The sugar conundrum

In February 2022, EFSA published a safety assessment of sugars in the diet and their potential links to health problems. The impact of excessive sugar intake has long been a concern for health professionals, but what to do about it is not so clear. The EFSA opinion concluded that intakes of added and free sugars should be as low as possible as part of a nutritionally adequate diet, but despite reviewing about 30,000 scientific articles on the topic uncertainty remained about more specific recommendations. So not much progress.

So where do we stand?

Sugars are commonly defined as monosaccharides like glucose and fructose, both of which occur naturally in honey, many fruits, and some vegetables, and disaccharides like table sugar (sucrose, extracted from sugarcane or sugar beets) and lactose abundant in milk. Sugars are part of the carbohydrate complex of chemicals. They serve as the main energy source for the body. Carbohydrates are also components of complex molecules that perform numerous key roles in living organisms. As carbohydrates coexists with essential nutrients in many foods their consumption is inescapable. Thereby the conundrum. How to limit their consumption while achieving an adequate intake of essential nutrients.

Adding to the confusion are the different categories and sources of sugars, which can be naturally occurring or added. Total sugars comprise all mono- and disaccharides, regardless of source, including those naturally present in fruit, vegetables, and milk. Added sugars are refined sugars used in food preparation and as table sugar. Free sugars includes added sugars plus those naturally present in honey and syrups, as well as in unsweetened fruit and vegetable juices.

To date, there has been little evidence-based analysis of the scientific basis for these different sugar classifications or implications of their adoption for consumer communication and nutrition labelling.

All clear now, or not? Let’s come back to this.

Health impact of excessive sugar intake

It is clear that sugars have a negative impact on health. Consumption of sugars is a known cause of dental caries. Evidence also links excessive consumption of sugars to some chronic metabolic diseases, including obesity, non-alcoholic fatty liver disease, and type 2 diabetes.

The goal of the EFSA scientific opinion was to establish a tolerable upper intake level for dietary sugars on the basis of available data on chronic metabolic diseases, pregnancy-related endpoints and dental caries. That is the maximum level of usual daily intake of sugars from all dietary sources judged to be unlikely to pose a risk of adverse health effects to humans. A threshold should be able to be identified from the scientific literature below which no risk from consumption of dietary sugars is expected for the general population, and above which the risk of adverse health effects, including risk of disease, increases.

Current sugar intake recommendations

There have been previous attempts to establish thresholds. In 2015, major evidence-based risk assessments with quantitative recommendations for sugar intakes were published by three major independent authorities. The World Health Organization suggested an energy intake of less than 10% from free sugars with a further reduction to below 5% considered beneficial. The United Kingdom Scientific Advisory Committee on Nutrition was a bit firmer with the recommended energy intake from free sugars at 5% or less. The United States Dietary Guidelines Advisory Committee based their recommendation on an energy intake of 10% or less from added sugars.

There is thus a bit of confusion about whether recommendations should be based on free or added sugars and at what level. This variation is also apparent in recommendations from other international authorities with recommended levels of added or free sugars hovering around the 10% of energy intake. However, this is not helping consumers as none seems to base their recommendations on “total” sugars, although globally that is most commonly used for labelling and informing consumers about the sugar contents of foods and beverages.

How to solve the conundrum

So the request to EFSA for a review of the situation was certainly justified as uncertainty remained. Could the latest science help in differentiating between the health impact of added, free and total sugars? Could scientific findings point to a justification for nominating a safe threshold level? How can food labelling of sugar content assist consumers in avoiding products with excessive sugars?

In answer to the first question there was little difference in health impact between added and free sugar consumption. European data indicated that intake of fruit juices was the main difference. Others have looked at evidence linking total compared with added or free sugars with weight gain or energy intake, type 2 diabetes, and dental caries. The relations were weakest for total sugars and most consistent for dietary sources corresponding to free sugars. 

In answer to the second question it was not possible to nominate a safe threshold level based on science as there was a linear relationship between the amount of sugars consumed and its impact on health. That is the more sugar consumed the higher the risk of disease with the opposite true as well all the way down to zero consumption, given that the overall diet remained nutritionally adequate. The scientific uncertainty of potential health impact was particularly high when the intake of sugars contributed to less than 10% of energy intake.

In answer to the third question it seems we have to stick to the current Codex Alimentarius Guidelines on Nutrition Labelling, which require the labelling of total but not added or free sugars. Adoption of free sugars for labelling purposes would carry challenges related to implementation, including consumer understanding, consensus on specifications, and the current lack of analytical capabilities to differentiate between naturally occurring and added sugar.

So what should you do?

If you want to keep your sugar consumption as low as possible you can be guided by the amount of total sugar declared on the food label while considering the importance of other nutrients in the food. Don’t exclude dairy products and intact fruit and vegetables from your diet just because they naturally contain sugars. If you consume less than 50g of sugars a day you should be below the recommendation for sugars to provide less than 10% of overall energy. For reference, 50g of sugars is equivalent to about 4 tablespoons of table sugar and not as challenging as it might sound.

It can also help to keep a keen eye on food groups contributing most to the intake of added and free sugars which in European countries were table sugar, honey, syrups, confectionery and water-based sweet desserts, followed by some beverages and fine bakery wares. In infants, children and adolescents, sweetened milk and dairy products were also major contributors to mean intakes of added and free sugars.

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