Background
Noncommunicable diseases (NCDs) are the leading causes of death and were responsible for 38 million (68%) of the world's 56 million deaths in 2012 (1). More than 40% of those deaths (16 million) were premature (i.e. under the age of 70 years). Almost three quarters of all NCD deaths (28 million), and the majority of premature deaths (82%), occurred in low- and middle-income countries. Modifiable risk factors such as poor diet and physical inactivity are some of the most common causes of NCDs; they are also risk factors for obesity1 – an independent risk factor for many NCDs – which is also rapidly increasing globally (2). A high level of free sugars2 intake is of concern, because of its association with poor dietary quality, obesity and risk of NCDs (3, 4).
Free sugars contribute to the overall energy density of diets, and may promote a positive energy balance (5-7). Sustaining energy balance is critical to maintaining healthy body weight and ensuring optimal nutrient intake (8). There is increasing concern that intake of free sugars – particularly in the form of sugar-sweetened beverages – increases overall energy intake and may reduce the intake of foods containing more nutritionally adequate calories, leading to an unhealthy diet, weight gain and increased risk of NCDs (9-13). Another concern is the association between intake of free sugars and dental caries (3, 4, 14-16). Dental diseases are the most prevalent NCDs globally (17, 18) and, although great improvements in prevention and treatment of dental diseases have occurred in the past decades, problems still persist, causing pain, anxiety, functional limitation (including poor school attendance and performance in children) and social handicap through tooth loss. The treatment of dental diseases is expensive, consuming 5–10% of health-care budgets in industrialized countries, and would exceed the entire financial resources available for the health care of children in most lower income countries (17, 19).
Objective
The objective of this guideline3 is to provide recommendations on the intake of free sugars to reduce the risk of NCDs in adults and children, with a particular focus on the prevention and control of unhealthy weight gain and dental caries. The recommendations in this guideline can be used by policy-makers and programme managers to assess current intake levels of free sugars in their countries relative to a benchmark. They can also be used to develop measures to decrease intake of free sugars, where necessary, through a range of public health interventions.
Methods
WHO developed the present evidence-informed guideline using the procedures outlined in the WHO handbook for guideline development (20). The steps in this process included:
identification of priority questions and outcomes;
retrieval of the evidence;
assessment and synthesis of the evidence;
formulation of recommendations;
identification of research gaps; and
planning for dissemination, implementation, impact evaluation and updating of the guideline.
Grading of Recommendations Assessment, Development and Evaluation (GRADE)4 methodology was used to assess the quality of evidence identified through recent systematic reviews of the scientific literature on preselected topics related to free sugars intake. An international, multidisciplinary group of experts – the WHO Nutrition Guidance Expert Advisory Group (NUGAG) Subgroup on Diet and Health – participated in the WHO technical consultations. The experts reviewed and discussed the evidence, drafted recommendations and reached consensus on the strength of the recommendations. They took into consideration desirable and undesirable effects of the recommendation, the quality of the available evidence, values and preferences related to the recommendation in different settings, and the cost of the options available to public health officials and programme managers in different settings. All members of the NUGAG Subgroup on Diet and Health, as well as external resource persons, completed a declaration of interests form before each meeting. An external expert and stakeholder panel was also involved throughout the process.
The evidence
Meta-analysis of randomized controlled trials (RCTs) 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. The overall quality of the available evidence for adults was considered to be moderate.5 RCTs in children – in which the interventions comprised or included recommendations to reduce sugar-sweetened foods and beverages – were characterized by generally low compliance, and showed no overall change in body weight. However, meta-analysis of prospective cohort studies, with follow-up times of 1 year or more, found that children with the highest intakes of sugar-sweetened beverages had a greater likelihood of being overweight or obese than children with the lowest intakes. The overall quality of the available evidence for an association between a reduction of free sugars intake and reduced body weight in children was considered to be moderate, whereas the quality of the evidence for an association between an increase in free sugars intake and increased body weight was considered to be low.
An analysis of cohort studies in children suggests a positive association between the level of free sugars intake and dental caries. The evidence suggests higher rates of dental caries when the level of free sugars intake is more than 10% of total energy intake compared with it being less than 10% of total energy intake. Furthermore, in three national population studies, lower levels of dental caries development were observed when per capita sugars intake was less than 10 kg/person/year (approximately 5% of total energy intake). Additionally, a positive log-linear dose-response relationship between free sugars intake and dental caries was observed across all studies, at free sugars intakes well below 10 kg/person/year (i.e. <5% of total energy intake). The overall quality of the available evidence from cohort studies was considered to be moderate, whereas that from the national population studies was considered to be very low.
Based on the entire body of evidence, WHO generated the following recommendations for free sugars intake in adults and children.
Recommendations
WHO recommends a reduced intake of free sugars throughout the lifecourse (
strong recommendation6).
In both adults and children, WHO recommends reducing the intake of free sugars to less than 10% of total energy intake
7 (
strong recommendation).
