Regular consumption of ultra-processed foods was associated with an increased risk of colorectal cancer, all-cause mortality, and cardiovascular mortality, according to findings from two studies published in The BMJ.

In the first paper, which analyzed three prospective U.S. cohort studies, men in the highest quintile of consumption had a 29% higher risk of developing colorectal cancer compared with those in the lowest (HR 1.29, 95% CI 1.08-1.53, P=0.01), with an even greater association seen for distal colon cancer (HR 1.72, 95% CI 1.24-2.37, P<0.001), reported Fang Zhang, MD, of Tufts University in Boston, and colleagues.

These associations remained significant even after adjusting for BMI and nutritional quality indicators, they noted, and no association between ultra-processed food intake and colorectal cancer was seen among women.

In the second paper, which involved an Italian prospective study, an adjusted multivariable analysis showed a higher risk of all-cause mortality (HR 1.19, 95% CI 1.04-1.35) and cardiovascular mortality (HR 1.32, 95% CI 1.06-1.64) among adults in the highest quarter of the Food Standards Agency Nutrient Profiling System (FSAm-NPS) dietary index compared with the lowest quarter.

When looking at only those who fell within the two highest categories of ultra-processed food intake, based on the NOVA classification system, the associations remained for all-cause mortality (HR 1.19, 95% CI 1.05-1.36) and cardiovascular mortality (HR 1.27, 95% CI 1.02-1.58), reported Marialaura Bonaccio, PhD, of IRCCS Neuromed in Pozzilli, Italy, and colleagues.

In an accompanying editorial, Carlos Monteiro, MD, PhD, and Geoffrey Cannon, MA, both of the University of São Paulo in Brazil, noted that “the overall positive solution includes making supplies of fresh and minimally processed foods … available, attractive, and affordable. And sustaining national initiatives to promote and support freshly prepared meals made with fresh and minimally processed foods, using small amounts of processed culinary ingredients and processed foods.”

“Enacted, this will promote public health. It will also nourish families, society, economies, and the environment,” they added.

Colorectal Cancer

For their study, Zhang and colleagues used data on healthcare workers from three large U.S. prospective cohorts, including 46,341 men from the Health Professionals Follow-up Study from 1986-2014, 67,425 women from the Nurses’ Health Study I from 1986-2014, and 92,482 women from the Nurses’ Health Study II from 1991-2015. The NOVA classification system was used to assess levels of ultra-processed foods, and only physicians were blinded.

Over 24 to 28 years of follow-up, 3,216 cases of colorectal cancer were documented, 1,294 in men and 1,922 in women.

A higher consumption of meat/poultry/seafood-based ready-to-eat products was associated with an increased risk of colorectal cancer in men (HR 1.44, 95% CI 1.20-1.73), as was higher consumption of sugar-sweetened beverages (HR 1.21, 95% CI 1.01-1.44), while ready-to-eat or heat mixed dishes were linked to an increased risk for women (HR 1.17, 95% CI 1.01-1.36).

Interestingly, dairy-based desserts and yogurt were tied to a 17% lower risk of colorectal cancer among women (HR 0.83, 95% CI 0.71-0.97).

Potential explanations for the different patterns between the sexes might be due to the effects of obesity or sex hormones, Zhang and team noted.

They also acknowledged that the self-administered validated food frequency questionnaires used in the study included a limited list of pre-defined foods, which was a limitation to their study.

Cardiovascular/All-Cause Mortality

In the so-called Moli-sani study, Bonaccio and colleagues examined data on 22,895 participants (mean age 55, 52% women) in Molise, Italy from March 2005 to December 2010.

Over a median follow-up of 12.2 years, 2,205 participants died.

The authors jointly analyzed the the FSAm-NPS — used to derive the Nutri-Score front-of-pack label — and the NOVA classification system to assess mortality, finding that the magnitude of the relationship between the FSAm-NPS dietary index and all-cause mortality was attenuated by 22.3%, which was slightly higher than that for cardiovascular mortality (15.4% attenuated), while mortality risks linked to high ultra-processed food intake were not changed.

“So the problem with ultra-processed products has been suggested to be simply their poor nutrient profiles,” Monteiro and Cannon noted.

Study limitations included possible recall bias from self-reported dietary data, as well as possible social desirability bias, since ultra-processed food intake may have been underreported, Bonaccio and team said.

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