But there’s no need to rush to your kitchen to toss out all your processed foods. The increased risk was modest. Furthermore, the study found only a correlation, not a cause-and-effect relationship, between heavily processed foods and early death.
The study’s findings, she added, are just a “step in our understanding of the link between ultra-processed food and health.”
Still, we need to be paying attention to this kind of research. For, as Tourvier and her co-authors point out in their paper, a growing number of studies are reporting links between the consumption of heavily processed foods and a higher risk of chronic disease, including type 2 diabetes, high blood pressure and cancer.
Those findings are particularly concerning here in the United States, where an estimated 60 percent of the calories we consume come from ultraprocessed foods.
How the study was done
For the current study, Tourvier and her colleagues used data collected from more than 44,000 French adults (aged 45 and older), who were participating in a larger, ongoing health study in France. The participants were followed for an average of seven years, and during that time each filled out detailed 24-hour food diaries at six-month intervals.
From that data, the researchers calculated the proportion of each participant’s diet that contained ultraprocessed foods. They define those foods as “products that contain multiple ingredients and are manufactured through multitude of industrial processes.”
“These foods products are usually ready to heat and eat, affordable, and hyperpalatable,” the researchers explain. “Examples include mass-produced and packaged snacks, sugary drinks, breads, confectioneries, ready-made meals, and processed meats.”
Among the study’s participants, ultraprocessed foods made up 14 percent of the weight of the total food consumed and about 29 percent of total calories. (That’s about half of the calories consumed from ultraprocessed foods by the average American.)
The people in the study who consumed the greatest amount of ultraprocessed foods tended to be younger (45 to 64 years old), more sedentary and more likely to be living alone. They were also more likely to have a lower income, a lower education level and a higher body mass index (BMI).
The link with early death
During the study’s seven-year follow-up, 602 (1.4 percent) of the participants died. Thirty-four of those deaths were caused by cardiovascular disease, and 219 were caused by cancer — two types of illnesses that can be diet-related. (The causes of the other deaths are not identified in the study.)
The researchers then looked for associations between the amount of ultra-processed foods in the participants’ diet and their risk of early death. They found that for each additional 10 percent increase in the proportion of ultraprocessed food the participants ate, the risk of death increased by 14 percent.
The researchers came by those results after first adjusting the data for a long list of non-diet-related factors that can contribute to early death, including smoking, alcohol use, physical activity levels and family history of cancer or cardiovascular disease.
The study’s results suggest “a positive association between increased ultraprocessed foods consumption and all-cause mortality risk,” the researchers conclude.
They offer several possible explanations for that association. Ultraprocessed foods, they point out, tend to contain high amounts of sodium (salt) and sugar, and consuming both those ingredients in high quantities has been linked to an increased risk of death from cardiovascular disease.
The researchers also point to the substances that are added to ultraprocessed foods during processing or that leach into the food from its packaging while it’s being stored. Some of those substances are suspected of having disease-causing properties.
Limitations and implications
Now for the caveats. The study’s biggest limitation is, of course, that this is an observational study, which means it can’t prove that eating high amounts of ultraprocessed foods increases the risk of early death. Furthermore, the participants self-reported what they ate, and such reports can be biased.
In addition, the researchers’ definition of ultraprocessed is based on how the foods were made rather than on their content, so even if the foods did contribute to the small increase in deaths observed in this study, it’s impossible to know which foods were involved.
So, what’s the take-home message from the study?
The anonymous expert who reviewed the study for “Behind the Headlines,” a consumer information site hosted by Great Britain’s National Health Service, may have put it best. “We certainly cannot conclude that all processed food is bad, or that eating processed food is killing us,” that expert writes.“But the study is a reminder that relying on pre-prepared food or eating too many snacks, sweets and ready-meals can make it easy to consume too much salt, sugar and saturated fat, and not enough fibre, green vegetables and fruit.”
FMI: You’ll find an abstract of the study on the JAMA Internal Medicine website, but the full study is behind a paywall.