Allulose vs Sucrose

Sugar – or not sugar?

Chemically, allulose is a monosaccharide, closely related to fructose. Nutritionally, however, it differs markedly from conventional sugars such as sucrose, glucose or fructose. In most countries where allulose is already authorised, it is not declared as “sugar” in nutrition labelling. This means that the labelled sugar content of a product is low when allulose is used as the sweetener. That makes products with allulose particularly attractive to consumers who are mindful of sugar and calories. In food law, allulose therefore holds a special position reflecting these unique properties:

No calories

Allulose has an extremely low energy value of 0.4 kilocalories (referred to here as “calories”) per gram, which is negligibly small compared to table sugar (sucrose) at 4 kilocalories per gram.

Barely metabolised

The human body absorbs allulose, but unlike glucose or fructose, it is barely metabolised. Most is excreted unchanged in the urine; a smaller part is excreted in the stool.

Minimal effect on blood glucose and insulin

Because absorbed allulose does not serve as a usable energy source, it has a negligible effect on blood glucose and insulin secretion.

Tooth-friendly

Unlike sucrose or glucose, allulose does not lower plaque pH because oral microorganisms cannot metabolise it. No acids are produced that attack enamel and promote caries.

Sugar is not all the same

Ingredient lists reveal the presence of many sugars and sugar alternatives. Allulose shares many sensory and application features with sucrose, yet differs strongly from it nutritionally. To understand the differences, it is helpful to examine the current definitions and properties of sugar.

Definition of sugar

In everyday language, “sugar” typically refers to sucrose, a disaccharide composed of glucose and fructose. It is energy-dense and raises blood glucose quickly. Chemically, sugars are carbohydrates classed as mono- and disaccharides. Sucrose is a disaccharide made of the monosaccharides glucose and fructose. In science and food law, “total sugars” refers to all mono- and disaccharides, whether naturally present or added. This corresponds to the way “sugars” must currently be declared on food packaging in the USA. Novel sugars with special properties, like allulose, do not fit neatly into this traditional definition from a nutritional perspective.

Calories are decisive

Allulose’s special status is linked to its energy content. Although it is a monosaccharide like glucose or fructose, it does not share their metabolic properties and contributes virtually no calories. Approximately 70–80% of ingested allulose is absorbed in the small intestine, enters the bloodstream, and is excreted via the urine; 20–30% reaches the large intestine, where the microbiota may partially ferment it, and is otherwise excreted. Hence, allulose has a very low energy value of 0.4 kcal/g. [1]

By contrast, mono- and disaccharides, such as glucose, fructose and sucrose, provide 4 kcal/g. If consumers want to estimate calories from such traditional sugars, they can multiply grams of “total sugars” per serving by four. Dietary guidelines recommend limiting calories from added sugars, especially those found in processed foods. Manufacturers, therefore, increasingly replace 4 kcal/g sugars with ingredients like allulose to reduce calories. Including allulose in “total sugars” despite its much lower energy would not accurately reflect a food’s calorie contribution.

Gentle on blood glucose and insulin

Since allulose is not a usable energy source, it has only a minimal effect on blood glucose levels. Conventional table sugar, by contrast, has a significant impact on blood glucose and insulin levels. During digestion, sugars are broken down to glucose, which cells use for energy or store as glycogen. [2] A rise in blood glucose triggers the release of insulin from the pancreas, promoting the uptake of glucose into muscle and fat tissue. Classic sugars, such as glucose and sucrose, thus cause marked glycaemic and insulinaemic responses, which, over time, eaten in large quantities, may affect health.[3] In a clinical study, allulose showed a glycaemic index of 1 (compared with glucose at 100) and an insulin index of 1.5 (compared with glucose at 100). It is therefore an extremely low-GI carbohydrate that combines sucrose-like mild sweetness and textural functionality without provoking glucose or insulin spikes. [4]

Tooth-friendly sweetness

Oral bacteria metabolise sugars, producing substances that adhere to teeth (plaque). The resulting drop in pH can demineralise enamel and increase the risk of caries. [5] [6] According to testing by the Centre for Dental Medicine at the University of Zurich, allulose is neither cariogenic nor erosive and can be described as “tooth-friendly.”[7] In this context, “total sugars” on labels also helps consumers assess caries risk.

Conclusion: Allulose is not a (dietary) sugar

Current evidence is clear: despite similar sensory properties, allulose is not considered a sugar in the conventional or legal-nutritional sense. Including it within “total sugars” would mislead consumers. It is scarcely metabolised, non-cariogenic, provides fewer than 0.4 kcal/g, and has a minimal impact on blood glucose and insulin levels. With its nutritional profile and contribution to improved product nutrition, allulose represents a new category of sweetness.

In 2020, the FDA issued guidance on declaring allulose on Nutrition Facts labels. The FDA permits the use of 0.4 kcal/g for energy calculation and the exclusion of allulose from “total sugars” and “added sugars” on labels – a significant step forward for allulose users in the USA.[8]

Sources

[1] Williamson, P., Schunk, T., Woodyer, R., Chiuu, D., Song, Q., Atiee, G. and Unger, S. (2014), A single-dose, microtracer study to determine the mass balance of orally administered, ¹⁴C-labeled sweetener in healthy adult men (LB450). The FASEB Journal, 28: LB450.

[2] Gropper, S.S., Smith, J.L., Groff, J.L. (2009). Advanced Nutrition and Human Metabolism (5th ed.), Chapter 3: Carbohydrates. Belmont, CA: Wadsworth, Cengage Learning

[3] Deutsche Gesellschaft für Ernährung e. V., Evidenzbasierte Leitlinie: Kohlenhydratzufuhr und Prävention ausgewählter ernährungsmitbedingter Krankheiten. Bonn (2011) URL: www.dge.de/leitlinie

[4] A randomised, crossover, simple blind, referent-controlled study to determine Glycemic Index and Insulinemic Index of D-cellobiose and D-allulose, Savanna Ingredients GmbH, unternehmenseigene Daten, 2020.

[5] Newman H.N. “The Relation between Plaque and Dental Caries.” J R Soc Med. 1986;79 Suppl 14:1-5.

[6] Selwitz R.H., Ismail A.I., Pitts N.B. “Dental Caries.” Lancet. 2007;369:51-59.

[7] Toothfriendly International, Allulose – Evaluation of Toothfriendly Quality, Zentrum für Zahnmedizin Universität Zürich, 16. Juni 2019.

[8] Food and Drug Administration, The Declaration of Allulose and Colories from Allulose on Nutrition and Supplement Facts Labels: Guidance for Industry, Oktober 2020.