Back in 2009, Carlos Monteiro wrote a commentary for Public Health Nutrition describing three classes of foods from minimally to ultra-processed, and the association of ultra-processed foods with adverse health effects^{(Reference Monteiro1)}. These classes were developed into the NOVA food classification, and many studies have since been conducted, showing the increasing consumption of ultra-processed foods and their association with many health outcomes, as well as with poorer dietary nutrient profiles^{(Reference Monteiro, Cannon and Moubarac2)}. The NOVA system was developed in Brazil and has been incorporated into the Brazilian Dietary Guidelines⁽³⁾; much of the research on NOVA food groups and ultra-processed foods has come from Brazil. In this issue, we include eight manuscripts describing studies of ultra-processed foods and other aspects of diet or health outcomes, seven of these were from Brazil and one from Spain.

Three studies were conducted in adults, covering gestational weight gain^{(Reference Gomes, Malta and Benicio4)}, cardiovascular events^{(Reference da Silva, Felicio and Caldas5)} and blood pressure^{(Reference Scaranni, Cardoso and Chor6)}. In 259 pregnant women in Brazil, dietary intake was assessed by two 24-h recalls and the percentage of energy from ultra-processed foods calculated. During the third gestational trimester, an increment of 1 % of energy from ultra-processed foods was associated with an additional weight gain of 4·17 (95 % CI 0·55, 7·79) g/week, which equates to an additional kilogram of weight gain over the 12-week trimester in the 75th compared to the 25th percentile of ultra-processed food intake^{(Reference Gomes, Malta and Benicio4)}. Excess weight gain has potential adverse effects on infant and maternal health. Another cross-sectional study in 2359 cardiac patients from centres across Brazil looked at associations between the dietary inflammatory index (DII^®) and number of cardiovascular events or cardiometabolic risk factors, and intakes of different NOVA food categories. People in the top tertile of DII^® had a higher risk of 2 or ≥3 cardiovascular events and consumed more of all classes of processed foods, hence less of the unprocessed or minimally processed class (% of energy)^{(Reference da Silva, Felicio and Caldas5)}. In the ELSA-Brasil study, dietary intakes were assessed at baseline using FFQ and participants followed up around 4 years later for hypertension incidence and changes in blood pressure. Participants were 8754 civil servants from six cities in Brazil. Ultra-processed food provided around 25 % of energy and intake was positively associated with risk of developing hypertension (OR 1·23 95 % CI 1·06, 1·44 for tertile 3 v. tertile 1)^{(Reference Scaranni, Cardoso and Chor6)}.

The remaining five studies were in children^{(Reference da Rocha, Rico-Campa and Romanos-Nanclares7–Reference de Souza, Vaz and Martins-Silva11)} or related to foods targeted to children^{(Reference da Rocha, de Araujo and de Morais12)}. In Spanish children with a mean age of 5·3 (sd 1·0) years, dietary intakes were collected using FFQ, foods classified according to the NOVA system and adherence to a Mediterranean style diet assessed by the KIDMED index. For each two-point increment in the KIDMED score (range −4 to +12), children consumed 3·1% (95 % CI 2·1, 4·0) less energy from ultra-processed foods. Maintaining a traditional diet was identified as a way to avoid ultra-processed foods^{(Reference da Rocha, Rico-Campa and Romanos-Nanclares7)}. In southern Brazil, the daily frequency of consuming ultra-processed foods was associated with the risk of dental caries. More than two out of three children consumed ultra-processed foods four or more times per day; the prevalence ratios for non-cavitated (PR 2·25, 95 % CI 1·19, 4·27) and cavitated caries (PR 3·48, 95 % CI 1·18, 10·30) in this group was elevated relative to less frequent consumption^{(Reference de Souza, Vaz and Martins-Silva8, Reference de Souza, Vaz and Martins-Silva11)}. Marçal et al ^{(Reference Marcal, Mendes and Fragoso9)} examined breast-feeding and ultra-processed food intake in Brazilian infants aged 6–24 months based on a single 24-h recall. These infants were from poor families participating in a cash transfer programme of government support. Of the 1604 infants studied, 223 (60·3 %) received some breast-feeding up to 1 year of age and 161 (47·6 %) until 2 years of age^{(Reference Marcal, Mendes and Fragoso9)}. Continuous breast-feeding was associated with less consumption of ultra-processed foods, of which the most consumed were biscuits, chocolate milk and baby food. The authors interpreted their results to recommend promotion of breast-feeding to minimise consumption of ultra-processed foods^{(Reference Marcal, Mendes and Fragoso9)}. In another study of infants aged 6–24 months, Spaniol et al ^{(Reference Spaniol, da Costa and Souza10)} observed that ultra-processed foods made up around one-third of dietary energy intake, and infants consuming more processed and ultra-processed foods consumed more energy from saturated fat and sugar and more Na than lower ultra-processed food consumers^{(Reference Spaniol, da Costa and Souza10)}. Similar to the previous study from Brazil, the main ultra-processed foods consumed were infant and child food products, milk-sweetened beverages and bakery products^{(Reference Spaniol, da Costa and Souza10)}. The last of the studies considered was a survey of commercially available foods indicated for children under the age of 36 months from shops in Natal in Brazil^{(Reference da Rocha, de Araujo and de Morais12)}. Across 100 retail stores, 1645 foods and/beverages were examined but after excluding duplicates 95 different foods were included. Of these, 32% were breast milk substitutes and 26% were cereals; 79% were ultra-processed. All breast milk substitutes and follow-up formulas were classified as ultra-processed. Overall, ultra-processed foods had higher absolute values per 100 g for total and saturated fat, protein and carbohydrate and lower fibre than other foods. The median energy density of the ultra-processed foods was 1540 kJ/100 g with 6·5 % of total energy from proteins, 73·9 % from carbohydrates and 19·6 % from lipids^{(Reference da Rocha, de Araujo and de Morais12)}. These findings in infants and children point to the importance of health promotion and education to support breast-feeding and the use of minimally processed traditional foods.

This issue has reinforced the different ways an increasing reliance on ultra-processed foods can impact health from early life to adulthood. Also, we have five articles relating to the COVID-19 pandemic, which continues to impact on health and life globally.