EFSA Publishes Draft Opinion on Tolerable Upper Intake Level for Dietary Sugars

The European Food Safety Authority (EFSA) panel on Nutrition, Novel Foods and Food Allergens (NDA) has published its draft Scientific opinion on the Tolerable Upper Intake Level for dietary sugars, following a comprehensive scientific review.

What was EFSA asked to do?

In light of more recent scientific evidence and the growing public interest in the impact of the consumption of sugar-containing foods and beverages on human health, EFSA was asked by five European countries (Denmark, Finland, Iceland, Norway and Sweden) to update their 2010 Scientific Opinion, and to review the scientific literature (on the links between intake of dietary sugars and various diseases (e.g. obesity, type 2 diabetes, cardiovascular diseases, gout, dental caries) to determine if a Tolerable Upper Intake Level (the maximum level of habitual intake which is unlikely to pose risk of adverse health effects in humans) could be set for dietary sugars.

EFSA was not asked to not recommend how much sugar consumers should include in their diets, as this is considered a task for national public health authorities, supported by international bodies (e.g. WHO). However, the information provided in the draft opinion is intended to assist EU Member States in setting population goals and recommendations for individuals for dietary sugars in their respective countries.

How did EFSA conduct their assessment?

Expert members of EFSA’s NDA panel conducted systematic reviews of the literature (in both 2018 and 2020) and screened over 30,00 publications to identify 120 eligible studies linking intake of dietary sugars (total, added and free sugars* – see Figure 1) and risk of chronic metabolic diseases, pregnancy-related effects, and dental caries. The assessment included the main types of sugars found in mixed diets (glucose, fructose, galactose, sucrose, lactose, maltose and trehalose). The methodology used for the assessment was described previously in a protocol EFSA developed (and consulted upon) in 2018, prior to commencement of the work.

Eligible studies included randomised controlled trials (RCTs) and prospective cohort and nested case-control studies in humans (PCs) on the exposures (dietary sugars) and endpoints of interest (see Table 1). Does-response analyses were conducted where data allowed for this.

The Panel also estimated the intake of dietary sugars from different categories of food using standardised consumption data from dietary surveys in 25 European countries (covering some 135,000 individuals).

Source: EFSA. ©European Food Safety Authority, 2021

* Added sugars were defined as mono- and disaccharides added to foods as ingredients during processing or preparation at home, and sugars eaten separately or added to foods at the table. Free sugars included added sugars plus sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates. Total sugars also included sugars naturally present in milk, fruits and vegetables.

What were the main findings?

• Based on the available scientific evidence, the Panel concluded that there is evidence for a positive and causal relationship between the intake of dietary sugars and the risk of developing chronic metabolic diseases and dental caries.

However, the available data in humans did not allow the setting of a Tolerable Upper Intake Level (UL) or a Safe Intake level for dietary sugars (see below for more information).

The Panel concluded:

• There are, with associated degrees of certainty, various links between the intake of different categories of sugars and the risk of different adverse health effects, (see Table 1). In some cases, the available evidence did not allow for conclusions to be made by the Panel.
• That the link between sugars and risk of dental caries (tooth decay) is well established.
• Based on the risk of developing chronic metabolic diseases and dental caries, the intake of added and free sugars should be as low as possible.
• The scientific evidence assessed supports recommendations in Europe to limit the intake of added and free sugars.

What were the findings for different types of dietary sugars?

• Total sugars from all sources: RCTs did not allow conclusions due to the complex nature of the exposure (see Figure 1). The available evidence from PCs for isocaloric (same energy content) exchange of total sugars with other macronutrients in the diet from PCs does not support a positive relationship between the intake of total sugars and any of the chronic metabolic diseases or pregnancy-related endpoints the Panel considered.
• Added and free sugars: positive and causal relationships were identified between intake of added and free sugars and risk of obesity, dyslipidaemia, type 2 diabetes, non-alcoholic fatty liver disease, and risk of hypertension, based on evidence from RCTs conducted in isocaloric exchange with other macronutrients (mostly starch) and/or ad libitum intake (no restrictions on intake).
• Sugar-sweetened beverages (SSBs): positive and causal relationships were identified between intake and risk of obesity and metabolic diseases (Table 1), based on evidence from RCTs and PCs. When dose-response relationships between intake of SSBs and incidence of disease could be established using data from PCs, these were positive and linear. There was some evidence from PCs that habitual consumption of SSBs by women of child-bearing age could increase the risk of gestational diabetes, and consumption of SSBs may increase the risk of having infants small for gestational age in women not developing gestational diabetes.
• Fructose: In eligible RCTs, fructose appeared to increase hepatic insulin resistance and uric acid levels more than equivalent amounts of glucose. As fructose is a component of added and free sugars in mixed diets (e.g. sucrose is composed of glucose and fructose), the fructose component could have been responsible for the specific metabolic effects of added and free sugars when consumed in isocaloric exchange with starch. Therefore, the Panel considered that the conclusions for added and free sugars also apply to fructose in that context.           

