Researchers found that men who consumed high rates of ultra-processed foods were at higher risk for developing colorectal cancer than those who did not
In a new study, researchers linked the consumption of ultra-processed foods and higher colorectal cancer incidence in men. They found that men who consumed high rates of ultra-processed foods had a 29% higher risk for developing colorectal cancer than men who consumed much smaller amounts. The researchers did not find the same association in women.
For many Americans, the convenience of pre-cooked and instant meals may make it easy to overlook the less-than-ideal nutritional information, but a team led by researchers at Tufts University and Harvard University hope that will change after recently discovering a link between the high consumption of ultra-processed foods and an increased risk of colorectal cancer.
"We started out thinking that colorectal cancer could be the cancer most impacted by diet compared to other cancer types," said study lead author Lu Wang. "Processed meats, most of which fall into the category of ultra-processed foods, are a strong risk factor for colorectal cancer. 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."
The study analyzed responses from over 200,000 participants -- 159,907 women and 46,341 men -- across three large prospective studies which assessed dietary intake and were conducted over more than 25 years. Each participant was provided with a food frequency questionnaire every four years and asked about the frequency of consumption of roughly 130 foods.
Participants’ intake of ultra-processed foods was then classified into quintiles (five groups), ranging in value from the lowest consumption to the highest. Those in the highest quintile were identified as being the most at risk for developing colorectal cancer. Although there was a clear link identified for men, particularly in cases of colorectal cancer in the distal colon, the study did not find an overall increased risk for women who consumed higher amounts of ultra-processed foods.
The analyses revealed differences in the ways that men and women consume ultra-processed foods and the prospective associated cancer risk. Out of the 206,000 participants followed for more than 25 years, the research team documented 1,294 cases of colorectal cancer among men, and 1,922 cases among women.
The team found the strongest association between colorectal cancer and ultra-processed foods among men come from the meat, poultry, or fish-based, ready-to-eat products. "These products include some processed meats like sausages, bacon, ham, and fish cakes. This is consistent with our hypothesis," Wang said.
The team also found higher consumption of sugar-sweetened beverages, like soda, fruit-based beverages, and sugary milk-based beverages, is associated with an increased risk of colorectal cancer in men.
The potential role of food additives in altering gut microbiota, promoting inflammation, and contaminants formed during food processing or migrated from food packaging may all promote cancer development, noted co-senior author Fang Zhang.
"Cancer takes years or even decades to develop, and from our epidemiological studies, we have shown the potential latency effect -- it takes years to see an effect for certain exposure on cancer risk," said co-senior author Minyang Song.
Today, there are many widely available plant-based alternatives to highly processed foods, and although these are also manufactured, they are much better for long-term health.
Wang L, et al. “Association of ultra-processed food consumption with colorectal cancer risk among men and women: results from three prospective US cohort studies.” BMJ, 2022; e068921