Scientists found that men who ate high levels of ultra-processed foods were more likely to develop colorectal cancer than those who did not.
Many Americans ignore less-than-ideal nutritional information for ready-made and instant meals for ease and convenience. However, a team of scientists led by researchers in Tufts University And the Harvard university He hopes that will change for many after they recently discovered a link between high consumption of ultra-processed foods and an increased risk of colorectal cancer.
Recently Posted in BMJThe study found that men who ate high levels of ultra-processed foods were 29% more likely to develop colorectal cancer than men who ate significantly less. Colorectal cancer is the third most diagnosed cancer in the United States. The researchers did not find the same association in women.
Colorectal cancer often begins as a growth called a polyp within the colon or rectum. Detecting and removing polyps can prevent colorectal cancer.
“We started to think that colorectal cancer could be the cancer most affected by diet than other cancers,” Lu Wang said. She is the study’s lead author and a postdoctoral fellow at Friedman School of Nutrition Science and Policy in Tufts. “Processed meat, most of which fall into the category of ultra-processed foods, is a strong risk factor for colorectal cancer. Ultra-processed foods are also high in added sugars and low in fiber, which contributes to weight gain and obesity, and obesity is a consistent risk factor for colon cancer.” and rectum.
The responses of the more than 200,000 participants, including 159,907 women and 46,341 men, were analyzed in the study across three large prospective studies evaluating dietary intake conducted over 25 years. Every four years, each participant was provided with a food frequency questionnaire asking about the frequency of consumption of approximately 130 foods.
to study in BMJThen, participants’ intake of ultra-processed foods was categorized into quintiles, ranging in value from lowest to highest consumption. Those in the top quintile were found to be most likely to develop colorectal cancer. A clear association was identified for men, particularly in cases of colorectal cancer in the distal colon (the last part of the colon), but the study did not find an overall increased risk for women who ate higher amounts of ultra-processed foods.
Effects of ultra-processed foods
Differences in the ways men and women consume ultra-processed foods and their associated potential cancer risk were revealed in the analyses. Of the 206,000 participants who were followed for more than 25 years, the research team documented 1,294 cases of colorectal cancer among men, and 1,922 cases among women.
Researchers have discovered that the strongest association between colorectal cancer and ultra-processed foods among men comes from ready-to-eat meat, poultry or fish. These products include some processed meats such as sausage, bacon, ham and fish cakes. This is consistent with our hypothesis,” Wang said.
These signs and symptoms, and others, may be caused by colon cancer or other conditions. Consult your doctor if you have any of the following:
- Change in bowel habits.
- Blood (light red or very dark) in the stool.
- Stools that are narrower than normal.
- Diarrhea, constipation, or a feeling that the bowels do not empty completely.
- Frequent gas pains, bloating, fullness and cramps.
- feeling very tired
- Weight loss for no known reason.
Research results show that higher consumption of sugar-sweetened beverages, such as soda, fruit-based beverages and sugary milk-containing beverages, is associated with an increased risk of colorectal cancer in men.
However, the team also found that not all ultra-processed foods are equally harmful in terms of colorectal cancer risk. “We found an inverse association between ultra-processed dairy products such as yogurt and the risk of colorectal cancer among women,” said co-senior author Fang Fang Zhang. She is a cancer epidemiologist and interim chair of the Department of Nutrition Epidemiology and Data Science at the Friedman School.
In general, no link has been found between consumption of ultra-processed foods and the risk of colorectal cancer among women. The composition of ultra-processed foods consumed by women is likely to be different from that of men.
“Foods like yogurt can counteract the harmful effects of other types of ultra-processed foods in women,” Zhang said.
Minjiang Song is a senior study co-author and assistant professor of clinical epidemiology and nutrition at Harvard T.H. Chan School of Public Health. He added, “Further research will need to determine whether there was a real difference between the sexes, or if the null results in the women in this study were caused solely by chance or some other uncontrolled confounding factor in the women that mitigated the association.”
Although ultra-processed foods are often associated with poor diet quality, there may be factors beyond the poor nutritional quality of ultra-processed foods that influence the risk of colorectal cancer.
For example, there are potential roles for food additives in altering the gut microbiota and promoting inflammation that may promote cancer development. Likewise, contaminants that form during food processing or travel from food packaging may also stimulate the development of cancer, Zhang noted.
With a follow-up rate of over 90% from each of the three studies, the team of researchers had sufficient data for processing and review.
“Cancer takes years or even decades to develop, and from our epidemiological studies, we have shown a potential latency effect — it takes years for us to see an effect of a particular exposure on cancer risk,” Song said. “Because of this long process, it is important to have long-term data exposure to better assess cancer risk.”
After an exclusion process to rule out previous diagnoses or incomplete surveys, the researchers were left with prospective data from 159,907 women from the two NHS studies and 46,341 men from the Occupational Health Follow-up Study.
Adjustments were made for potential confounding factors such as family history of cancer, race, hours of physical activity per week, endoscopy history, smoking status, total alcohol intake and total calorie intake, regular aspirin use, and menopausal status.
Chang realizes that results for this group may differ from those of the general population because study participants may be more inclined to eat healthy food and stay away from highly processed foods because they all worked in the healthcare industry. Due to changes in food processing methods over the past 20 years, the statistics may also be skewed.
“But we’re comparing these populations with those consuming higher versus lower,” Zhang reassured. “So these comparisons are valid.”
Changing dietary patterns
In an earlier study that Wang and Zhang previously published, they said that they set the direction in the increased consumption of ultra-processed foods in children and adolescents in the United States. Both studies support the hypothesis that many different populations may rely on highly processed foods as part of their daily diets.
“The heavy reliance on these foods could be due to factors such as food access and convenience,” said Zhang, who is also a member of the Tufts Institute for Global Obesity Research. “Chemical processing of foods can help extend the shelf life, but many processed foods are less healthy than unprocessed alternatives. We need to educate consumers about the risks associated with consuming unhealthy foods in large quantities and make healthier options easier to choose instead.”
Although Wang knows that change won’t happen overnight, she hopes that this research study will contribute, among other things, to changes in dietary regulations and recommendations.
“Long-term change will require a multi-step approach,” Wang added. Researchers continue to study how nutrition policies, dietary recommendations, and changes to recipes and formula, along with other healthy lifestyle habits, can improve overall health and reduce the burden of cancer. It will be important for us to continue to study the link between cancer and diet, as well as potential interventions to improve outcomes.
Reference: “Association of ultra-processed food consumption with risk of colorectal cancer in men and women: results from three prospective US cohort studies” by Lu Wang, Mingxi Du, Kai Wang, Neha Khandpur, Cynara Laurini Rosato, Jean-Philippe Drouin-Chartier, Eurydice Martinez Steel, Edward Giovannucci, Minjiang Song and Fang Fang Zhang, August 31, 2022, Available here. BMJ.
DOI: 10.1136 / bmj.o1972
The research reported in this article was supported by awards from the National Institute of Health and Health Disparities of the National Institutes of Health (R01MD011501), the National Cancer Institute (UM1CA186107; P01CA087969; U01CA176726; U01CA167552; and R00CA215314) and directed research grant. Applied and Clinical Research of the American Cancer Society. The content is the sole responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.