Table 1. Certainty of evidence linking intake of dietary sugars with adverse metabolic and pregnancy-related health effects.

Certainty of evidence: very low (<15% certainty); low (15-50% certainty); moderate (50-75% certainty). *Non-alcoholic fatty liver disease; **Dyslipidaemia; ***Small for gestational age.

Why was it not possible to set a Tolerable Upper Intake Level?

The EFSA NDA panel found that all ‘dose-response’ relationships between intake of sugars and adverse health effects identified were positive and linear, where these could be established, meaning that the risk of adverse health effects (response) increased across the whole range of observed intake levels (doses). Therefore, the panel concluded it was not possible to determine a ‘threshold’ value below which there is a negligible risk to health, or a safe level of intake up to which no adverse health effects were observed.

What are the main sources of dietary sugars in European diets?

Based on their assessment of intakes of dietary sugars from European dietary surveys, the Panel concluded that:

• Core foods (i.e. foods providing most macro- and micronutrients in the diet as recommended in food-based dietary guidelines) such as fresh fruits and vegetables, milk and dairy, and cereal products represent a large proportion of total sugars intake. No conclusions were drawn with regards total sugars intake and metabolic disease endpoints considered by the Panel, and observational studies did not show a positive relationship.
• Non-core foods such as beverages (SSBs and fruit juices), fine bakery wares (e.g. cakes, biscuits, pastries) and “sugars and confectionery” (i.e. table sugar, honey, syrups, confectionery and water-based sweet desserts) are other major contributors.
• Food groups contributing the most to the intake of added and free sugars in European countries are “sugars and confectionery”, followed by beverages (SSBs and fruit juices), and fine bakery wares, in most population groups, although there is high variability across countries.
• In infants, children and adolescents, sweetened milk and dairy products are also major contributors to the intake of added and free sugars.
• Intakes of added and free sugars from all sources were higher in consumers of SSBs than in consumers of any other non-core food group that significantly contributed to the intake (e.g. fine bakery wares, confectionery, table sugar, honey, syrups), in virtually all countries and population groups. However, the proportion of consumers of SSBs in Europe varied widely across population groups and countries, ranging from 2% to 97% of the sample in dietary surveys. With a few exceptions, the contribution of SSBs to the intake of added and free sugars ranged from 15% to about 50%.
• The proportion of consumers of “fruit and vegetable juices” (which were 100% fruit juices in 88% of consumption occasions) varied widely across population groups and countries (from 15% to 96% of the survey sample). In toddlers, intakes of free sugars from all sources were higher in consumers of “fruit and vegetable juices” than in consumers of any other non-core food group in most countries.

What were some of the limitations of the assessment?

• The panel acknowledged that exploring the relationship between the intake of dietary sugars and health is challenging, as sugars are an energy-containing macronutrient.
• A notable limitation in the evidence assessed was that the characterisation of the specific (non-energy related) effects of dietary sugars in relation to metabolic disease risk could not be systematically addressed across studies and endpoints.
• This was due to limitations of individual studies (e.g. incomplete control for energy in RCTs, inadequate control for energy in cohort studies), and the disparity of available studies in terms of the choice and characterisation of the exposure of interest (dietary sugar), the measurement of health endpoints, and the analytical strategies used for data analysis and control for potential mediators/confounders that could affect the observed relationships.
• While energy-related effects of dietary sugars could derive from excess energy intake owing to their hedonic properties, this was not addressed in the majority of eligible PCs, where dietary sugars were analysed only in isocaloric exchange with other macronutrients.

Consultation and stakeholder meeting

EFSA has launched an open consultation on the Draft scientific opinion and interested parties are invited to submit their comments by the deadline on 30 September 2021. EFSA welcomes new scientific insights that can contribute to finalisation of the opinion by the end of 2021.

A public meeting of stakeholders has also been organised to discuss the draft scientific opinion to be held on 21 September 2021.

Links

• A copy of the full draft opinion is available to download from the EFSA website.
• A summary explaining EFSA’s draft opinion and an infographic summarising the main findings from the draft opinion can be found on the EFSA.