The World Health Organization recommends that consumption of free sugars should be reduced throughout the life course. It is recommended that the free sugars in an individual’s daily diet should not comprise more than 5% of their total energy intake (1).
Based on the average adult diet, individuals aged 11 years and over should not consume more than 30 g of free sugars, which is equal to 7 sugar cubes. The maximum free sugars consumption for children aged 4 to 6 is 19 g, and for children 7 to 10 years old it is 24 g (2).
What exactly are “free sugars” and what is the issue?
They are the sugars added to food to enhance the flavour or those that are naturally present in fruit juices, honey and syrups. However, the sugars found in milk and whole fruit and vegetables (not juiced), are not classified as free sugars (2).
The consumption of free sugars increases our overall energy intake and the energy density of our diets (meaning that we consume more calories per gram of food). This increase can make the maintenance of a healthy body weight more challenging. In addition, consuming large amounts of free sugars is linked to an increased risk of Noncommunicable Diseases (NCDs), such as dental caries, cardiovascular disease, cancer, respiratory disease and diabetes (1).
Naturally, sugars occur in a combination with other nutrients such as fibre, vitamins and minerals- for example in fruit and vegetables, which form an important part of our diet. These combinations can be beneficial for our health. In contrast, many processed foods are high in free sugars and low in fibre and other nutrients, so they are of little nutritional value (2).
What does ‘sugar-free’ mean?
The nutrition claims that we see on food packaging are regulated by the European Commission (3). There are three approved nutrition claims regarding the sugar content of food:
What is there in sugar-free products?
Sweeteners are often used in sugar-free foods and beverages to enhance their sweetness and can generally be grouped as either natural or artificial. In addition, sweeteners can be nutritive (those that have a nutritive value) and non-nutritive or ‘low-calorie’ sweeteners (without nutritive value/calories) (4).
Polyols (sugar alcohols) are a group of carbohydrates that have a sweet taste, but are not classified as sugars.
Polyol sweeteners include:
Polyols have less calories and exert a smaller effect on blood glucose levels, compared to sugar (sucrose). They are often used in products which are advertised as suitable for diabetics, however, Diabetes UK does not recommend them to diabetic people. These products often have a high fat and calorie content, and excessive consumption can cause a laxative effect, bloating and diarrhoea (4).
Non-nutritive sweeteners can be natural or artificial.
Artificial sweeteners include:
An example of a natural non-nutritive sweetener called steviol glycoside, which is extracted from the stevia plant (4).
Artificial and natural sweeteners are subject to rigorous safety testing before being approved by the European Commission. The sweeteners should not cause any adverse effects, affect reproduction or cause allergic reactions. In addition, they should not be stored in the body or converted to other unsafe products when metabolised (4).
What does research suggest?
There has been a lot of controversy around the safety and the potential health effects of natural and artificial sweeteners. The results of studies are often inconclusive and conflicting. Common concerns regard the effect on dental health, hunger and satiety, weight loss and gastrointestinal side effects (5-13).
Steviol glycosides have been shown to be safe, as they do not cause dental caries, high blood pressure, gastrointestinal side effects or increase in hunger. In addition, steviol glycosides reduce blood glucose after a meal (postprandial), sugar and energy intake (5).
Polyols may cause increased bowel movement frequency, diarrhoea, abdominal pain and bloating due to the osmotic effect they exert on the intestines and the production of intestinal gas during fermentation (6).
However, studies suggest that chewing gums with Sorbitol and Xylitol can have a caries-reducing effect, possibly due to saliva stimulation by the chewing process and the sugar that can be fermented by bacteria to produce acids, which cause dental caries (7). It should be noted that although polyol-sweetened products are considered to be 'tooth friendly', the acidic flavourings and preservatives that are often present in sugar-free products can cause irreversible loss of dental hard tissue- a condition known as dental erosion (8).
In addition, research suggests that xylitol may not only beneficial for dental health, but might also possess prebiotic characteristics, as it is a non-digestible, selectively fermentable carbohydrate. It has the potential to benefit the respiratory microbiota and respiratory infections. It is also considered to have immune function modulating and anti-inflammatory effects. Its suggested ability to enhance Calcium absorption possibly accounts for xylitol’s suggested benefit on bone health. Its low-calorie content and satiety-stimulating properties can potentially contribute to weight loss. The majority of research, however, is based on a limited amount of human studies, and mostly animal and in vitro tests, often with large xylitol doses, far from representative of the amount usually consumed in human diets (9).
According to the results of a an 18-month trial, replacing sugar-containing beverages with sugar-free artificially sweetened beverages daily in normal-weight children, reduced weight gain and fat accumulation (10). In another study, however, consumption of a mineral water, a sugar-free beverage or a sugar-rich beverage in male adults did not result in significant differences in feelings of hunger and total energy intake during the experiment (snack and lunch) and until the end of the day (11).
