Ultra-processed foods are part of everyday life, filling 60% to 70% of the American diet. That umbrella term covers a wide range of packaged foods, from snacks with added sugar, salt and saturated fat in combination with preservatives for shelf life, additives for flavor, colorants for an attractive appearance and chemicals such as bisphenols in the packaging itself. Processed meat, as the name suggests, also belongs in this category.
But ultra-processed foods are not all the same. Whole grains and breads also qualify for the label, as do yogurt and some other dairy desserts. JoAnn Manson, professor of medicine at Harvard Medical School and Brigham and Women’s Hospital, reported in Lancet Regional Health last month on a major analysis of long-term studies on links between ultra-processed foods and cardiovascular disease. The bottom line is: one size fits all doesn’t fit all.
To fill a gap in what is known about these foods, the researchers used data from three prospective cohort studies of more than 200,000 nurses and doctors over three decades, as well as a meta-analysis of 22 international studies involving 1 .2 million participants. They found a significant increase in coronary heart disease (23%), overall cardiovascular disease (17%) and stroke (9%) in people who said they consumed the most ultra-processed foods, compared to those who said they ate the least .
A closer look found that some foods were more closely linked to a higher risk of disease: sugar-sweetened drinks and processed meats were associated with a higher risk, while breakfast cereals, yogurt, some dairy desserts and whole grains were associated with a relatively lower risk .
Manson spoke to STAT about the study’s conclusions last week, following a meeting of the Dietary Guidelines for Americans Committee in which no recommendations on ultra-processed foods were made due to a lack of strong evidence. This conversation has been edited for length and clarity.
The committee charged with making recommendations for U.S. dietary guidelines has not ruled on ultra-processed foods because the evidence is lacking. Why is this such a difficult question to answer?
It was challenging to conduct this study because most nutritional assessments across studies do not really rigorously classify people based on ultra-processed food intake. Randomized trials need to be very large and long lasting to get answers about chronic disease prevention. And so it’s just not realistic.
In the recent Lancet Regional Health publication we had 1.2 million people in the meta-analysis, which is obviously huge. And that was necessary to look at the relationship between the intake of ultra-processed foods and the risk of cardiovascular disease, and then to look at subtypes of ultra-processed foods, where we did see diversity. It wasn’t one size fits all.
Were you surprised by what you discovered?
We were actually surprised that there were several types of ultra-processed foods that were associated with a lower risk of cardiovascular disease. We didn’t expect so much diversity among the types of ultra-processed foods.
Can certain types of these foods be part of a healthy diet?
I think we have to accept that there is complexity and diversity in this association between ultra-processed foods and health. It is important to focus on a whole food diet, mainly plant based. However, it does mean that certain types of ultra-processed foods can be included in a healthy diet. They do not need to be eliminated completely. They don’t have to become taboo. We know that doesn’t work with dietary guidelines.
Some of these other foods that fall into the UPF category—cereals, yogurt, whole-wheat bread—are not linked to an increased risk of cardiovascular disease in these large epidemiological studies. There may be some wiggle room in including certain types of ultra-processed foods in a healthy diet and not eliminating them completely. And then we’ll see how the evidence will develop in the coming years.
Should the next round of dietary guidelines reflect this?
I suspect ultra-processed foods will be in the 2030 dietary guidelines. I think it will probably take a number of years before there is enough evidence. But I think it’s moving in that direction and more and more of the large cohort studies are being able to look at the relationship with cardiovascular disease, cancer, diabetes, all-cause mortality, cognitive outcomes, depression – many of these really important health outcomes. . I think we will have a much larger evidence base by then.
What can speed up the process?
The research is moving towards trying to look at more biomarkers of ultra-processed intake: not just insulin resistance, glucose tolerance and weight change, but also looking at the effect on the microbiome, the metabolomic patterns, the changes in the proteome, and then DNA methylation markers for epigenetic aging. All of this can be viewed in terms of chronic disease outcomes, and I think this will further accelerate research in this area.
I think there are ways to do randomized trials. They probably won’t be like some of our studies with 25,000 participants. But they could also be studies where 100 people look at changes in some of these biomarkers and changes in weight over a few months.
What about alcoholic drinks?
More risks are being identified for even moderate alcohol intake and cardiovascular outcomes. For example, atrial fibrillation, which is becoming increasingly common, is linked to alcohol consumption. And a brain hemorrhage. There is also concern about breast cancer and other cancers. I think there will probably be more and more research done on alcohol and health. And again, as with ultra-processed foods, it may be a few years before this actually becomes more widely included in the guidelines. I think it’s going that way.
We should certainly not recommend that people who do not currently drink consume alcohol to reduce the risk of cardiovascular disease. This is not likely to improve health and can have very adverse health consequences.
Do you see progress?
I’m hopeful. I think the research on dietary patterns has been very useful. Identifying certain patterns that allow for flexibility, including some cultural influences and cultural differences, can really make a difference in not forcing people into these very restrictive types of recommendations.
I absolutely agree with the recommendations to reduce and minimize ultra-processed foods. And if you’re going to have them, you might lean more toward those that have been linked to lower risk or neutral associations with cardiovascular disease or other chronic diseases, rather than the increased risk, especially cutting down on sugar sweetened drinks and processed meats. .
Does the increasing use of anti-obesity medications play a role in any of these guidelines?
I think it’s too early to know. I think we need a lot more research into the long-term effects of the GLP-1s. And I still think the composition of the diet is going to be important. I think the answer won’t just be throwing drugs at these huge chronic health problems. We need much more attention to prevention.
STAT’s coverage of chronic health conditions is supported by a grant from Bloomberg Philanthropies. Us financial supporters are not involved in decisions about our journalism.