Ultra-processed foods and obesity and adiposity parameters among children and adolescents: a systematic review.
European journal of nutrition. 2022
Plain language summary
Ultra-processed foods (UPFs) are mostly or entirely lacking whole foods and fibre and are often high in fat sugar and salt. The consumption of UPFs may be linked to obesity in adolescents and this systematic review and meta-analysis aimed to synthesis the current research investigating this link. The results showed that over the long-term, the consumption of UPFs was associated with obesity, abdominal obesity, and increased body mass index in children. It was concluded that the long-term consumption of UPFs negatively impacts body composition in children and adolescents. This study could be used by healthcare professionals to understand the importance of dietary advice recommending whole foods with limited or no processed foods for the healthy body development of children.
PURPOSE According to the NOVA classification, ultra-processed foods are products made through physical, biological and chemical processes and typically with multiple ingredients and additives, in which whole foods are mostly or entirely absent. From a nutritional point of view, they are typically energy-dense foods high in fat, sugar, and salt and low in fiber. The association between the consumption of ultra-processed food and obesity and adiposity measurements has been established in adults. However, the situation remains unclear in children and adolescents. METHODS We carried out a systematic review, in which we summarize observational studies investigating the association between the consumption of ultra-processed food, as defined by NOVA classification, and obesity and adiposity parameters among children and adolescents. A literature search was performed using PUBMED and Web of Science databases for relevant articles published prior to May 2021. RESULTS Ten studies, five longitudinal and five cross-sectional, mainly conducted in Brazil, were included in this review. Four longitudinal studies in children with a follow-up longer than 4 years found a positive association between the consumption of ultra-processed food and obesity and adiposity parameters, whereas cross-sectional studies failed to find an association. CONCLUSION These data suggest that a consistent intake of ultra-processed foods over time is needed to impact nutritional status and body composition of children and adolescents. Further well-designed prospective studies worldwide are needed to confirm these findings considering country-related differences in dietary habits and food production technologies.
A Systematic Review on Processed/Ultra-Processed Foods and Arterial Hypertension in Adults and Older People.
Plain language summary
The NOVA system is a way of classifying the level of processing a food has undergone; ranging from un-processed to ultra-processed. Ultra-processed foods (UPFs) are nutritionally imbalanced and are often highly calorific. Processed foods (PFs) are the next level down from UPFs and usually have added salt or sugar. Both foods pose a potential health-risk if eaten in excess, with high blood pressure being a potential resulting disease. This systematic review and meta-analysis aimed to determine the relationship between the consumption of PFs and UPFs and high blood pressure in adults. The results showed that as the consumption of UPFs increased, so did the risk for high blood pressure, however this relationship was not seen with the consumption of PFs. It was concluded that the high consumption of UPFs is associated with a greater risk of developing high blood pressure in adults and older people. This study could be used by healthcare professionals to recommend a diet without UPFs to those who are at risk of high blood pressure or in those who have already been diagnosed.
The increase in the availability of processed and ultra-processed foods has altered the eating patterns of populations, and these foods constitute an exposure factor for the development of arterial hypertension. This systematic review analyzed evidence of the association between consumption of processed/ultra-processed foods and arterial hypertension in adults and older people. Electronic searches for relevant articles were performed in the PUBMED, EMBASE and LILACS databases. The review was conducted following the PRISMA guidelines and the Newcastle-Ottawa Scale. The search of the databases led to the retrieval of 2323 articles, eight of which were included in the review. A positive association was found between the consumption of ultra-processed foods and blood pressure/arterial hypertension, whereas insufficient evidence was found for the association between the consumption of processed foods and arterial hypertension. The results reveal the high consumption of ultra-processed foods in developed and middle-income countries, warning of the health risks of such foods, which have a high energy density and are rich in salt, sugar and fat. The findings underscore the urgent need for the adoption of measures that exert a positive impact on the quality of life of populations, especially those at greater risk, such as adults and older people.
Impacts of Consumption of Ultra-Processed Foods on the Maternal-Child Health: A Systematic Review.
Frontiers in nutrition. 2022;9:821657
Plain language summary
Ultra-processed foods (UPFs) are foods of little or no nutritional quality and often contain high amounts of saturated fat, trans fats, salt, additives, preservatives, colourings, and flavourings. These foods have become increasingly present in the diet of individuals who live in lower-middle, upper-middle, and high-income countries and may be part of the reason why several non-communicable diseases, such as obesity, type 2 diabetes, heart disease and cancer, are increasing. These foods may impact health at many stages in an individual’s lifecycle and in those who are pregnant increased consumption of UPFs may negatively affect both mother and child. This systematic review and meta-analysis aimed to determine the health impacts of UPFs on the health of mother and child. The results showed that higher dietary intake of UPFs was associated with gestational weight gain, early weaning, lower diet quality, alterations to metabolism in the baby and increased weight in the baby. It was concluded that UPF negatively affected nutrition and disease in the mother and child. There was a limited amount of research, however the quality was deemed quite high. This study could be used by healthcare professionals to recommend a high quality nutrient rich diet with limited UPFs during pregnancy.
