Ultra-processed foods have been linked to a higher risk of more than 30 health conditions, a new study has found. These range from all-cause mortality, cancer, anxiety, mood disorders, heart disease and obesity.
The study, published in The BMJ, is an umbrella review of 45 meta-analyses, drawing on data from nearly 10 million people.
The term ultra-processed refers to a broad category of ready-to-eat food products, including packaged snacks, carbonated drinks, instant noodles and ready meals. These products usually contain a long list of often unrecognizable ingredients and are filled with preservatives, emulsifiers, sweeteners and artificial flavorings and colors.
"Many foods classified as ultra-processed tend to be high in added sugar, fat, and/or salt, while lacking essential vitamins and fiber," Melissa Lane, an associate research fellow at Deakin University in Australia and first author on the paper, told Newsweek. "This poor nutrient profile is one reason why regularly consuming higher amounts of ultra-processed foods is linked to negative health outcomes.
"While nutrients like salt, sugar, and fat will always be important to consider, there's increasing evidence that other aspects of ultra-processed foods, such as additives (like emulsifiers and flavorings) and the way they're made (using high temperatures and breaking down food particles), may also affect our health in various ways, including through inflammatory processes and the (related) gut microbiome."
In the U.S., these foods account for over half of people's daily calorie intake, which is concerning considering their potential role in increasing the risk of chronic disease and death. But although numerous meta-analyses have investigated the associations between exposure to these foods and adverse health outcomes, a broad overview of these associations is still lacking.
To bridge this gap, researchers from Australia, France and the U.S. carried out a high-level evidence summary of 45 distinct pooled meta-analyses to assess the evidence linking ultra-processed foods to adverse health outcomes. The reviews were all published in the past three years and involved 9,888,383 participants. Exposure to ultra-processed foods was determined using a combination of food frequency questionnaires, dietary recall and dietary history.
Overall, the analysis showed that eating ultra-processed foods was associated with an increased risk of 32 adverse health outcomes, including a 40 to 53 percent increased risk of anxiety and common mental disorders, a 50 percent increased risk of cardiovascular disease-related deaths and a 12 percent greater risk of Type 2 diabetes.
There was also strong evidence for a 21 percent increased risk of all-cause mortality, a 22 percent increased risk of depression and a 40 to 66 percent increased risk of heart disease–related death, obesity, Type 2 diabetes and sleep problems.
Evidence linking ultra-processed food intake to asthma, gastrointestinal problems, cancers, high blood fats and low levels of "good" cholesterol was limited. However, Lane said that the relationship between these foods and respiratory illnesses was worth further investigation.
"You might not typically associate diet with respiratory issues like wheezing, but there's some evidence suggesting that ultra-processed foods are associated with inflammation in the body," she said. "So, while it's surprising, there's a biological possibility that what we eat could play a role in respiratory outcomes like wheezing through inflammation which may make the airways hypersensitive to various triggers. However, we need much more research as these findings are preliminary."
The researchers said umbrella reviews like this can provide only high-level overviews of the available evidence and cannot rule out the possibility of other unmeasured factors. Variations in dietary assessments between studies may have also influenced their results. However, these findings highlight the extent to which ultra-processed foods can affect multiple aspects of our mental and physical health.
"These findings support urgent mechanistic research and public health actions that seek to target and minimize ultra-processed food consumption for improved population health," the researchers wrote.
To avoid ultra-processed foods, the easiest method is to look at the product's ingredients list. If it contains dozens of ingredients that don't sound like real food, it's most likely ultra-processed.
"Whenever feasible, aim for less processed choices in your meals, like fresh, frozen, or canned fruits, vegetables, beans, legumes, and whole grains," Lane said. "Small changes, such as selecting plain yogurt instead of flavored options and preferring water over sugary drinks, can have a notable impact. Furthermore, when eating out, favor local restaurants and cafes over fast-food chains, as they're less inclined to provide or endorse ultra-processed foods."
Update 03/01/2024 06:50 a.m. ET: This article was updated to include an interview with first author Melissa Lane.
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