Public Health Nutrition special issue on ultra-processed foods

This special issue on ultra-processed foods considers the role and utility of food processing-based classification systems in food and nutrition research and public policy. Such classification systems have been developed as industrialised food processing and the transnational corporations that drive the production, advertising and sales of industrially processed foods have become a major influencer in the global food system and an important determinant of nutrition-related health outcomes. As highlighted by Monteiro and colleagues in this special issue, in the past decade, food processing-based classification systems have been increasingly acknowledged in reports and commentary from the WHO, FAO and the Pan American Health Organization (PAHO). During this time, such systems have also been applied in nutrition monitoring and in epidemiological and intervention studies published in Public Health Nutrition and other journals. Globally, there are at least seven frameworks that have been devised for classifying foods according to their level of food processing. The most commonly applied framework is the NOVA system, first defined in a commentary published in Public Health Nutrition in 2009 and further refined to include four food groups: unprocessed or minimally processed foods, processed culinary ingredients, processed foods and ultra-processed foods. Originally developed in Brazil, its global application is evident from the range of countries represented in this special issue, spanning Latin America, North America, Europe, the Middle East and Australia. The term ‘ultraprocessed’ foods is unique to the NOVA system and is defined as ‘. not modified foods but formulations made mostly or entirely from substances derived from foods and additives, with little if any intact food’. Ultra-processed foods dominate the food supply in high-income countries and this is increasingly the case in lowand middle-income countries, where urbanisation, a globalised industrial food supply including massively increased foreign direct investment in locally based food companies, and mass and now social media marketing have dramatically shifted population diets away from unprocessed or minimally processed foods and freshly prepared meals. Population nutrition monitoring studies presented in this special issue highlight this dominance of ultra-processed foods, particularly in North America and Europe but also in Latin America. According to these studies, all applying the NOVA system to national 24 h dietary recall data, the energy contribution of ultra-processed foods was 57·6% for children and adults in the USA, 35·9% for French adults, 29·8% for Mexican children and adults and 28·6% for Chilean children and adults. It has been noted that ultra-processed foods contribute substantially to population intakes of micronutrients across many countries. Findings from the studies in this special issue challenge that assertion and demonstrate an association between higher consumption of ultra-processed foods and poorer nutritional intakes, including higher intakes of energy and free/added sugar and lower intakes of fibre, micronutrients and protein. Epidemiological evidence has previously demonstrated that ultra-processed food consumption is associated with poorer diet quality in the USA, Canada and Brazil; obesity in Brazil, Guatemala, Spain and Sweden; hypertension in Spain; metabolic syndrome in Brazil; and dyslipidaemia in children in Brazil. Papers in this special issue reinforce the aetiology between ultra-processed food consumption and nutritional outcomes and chronic conditions, and extend such evidence to new populations. Notably, two papers describe the relationship between ultra-processed food consumption and nutrition and health outcomes in First Nations peoples in Canada and are the first studies to apply NOVA to Indigenous populations. Higher energy contribution from ultra-processed foods was significantly associated with poorer diet quality and with metabolic syndrome in First Nations peoples. Percentage energy intake from ultra-processed foods has been proposed as a summary indicator of population diet quality. Evidence presented in this special issue supports this idea, with ultra-processed food consumption being a better predictor of metabolic syndrome in an Indigenous Cree population compared with other indices of diet quality. Other papers in this special issue find positive associations between ultra-processed food consumption and poorer diet quality (in Brazil and Colombia), obesity (in young people; and in adults in Europe) and metabolic syndrome (in Lebanon). To date, a small number of longitudinal studies have specifically applied the NOVA system for classifying diets and they support identified associations between higher ultra-processed food consumption and chronic conditions. Other cohort studies (e.g.) identify associations between specific ultra-processed products, such as sugary drinks, and nutritional and health outcomes. The reanalysis of existing cohort study data using the NOVA classification would be a worthy endeavour. P u b lic H ea lt h N u tr it io n Public Health Nutrition: 21(1), 1–4 doi:10.1017/S1368980017002853