• Our modern lifestyles are thought to damage our gut health in a way that raises the risk of colon cancer.
• Lifestyle changes can improve the gut microbiome, which could in turn lower the risk of colon cancer.
• As well as eating healthily, GI surgeon James Kinross eats enough vitamin D to prevent the disease.

Colon cancer is rising in people under 50. James Kinross, a gastrointestinal surgeon who researches how the gut microbiome affects our risk of the disease, told Business Insider that poor gut health could be partly to blame.

Research suggests the gut microbiome, the trillions of microbes that live in the digestive tract, has a wide-ranging effect on our health. But our sterile, urbanized lifestyles, appear to have made them less diverse overall and, therefore, weaker, according to Kinross, who is based at Imperial College London.

"You're seeing a generational loss in our internal ecology, which is being hammered with a series of environmental hits that it simply cannot adapt to," he said, referring to factors including microplastics, ultra-processed foods, and minimal access to nature. Many studies have linked these changes in the gut microbiome to an increase in colon cancer risk.

But, the gut microbiome is changeable, meaning there are things we can do to increase its diversity, which in turn could help lower colon cancer risk. "It is an ecosystem which you can adapt, and you can modify," he said.

Kinross previously shared with BI how he eats to boost his gut microbiome. He shared the three things he does aside from healthy eating to lower his colon cancer risk.

Don't take antibiotics if you don't need to

As a surgeon, Kinross is acutely aware that antibiotics are often necessary and save millions of lives each year, but he believes we use them too liberally — particularly to treat viral infections they can't tackle.

"In my house, to qualify for antibiotics, you've really got to have a pathogen that you need treated," Kinross said.

Kinross and his family limit their use of antibiotics as much as possible because taking them can disrupt the ecosystem of the gut microbiome, killing off good bacteria along with pathogens, and reducing diversity.

He likened it to pouring weed killer all over your garden. "Your garden won't really grow into a lovely garden full of wild meadows and flowers and color. It will just be brown and lifeless," he said.

Take vitamin D

Kinross takes a vitamin D supplement because evidence suggests that having enough of the nutrient is important for gut health.

Vitamin D is crucial for several biological processes, including calcium absorption and cellular repair — but also keeps the lining of the small intestine strong. If the lining becomes weak, microbes can pass through it into the bloodstream and cause inflammation. Chronic inflammation is linked to a higher risk of chronic diseases, including cancer.

Vitamin D is found in foods including oily fish, egg yolks, and red meat, as well as from sunlight. In countries with climates like the UK's, where Kinross lives, it can be difficult to get enough vitamin D in the colder months, and residents are advised to supplement from October to March.

Socialize

Kinross goes cycling with friends regularly and makes sure to sit down to eat dinner with his family in the evenings. As well as being a pillar of overall health, research suggests that socializing positively impacts the composition of our gut microbiomes, Kinross said.

We exchange microbes through physical touch, and studies have found that friends, family members, and spouses have similar gut microbes to one another.

A 2024 study published in the journal Nature, based on 1,787 adults from 18 isolated villages in Honduras, found that people in the same social network shared more similarities in their gut microbiomes compared to those outside of it. This was regardless of diet, water sources, and medications. Spouses and people living together had the highest amount of microbial sharing, but the phenomenon still occurred among friends and even friends of friends.

"Our social interactions, our real-world social interactions, define so much of our health," Kinross said. "It's good for all aspects of our health. It's good for our mental health, it's good for our cardiovascular health. It's good for everything. But if you're not having real-world social interaction, you are not really optimizing your gut health, I believe."

• Metformin is the most widely prescribed diabetes drug in the world.
• Scientists have noticed that people who take it may also get some colon cancer prevention benefits.
• Early research gives hints about how it might be used to help in colon cancer treatment.

A cheap, widely-prescribed diabetes drug that some doctors have called a "wonder drug" may hold promise as a colon-cancer-stopping supplement.

Scientists who presented at the American Association for Cancer Research conference in Chicago last week are studying how metformin — the most popular diabetes medication worldwide — interacts with tough-to-treat colon cancer cells. Their research is still early and ongoing.

"Metformin seems like it could have a really interesting supplemental approach to therapy," Holli Loomans-Kropp, a gastrointestinal cancer prevention researcher at The Ohio State University, who is leading the ongoing study, told Business Insider. "We're opening up some doors to what this could do."

Previous research has highlighted how people taking metformin for diabetes have lower colon cancer rates, suggesting the drug may be doing something protective to help prevent cancer from developing. This new study is one of the first to look at whether metformin can actually fight back against colon cancer cells once the disease develops.

Based on what Loomans-Kropp and her team have seen so far in cell culture dishes, metformin looks like it could become a helpful "supplement" to certain cancer treatment regimens in the future. It wouldn't be potent enough to treat cancer on its own, but could be used alongside other treatments.

She is especially excited about what it might do for a common type of colon cancer with a mutated KRAS gene, which tends to be very tough to treat. Her work, if successful, would require additional positive results in animals and then in people to become a prescription that oncologists can reliably use in the clinic.

