The role of sweetness in the diet; past present and future
Professor Kees (C) de Graaf, Chairman Division of Human Nutrition, Professor in Sensory Science and Eating Behaviour, Wageningen University, Netherlands.
Sweetness has not always been a large part of the human diet. In the Neolithic diet, sweetness was nearly absent. Up to the 1500’s sugar was considered as a spice in the diet, next to other spices like pepper. With the upcoming of sugar cane production in the America’s, sugar production and consumption rose, alongside with the introduction of coffee, tea and chocolate drinks. Sugar became cheaper through the introduction of sugar beet, and consumption rose considerably from the start of the industrial revolution around 1800 until the 1960’s. Since then sugar consumption in the Netherlands is stable around 125 g/person/day. Humans are born with an inborn preference for sweetness; optimal sugar levels decline from birth until young adulthood. In the industrialized world, the vast majority of the energy consumed comes from sweet and savoury/salty foods. In various recent meta-analyses it was concluded that the consumption of sugar sweetened beverages may contribute to the prevalence of obesity and type 2 diabetes. There is not such evidence for sugar in solid form. A recent meta-analysis on the role of low energy sweeteners (LES) in appetite control showed that LES in beverages behaved like water. One of the mechanisms behind this effect may be the fact that liquid calories are not well sensed with respect to satiety compared to solid calories. One of the interesting remaining questions is whether or not LES would also contribute to a lower energy intake/body weight when replacing sugar in solid foods. One important question regarding sweetness preferences is whether preferences for sweetness are stable or whether they change after exposure. Some scientific studies and industrial examples suggest that sweetness preferences may change into the direction of the level of exposure, although one recent study suggested stable sugar preferences despite lower exposure to sweetness. One of the scientific challenges is to find out how exposure to sweet taste in the diet may change preferences for sweetness.
Low calorie sweeteners: effects on appetite and body weight regulation
Professor Anne Raben, Department of Nutrition, Exercise and Sports, SCIENCE, University of Copenhagen. Professor.
It has been claimed that low calorie sweeteners (LCS) increase appetite and thereby food intake and body weight (BW) in the long term. This is mainly based on a few acute meal test studies in the 1980’ies. However, several intervention studies conducted over the past 25-30 years have shown that LCS do not stimulate appetite or increase BW, as suggested early on. Comprehensive meta-analyses from recent years have quite unanimously found that the use of LCS may lead to relatively reduced body weight compared with sugar (1). The pattern is the same for children and adults, although more studies have been conducted in adults. In addition, it has been shown that ectopic fat accumulation, glycemia, insulinemia and lipidemia do not increase as observed with sucrose intake. Lately, RCTs have also compared intake of LCS with water and changes in BW. This is based on the assumption that LCS would increase appetite and energy intake and thereby BW, if replacing water. Interestingly, one recent study in 303 overweight and obese individuals showed that after an intial weight loss period subjects receiving water had maintained a 2.5 kg weight loss after a 1-year behaviroual treatment programme, while those receiving LCS beverages maintained a loss of 6.2 kg (P > 0.001) (2). LCS beverages were therefore superior for weight loss and weight maintenance in this population. Some longitudinal cohort studies have reported a positive association between LCS intake and BMI, suggesting that LCS may promote weight gain. However, when interpreting data from cohort studies, it is important to remember that only associations and not causeand-effect relationships can be established. Thus, reverse causality or residual confounding can happen, and therefore caution should be used. A recent retrospective analysis of data from 22,231 adults (NHANES) showed that LCS usage was associated with selfreported intention to lose weight during the previous 12 months (3). This therefore supports the hypothesis that overweight subjects are more likely to consume LCS products than normal-weight subjects.
The role of low calorie sweeteners in obesity and diabetes epidemics from a public health perspective
Dr Caomhan Logue, Northern Ireland Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland. Lecturer in Dietetics.
- Rogers et al. Int J Obes 2015.177;doi 10.1038
- Peters et al. Obesity 2016;24:297-304.
- Drewnowski & Rehm. Nutr Diab 2016;6 e202;doi 10.1038.
Obesity and related disorders, including type 2 diabetes, have become major public health concerns resulting in significant implications for the clinical, economic and social arenas.(1,2) Many factors have been implicated in the development of weight gain and diabetes and therefore a multi-faceted approach has been advocated to tackle these global health issues. Public health initiatives have focused on encouraging healthier dietary practices and increased physical activity within the population, with a partnership approach for tackling these health issues being suggested.(3) One suggested strategy is to make healthy dietary options available to consumers through reformulation of products.(4,5) The over-consumption of free sugars, particularly from sugar-sweetened beverages, has been implicated in the development of weight gain and type 2 diabetes.(6,7) Therefore, recent reports recommend that intake of free sugars should ideally not exceed 5-10% of total energy intake.(6,7) With current estimated intakes ranging from 7-17% in adults and 12-25% in children (7), adherence to such recommendations is likely to prove challenging. One strategy to augment efforts to reduce overall free sugar intake may be to substitute them for low-calorie sweeteners (LCS). LCS provide a sweet taste without contributing to the overall energy content of the product. Controversy has surrounded the use of LCS for some time; however despite some observational (human) and animal-based data indicating a potential adverse role of LCS in terms of weight management and/or glycaemic control, these findings have not been supported by randomised controlled trials in humans which demonstrate that LCS may indeed be a useful weight management tool.(8) Furthermore, it has been reported that LCS consumption is associated with healthier diets and lifestyle behaviours.(9,10) Inadequate assessments of LCS intakes in observational studies may explain some of the variances between observational and experimental data. As such, obtaining more robust intake data, potentially via a biomarker approach (11), offers more objective opportunities to overcome limitations with existing datasets. Therefore, based on existing evidence and current government policies, LCS seem well positioned to play a positive role in tackling the obesity and diabetes epidemics by helping to reduce sugar consumption while maintaining the palatability of the diet.
- WHO (2015) Obesity and Overweight, Fact sheet No. 311.
- WHO (2016) Global Report on Diabetes.
- European Commission (2007) White Paper: A strategy for Europe on nutrition, overweight and obesity related health issues.
- Public Health England (2015) Sugar reduction: From Evidence into action.
- World Cancer Research Fund International (2015) Curbing global sugar consumption.
- WHO (2015) Guideline: Sugars intakes for adults and children.
- Scientific Advisory Committee on Nutrition (2015) Carbohydrates and health.
- Peters J.C. & Beck J (In press) Low calorie sweetener (LCS) use and energy balance. Physiology and Behavior.
- Drewnowski & Rehm (2014) Consumption of Low-Calorie Sweeteners among U.S. Adults Is Associated with Higher Healthy Eating Index (HEI 2005) Scores and More Physical Activity. Nutrients 6: 4389-4403.
- Gibson S A et al (2016) Low Calorie Beverage Consumption Is Associated with Energy and Nutrient Intakes and Diet Quality in British Adults. Nutrients 8 (1): 9 doi: 10.3390/nu8010009.
- Logue C et al (2015) A novel method for the simultaneous determination of five low calorie sweeteners in human urine. Proceedings of the Nutrition Society 74 (OCE1): E72.