People who consume large amounts of ultra-processed foods are at greater risk of heart attack, stroke and premature death than those who eat mostly whole or minimally processed foods, according to two large European studies published this week in the British Medical Journal (BMJ).
Neither study proves that ultra-processed foods are harmful to health, but their findings add to a growing body of evidence that suggests there is something about the composition of these foods that appears to have an adverse effect on the body. Earlier studies have linked ultra-processed foods to an increased risk of obesity, high blood pressure, high cholesterol and certain cancers.
Just last week, the authors of a randomized controlled trial reported that ultra-processed meals tend to cause people to take in more calories and gain weight, even when ultra-processed and unprocessed meals are similar in terms of calories, protein, fat, carbohydrates and other nutrients.
Ultra versus minimally processed
There’s no universally accepted definition of ultra-processed foods, but the two new BMJ studies (like the earlier randomized controlled trial) used a diet classification system developed by scientists in Brazil, called NOVA. It places foods and beverages into four categories, ranging from “unprocessed/minimally processed” to “ultra-processed.”
As one of the BMJ studies explains, the ultra-processed category includes “foods and drink products that are made predominantly or entirely from industrial substances and contain little or no whole foods. These products are ready to eat, drink, or heat — that is, carbonated drinks, sausages, biscuits (cookies), candy (confectionery), fruit yogurts, instant packaged soups and noodles, sweet or savoury packaged snacks, and sugared milk and fruit drinks.”
By comparison, unprocessed/minimally processed foods are ones that are “fresh or processed in ways that do not add substances such as salt, sugar, oils, or fats, and infrequently contain additives. … Examples in this group include fruit and vegetables, grains (cereals), flours, nuts and seeds, fresh and pasteurized milk, natural yogurt with no added sugar or artificial sweeteners, meat and fish, tea, coffee, spices, and herbs.”
The majority of the calories consumed by Americans today come from ultra-processed foods.
In the first study, researchers analyzed data gathered from 105,159 French adults. Their average age was 43, and most (79 percent) were women. At the start of the study, they filled out a detailed questionnaire about the food they had eaten within the previous 24 hours — a process that was repeated at least six times over the next five years. Using the NOVA classification system, the researchers categorized the foods by their degree of processing.
The study found that higher consumption of ultra-processed foods was associated with a higher risk of cardiovascular disease, including heart attack, stroke and coronary heart disease.
Specifically, for every 10 percent increase in the amount of ultra-processed foods consumed by the participants, the risk of cardiovascular disease rose 12 percent.
The study also found a statistically significant lower risk of cardiovascular disease among the study’s participants who ate the greatest amount of unprocessed/minimally processed foods.
“It is important to inform consumers about these associations” and to promote the consumption of unprocessed or minimally processed foods, the researchers conclude. They also propose that ultra-processed foods be taxed to discourage their consumption and that steps be taken to reformulate (improve) their nutritional quality.
In the second study, researchers in Spain analyzed data collected from almost 20,000 university graduates. Their average age was 38, and 60 percent were women. They filled out a detailed questionnaire about their dietary habits at the start of the study. All the foods were then categorized according to their degree of processing, and the researchers divided the study’s participants into four groups, based on the amount of ultra-processed foods they ate.
The university graduates were followed for an average of 10 years. The study found that those in the quarter of participants who consumed the highest amount of ultra-processed foods were 62 percent more likely to have died from all causes during the 10 years than those in the quarter of participants who consumed the lowest amount of those foods.
For each additional daily serving of ultra-processed food, the mortality risk increased by 18 percent.
Those findings came after the researchers adjusted for a variety of factors known to be associated with early death, such as smoking, obesity and age.
“Discouraging the consumption of ultra-processed foods; targeting products, taxation, and marketing restrictions on ultra-processed products; and promotion of fresh or minimally processed foods, should be considered part of important health policy to improve global public health,” the researchers conclude.
A ‘relatively straightforward’ message
Both studies come with important caveats. Most notably, they are observational studies. That means, as already noted, their findings don’t prove that ultra-processed foods lead to cardiovascular disease and early death. Other factors, not accounted for in the final analyses of the data, might also explain the results.
Still, the evidence that ultra-processed foods contribute to poorer health is mounting. It’s not yet entirely clear how these products do that, but as an editorial that runs with the two studies in BMJ points out, ultra-processed foods “deliver risk nutrients into the body, displace nutritious foods from the diet, and as the products of industrial processing they can have peculiar physical structures or chemical compositions that are also risk factors for adverse health outcomes.”
The authors of that editorial — two researchers at Deakin University in Australia — say that the dietary message from the accumulating research on ultra-processed foods “is relatively straightforward: eat less ultra-processed food and more unprocessed or minimally processed food.”
They also stress that policymakers “should shift their priorities away from food reformulation — which risks positioning ultra-processed foods as a solution to dietary problems — towards a greater emphasis on promoting the availability, affordability, and accessibility of unprocessed or minimally processed foods.”
For more information: You can read both studies — and the editorial — on BMJ’s website.