Advances in Nutrition review finds ultra-processed foods are associated with a higher risk of diabetes, hypertension, obesity, and cardiovascular disease

Ultra-processed foods are ready-to-eat or ready-to-heat industrial preparations.  They are often made largely or entirely with chemically modified substances extracted from food, often with just a small proportion of whole food.  Ultra-processed foods may also contain cosmetic additives that have no nutritive value to enhance palatability, profitability, and shelf-life.

Soft drinks, packaged snacks, sugared breakfast cereals, cookies, processed meats, and packaged frozen and shelf-stable meals are all categorized as ultra-processed foods.  In addition, many consumers may not be aware that flavored yogurts, low-calorie or low-fat products, and nutrient-fortified products are also often considered ultra-processed foods.

The United States is a leading consumer of ultra-processed foods globally, with 55% of American adults’ energy intake, on average, coming from these products.  Unfortunately, consumption of ultra-processed foods has been linked to a variety of poor health outcomes.

Recent studies, for example, have linked higher consumption of ultra-processed foods to poor cardiometabolic health, increasing the risk of obesity, type 2 diabetes, dyslipidemia (i.e., abnormal concentrations of lipids or lipoproteins in the blood), and cardiovascular disease.  It is not fully clear, however, how much the association between ultra-processed foods and a higher risk of cardiometabolic disease is real and how much has been influenced by the various methods used to assess the impact of ultra-processed food consumption.  For example, the same amount of ultra-processed food consumption is categorized as high in some studies and low in others, leading to difference conclusions.

In response, the authors of Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies, published in Advances in Nutrition, the international review journal of the American Society for Nutrition, conducted an analysis of the evidence.  Working with the results of 25 studies, the authors assessed the association of ultra-processed food consumption with the occurrence of diabetes, hypertension, dyslipidemia, and obesity, all major cardiovascular disease risk factors.  Next, they performed a sensitivity analysis to account for possible differences in study findings resulting from the use of different study methods.  Finally, they assessed the quality of their findings using NutriGrade, a scoring system that evaluates the quality of evidence from randomized controlled trial and cohort study meta-analyses in nutrition research.

The results of this review “show that total ultra-processed food consumption is associated with a higher risk of diabetes, hypertension, dyslipidemia, and obesity.”  The authors caution, however, that, according to the NutriGrade scoring system, the evidence is of low quality.  In addition, their sensitivity analysis underscored that “the level of risk consistently changes depending on the methodology used to assess ultra-processed food intake.  Therefore, caution should be used when interpreting and extrapolating the results.”

Overall, the authors believe their study “supports current recommendations to limit total ultra-processed food consumption.”  They further believe that to “assess the health effects of ultra-processed food more accurately, new tools should be used to assess ultra-processed food consumption that can specify food classes, the nutrient composition of ultra-processed foods, and the specific processes or additives used in their production.”

This review is accompanied by an editorial, Quantity and Quality of Evidence Are Sufficient: Prevalent Features of Ultra-processed Diets Are Deleterious for Health, also published in Advances in Nutrition.  This editorial is the second in a new series of editorials that will be published in connection with select Advances in Nutrition reviews.  These editorials offer an additional independent perspective on key and often controversial topics in nutrition research.

Building on a growing body of literature, the editorial points out how the findings from Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies have expanded our understanding of the harmful effects of ultra-processed foods, demonstrating, for example, that “heterogeneity in risk estimates is not as profound as some ultra-processed food industry and other stakeholders argue.”  Moreover, “although the quality of ultra-processed food research can (and should) be improved on,” the editorial authors argue that “limitations of the current evidence base are not insurmountable, nor do they serve as sole justification to delay public health interrogation around ultra-processed foods.”

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