WHO suggests a further reduction of the intake of free sugars to below 5% of total energy intake (
conditional recommendation8).
Remarks
Free sugars include monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.
For countries with a low intake of free sugars, levels should not be increased. Higher intakes of free sugars threaten the nutrient quality of diets by providing significant energy without specific nutrients (
3).
These recommendations were based on the totality of evidence reviewed regarding the relationship between free sugars intake and body weight (low and moderate quality evidence) and dental caries (very low and moderate quality evidence).
Increasing or decreasing free sugars is associated with parallel changes in body weight, and the relationship is present regardless of the level of intake of free sugars. The excess body weight associated with free sugars intake results from excess energy intake.
The recommendation to limit free sugars intake to less than 10% of total energy intake is based on moderate quality evidence from observational studies of dental caries.
The recommendation to further limit free sugars intake to less than 5% of total energy intake is based on very low quality evidence from ecological studies in which a positive dose–response relationship between free sugars intake and dental caries was observed at free sugars intake of less than 5% of total energy intake.
The recommendation to further limit free sugars intake to less than 5% of total energy intake, which is also supported by other recent analyses (
15,
16), is based on the recognition that the negative health effects of dental caries are cumulative, tracking from childhood to adulthood (
21,
22). Because dental caries is the result of lifelong exposure to a dietary risk factor (i.e. free sugars), even a small reduction in the risk of dental caries in childhood is of significance in later life; therefore, to minimize lifelong risk of dental caries, the free sugars intake should be as low as possible.
No evidence for harm associated with reducing the intake of free sugars to less than 5% of total energy intake was identified.
Although exposure to fluoride reduces dental caries at a given age, and delays the onset of the cavitation process, it does not completely prevent dental caries, and dental caries still progresses in populations exposed to fluoride (
23-
35).
Intake of free sugars is not considered an appropriate strategy for increasing caloric intake in individuals with inadequate energy intake if other options are available.
These recommendations do not apply to individuals in need of therapeutic diets, including for the management of severe and moderate acute malnutrition. Specific guidelines for the management of severe and moderate acute malnutrition are being developed separately.
- 1
Overweight and obesity are defined as follows:
- -
Children (<5 years):
- -
School-aged children and adolescents (5–19 years):
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| Overweight: | body mass index (BMI)-for-age >+1 SD of the WHO growth reference for school-aged children and adolescents (equivalent to BMI 25 kg/m2 at 19 years) |
|---|
| Obesity: | >+2 SD of the WHO growth reference for school-aged children and adolescents (equivalent to BMI 30 kg/m2 at 19 years) |
|---|
- -
Adults (≥20 years):
- 2
The term “free sugars” was used by the 2002 Joint WHO/FAO Expert Consultation on Diet, Nutrition and the Prevention of Chronic Diseases (3) when updating the population nutrient intake goals, which were originally established by the WHO Study Group in 1989 (4). The term “free sugars” was referred to in the 2002 WHO/FAO Expert Consultation as “all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and fruit juices” (3). However, as noted in the Remarks section under the Recommendations, the term has been further elaborated for this guideline by the WHO Nutrition Guidance Expert Advisory Group (NUGAG) Subgroup on Diet and Health as follows: “Free sugars include monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates”.
- 3
This publication is a World Health Organization (WHO) guideline. A WHO guideline is a document, whatever its title, containing WHO recommendations about health interventions, whether they be clinical, public health or policy interventions. A recommendation provides information about what policy-makers, health-care providers or patients should do. It implies a choice between different interventions that have an impact on health and that have ramifications for the use of resources. All publications containing WHO recommendations are approved by the WHO Guideline Review Committee.
- 4
- 5
Based on the grades of evidence set by the GRADE Working Group: high quality, we are very confident that the true effect lies close to that of the estimate of the effect; moderate quality, we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different; low quality, our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect; very low quality, we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of the effect.
- 6
Strong recommendations indicate that “the desirable effects of adherence to the recommendation outweigh the undesirable consequences” (20). This means that “the recommendation can be adopted as policy in most situations” (20).
- 7
Total energy intake is the sum of all daily calories/kilojoules consumed from food and drink. Energy comes from macronutrients, such as fat (9 kcal/37.7 kJ per gram), carbohydrate (4 kcal/16.7 kJ per gram) including total sugars (free sugars + intrinsic sugars + milk sugars) and dietary fibre, protein (4 kcal/16.7 kJ per gram) and ethanol (i.e. alcohol) (7 kcal/29.3 kJ per gram). Total energy intake is calculated by multiplying these energy factors by the number of grams of each type of food and drink consumed and then adding all values together. A percentage of total energy intake is therefore a percentage of total calories/kilojoules consumed per day.
- 8
Conditional recommendations are made when there is less certainty “about the balance between the benefits and harms or disadvantages of implementing a recommendation” (20). This means that “policy-making will require substantial debate and involvement of various stakeholders” (20) for translating them into action.
