Ultra-processed food linked to 32 harmful effects to health, review finds

According to a massive review, Ultra-processed food (UPF) is associated with 32 health risks including a higher probability of heart disease, cancer, type 2 diabetes, mental health problems, and premature death. These outcomes arise from the first comprehensive umbrella review of evidence in this area. This situation is made more urgent by the escalating global intake of UPF like cereal, protein bars, sodas, ready-made meals, and fast food.

In the UK and the US, over half of the average diet comprises UPF, and in some instances, especially among younger, financially challenged, or marginalized individuals, UPF may account for as much as 80% of the diet.

The BMJ published the findings, which suggest that UPF-heavy diets can be harmful across a spectrum of health measures. The review, which engaged nearly 10 million people, underscores the necessity for interventions to curtail and minimize exposure to UPF, as per the researchers.

Contributing to the review were experts from prominent institutions including the Johns Hopkins Bloomberg School of Public Health in the US, the University of Sydney, and Sorbonne University in France. The researchers concluded in the BMJ: “In general, direct associations were discovered between UPF exposure and 32 health outcomes, covering mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health issues.”

They further noted: “Greater UPF exposure was connected with a higher risk of adverse health outcomes, specifically, cardiometabolic conditions, general mental issues, and mortality outcomes.” They argued that these findings justify the development and assessment of measures aimed at reducing dietary UPF intake for better public health.

Ultra-processed foods, like packaged snacks, soft drinks, sugary cereals, and ready-to-eat or ready-made meals, are typically produced through multiple industrial steps and frequently contain artificial colors, emulsifiers, flavors, and other additives. These products are often high in added sugar, fat, and/or salt while being low in vitamins and fiber.

While prior studies have established a link between UPF and poor health, no comprehensive review had systematically examined the evidence until this umbrella review. To bridge this gap, the researchers scrutinized 14 review articles from the past three years encompassing 9.9 million people. None of these articles received funding from UPF manufacturers.

Estimates of UPF exposure were obtained from a range of dietary assessments and were measured against lower consumption, additional daily servings, or a 10% increase in consumption. The evidence was graded as convincing, highly suggestive, suggestive, weak, or no evidence, and the quality of evidence was assessed as high, moderate, low, or very low.

Overall, the results demonstrate that higher UPF consumption was consistently associated with a higher risk of 32 adverse health outcomes. The BMJ detailed that convincing evidence indicated a 50% increased risk of cardiovascular disease-related death and a 48 to 53% higher risk of anxiety and common mental disorders associated with increased UPF intake. High suggestive evidence showed a 21% increased risk of all-cause death, a 40 to 66% higher risk of heart disease-related death, obesity, type 2 diabetes, sleep problems, and a 22% increased risk of depression.

Associations were also found with asthma, gastrointestinal health, certain cancers, and cardiometabolic risk factors such as high blood fats and low levels of “good” cholesterol, although the researchers cautioned that the evidence for these links remains limited.

The researchers acknowledged limitations to the umbrella review, including potential unmeasured factors and variability in UPF intake assessment. Some experts not involved in the study cautioned that much of the research included in the review was weak and that the findings did not establish causation.

However, Dr. Chris van Tulleken, an associate professor at University College London and a UPF expert, noted that the findings align with a considerable body of independent studies linking a high UPF diet to multiple adverse health outcomes including premature death. He further stated, “We have a good understanding of the mechanisms through which these foods cause harm. They are often poor in nutrition – high in saturated fat, salt, and free sugar.”

He also explained that the way UPFs are processed and marketed contributes to their health impacts, noting that they are usually soft, energy-dense, and aggressively marketed, often to marginalized communities.

In a linked editorial, academics from Brazil criticized UPFs as often comprising cheap, chemically manipulated ingredients and being made appealing through various additives. They called for international bodies to develop and implement a framework convention on UPFs, similar to the framework for tobacco.

Meanwhile, a separate study published in The Lancet Public Health suggested that displaying calorie information on menus in restaurants and other food establishments could prevent over 9,000 heart disease-related deaths in England over the next two decades.