A drug that changes how the body uses energy

One of the big benefits Loomans-Kropp sees to studying metformin for colon cancer treatment is a practical one — it's a drug that's already widely accessible and affordable.

"I always like to ask the question: are there medications or agents that we already know, that are already used, that we have safety/toxicity profiles for, that we can then repurpose for something else?"

Metformin has been studied and used by millions of patients worldwide. And it's cheap — an off-patent, generic drug that costs about 10 to 20 cents per pill.

It's sometimes referred to as a "wonder drug" by doctors for the beneficial effects it may have on patients who take it, beyond blood sugar control. Scientists have studied it for heart health, cancer prevention, and dementia.

Metformin works for diabetes because it changes the way the body processes and produces sugar. Some scientists suspect it may hold promise for improving aging for a similar reason: because it regulates how the body uses energy, and encourages more self-eating (autophagy), much like exercise or fasting. Perhaps metformin could also inhibit the ways that colon cancer finds energy to grow and develop.

"If metformin maybe can be used to redirect or change how the cell uses energy, which then ultimately changes how it divides and how it proliferates, this could be a mechanism to exploit," Loomans-Kropp said.

It's this same energy-shifting mechanism that has longevity researchers excited about metformin as a tool for disease prevention.

Dr. Nir Barzilai, a leading longevity researcher who suspects metformin may be beneficial for healthy aging, says he thinks metformin may be a "suitable" option for cancer prevention. When it comes to fighting cancer, he agrees with Loomans-Kropp that more study is needed.

"Let the science lead," he told Business Insider in an email.

Loomans-Kropp is hoping that if these initial cancer cell results are successful, she can begin testing metformin as colon cancer treatment on animals within a year.

• Naiké Vorbe, 42, experienced abdominal pain for years and went on multiple diets.
• At 31, she learned she had a genetic predisposition for colon cancer and was diagnosed at stage 3B.
• After learning about the genetic risks, Vorbe's mom was diagnosed early with stage 1 uterine cancer.

For years, Naiké Vorbe tried to ease her abdominal pain. A dietitian advised her to cut gluten and lactose, but nothing worked.

Stomach discomfort wasn't new for her: throughout most of her adult life, she cycled from being constipated to having diarrhea. "I was constantly one or the other," Vorbe, 42, told Business Insider. When she was pregnant with her second child, she saw a gynecologist. Her bowel movements were explained away as common pregnancy symptoms.

Then the pain intensified. After she gave birth to her daughter, "going to the bathroom was more excruciating for me than giving birth," Vorbe said. She kept touching her stomach, knowing that something was wrong. Lying down, she felt a lump.

Shortly after, Vorbe, who lived in Haiti, booked an appointment with a GI. He immediately told her to fly to Miami from Haiti and see a specialist for colon cancer at the Sylvester Comprehensive Cancer Center at the University of Miami.

At 31, two months after giving birth, Vorbe was diagnosed with stage 3B colon cancer.

Fighting for her fertility

In 2014, a few weeks after her colonoscopy revealed a malignant tumor, Vorbe underwent surgery to get part of her colon removed. Months later, the cancer spread to her liver.

Vorbe had no idea what her immediate future would look like. She had a six-year-old daughter and a newborn back in Haiti, along with the rest of her family. Her then-fiancé (now husband), a film director, was traveling a lot for his first movie.

She said she asked her doctor to end her chemotherapy appointments on Thursdays, so she could fly back to Haiti on Friday and stay through Monday to be with her older daughter for the next 10 days. Then, she'd repeat the process.

Zooming out even more, she was concerned about how chemotherapy would affect her fertility. She wanted more kids, so she asked her doctor if she'd be able to have children after treatment.

She said he told her that saving her life was the priority. "But for my life to be worth it, I need the answer to this," Vorbe told him.

He connected her to a gynecologist who administered a gonadotropin-releasing hormone (GnRH) every month, which temporarily suppressed ovary function and reduced the risk of chemotherapy-induced infertility.

Vorbe described him as a "big angel" in her life. "Every ball I threw at him, he worked with me," she said.

She did 12 rounds of chemotherapy. After her 4th, she was scheduled to have part of her liver removed. She took a break from chemo for a few weeks to recover, marrying her husband back in Haiti. When she returned, the tumor on her liver was gone. The part was still removed out of caution, but when it was dissected, no traces of cancer could be found.

Vorbe wanted to quit chemotherapy earlier, now that the tumors were gone. Her doctor insisted on 12 cycles, to give her the best chance of long-term survival. Dr. Daniel Sussman, Vorbe's physician and a gastroenterologist at the University of Miami Health System, told BI that in 2014, when Vorbe was treated, 12 cycles of chemo was "probably considered what was necessary" to increase the likelihood of successful treatment.

An underlying genetic risk

As a child, Vorbe remembers having unexplained stomach pain. Her father would take her to the doctor to be tested for worms and parasites. When she developed the lump in her abdomen as an adult, a gynecologist initially told her to try an enema.

"I was overlooked and pushed to the side because I was so young, I looked healthy," she said.

Additionally, she said discussions around bowel movements are taboo in Haitian culture. "You don't really speak about gastrointestinal issues."

