The Importance of Food Processing and Eating Behavior in Promoting Healthy and Sustainable Diets

Food essentialism: Implications for expectations and perceptions of the properties of processed foods

Despite the impact of processed foods on health, sustainability, and food security, consumers vary greatly in expectations about and preferences for processed foods. Essentialism is the lay belief that items in a category share a fundamental and immutable essence that generates the category's defining characteristics. Although essentialism may be an important determinant of consumers' cognitions about processed foods, there has been limited investigation of essentialism's role in food-related perceptions. Across two studies (n=598 total), we used a novel measure of food essentialism to examine whether individual differences in beliefs about foods as having essences (food essentialism) are related to perceptions of foods retaining more of their natural characteristics (sensory and nutritive properties) despite their level of processing. Across diverse food categories (meats, vegetables, fruits, legumes, dairy), higher levels of perceived food processing were associated with lower perceived retention of naturalness, nutritiousness, natural taste, functional post-ingestive benefits, and acceptability (liking). However, participants endorsing greater (vs. lower) food essentialism beliefs exhibited weaker relationships between perceived processing and these characteristics. We also observed variations across food categories in relationships between perceived level of processing and food properties, suggesting that some foods (i.e., milk-based products) are perceived to possess essences that are more robust despite undergoing higher levels of processing. These findings demonstrate that food-specific essentialism beliefs may be a fundamental determinant of consumers' expectations of how human intervention, such as processing, affects natural properties of foods. These beliefs may be a promising target for future research to shift consumer acceptance of processed foods.

The association of ultra-processed food intake with neurodegenerative disorders: a systematic review and dose-response meta-analysis of large-scale cohorts

OBJECTIVES

Our systematic review and meta-analysis aimed to uncover the relationship between UPFs intake and neurodegenerative disorders, including multiple sclerosis (MS), Parkinson's disease (PD), Alzheimer's disease (AD), cognitive impairment, and dementia.

SETTING

A systematic search was conducted using the Scopus, PubMed/MEDLINE, and ISI Web of Science databases without any limitation until June 24, 2023. Relative risk (RR) and 95% confidence interval (CI) were pooled by using a random-effects model, while validated methods examined quality and publication bias via Newcastle-Ottawa Scale, Egger's regression asymmetry, and Begg's rank correlation tests, respectively.

RESULTS

Analysis from 28 studies indicated that a higher UPFs intake was significantly related to an enhanced risk of MS (RR = 1.15; 95% CI: 1.00, 1.33; I2 = 37.5%; p = 0.050; n = 14), PD (RR = 1.56; 95% CI: 1.21, 2.02; I2 = 64.1%; p = 0.001; n = 15), and cognitive impairment (RR = 1.17; 95% CI: 1.06, 1.30; I2 = 74.1%; p = 0.003; n = 17), although not AD or dementia. We observed that a 25 g increment in UPFs intake was related to a 4% higher risk of MS (RR = 1.04; 95% CI: 1.01, 1.06; I2 = 0.0%; p = 0.013; n = 7), but not PD. The non-linear dose-response relationship indicated a positive non-linear association between UPF intake and the risk of MS (Pnonlinearity = 0.031, Pdose-response = 0.002). This association was not observed for the risk of PD (Pnonlinearity = 0.431, Pdose-response = 0.231).

CONCLUSION

These findings indicate that persistent overconsumption of UPFs may have an adverse impact on neurodegenerative conditions, potentially leading to a decline in quality of life and reduced independence as individuals age.

Ultra-processed Food and Obesity: What Is the Evidence?

PURPOSE OF REVIEW

Obesity is a growing global healthcare concern. A proposed driver is the recent increase in ultra-processed food (UPF) intake. However, disagreement surrounds the concept of UPF, the strength of evidence, and suggested mechanisms. Therefore, this review aimed to critically appraise the evidence on UPF and obesity.

RECENT FINDINGS

Observational studies demonstrate positive associations between UPF intake, weight gain, and overweight/obesity, more clearly in adults than children/adolescents. This is supported by high-quality clinical data. Several mechanisms are proposed, but current understanding is inconclusive. Greater UPF consumption has been a key driver of obesity. There is a need to change the obesogenic environment to support individuals to reduce their UPF intake. The UPF concept is a novel approach that is not explained with existing nutrient- and food-based frameworks. Critical analysis of methodologies provides confidence, but future observational and experimental research outputs with greater methodological rigor will strengthen findings, which are outlined.

