Ultra-processed foods account for 58% of daily calorie intake for the average U.S. diet. A prospective observational study headed by scientists at New York University School of Public Health has now linked higher consumption of ultra-processed foods with an increased risk of cardiovascular disease (CVD) incidence and CVD mortality. Findings from the study, which followed more than 3,000 adults in the Framingham Offspring Study (FOS) for up to two decades, indicated that participants consumed on average 7.5 servings per day of ultra-processed foods, and for each additional serving the risk of CVD risk increased by a further 7%, and the risk of CVD mortality increased by 9%.
“The consumption of ultra-processed foods makes up over half of the daily calories in the average American diet and are increasingly consumed worldwide,” said Filippa Juul, PhD, a faculty fellow at New York University School of Public Health. “Ultra-processed foods are ubiquitous and include many foods that are marketed as healthy, such as protein bars, breakfast cereals and most industrially produced breads … Our findings add to a growing body of evidence suggesting cardiovascular benefits of limiting ultra-processed foods. As poor diet is a major modifiable risk factor for heart disease, it represents a critical target in prevention efforts.”
Juul is lead author of the study, which is published in Journal of the American College of Cardiology, titled, “Ultra-Processed Foods and Incident Cardiovascular Disease in the Framingham Offspring Study.”
Cardiovascular diseases remain a leading cause of chronic disability and death worldwide, and poor diet is “a major modifiable CVD risk factor” that represents a critical target for cardiovascular prevention efforts, the authors wrote. The production of ultra-processed foods—these are highly processed “industrial formulations” made with little or no whole foods—involves techniques that can remove beneficial nutrients and other bioactive components, while adding non-beneficial nutrients, colorings, and preservatives. Processing also changes the physical structure of foods. “Beyond nutrient composition, processing modifies the physical structure of the food matrix which may alter nutrient bioaccessibility, absorption kinetics, and the gut microbiota profile,” the team noted.
And while observational studies have linked the consumption of ultra-processed foods with metabolic disorders including obesity hypertension, metabolic syndrome, and type 2 diabetes, few studies have investigated the role of ultra-processed foods in relation to CVD risk.
For their newly reported study, Juul and colleagues used data from the Framingham Offspring Study to examine the role ultra-processed foods play in cardiovascular disease. After excluding participants with pre-existing CVD or missing data, the study included 3,003 primarily Caucasian, middle-aged adults (on average 53.5 years of age). Over half of the participants were female, and two-thirds were either former or current smokers. Overall, 5.8% of the participants had diabetes and 19% had high blood pressure; prevalence was higher among participants who were high consumers of ultra-processed foods compared to low consumers.
Diet was assessed by mail using a food questionnaire where participants reported the frequency of consumption of certain foods in the previous year, with options ranging from <1 serving/months to >6 servings/day. During in-person examinations, trained personnel reviewed the questionnaires. The U.S. Department of Agriculture nutrient database was used to calculate nutrient intakes from reported dietary intakes.
Using a modified version of the NOVA framework, which classifies foods according to the level and purpose of industrial processing undergone to produce them, researchers classified the food questionnaire food items into five categories:
- Unprocessed or minimally processed foods, including fresh, dry, or frozen plant and animal foods
- Processed culinary ingredients, including table sugar, oils, fats, salts, and other items used in kitchens to make culinary preparations
- Processed foods, including foods such as canned fish and vegetables and artisanal cheeses
- Ultra-processed foods, including industrial formulations made with no or minimal whole foods and produced with additives such as flavorings or preservatives
- Culinary preparations, which encompassed mixed dishes that were indicated to be homemade or assumed to be homemade due to lack of detailed information.
The researchers examined diet in relation to events including incident hard CVD (sudden and non-sudden coronary death, heart attack, and fatal/non-fatal stroke), and hard coronary heart disease (sudden and non-sudden coronary death and heart attack). During an average of 18 years of follow-up, a total of 648 cardiovascular events occurred, including 251 cases of hard CVD and 163 cases of hard coronary heart disease (CHD). There were 713 deaths during the follow-up period, including 108 CVD deaths. Participants with the highest intakes of ultra-processed foods had higher incident rates compared to those consuming the least amount of ultra-processed foods.
Analyzing the results, the researches found that compared with participants consuming the least ultra-processed foods, those with the highest intakes had higher incidence rates per 1000 person-years of hard CVD and hard CHD. And each additional daily serving of ultra-processed food above the 7.5 average per day was associated with a 7% increase in the risk of hard CVD, a 9% increase in the risk of hard CHD, a 5% increase in overall CVD, and a 9% increased risk in cardiovascular disease mortality.
Looking at individual food types, the researchers found that intake of bread was associated with an increased risk of hard CVD, hard CHD, and overall mortality, while ultra-processed meat intake was associated with an increased risk of hard CVD and overall CVD. Salty snack foods were associated with increased risk of hard CVD and CHD, while consumption of low-calorie soft drinks were associated with increased risk of overall CVD. Conversely, they wrote, “each additional daily serving of minimally processed foods was associated with a 3% lower risk of incident overall CVD in age-adjusted models,” although this association was not statistically significant in multivariable-adjusted models.
The authors acknowledged some limitations to their study, which was observational, and also there was the potential for measurement error in dietary assessment and under- and over-estimation of ultra-processed food intake due to misclassification. Participants in the Framingham Offspring Study are also primarily Caucasian, and have higher educational levels and income than the general U.S. population, which limits how the findings can be generalized.
The researchers say that their findings nevertheless have important potential implications for cardiovascular prevention. “From a public health perspective, our study suggests the need for increased efforts to implement population-wide strategies,” they wrote. Juul concluded, “Population-wide strategies such as taxation on sugar-sweetened beverages and other ultra-processed foods and recommendations regarding processing levels in national dietary guidelines are needed to reduce the intake of ultra-processed foods. Of course, we must also implement policies that increase the availability, accessibility, and affordability of nutritious, minimally processed foods, especially in disadvantaged populations. At the clinical level, there is a need for increased commitment to individualized nutrition counseling for adopting sustainable heart-healthy diets.” The authors added, “Another promising strategy is to require front-of package warning labels on ultra-processed products.”
In an accompanying editorial, Robert J. Ostfeld, MD, MSc, and Kathleen E. Allen, MS, RD, commented, “… given the prevalence of ultra-processed food consumption and given that ultra-processed foods tend to displace more healthful foods in the diet, timely action to curb the consumption of ultra-processed foods is needed … Recognizing that multiple factors feed into individual food choice, where do we go from here? Ultimately, the goal should be to make the unhealthy choice the hard choice and the healthy choice the easy choice.”