The science behind the sweetness in our diets - WHO

1 News The science behind the sweetness in our diets Jim Mann tells Fiona Fleck what happened when WHO applied a rigorous new method of scientific evaluation to its guideline recommending that we keep our intake of free sugars in food and drink to less than 10% of dietary intake. Q: What are free sugars ? A: According to WHO, the term Jim Mann has spent the last 35 years investigating the free sugars refers to all monosaccha- link between sugars and noncommunicable diseases rides and disaccharides added to foods (NCDs). He has been a professor in human nutrition by the manufacturer, cook or consumer, and medicine at the University of Otago and consultant plus the sugars that are naturally present Courtesy of Jim Mann physician in endocrinology in Dunedin Hospital in in honey, syrups and fruit juices.

2 Mono- New Zealand for 27 years. Prior to that he lectured at saccharides have one sugar molecule and include glucose, galactose and fructose. the University of Oxford in England and worked as a Disaccharides have two molecules. The physician at the Radcliffe Infirmary. He is the director most widely consumed disaccharide is of the Edgar National Centre for Diabetes and Obesity sucrose or table sugar. Research and the WHO Collaborating Centre for Human Nutrition in Dunedin, New Zealand. Since 2010, he has been a member of the Q: So the recommendations don't apply WHO Nutrition Guidance Expert Advisory Group that provided guidance to WHO. to other types of sugar? in updating the guideline on free sugars intake, which was put out for public A: That's right.

3 The WHO recom- consultation this year. He was also a senior author of one of the systematic mendations only apply to free sugars. reviews that provided a scientific basis for updating this guideline. These do not include the sugars present in whole fruit and vegetables, which are sometimes known as intrinsic sugars. These sugars are encapsulated by a plant our consumption of free sugars should our other focus because everyone now cell wall. They tend to be digested more account for less than 10% of our dietary acknowledges that we have a global slowly and take longer to enter the blood intake. The food industry and some epidemic of obesity and that obesity stream than free sugars. countries, particularly the United States, drives other NCDs type 2 diabetes, questioned very strongly whether WHO certain cancers ( post-menopausal Q: Food labels don't refer to free sugars , had good enough evidence for this and breast cancer, colorectal cancer) and, to but added sugar , what is that?

4 Doubts have lingered since then. When some extent, cardiovascular disease. It A: The term added sugar is widely WHO decided to update the guideline, would have been interesting to examine used in the United States and some as part of WHO's nutrition and dietary the effect of sugars on cardiovascular other countries although there is guidelines, the Nutrition Guidance disease, other NCDs and their risk fac- no universally agreed definition of Expert Advisory Group (the body of tors, but the Nutrition Guidance Expert added sugar . For the most part the experts responsible for advising WHO Advisory Group believed that focusing term added sugar describes the same on nutrition guidelines) was asked to on dental caries and obesity would be group of sugars as free sugars, but the answer two questions: what are the sufficient.

5 Term free sugars is more precise. For health effects of the consumption of free example, it is unclear whether concen- sugars and has any evidence emerged Q: How did you set about conducting trated fruit juice contains added sugar since 2003 to suggest that the existing the systematic review on free sugars while there is no doubt that it contains recommendation (to keep the intake of and obesity? free sugars. WHO decided that a more free sugars below 10% of total energy) A: We focused on answering four precise definition was needed for the should be revised? Our guidance group questions: does decreasing the intake purpose of guidelines and developed the decided to request two systematic re- of free sugars reduce body weight and definition of free sugars.

6 The term free views to help answer these questions does increasing free sugars result in sugars is becoming more widely used. focusing on the health outcomes, which increased body weight? Each of these The recent draft report from the Special- they identified as the two priorities for questions was examined separately in ist Advisory Committee on Nutrition this work: one on dental caries (tooth adults and in children. We set criteria to the United Kingdom government decay) and one on unhealthy weight gain for the studies that we would include has also recommended use of the term. ( overweight and obesity). in our search for the answers, such as: There are other unhelpful terms when it was the study of an appropriate design? comes to describing sugars, for example: Q: Why just those two?

7 Was dietary intake measured appro- raw sugar, unrefined sugar and natural A: There are more data on the ef- priately? Were the studies done in an sugar. These are all free sugars. fect of free sugars on dental caries than unbiased way? Two types of studies were for other NCDs. Dental caries are not included: first, randomized controlled Q: Why was the guideline updated? only a very unpleasant condition for trials that involved asking participants A: The Organization made a clear the person affected, but treatment of to alter their usual sugar intake, so that recommendation in number 916 of its caries consumes 6 to 10% of health- the effects of increasing or decreasing Technical Report series in 2003 that care budgets worldwide. Obesity was their intake could be compared with 780 Bull World Health Organ 2014;92:780 781 | doi: News a control group, who maintained their cations of this affirmation of the earlier high, medium or low in free sugars and usual intake; and second, cohort stud- recommendation?

8 Other nutrients, for example. Such a ies, which involved following people A: It is immensely reassuring for all labelling system should be consistent with known intakes of free sugars or health professionals and, indeed, for the and compulsory in each country and . sugar-sweetened drinks to determine general public to hear the strong rein- better still internationally. We are still the extent to which consumption in- forcement and potential strengthening far away from such an approach and, of fluences long-term weight outcomes. of this message. Further reinforcement course, many foods are not packaged We started by searching databases with recently came from another highly and have no labels. keywords and combing through the regarded body, the Specialist Advisory scientific literature for every conceiv- Committee on Nutrition in the United Q: In some countries there have been ably relevant research publication.

9 Kingdom in a draft report on carbohy- arguments over conflicts of interest: Then we had to put the different sets of drates released in July, which includes government advisers on nutrition com- results together so that a much clearer remarkably similar advice on free sugars mittees having close ties to industry. Are picture emerged than could be obtained to that of WHO and, further reinforcing conflicts of interest unavoidable? by looking at the studies individually. the message, the two sets of recommen- A: In some countries it may be Three researchers worked for almost a dations were developed independently difficult to recruit expert advisers who year on this and, of course, others were of each other. have no connection to the food industry.

10 Involved too. We started with 17 000 When expert advisers do have such con- research papers, but, after applying the Q: If countries follow the draft WHO nections, it is essential that they declare criteria, we narrowed down our selec- recommendations, what contribution any potential conflicts of interest that tion to 68. Then we did a meta-analysis could this make to halting the rise of could affect their ability to provide im- of the 68 to produce the strongest and diabetes and obesity , one of the goals partial advice. These potential conflicts most up-to-date evidence. in the Global Action Plan for the Preven- of interest may range from the fairly tion and Control of Noncommunicable trivial, such as having provided infor- Q: In what way were your team's find- Diseases?