Conflicts of interest:
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
B: Systematic reviews including RCTs of limited number
C: Non-randomized trials, observational studies, narrative reviews
D: Case-reports, evidence-based clinical findings
E: Opinion piece, other
This systematic review aimed to summarise the consumption of Ultra-Processed Food (UPF) in pregnant and lactating women, and infants or children, and identify any associations with relevant health outcomes.
In informing their research question, the authors reference a marked increase in consumption of UPF in recent years, stating that consumption is estimated to count for >50% of energy intake in high-income countries such as the UK. They describe the literature associating UPF with non-communicable disease (NCD) risk, depression, and other morbidities in adulthood, as well as increasing evidence indicating negative associations during key developmental life stages such as the first 1,000 days, childhood, and adolescence.
Methodology followed standard robust systematic review procedures, including an assessment of quality. Of note; percentage of total energy from dietary UPF was defined by NOVA classification*.
From 7,801 hits, 15 studies (eight cohort and seven cross-sectional) were included in the final review; nine conducted in children <10 yr, five in pregnant women and one in lactating women. Fourteen of 15 studies were of high methodological quality.
UPF dietary contribution ranged from 15% to 76% with higher consumption rates reported in English children >1.5 yr, in whom 75% had an excessive free sugar intake. Overall, 12/15 studies found an association between UPF and negative health outcomes.
Pregnancy and lactation: positive associations or trends with: gestational weight gain, indicators of glucose metabolism, feelings of depression/sadness, neonatal adiposity, increased ADHD symptoms and reduced vitamin E status in lactation.
Childhood: positive associations or trends with: weight gain/BMI, waist circumference, fat mass, sugar intake, dental caries, wheezing and respiratory diseases, and urinary biomarkers of plastic compounds (phthalates and bisphenols). Dietary intake revealed increases in dietary energy, saturated fat, carbohydrates, total sugars and vitamin D, and a negative association with protein, polyunsaturated fats, sodium, zinc, vitamin A, folate and fibre.
Authors main conclusion: UPF consumption negatively affects dietary nutritional quality and health outcomes in pregnant and lactating women and their infants, and children. However, literature in this area is limited.
- Robust systematic review methodology.
- Registered protocol on PROSPERO (CRD42021236633).
- Assessment of quality of included studies.
- Subgroup analyses between the highest and lowest UPF consumption groups.
- Limited number of studies included.
- Exclusion of studies that did not assess dietary patterns using the NOVA classification, which may have missed other relevant articles.
- Only includes cross-sectional and cohort studies, which are prone to confounding and bias (Murad et al, 2016).
- Meta-analyses not attempted or not possible.
- No randomized controlled trials (e.g., assessing changes in response to reductions in UPF) included, and unclear from the review if such studies exist.
- Lacking a discussion on possible fortification of UPFs with vitamins and minerals that may be helpful to some population groups e.g., non-meat substitutes fortified with vitamin B12.
Funding: CAPES Foundation (Coordination for the Improvement of Higher Education Personnel in Brazil.
Conflicts of Interest: none declared
*The NOVA classification system was developed by researchers at the University of Sao Paulo, Brazil, and published in 2010. At that time, the term “ultra-processed foods” was a concept (FAO, 2019) that is now considered mainstream. NOVA classifies all foods into four groups according to the nature, extent and purposes of the industrial processes they undergo. The four groups are 1. Unprocessed and minimally processed foods; 2. Processed culinary ingredients; 3. Processed foods; 4. Ultra-processed foods.
FAO 2019. Ultra-processed foods, diet quality, and health using the NOVA classification system. Available at https://www.fao.org/3/ca5644en/ca5644en.pdf, accessed 22.07.2022
Murad MH, Asi N, Alsawas M, et al. New evidence pyramid. BMJ Evidence-Based Medicine 2016;21:125-127.
Clinical practice applications:
- UPF are ubiquitous in the food system, though many people may not be aware of the negative implications of their consumption.
- Education about UPF consumption and the risks associated should be provided, alongside recommendations and advice on how to adopt and maintain a more whole-foods dietary pattern. Education should refer to UPF available in the patient/client’s locality and include help with reading and interpreting food labels.
