New WHO diet and nutrition review:: Implications for dental disease prevention

Abstract

In recognition of the increasing burden of chronic diseases across developed and developing nations, the World Health Organization (WHO) recently published an expert review of the evidence of the effects of diet and nutrition on chronic diseases.1 The joint publication of the WHO and the Food and Agriculture Organization (FAO) has set a variety of targets related to diet and nutrition and outlines recommendations for public health policies and strategies that encompass societal, behavioral, and ecologic dimensions. The Expert Review is an update of a previous WHO report on this topic.2 The current report focuses on chronic diseases that are related to diet and nutrition and present the greatest public health burden. These include obesity, diabetes, cardiovascular diseases, cancer, osteoporosis, and dental diseases. The epidemiologic evidence reviewed indicates that the burden of chronic diseases is rapidly increasing worldwide. In five of the six regions of the WHO, deaths caused by chronic diseases dominate mortality statistics.3 Chronic diseases should no longer be seen as “diseases of affluence” when they affect the poorer nations of the world and the poorest groups in the developed world. Global food consumption patterns and trends are outlined, and the impact of the “nutrition transition” on the developed world is highlighted. The “transition” is characterized by a shift in structure of the diet toward a higher energydensity diet with a greater role for fat and added sugars in foods, greater saturated fat intake, reduced intakes of complex carbohydrates and dietary fiber, and reduced fruit and vegetable intakes.4 These dietary changes are largely driven by social, economic, and political factors. In recognition of the recent body of public health research that has emphasized the importance of the social determinants on health, a life-course perspective has been adopted in the report.5 This highlights the impact of diet and nutrition at key life stages and identifies opportunities for intervention. The five life stages include fetal development and maternal environment; infancy; childhood and adolescence; adulthood; and aging and older people. These life stages are closely linked to biological and social factors influential to oral health. Based on criteria used by the World Cancer Research Fund,6 the evidence linking diet and nutrition to the etiology of chronic diseases is reviewed and summarized. Pragmatic but rigorous epidemiologic criteria were used that classified the evidence into the following levels: convincing, probable, and possible and insufficient. The review of the oral health evidence considered a range of different types of evidence including human interventional studies, human observational surveys, animal experiments, and in vitro studies. The totality of evidence from these different sources provides a clear and balanced perspective. What is the relevance of this report specifically for the promotion of oral health? A range of nutrient intake goals are presented, which include less than 10% of total energy from free sugars (free sugars are defined as all monosaccharides and disaccharides added to foods by the manufacturer, cook, or consumer, plus sugars naturally present in honey, syrups, and fruit juices). The basis for this goal is the recognition that higher intakes of free sugars threaten the nutrient quality of diets by providing significant energy without specific nutrients and that restriction of free sugars is likely to contribute to reducing the risk of weight gain. A particular concern was the high intake of sugar-sweetened drinks in promoting weight gain. Concerns over the relation between a reduction in sugars leading to an increase in fats, the so-called fatand-sugar seesaw, were largely dismissed. A very comprehensive, balanced, and detailed review is presented of the evidence linking diet and nutrition to dental caries and dental erosion. Key points include: