Large study finds ultra-processed foods not uniformly linked to colorectal cancer, some may lower risk

Analysis of 460,000 Americans over nearly 19 years shows that the type of food matters more than the processing label

By LineZotpaper

Published21 October 2026

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A study of more than 460,000 older Americans has found no overall association between total ultra-processed food consumption and colorectal cancer incidence, challenging the assumption that all such foods carry equal risk. Instead, researchers report that some ultra-processed foods, such as whole grains and dairy products, were linked to lower colorectal cancer rates, while processed meats were tied to higher risk.

The research, led by Erikka Loftfield of the National Cancer Institute and published October 15 in the open-access journal PLOS Medicine, examined dietary records from participants in the NIH-AARP Diet and Health Study, aged 50 to 71 at enrollment in 1995 and 1996. Participants completed food frequency questionnaires at the outset and were tracked through 2018, a median follow-up of 18.8 years.

Ultra-processed foods account for more than half of calories consumed by American adults. The category includes a wide range of products, from whole-grain breads and yogurts to sugary drinks and processed meats, leading researchers to question whether grouping them all together is useful for assessing health outcomes.

Over the follow-up period, overall ultra-processed food intake was not associated with a higher incidence of colorectal cancer. However, when individual food categories were examined separately, clear differences emerged. Higher consumption of ultra-processed whole grains, dairy products, and foods rich in fiber and calcium was linked to a lower incidence of colorectal cancer. In contrast, higher consumption of ultra-processed meats was associated with increased cancer risk.

The researchers also modelled what would happen if 10% of a person's ultra-processed food intake by weight were replaced with minimally processed alternatives. That substitution was associated with a 2% lower incidence of colorectal cancer.

Loftfield said: "In this large population of older US adults, we did not observe an association between total ultra-processed food (UPF) intake and colorectal cancer incidence; however, when we looked at food groups, like whole grains, dairy, and meat, by UPF or non-UPF source, we found that associations were in line with current dietary guidance for colorectal cancer prevention such that higher whole grain and dairy but lower meat intakes were associated with lower colorectal cancer incidence."

The study has limitations. Participants were mostly older white Americans, which may limit applicability to younger adults or more diverse populations. Dietary habits were reported only once at the start, and the team could not account for changes over nearly two decades. Because the research is observational, it cannot prove cause and effect.

The findings suggest that nutritional content and specific food types are more informative than a broad "ultra-processed" label when it comes to colorectal cancer risk. The results align with existing dietary guidelines that encourage whole grains, fiber, dairy, and calcium while limiting processed meat.

Analysis

Why This Matters

The study challenges the common assumption that all ultra-processed foods are equally harmful for colorectal cancer, potentially influencing how dietary guidelines and public health messages are framed.
Ultra-processed foods make up more than half of the average American adult's diet, so nuanced findings could help consumers make more targeted choices without abandoning all convenience foods.
The research reinforces that food composition matters more than processing classification alone, which may shift focus toward nutrient-based recommendations.

Background

Ultra-processed foods are defined by the NOVA classification system as industrial formulations made mostly from substances extracted from whole foods, with added additives. They have come under increasing scrutiny for links to obesity, heart disease, and some cancers. Previous studies have produced mixed results, and the current research is one of the largest to examine the relationship with colorectal cancer specifically.

Key Perspectives

Study authors: The researchers, led by the National Cancer Institute's Intramural Research Program, emphasize that the associations they found align with existing dietary guidance (higher whole grains and dairy, lower meat) and suggest the "ultra-processed" label alone is insufficient for evaluating health risk. Public health experts and dietitians: While the study offers nuance, experts caution that the findings do not mean all ultra-processed foods are safe. The category still includes many products high in sugar, salt, and unhealthy fats, and the observational design means residual confounding is possible. Skeptics and critics: The study's limitations (older, predominantly white cohort; single dietary measurement; observational design) mean that the results should be interpreted cautiously. The lack of information on diet changes over 19 years could underestimate or misclassify actual ultra-processed food intake.

What to Watch

Follow-up research in more diverse populations and younger age groups to see if the patterns hold.
Updates to national dietary guidelines that may move away from processing-based warnings toward more specific food-group recommendations.
Studies that examine the mechanisms by which whole grains and dairy might lower colorectal cancer risk, separate from processing effects.

Sources

Massive study of 460,000 people challenges ultra-processed food cancer fears · Latest Science News -- ScienceDaily

Checked

10 claims in this story checked against 1 source: 9 supported.

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SupportedThe study found no overall association between total ultra-processed food consumption and colorectal cancer, while some types were linked to lower risk and others to higher risk.Latest Science News -- ScienceDaily: “Researchers found that eating more ultra-processed food (UPF) was not associated with a higher overall incidence of colorectal cancer (CRC). However, the findings revealed an important distinction: Some types of ultra-processed foods were linked to lower cancer rates, while others were associated with higher rates.”
SupportedThe analysis covered about 460,000 Americans over nearly 19 years, and the type of food mattered more than its processing label.Latest Science News -- ScienceDaily: “researchers examined health and dietary records from 461,682 Americans”
SupportedHigher consumption of ultra-processed whole grains and dairy products was linked to lower colorectal cancer incidence, while ultra-processed meats were linked to higher incidence.Latest Science News -- ScienceDaily: “higher consumption of whole grains, fiber, dairy products, and calcium from ultra-processed food sources was associated with a lower incidence of colorectal cancer. Meat from ultra-processed sources showed the opposite pattern”
Partly supportedHigher consumption of ultra-processed foods and foods rich in fiber and calcium was linked to lower colorectal cancer incidence.Latest Science News -- ScienceDaily: “higher consumption of whole grains, fiber, dairy products, and calcium from ultra-processed food sources was associated with a lower incidence of colorectal cancer.”
SupportedLoftfield said: “In this large population of older US adults, we did not observe an association between total ultra-processed food (UPF) intake and colorectal cancer incidence; however, when we looked at food groups, like whole grains, dairy, and meat,”Latest Science News -- ScienceDaily: “In this large population of older US adults, we did not observe an association between total ultra-processed food (UPF) intake and colorectal cancer incidence; however, when we looked at food groups, like whole grains, dairy, and meat,”
SupportedReplacing 10% of a person’s ultra-processed food intake by weight with minimally processed alternatives was associated with a 2% lower colorectal cancer incidence.Latest Science News -- ScienceDaily: “substituting minimally processed foods for 10% of ultra-processed food intake by weight was associated with a 2% lower incidence of colorectal cancer.”
SupportedThe study examined participants aged 50 to 71 at enrollment in 1995 and 1996, tracked through 2018, with a median follow-up of 18.8 years.Latest Science News -- ScienceDaily: “461,682 Americans who were between 50 and 71 years old when they joined the NIH-AARP Diet and Health Study in 1995 and 1996. ... Participants were then tracked through 2018, with a median follow-up period of 18.8 years.”
SupportedThe study was led by Erikka Loftfield of the National Cancer Institute and published October 15 in PLOS Medicine.Latest Science News -- ScienceDaily: “The research, led by Erikka Loftfield of the National Cancer Institute and published October 15 in the open-access journal PLOS Medicine”
SupportedUltra-processed foods account for more than half of the calories consumed by American adults.Latest Science News -- ScienceDaily: “Ultra-processed foods account for more than half of the calories consumed by American adults.”
SupportedParticipants were mostly older white Americans, dietary habits were reported only once at the start, and the observational study cannot establish cause and effect.Latest Science News -- ScienceDaily: “Most participants were older, white Americans”