- In the cases of childhood overweight or obesity, ADHD or respiratory disorders, or during peri-conception, pregnancy and lactation, and especially where there is risk of excessive gestational weight gain, diabetes mellitus, hypertension, depression or risk of depression, UPF should be limited or avoided.
Considerations for future research:
- Evidence in this area is sparse.
- Robust, high quality clinical trials to assess the response on health outcomes to UPF reduction or avoidance, particularly at critical life stages, are warranted.
- In particular, research during the lactation period is lacking. No study was identified investigating the effect of UPF consumption on production and composition of breastmilk and development of specific nutritional deficiencies in infants.
Background and Aims: Changes in eating patterns have been leading to an increase in the consumption of ultra-processed foods (UPF), negatively impacting the quality of the diet and generating risk of harm to the health of the adult population, however, there is no systematized evidence of the impact of UPF in maternal-child health. Thus, in this study we aimed to evaluated the association between UPF consumption and health outcomes in the maternal-child population. Methods: Systematic review registered on the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021236633), conducted according to the PRISMA diagram in the following databases: PubMed, Medline, Scopus, Web of Science, Scielo, and CAPES thesis and dissertation directory. We included original cross-sectional, case-control and cohort studies in any language. Eligibility criteria were (a) food consumption assessment by the NOVA classification, (b) health outcome (nutritional or diseases), and (c) maternal-child population (pregnant, lactating women and infants/children). All data were analyzed and extracted to a spreadsheet structured by two independent reviewers. We evaluated the methodological quality of the studies included using the Newcastle-Otawa Scale and RoB 2. Results: Searches retrieved 7,801 studies and 15 contemplated the eligibility criteria. Most studies included were cohort studies (n = 8, 53%), had children as their population (n = 9, 60%) and only one study evaluated UPF consumption in infants and lactating women. Panoramically, we observed that a higher participation of UPF in children's diet has been associated with different maternal-child outcomes, such as increase of weight gain, adiposity measures, overweight, early weaning, lower diet quality, metabolic alterations, diseases, and consumption of plastic originated from packaging. Only one of the studies included did not present high methodological quality. Conclusion: Despite the limited literature on UPF consumption and health outcomes in the maternal-child population, the highest UPF consumption negatively impacted nutrition and disease development indicators in pregnant, lactating women and children. Considering the expressive participation of these foods in the diet, other studies should be conducted to further investigate the impact of UPF consumption on different health indicators, especially in the lactation phase for this was the one to present the most important knowledge gap. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021236633], identifier [CRD42021236633].
The Western Diet-Microbiome-Host Interaction and Its Role in Metabolic Disease.
Plain language summary
The Western diet is characteristically high in ultra-processed foods, which may change the gut microbiome. As the gut microbiome is unique, any alterations may be associated with disease. This review study aimed to highlight how ultra-processing can affect the gut microbiome and its impact on the development of disease to better inform dietary guidelines. Associations between poor health outcomes and ultra-processed foods have been shown with processed meats, refined grains, and processed fish. Traditionally research has focussed on added salt, sugar and fat, however processed foods may contain or be processed in a way that promotes disease. Gut microbial changes can be driven by diet, which could be detrimental, permanent, and inheritable. Food processing such as heat treatment, and additives such as sweeteners and emulsifiers can all alter the gut microbiota, however these do not need to undergo microbiome testing before being approved for consumption. Effects of ultra-processed foods on the gut microbiome need to be extensively investigated in terms of health outcomes to better inform dietary guidelines. This study could be used by healthcare professionals to better understand how ultra-processed foods play a part in diseases beyond that of added salt, fat and sugar and that the microbiome has a pivotal role.
The dietary pattern that characterizes the Western diet is strongly associated with obesity and related metabolic diseases, but biological mechanisms supporting these associations remain largely unknown. We argue that the Western diet promotes inflammation that arises from both structural and behavioral changes in the resident microbiome. The environment created in the gut by ultra-processed foods, a hallmark of the Western diet, is an evolutionarily unique selection ground for microbes that can promote diverse forms of inflammatory disease. Recognizing the importance of the microbiome in the development of diet-related disease has implications for future research, public dietary advice as well as food production practices. Research into food patterns suggests that whole foods are a common denominator of diets associated with a low level of diet-related disease. Hence, by studying how ultra-processing changes the properties of whole foods and how these foods affect the gut microbiome, more useful dietary guidelines can be made. Innovations in food production should be focusing on enabling health in the super-organism of man and microbe, and stronger regulation of potentially hazardous components of food products is warranted.