- New research shows that a diet high in processed foods may increase the risk of death among older Americans by as much as 10%.
- The study followed the diet and health of more than half a million participants for more than 20 years.
- The highest consumption of ultra-processed foods was found among the younger members of the researcher’s older adult group.
A large new study finds that eating highly processed foods is linked to an increased risk of death in older adults.
People who ate significant amounts of ultra-processed foods were 10 percent more likely to die during the study’s long follow-up period than people who didn’t.
The study was based on data from the
The researchers assessed their diets using the NOVA system, which classifies foods based on the degree and type of processing used in their preparation.
They looked at the Healthy Eating Index (HEI)-2015 scores, and not just the NOVA processing, and found that people with higher UPF intakes tended to have poorer diets and higher BMIs.
What makes this study particularly noteworthy are the two approaches the researchers used to further validate the food frequency questionnaires (FFQ): expert consensus and an alternative and novel food-based approach to define UPF intake (grams per day). This was split into food codes, then ingredient codes, and then classified via NOVA.
The researchers also used two 24-hour dietary recalls in a subsample to calibrate their FFQ risk estimates. This is not standard practice and adds to the potential accuracy of the study’s findings.
The research was presented this week at the American Society for Nutrition’s NUTRITION 2024 conference.
According to the NOVA system, natural, processed and ultra-processed foods are defined as follows:
- Unprocessed, or natural, foods come directly from plants or animals, without any alteration or processing other than transportation to the point of sale.
- Minimally processed foods are similar, except that they have been cleaned and inedible or unwanted parts have been removed. They may be portioned, ground, dried, fermented, pasteurized, refrigerated, or frozen en route to the table. However, they have no added oils, fats, sugar, salt, or other substances.
- NOVA also includes a category called Processed Culinary Ingredients, which are substances that have been extracted from natural foods. These include oils, fats, salt and sugar, and are ideally used in small quantities to season and cook foods without nutritionally degrading the overall quality of the diet.
- Processed foods are foods that have been produced for consumption using sugar, salt, and oil added to natural foods for flavor and to extend their shelf life. They typically contain no more than two or three ingredients.
- Ultraprocessed foods, or UPF, are industrial creations formed primarily from substances including oils, fats, sugars, and proteins derived from natural foods, along with modified starches and hydrogenated fats, with added colorings and flavor enhancers. They are inexpensive to the consumer and convenient, and can contain five or (many) more ingredients.
It has long been known that a diet high in ultra-processed foods can be harmful to health. However, the large number of people in this study — 318,889 men and 221,607 women — and the long follow-up time are unusual.
Dietitian Kristin Kirkpatrick, MS, RDN, who was not involved in the study, said, “The very long follow-up period is interesting; however, the researchers also note that it’s unclear what was done between the time the data were collected and the follow-up. Did these people change their diet? Were there other activities that were risky to their overall health? We’re not sure about the details.”
Compared to the lowest consumption of processed foods, the highest amount wasassociated with an increased risk of death from heart disease and diabetes, but not from cancer.
“This study shows that higher consumption of ultra-processed foods is associated with an increased risk of death, independent of other factors such as smoking, obesity, and diet quality,” said Michelle Routhenstein, MS, RD, CDCES, a preventive cardiology dietitian at EntirelyNourished.com, who was also not involved in the study.
“This suggests that the harmful effects of ultra-processed foods on health may persist regardless of overall lifestyle factors,” Routhenstein said.
“Ultra-processed foods tend to be higher in added sugars, unhealthy fats, and additives, while lacking in essential nutrients like fiber and vitamins, which can negatively impact cardiometabolic health. These foods contain higher levels of advanced glycation end products (AGEs) due to their processing methods, which can increase oxidative stress and inflammation in the body. AGEs can also increase cystatin C levels, which has been associated with decreased kidney function and increased risk of cardiovascular disease.”
— Michelle Routhenstein, MS, RD, CDCES
Given the longer follow-up period, participants were approximately 73 to 94 years old at the time of follow-up.
“Research on the impact of ultra-processed foods specifically in older adults is limited but growing. The specific long-term impact on mortality in older populations is still an area of active study,” Routhenstein said.
“It’s never too late to make beneficial changes to your diet,” Kirkpatrick said. “Previous research has shown similar results for longevity, such as a study that assessed UPF in ages 57-91.”
She noted that much of the research she saw involved younger people and focused on preventing later problems through better nutrition.
The researchers found that younger members of their study population tended to consume more UPF than older members.
“Younger participants — particularly middle-aged people — may consume more ultra-processed foods due to factors such as convenience, affordability and advertising. These foods are often widely available, require minimal preparation and are heavily promoted, making them appealing to busy lifestyles,” Routhenstein said.
It may also be, Kirkpatrick noted, that “younger individuals who are generally healthy and have not had symptoms of/or serious illness are not thinking about what the future holds with regard to their diet today.”
The American diet typically includes a wide variety of foods spanning the entire processing spectrum.
“Some of these foods, like breakfast cereals, can even help fill in some nutritional gaps through fortification,” Kirkpatrick said.
However, she said, “If you consume a lot of these foods, you don’t have the opportunity to nourish your body with [more] nutrient-dense options.” The result can be high consumption of high-calorie foods that have little nutritional value.
Kirkpatrick was concerned about the overreliance on the NOVA classification system for assessing the impact of processed foods.
“The NOVA scale is strictly related to the degree of processing and has nothing to do with the nutritional value of the food. So it doesn’t take into account things like added sugar, protein or fiber content,” she explains.
“If you lump all processed foods together, you risk oversimplifying nutritional science, which is why limiting UPF should also involve educating individuals,” Kirkpatrick said.
“There is no one-size-fits-all dietary approach, so each patient deserves a personalized approach to their dietary needs and goals,” she said.