Ultra-processed foods linked to cancer, death: studies

Eating lots of ultra-processed foods dramatically increases the risk of colorectal cancer in men and can lead to heart disease and early death in both men and women, according to two new large-scale studies of people in the United States and in Italy published Wednesday in British medical journal The BMJ.

Ultra-processed foods include prepackaged soups, sauces, frozen pizzas, convenience foods, and pleasure foods such as hot dogs, sausages, fries, soda, store-bought cookies, cakes, candy, donuts, ice cream and more.

“Hundreds of studies link ultra-processed foods to obesity, cancer, cardiovascular disease and overall mortality,” said Marion Nestle, Paulette Goddard Emeritus Professor of Nutrition, Food Studies and Health. Public Health at New York University and author of numerous books on food policy and marketing, including 2015’s « Soda Politics: Taking on Big Soda (and Winning) ».

“These two studies maintain consistency: ultra-processed foods are unambiguously associated with an increased risk of chronic disease,” said Nestlé, which was not involved in either study.


The US-based study looked at the diets of more than 200,000 men and women for 28 years and found a link between ultra-processed foods and colorectal cancer – the third most diagnosed cancer in the US – in men, but not in women.

According to the World Health Organization, the American Cancer Society and the American Institute for Cancer Research.

The new study, however, found that all types of ultra-processed foods played a role to some degree.

“We found that men in the highest quintile of ultra-processed food consumption, compared to those in the lowest quintile, had a 29% higher risk of developing colorectal cancer,” said the co- senior author Fang Fang Zhang, cancer epidemiologist and president of the division. in Nutritional Epidemiology and Data Science at the Friedman School of Nutrition Science and Policy at Tufts University in Boston.

This association remained even after researchers took into account a person’s body mass index or dietary quality.

Why didn’t the new study find the same colorectal cancer risk in women?

« The reasons for such a gender difference are still unknown, but may involve the different roles that obesity, sex hormones, and metabolic hormones play in men versus women, » Zhang said.

« Alternatively, women may have chosen ‘healthier’ ultra-processed foods, » said Dr. Robin Mendelsohn, a gastroenterologist at Memorial Sloan-Kettering Cancer Center in New York City, who was not involved in the study. .

The study found that consuming a « higher intake of ultra-processed dairy products – such as yogurt – was associated with a lower risk of colorectal cancer in women, » Zhang said. « Some ultra-processed foods are healthier, like whole-grain foods that have little or no added sugars, yogurts, and dairy products. »

Women had a higher risk of colorectal cancer if they ate more ready-to-eat or reheat foods like pizza, she said. However, men were more likely to have a higher risk of bowel cancer if they ate a lot of meat, poultry or ready-to-eat seafood and sugary drinks, Zhang said. .

“Americans consume a large percentage of their daily calories from ultra-processed foods — 58% among adults and 67% among children,” she added. « We should consider replacing ultra-processed foods with unprocessed or minimally processed foods in our diets for cancer prevention and the prevention of obesity and cardiovascular disease. »


The second study followed more than 22,000 people for a dozen years in the Molise region of Italy. The study, which began in March 2005, aimed to assess cancer risk factors as well as heart and brain diseases.

An analysis published in The BMJ compared the role of nutrient-poor foods – such as foods high in sugar and saturated or trans fats – versus ultra-processed foods in the development of chronic disease and early death. The researchers found that both types of food independently increased the risk of premature death, particularly from cardiovascular disease.

However, when the researchers compared the two types of food to see which contributed the most, they found that ultra-processed foods were « primary in defining mortality risk, » said first author Marialaura Bonaccio, an epidemiologist at department of epidemiology and prevention. at the IRCCS Neurologico Mediterraneo Neuromed in Pozzilli, Italy.

In fact, more than 80% of foods classified by the guidelines followed in the study as nutritionally unhealthy were also ultra-processed, Bonaccio said in a statement.

« This suggests that the increased risk of mortality is not due directly (or exclusively) to the poor nutritional quality of certain products, but rather to the fact that these foods are mostly ultra-processed, » Bonaccio added.


Why are ultra-processed foods so bad for us? On the one hand, they are « industrial ready-to-eat or heat-to-heat formulations that are made with ingredients extracted from foods or synthesized in a laboratory, with little or no whole foods, » Zhang told CNN.

These overly processed foods are often high in added sugars and salt, low in dietary fiber and full of chemical additives, such as artificial colors, flavors or stabilizers.

“Although some ultra-processed foods may be considered healthier than others, in general we recommend staying away from ultra-processed foods completely and focusing on healthy unprocessed foods – fruits, vegetables , legumes, » Mendelsohn said.

In 2019, the National Institute of Health (NIH) published the results of a controlled clinical trial comparing a processed and unprocessed diet. Researchers found that those who followed an ultra-processed diet ate faster and ate 500 more calories per day than people who ate unprocessed foods.

« On average, participants gained 0.9 kilograms or 2 pounds while on the ultra-processed diet and lost an equivalent amount on the unprocessed diet, » the NIH noted.

« There’s clearly something about ultra-processed foods that makes people eat more of them without necessarily wanting to or realizing it. » says Nestle.

“The effects of ultra-processed foods are quite clear. The reasons for these effects are not yet known,” Nestlé continued. « It would be nice to know why, but until we know that, it’s best to advise eating ultra-processed foods in as small amounts as possible. »


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