental caries, as caries development related to consumption of sucrose and other cariogenic carbohydrates does not depend only on the amount of sugar consumed, but it is also influenced by frequency of consumption, oral hygiene, exposure to fluoride and various other factors.

Type 2 Diabetes

The SACN report (1) concluded that there is no association between the incidence of type 2 diabetes mellitus and total or individual sugars intake. However, prospective cohort studies indicate that greater consumption of sugar-sweetened beverages is associated with an increased risk of type 2 diabetes mellitus.

Consumption

Consumption of sugars, along with other components in the diet, is notoriously difficult to quantify accurately with widely suspected underreporting. The main source of dietary information in the UK is derived from the National Diet and Nutrition Survey (36). The data from the latest survey indicates that mean intakes of total sugars were around 95 – 103 g/day in adults, about half the total sugars comprise sucrose 40 – 50 g/day, with glucose and fructose each accounting for 15 – 18 g/day, lactose 10 – 13 g/day and maltose 5 – 8 g/day. Mean intakes of non-milk extrinsic sugars (NMES) exceeded the daily reference value (DRV) set by COMA (25) i.e. no more than 10 % of total dietary energy with the highest intakes in children 4 – 10 years (14.7 %) and 11 – 18 years (15.4 %). Adults aged 65 and over had mean intakes (11.2 %) closest to the dietary reference value, DRV.

DEFRA Family Food statistics provide a complementary measure of sugars intake based on foods and drinks purchased. The 2014 data (37) indicates an average total sugars intake for 2014 of 115 g/day/person and an average NMES intake of 73 g/day/person. The family food survey is carried out every year and from 2001 included eating out, confectionery and soft drinks. Comparing the data from 2001/2 to the 2014 figures it indicates a reduction in consumption of 15.4 % for total sugars (136 g to 115 g) and 20.65 % for NMES (92 g to 73 g).

The SACN report 2015(1) recommends that free sugars intake should not exceed 5 % of energy intake. Public Health England (PHE) (38) calculated this figure to be equivalent to no more than 30 g/day for children aged above 11 and adults. To put this into perspective, the sugar ration at the end of WWII was 8 oz (227 g) a week for adults (39). This equals 32 g/day.

Reformulation

In reformulation the product developer is trying to replicate the functionalities of sugars using other ingredients. There is no universal single sugars replacer that can replace all the many functions of sugars in every application. Therefore different ingredients must be used to deliver a particular functionality in a specific application.

The types of alternative ingredients that can replicate the functionality of sugar are highlighted in table 4.

Table 4. Ingredients that could replace some of the functions of sugars (after 6)

Sugars Function

Alternative ingredients

Sweetness

High potency sweeteners, polyols

Mouthfeel/texture

Gums, thickeners, polyols

Bulk

Bulking agents, dietary fibres, polyols, gels, gums

Colour

Colours

Flavour

Flavours

Preservative

Preservatives

Humectancy

Polyols, glycerol,  humectants

In many reformulated products there may be an increase in the number of ingredients used to replicate the many functions of sugars; this may also require additional labelling and consumer warnings about the presence of these alternative ingredients.  In many instances even large reductions of sugars may not result in a significant reduction in calories. Consumers expect a reduction in sugars to deliver a reduction in calorie content, but this may not always be the case due to other changes that are made to maintain the taste and physical attributes of the product (40). As highlighted above sugars provide a preservative effect in certain products and therefore if sugars are reduced without due consideration to food safety it can have unintended consequences e.g. the botulism outbreak in 1989 (17).

References
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  2. Food and Agriculture Organisation (1998) FAO Food and Nutrition Paper No 66. Report of a Joint FAO/WHO  expert Consultation; Carbohydrates in Human Nutrition report
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  10. Caramelisation in foods and beverages. Krohl L W Food Chemistry 51 (1994) 373 – 379
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  17. Botulism in the UK. Brett M Eurosurveillance, Vol 4 Issue 01 January 1989
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Essential Reading
Glossary

Monosaccharide = single sugar unit – most common ones are glucose, fructose and galactose

Disaccharide = two sugar units linked together  – most common ones are sucrose (glucose & fructose); lactose (glucose & galactose) and maltose (glucose & glucose).

Furan = 5 membered heterocyclic ring containing and oxygen atom

Pyran = 6 membered heterocyclic ring containing an oxygen atom

RNA = ribonucleic acid

DNA = deoxyribonucleic acid

α = alpha anomer – usually axial bond of the C1 hydroxyl

β = beta anomer  – usually equatorial bond of the C1 hydroxyl

NSP = Non starch polysaccharides

Polyols = hydrogenated sugars (for more information see IFST Information Statement – Carbohydrates)

EFSA = European Food Safety Authority

HFCS = High Fructose Corn Syrup (F55)

DE = Dextrose Equivalent

NMES = Non-milk extrinsic sugars

COMA = Committee on the Medical Aspects of Food

SACN = Scientific Advisory Committee on Nutrition (official advisory board to governmental organisations)

NDNS = National Diet and Nutrition Survey

DEFRA = Department of Environment, Farming and Rural Affairs

PHE = Public Health England

WHO = World Health Organisation

aw = Water Activity

GC = Gas Chromatography

HPAEC-PAD = High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection 

This statement has been prepared by Professor Julian Cooper, CSci, and peer reviewed by professional members of the IFST .

The Institute takes every possible care in compiling, preparing and issuing the information contained in IFST 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.

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