Consumption of ultra-processed foods and multiple health outcomes: An umbrella study of meta-analyses

Consumption of ultra-processed foods (UPFs) is associated with various adverse health outcomes, which significantly influence the global disease burden. This umbrella review aimed to fill the knowledge gap and guide public health practices by summarizing the association between UPFs and multiple health outcomes. A total of four databases were systematically searched from inception to December 2022, and 14 eligible systematic reviews (SRs) with meta-analyses (MAs) were identified. The SRs were published in 10 journals from 2020 to 2023, with 54,147-5,750,133 participants and 5-61 studies. The overall corrected covered area (CCA) was corresponded to a slight overlap. The results showed that an increased UPFs consumption is associated with multiple health outcomes (e.g., obesity, diabetes, hypertension, mortality). Only two SRs were "Moderate" regarding the overall methodological quality, while the other twelve were "Low" or "Critically low". Therefore, well-conducted SRs with high-quality prospective cohorts with a particular focus on special populations are needed to verify these findings further.

Effects of acrylamide exposure during pregnancy and lactation on the development of myelin sheath of corpus callosum in offspring rats

Acrylamide is an alkene known to induce neurotoxicity in humans and experimental animals. However, the effects of acrylamide on the development of myelin sheath are unclear. The present study was to explore the effects of acrylamide exposure during pregnancy and lactation on the development of myelin sheath in offspring rats. Four groups of thirty-two pregnant Sprague-Dawley rats were exposed to 0, 4.5, 9 and 18 mg/kg BW acrylamide by gavage from gestational day 15 to postnatal day 13. The corpus callosum of nine offspring rats per group were dissected in postpartum day 14. Structural changes and lipid contents in myelin sheaths were examined by transmission electron microscopy(TEM) and Luxol Fast Blue staining(LFB). The expression of MBP and PLP was evaluated by immunohistochemistry and Western blotting. TEM showed that the myelin sheaths in the 18 mg/kg group were disordered compared with control group. Luxol Fast Blue staining gradually decreased with increasing acrylamide maternal exposure. The immunohistochemistry and Western Blotting results showed that maternal exposure to acrylamide caused a decreasing trend in MBP and PLP in the corpus callosum of rats at postnatal day 14. Furthermore, these reduced protein levels may be neurodevelopmental toxicity's mechanism in response to maternal exposure to acrylamide.

Perspective: A Research Roadmap about Ultra-Processed Foods and Human Health for the United States Food System: Proceedings from an Interdisciplinary, Multi-Stakeholder Workshop

Our objective was to convene interdisciplinary experts from government, academia, and industry to develop a Research Roadmap to identify research priorities about processed food intake and risk for obesity and cardiometabolic diseases (CMD) among United States populations. We convened attendees at various career stages with diverse viewpoints in the field. We held a "Food Processing Primer" to build foundational knowledge of how and why foods are processed, followed by presentations about how processed foods may affect energy intake, obesity, and CMD risk. Breakout groups discussed potential mechanistic and confounding explanations for associations between processed foods and obesity and CMD risk. Facilitators created research questions (RQs) based on key themes from discussions. Different breakout groups convened to discuss what is known and unknown for each RQ and to develop sub-RQs to address gaps. Workshop attendees focused on ultra-processed foods (UPFs; Nova Group 4) because the preponderance of evidence is based on this classification system. Yet, heterogeneity and subjectivity in UPF classification was a challenge for RQ development. The 6 RQs were: 1) What objective methods or measures could further categorize UPFs, considering food processing, formulation, and the interaction of the two? 2) How can exposure assessment of UPF intake be improved? 3) Does UPF intake influence risk for obesity or CMDs, independent of diet quality? 4) What, if any, attributes of UPFs influence ingestive behavior and contribute to excess energy intake? 5) What, if any, attributes of UPFs contribute to clinically meaningful metabolic responses? 6) What, if any, external environmental factors lead people to consume high amounts of UPFs? Uncertainty and complexity around UPF intake warrant further complementary and interdisciplinary causal, mechanistic, and methodological research related to obesity and CMD risk to understand the utility of applying classification by degree of processing to foods in the United States.

Current Perceptions of Sustainable Diets in Ireland and the Outlook of Circular Eating Practices

Encouraging sustainable dietary practices is a positive step towards alleviating the negative impact of increasing food waste. This study explores consumers' perceptions of sustainable diets and factors influencing their adoption of sustainable practices, such as circular eating. Fifteen consumers in Ireland aged 18-65+ years were recruited for a qualitative study exploring their views on sustainable diets and their opinions on the use of peels, trimmings, and other by-products from fruit and vegetables as potential new ingredients or new circular food products. Age, gender, dietary preferences and educational background were important considerations during recruitment. Online interviews were conducted, and the data were analyzed using thematic analysis managed by NVivo 12. The results highlighted two overarching themes impacting circular eating, namely, food choice motives and awareness of food waste. These were linked to the participants' knowledge of and potential adoption of sustainable diets. Daily trade-offs were evident, linked to the product and the person who was also strongly influenced by their micro-environment. Consumer education from credible sources would be required to create awareness of circular eating. Most respondents were positively disposed to the concept of circular eating, as long as food safety concerns and affordability considerations were addressed through industry transparency.

