Experts
not involved in the study told Healthline that the findings back up
previous research on colorectal cancer risk in younger adults.
“There is a global epidemic with rising incidence of colorectal cancer in younger adults,” said Katherine Van Loon,
MD, a specialist in gastrointestinal cancer at the University of
California San Francisco. “Up to this point, there has not been a clear
explanation for the rising numbers, although we have a growing body of
literature that diet, obesity, and other environmental exposures may
contribute to the increased risks.”
“This study
elucidates another potential contributing risk factor for the
development of precancerous lesions in young woman,” Van Loon noted.
“This
study is in line with previous data showing a link between early onset
of [colorectal cancer] and the lifestyle connections associated with
this risk,” added Kristin Kirkpatrick,
RD, the president of KAK Consulting and a dietitian at the Cleveland
Clinic Department of Wellness & Preventive Medicine in Ohio. “This
is also consistent with previous data showing the general adverse impact
of a high consumption of [ultra-processed foods].”
“Overall,
this study adds to the growing evidence that high consumption of
ultra-processed foods may play a role in early colorectal cancer
development,” said a principal scientist in epidemiology research at the American Cancer Society.
“Although
further research is needed to confirm these findings and understand
underlying mechanisms, limiting ultra-processed foods and emphasizing
whole, nutrient-rich options align with current cancer prevention
guidelines,” Um said.
However, a specialist in general and colorectal surgery and chief of surgery
at Providence Saint John’s Health Center and an adjunct associate
professor of surgery at Saint John’s Cancer Institute in California,
noted these findings should be expanded to include males.
“One
cannot make the assessment that women are higher risk than men in
developing colorectal cancer from ultra-processed foods as this study
was only done in women and did not look at men at all,” Childs said.
For
the current study, the researchers analyzed the medical records of more
than 29,000 female nurses under the age of 50 who had participated in
the Nurses Health Study II.
The
study participants provided baseline data in 1991. They had follow-up
check-ins between June 1991 and June 2015. The median follow-up period
was 13 years.
The nurses reported on their food intake the previous 12 months via questionnaires they received every 4 years.
The
nurses in the study had an average age of 45 during the 24-year
follow-up period. They had undergone at least one lower endoscopy before
age 50 years after baseline and had no history of cancer — except for
nonmelanoma skin cancer — before their endoscopy.
The researchers examined the data thus gathered between October 2024 and July 2025.
For
this study, ultra-processed food intake was primarily from processed
breads, breakfast foods, sauces, spreads, condiments, and
sugar-sweetened or artificially sweetened beverages.
The
researchers reported there were 1,189 study participants who were
documented as having early-onset conventional adenomas and another 1,598
who had serrated lesions during the follow-up check-ins.
In their study, the researchers reported that
participants with the highest intake of ultra-processed foods, which was
described as about 10 servings per day, had a 45% higher risk of
developing adenomas by age 50 when compared with those with the lowest
consumption, which was classified as about three servings per day.
There was no association observed between ultra-processed foods and serrated lesions.
Experts
noted some limitations to this particular research besides the fact it
only involved women. They pointed out that the information was gathered
by questionnaire and that the definition of “ultra-processed” was
somewhat general in nature.
Um said that alcohol was included as an ultra-processed food in this study.
“Because
alcohol independently raises cancer risk, it would be helpful for
future studies to examine ultra-processed food intake with and without
alcohol,” she noted.
The Centers for Disease Control and Prevention (CDC) reportTrusted Source
there were nearly 150,000 cases of colorectal cancer in the United
States in 2022, the latest year for which statistics are available.
The
agency adds that more than 50,000 people died from the disease in 2023.
Men had a higher incidence and death rate than women from colorectal
cancer.
The American Cancer Society reportsTrusted Source
that the incidence of colorectal cancer has been declining in people 65
years and older. The incidence rate has remained stable for people ages
50 to 64.
However, the organization notes that
colorectal cancer cases have been rising about 2% per year for U.S.
adults ages 50 to 54 as well as those under the age of 50.
Previous research has concluded the obesity and diabetes are high risk factors for colorectal cancer in younger adults.
In addition, an April 2025 study reported that ultra-processed foods were linked to more than 120,000 preventable deaths per year in the United States.
The organization Food Tank estimates that 73% of the food supply in the United States consists of ultra-processed foods.
In addition, a 2022 study reported that almost 60% of the caloric intake of U.S. adults is ultra-processed foods.
Ultra-processed foods are described as mass-produced foods with a high level of industrially processed ingredients that are designed to ensure longer shelf lives.
Examples
include commercially produced breads, most breakfast cereals, flavored
yogurts, hot dogs, frozen meals, potato chips, soft drinks, and candy
bars.
The study authors said that “ultra-processed
foods are typically low in bioactive compounds, such as dietary fiber,
vitamins, and polyphenols, and high in unhealthy fats, refined starches,
and food additives such as emulsifiers and artificial sweeteners.”
They
said these ingredients “could disrupt gut microbiota, increase
intestinal inflammation, and contribute to colorectal carcinogenesis.”
Experts
agreed. “The concept is that ultra-processed foods change the
intestinal microbiome as well as enhance a pro-inflammatory environment,
increasing the risk of pre-cancerous changes, which then can lead to
early onset colon cancer,” said Childs.
“It’s also
important to note that many ultra-processed foods contain a wide variety
of additives, and we do not fully understand their effects on long-term
health,” said Um.
Van Loon added that ultra-processed foods can lead to weight gain, which can also raise the risk of colorectal cancer.
“There
is evidence from other research that ultra-processed foods promote
excess energy intake, which can result in rapid weight gain,” she said.
A healthy, balanced diet is a key factor in reducing the risk of colorectal cancer.
- nutrient-rich foods that help you maintain a healthy body weight
- a variety of vegetables and fruits in different colors
- whole grains.
The ACS also recommends the avoidance of:
- red and processed meats
- sugar-sweetened beverages
- highly processed foods and refined grain products
- alcohol.
Beyond diet, ACS recommends:
- maintaining a healthy body weight throughout life
- being physically active
- reducing sedentary time.
Other experts are in agreement with these guidelines.
“I
recommend a diet that is low in processed meats, low in red meat, low
in processed grains, and low in sugar,” said Van Loon. “Choose whole
grain breads and brown rice, and try to consume sugars from healthy
sources such as fruits and vegetables.”
Kirkpatrick recommended a goal of eating healthy foods 90% of the time and indulging in less healthy foods 10% of the time.
“It’s
not the frozen pizza that we may have once a month that does great
harm. It’s when the frozen pizza becomes dinner three times a week. The
greater the frequency of consumption of [ultra-processed foods], the
greater the risk,” she said.