Most concerns regarding the consumption of artificially sweetened beverages are due to their low nutrient density composition, usually high in food additives and the consumption patterns that these beverages promote- for example preference for sweet taste (12).
There is a lot of controversy about the safety of non-nutritive sweeteners. While rigorous research has provided evidence of the safety of the currently approved sweeteners, there are studies that suggest they can cause a number of adverse effects. Most of these studies, however, have important limitations as they are often carried out on animal subjects, small sample sizes or at extremely high doses (13).
Sugar-free products contain natural and artificial sweeteners, which have been approved for safe use in food and beverages. While they do not contain sugar, sugar-free products are usually high in saturated fat and calories and have a low nutritive value.
When choosing which foods to consume, it is important to address the food as a whole- many foods contain sugar, but also other important nutrients that are beneficial in keeping a balanced diet. For example, fruit does contain sugar, but it can also provide us with fibre, vitamins and minerals (2).
This blog post was written by Daniela Dimitrova, a Registered Associate Nutritionist who has recently graduated BSc Human Nutrition course at Kingston University. Daniela is passionate about cooking and yoga. She has worked with children for years and hopes to be able to help improve the nutrition status of children. She also wishes to work with people to help them lose weight and maintain a happy and healthy relationship with food. You can find Daniela on Instagram @nutrition_with_daniella.
1) WHO (2015) World Health Organization, Guideline: Sugars intake for adults and children. Geneva
2) BDA (2020) Sugar: Food Fact Sheet Available at: https://www.bda.uk.com/resource/sugar.html Accessed 23/10/2020
3) 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 OJ L 404, 30.12.2006, pp. 9–25 Available at: https://eur-lex.europa.eu/legal-content/en/ALL/?uri=CELEX:32006R1924 Accessed 23/10/2020
4) Diabetes UK (2020) Sugars, sugar substitutes and sweeteners: natural and artificial Available at: https://www.diabetes.org.uk/guide-to-diabetes/enjoy-food/carbohydrates-and-diabetes/sugar-sweeteners-and-diabetes Accessed: 23/10/2020
5) Samuel, P., Ayoob, K.T., Magnuson, B.A., Wölwer-Rieck, U., Jeppesen, P.B., Rogers, P.J., Rowland, I. and Mathews, R. (2018) ‘Stevia Leaf to Stevia Sweetener: Exploring Its Science, Benefits, and Future Potential’ The Journal of Nutrition 148(7) pp. 1186S–1205S https://doi.org/10.1093/jn/nxy102
6) Zumbé, A., Lee, A., & Storey, D. (2001) ‘Polyols in confectionery: The route to sugar-free, reduced sugar and reduced calorie confectionery’ British Journal of Nutrition 85(S1) pp. S31-S45. doi:10.1079/BJN2000260
7) Mickenautsch, S., Leal, S.C., Yengopal, V., Bezerra, A.C. and Cruvinel, V. (2007) ‘Sugar-free chewing gum and dental caries: a systematic review’ J. Appl. Oral Sci. 15(2) pp.83-88. https://doi.org/10.1590/S1678-77572007000200002.
8) Nadimi, H., Wesamaa, H., Janket, S.-J., Bollu P. and Meurman, J. H. (2011) ‘Are sugar-free confections really beneficial for dental health?’ British Dental Journal 211, p E15
9) Salli, K., Lehtinen, M.J., Tiihonen, K. and Ouwehand, A.C. (2019) ‘Xylitol’s Health Benefits beyond Dental Health: A Comprehensive Review’ Nutrients 11(8) 1813 https://doi.org/10.3390/nu11081813
10) Ruyter, J.C., Olthof, M.R., Seidell, J.C. and Katan, M.B. (2012) ‘A Trial of Sugar-free or Sugar-Sweetened Beverages and Body Weight in Children’ N Engl J Med 367 pp. 1397-1406 DOI: 10.1056/NEJMoa1203034
11) Holt, S.H.A., Sandona, N. and Brand-Miller, J.C. (2009) ‘The effects of sugar-free vs sugar-rich beverages on feelings of fullness and subsequent food intake International’ Journal of Food Sciences and Nutrition 51(1) pp. 59-71 https://doi.org/10.1080/096374800100912
12) Borges, M.C. et al. (2017) ‘Artificially Sweetened Beverages and the Response to the Global Obesity Crisis’ PLoS Med 14(1): e1002195 https://doi.org/10.1371/journal.pmed.1002195
13) Tandel, K.R. (2011) ‘Sugar substitutes: Health controversy over perceived benefits’ J Pharmacol Pharmacother 2(4) pp. 236–243 doi: 10.4103/0976-500X.85936
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