Story at a glance
- The increased popularity and proliferation of ultra-processed foods in the United States has raised concerns among health professionals, as these foods are linked with a host of poor health outcomes.
- Now, new research shows that for U.S. men, eating more of these foods is associated with a nearly 30 percent increased risk of colorectal cancer.
- Colorectal cancer is the third most diagnosed cancer in the United States.
U.S. men who consume higher rates of ultra-processed food are at a 29 percent greater risk of developing colorectal cancer, according to new study results published in The BMJ. However, no association was seen among women in the study.
Colorectal cancer is the third most diagnosed cancer in the country and the second leading cause of cancer deaths worldwide.
Furthermore “ultra-processed foods (that is, industrial ready-to-eat or ready-to-heat formulations made of little or no whole foods) now contribute 57 percent of total daily calories consumed by American adults, which has been continuously increasing in the past two decades,” authors wrote.
In recent years, the consumption of ultra-processed foods has been linked with a host of poor health outcomes including coronary heart diseases, obesity, hypertension and metabolic syndrome, to name a few.
To better understand any association between ultra-processed food intake and colorectal cancer, researchers assessed data from the Health Professionals Follow-up Study, the Nurses’ Health Study and the Nurses’ Health Study II. As part of the studies, participants filled out food frequency questionnaires every four years.
A total of 46,341 men and 159,907 women were included in the analyses. Between 24 and 28 years of follow-up, 1,294 cases of colorectal cancer among men were recorded and 1,922 among women.
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Compared with men who ate the lowest proportion of ultra-processed food, those in the highest-consumption group had a significantly heightened risk of the cancer that remained after adjusting for body mass index.
Among the at-risk men, risk was particularly high for distal colon cancer.
“Processed meats, most of which fall into the category of ultra-processed foods, are a strong risk factor for colorectal cancer,” explained lead study author Lu Wang of Tufts University in a statement.
“Ultra-processed foods are also high in added sugars and low in fiber, which contribute to weight gain and obesity, and obesity is an established risk factor for colorectal cancer.”
When divided into subgroups, researchers found increased consumption of meat, poultry and seafood based ready-to-eat products and sugar sweetened beverages (i.e. soda and fruit-based beverages) posed the highest risk among men.
However, an inverse association was discovered between ultra-processed dairy foods like yogurt and colorectal cancer risk in women, authors noted.
“Foods like yogurt can potentially counteract the harmful impacts of other types of ultra-processed foods in women,” said co-author Fang Fang Zhang, also of Tufts University.
More research is needed to better understand the sex differeneces seen with regard to colorectal cancer risk and intake of processed foods and to determine whether the lack of association among women was due to chance or other confounding factors.
Authors point to food additives as a potential root cause for the association documented, as these can alter gut microbiota and promote inflammation. Contaminants from food processing or packaging may also account for the link.
“Chemically processing foods can aid in extending shelf life, but many processed foods are less healthy than unprocessed alternatives,” Zhang added.
Because the foods are often cheap and readily available “we need to make consumers aware of the risks associated with consuming unhealthy foods in quantity and make the healthier options easier to choose instead.”
