In a recent review article published in the journal Nutrients, researchers summarized the debate around ultra-processed foods (UPFs) and their impact on non-communicable diseases (NCDs).
They concluded that there is a lack of causal evidence regarding the effect of UPFs on NCDs and that reformulating these foods instead of banning them altogether could yield significant health benefits.
Study: Ultra-Processed Foods—Dietary Foe or Potential Ally? Image Credit: AtlasStudio / Shutterstock
Background
Research has highlighted the global spread of Western dietary patterns, particularly the increased consumption of UPFs across different economic stages. While UPFs are often high in saturated fats, salt, and sugar, their classification has become more complex due to evolving formulations.
Despite ongoing debates about the classification and health impact of UPFs, their significance in global food systems cannot be ignored. According to some estimates, UPFs contribute over 50% of the population's caloric intake in the United States, while consumption of health-beneficial foods has decreased.
Many people may face challenges accessing and affording healthier alternatives, leading to poorer health practices. However, current UPFs can contribute to raising scores according to the Healthy Eating Index (HEI) despite lacking essential nutrients.
Epidemiological evidence links UPF consumption to NCDs like obesity, diabetes, and cardiovascular disease. Debates surround whether UPFs' adverse health effects stem from their nutrient-poor content or additives that imitate natural flavors, leading to discussions on banning UPFs or reformulating them for better health outcomes.
The narrative review aims to advance understanding by examining systems for food classification and proposing guidelines for UPF formulation and consumer selection.
Systems for food classification
Food classification systems aim to categorize foods based on shared characteristics, typically for providing dietary guidance and informing nutrition policies. Traditional systems, like the US Dietary Guidelines, focus on culinary definitions and nutritional needs.
However, concern over the health impacts of food processing has led to alternative classification schemes. These newer systems, such as NOVA, categorize foods based on the extent and purpose of processing, distinguishing between minimally processed, extracted substances and UPFs.
While the NOVA system is widely used, it has faced criticism, prompting research into alternative classification methods. Recent advancements include machine learning algorithms, like FoodProX, which assess the degree of food processing and link dietary quality to NCD risk biomarkers.
Causal evidence regarding UPFs
Studies indicate a lack of clear causal evidence linking UPFs directly to adverse health outcomes. The researchers identified four categories for further investigation: energy balance, nutrient density, food processing, and use of non-culinary additives.
The current evidence suggests a positive association between UPF intake and obesity risk, even when controlling for calorie intake, suggesting that energy balance alone may not explain the association between UPFs and health issues.
While early assumptions linked UPFs with poor nutritional content, many nutrient-dense UPFs are now available. Poor nutritional status could be a biomarker for other processes that modify NCD risk, but whether these products affect the likelihood of NCDs is unclear.
Specific food processing techniques and additives have been implicated in a higher risk of NCD. These alterations may affect the gut microbiome and contribute to metabolic diseases. It is crucial to investigate the effects of refined macronutrients, additives, microbial products, and novel chemicals formed during processing.
A decision tree framework can be used to explore causality by implementing a series of experiments to determine whether factors related to UPFs affect NCD risk. Preclinical models, such as mouse models of hepatic steatosis, can be used to investigate these factors systematically.
Reformulating UPFs for health benefits
Developers of the NOVA system recommend limiting UPF intake. Several strategies have been identified to promote healthier eating habits and counteract the dominance of UPFs in the food system, such as promoting the preparation of healthy food, increasing support for family farmers, and creating public health policies to regulate UPFs with low nutritional value.
However, these recommendations overlook the appeal of UPFs to consumers, including their palatability and convenience. Limiting UPF availability and consumption could reduce food security, especially among vulnerable populations like older adults.
An alternative approach is reformulating UPFs to make them healthier. Whole-food formulation, which replaces processed ingredients with intact or minimally processed ones, is one such approach. Changing agricultural and economic incentives could encourage the development of healthier processed foods.
Additionally, the military's ready-to-eat meals (MREs) framework could be used as a model for UPF formulation. It focuses on evidence-based nutritional standards and emphasizes convenience, adjustability, and palatability. Collaboration between the food industry and research sectors could lead to mutual benefits and improved consumer health.
Conclusions
UPFs are often misunderstood, with unclear causal links to health outcomes. Standardization issues in food classification systems like NOVA further complicate matters; while technology, like machine learning, aids in understanding UPFs, caution is required to avoid bias. Collaboration and research are needed to improve UPF formulations for better health outcomes.
Article Revisions
- Apr 2 2024 - Correction to the journal paper title and link.