Beyond ultra-processed: considering the future role of food processing in human health

Food-based dietary guidelines have been the basis of public health recommendations for over half a century, but more recently, there has been a trend to classify the health properties of food not by its nutrient composition, but by the degree to which it has been processed. This concept has been supported by many association studies, narrative reviews and the findings from one randomised controlled feeding trial, which demonstrated the sustained effect of ultra-processed diets on increasing both energy intake and body weight. This has led to widespread speculation as to specific features of ultra-processed foods that promote increased energy intakes. Rising interest in the ultra-processed topic has led to proposals to include guidance and restrictions on the consumption of processed foods in national dietary guidelines, with some countries encouraging consumers to avoid highly processed foods completely, and only choose minimally processed foods. However, there remains a lack of consensus on the role of processed foods in human health when faced with the challenges of securing the food supply for a growing global population, that is, healthy, affordable and sustainable. There has also been criticism of the subjective nature of definitions used to differentiate foods by their degree of processing, and there is currently a lack of empirical data to support a clear mechanism by which highly processed foods promote greater energy intakes. Recommendations to avoid all highly processed foods are potentially harmful if they remove affordable sources of nutrients and will be impractical for most when an estimated two-thirds of current energy purchased are from processed or ultra-processed foods. The current review highlights some considerations when interpreting the dietary association studies that link processed food intake to health and offers a critique on some of the mechanisms proposed to explain the link between ultra-processed food and poor health. Recent research suggests a combination of higher energy density and faster meal eating rates are likely to influence meal size and energy intakes from processed foods and offers new perspectives on how to manage this in the future. In going beyond the ultra-processed debate, the aim is to summarise some important considerations when interpreting existing data and identify the important gaps for future research on the role of processed food in health.

Food Processing, According to the Nova Classification System, and Dietary Intake of US Infants and Toddlers

BACKGROUND

High intake of ultra-processed foods (UPFs) is associated with increased risk of chronic disease; thus, it is important to understand how UPFs influence diet quality early in life.

OBJECTIVES

We describe complementary foods and beverages (CFBs) according to the Nova Classification System of Food Processing for infants and toddlers in the United States and estimate how Nova groups and subgroups contribute to energy and select nutrients and food groups.

METHODS

We used day 1 24-h recall from infants and toddlers aged 6-23 mo from the cross-sectional, nationally representative 2013-18 National Health and Nutrition Examination Survey (n = 1140). We estimated contributions of Nova groups and subgroups to energy and select nutrients and food groups consumed as CFBs (excluding human milk and formula) using the population ratio with weighted survey commands in SAS.

RESULTS

For infants and toddlers in the United States, 42 ± 0.9% (mean ± standard error of the mean) of energy intake from CFBs came from unprocessed/minimally processed foods (U/MPFs) and 45 ± 0.8% from UPFs. U/MPFs contributed most to nutrient intakes (except iron, zinc, and sodium); ≥20% of all selected nutrients was from UPFs. UPFs contributed most to iron (75 ± 1.0%) and zinc (48 ± 1.3%); breakfast cereals were the top source. Most fruit, vegetables, and dairy were from U/MPFs. More than 80% of total grains, whole grains, refined grains, and added sugars were UPFs.

CONCLUSIONS

U/MPFs support healthy dietary intake of infants and toddlers in the United States, whereas UPFs contribute meaningfully to nutrients and food groups to be encouraged (iron, zinc, and whole grains), as well as some that should be limited (added sugars and sodium). More research is needed to better understand the utility and sensitivities of using Nova for providing dietary guidance for infants and toddlers in the United States.

Iron Bioavailability Should be Considered when Modeling Omnivorous, Vegetarian, and Vegan Diets

BACKGROUND

To lower environmental impact of human food consumption, replacement of animal proteins with plant-based proteins is encouraged. However, the lower iron bioavailability of plant-based foods is rarely considered when designing healthy and sustainable diets by using diet modeling. The estimated absorbable iron content of vegetarian and vegan menu plans might therefore be too optimistic.

OBJECTIVE

The main aim of this study was to investigate and compare the impact of various methods to estimate absorbable iron intake on the nutritional adequacy of omnivorous, vegetarian, and vegan menu plans designed for women of reproductive age.

METHODS

A diet model was developed to design menu plans consisting of a selection of meals that best complied with nutritional requirements. Meals used for modeling were created based on food intake data from the National Health and Nutrition Examination Survey (NHANES). For each meal, absorbable iron concentrations were estimated by using 2 constant absorption factors (18% and 10%) and 2 diet-dependent absorption equations (Conway and Hallberg). For each absorption method and diet type, we used the diet model to design the optimal menu plan. Retrospectively, menu plans were evaluated by estimating the absorbable iron content by using the other absorption methods.

RESULTS

Retrospective diet-dependent absorbable iron estimates were consistently lower than estimates based on constant absorption factors. Using diet-dependent estimates increased absorbable iron by optimizing enhancer and inhibitor concentrations.

CONCLUSION

Iron bioavailability should be considered when modeling diets.