When she was diagnosed with colon cancer, she took a recommended gene panel and learned she had Lynch syndrome, a symptomless genetic condition that raises the risk of developing colon cancer. She wondered if her grandmother, who died at 48, had it, too. "Nobody ever understood that's what happened to her," Vorbe said.

Sussman, who specializes in Lynch syndrome and was involved in diagnosing Vorbe, said that because the field of genetics is so young, entire families may have unknown genetic predispositions for certain cancers. Naiké "ended up being that first person in the family to undergo that genetic evaluation," he said.

Her mom was diagnosed with uterine cancer earlier

Vorbe, now a mom of five, has been in remission for 10 years. As a former colon cancer patient, she gets the recommended yearly colonoscopies. She also gets an endoscopy every two years, as Lynch syndrome puts her at risk of developing other cancers.

She said learning about Lynch syndrome not only helped her understand her diagnosis better. It also helped her mom, who carries the same genetic risk, to get diagnosed with uterine cancer early.

Her mother had a polyp in her uterus that was left alone because it hadn't grown over the years. When she told her gynecologist that Vorbe had Lynch syndrome and was being treated for colon cancer, her doctor immediately scheduled a biopsy. Vorbe's mother was diagnosed with stage 1 uterine cancer and had her uterus removed.

Vorbe said her family is what kept her going through treatments. She remembers thinking "There's no way I can die: I have these two beautiful little girls right in front of me. I want to see them grow up."

Despite being over a two-hour flight away, her family buoyed her throughout her recovery. Her godmother flew with her to her first chemo appointment. Her cousins flew to Miami to be in the house after the appointment, to cheer her up. In Haiti, her sister-in-law would care for Vorbe's baby overnight, then bring her to Vorbe in the morning.

"I had so much love and light around me, it just carried me," Vorbe said.

• More people under the age of 50 are developing colon cancer.
• James Kinross, a colon cancer surgeon, said changes to the microbes in our gut could be a contributing factor.
• Following a vegetarian diet is one of the ways Kinross tries to reduce his risk of colon cancer.

Rates of colon cancer in people under the age of 50 are rising. James Kinross, a GI surgeon who researches how the gut microbiome affects our risk of the disease, believes "an internal climate crisis" among people in Western countries could be partly to blame.

But "the gift of the gut microbiome is that you can change it," said Kinross, referring to the trillions of microbes that populate our digestive system, and which research suggests have a wide-ranging affect on our health. "It is an ecosystem that you can adapt," the researcher at Imperial College London told Business Insider.

To lower his own risk of developing colon cancer, the second deadliest form of cancer disease in the US, Kinross follows dietary principles including eating a vegetarian diet. However, as BI has previously reported, a person's diet is just one piece of the puzzle when it comes to colon cancer risk.

Environmental factors such as ultra-processed foods, the use of antibiotics, which kill gut bacteria, microplastics, and limited exposure to nature, are thought to have made our gut microbiomes less diverse, he said. That means it's less healthy and resilient.

He gave the example of a child who is born by C-section, which means missing out on microbes that would have been passed on via the birth canal, to a mom whose gut microbiome is depleted by antibiotics, and fed a diet of ultra-processed foods, he said.

"You're seeing a generational loss in our internal ecology, which is being hammered with a series of environmental hits that it simply cannot adapt to," Kinross said.

The consequence is "a very unhappy microbiome," which produces harmful molecules and toxins that affect colon cancer risk, he said.

Kinross shared how he eats to lower his risk of colon cancer.

Eat 30 grams of fiber a day

"What I really want in my gut is diversity," Kinross said, "and the way you get that is by having a really good diverse diet which is really high in fiber."

Fiber is found in plant foods such as fruits, vegetables, nuts, seeds, legumes, and whole grains, and studies suggest that a diverse gut microbiome is linked to a range of health benefits, such as a strong immune system.

Kinross aims to eat 30 grams of dietary fiber a day, as recommended by the Food and Drug Administration. He tries to "eat the rainbow," ensuring that his plate is filled with plant foods of lots of different color and, therefore, nutrients.

Follow a vegetarian diet

Research has found a strong link between eating processed and red meats and colon cancer risk, so Kinross tries to follow a vegetarian diet as much as possible.

One 2020 study published in the International Journal of Epidemiology looked at data from around 500,000 people over a seven-year period to assess whether eating meat affected their cancer risk. It found that those who ate 79 grams of red or processed meat, or the equivalent of three slices of deli meat per day on average, had a 32% higher risk of colon cancer compared to those who ate less than 11 grams.

In 2015, The International Agency for Research on Cancer, the cancer research agency of the World Health Organization, classified processed meat as a "definite" cause of cancer, and red meat as a "probable" cause.

"I don't necessarily believe that we all have to be vegetarian, but I think meat consumption is a big part of our problem," he said, referring to rising colon cancer cases.

Eat fermented foods daily

Fermented foods, such as sauerkraut, kefir, and kombucha, contain probiotics, the "good" bacteria that live in the gut.

Kinross eats a serving of them daily, as research suggests they can improve the diversity of the gut microbiome. A 2021 study by Stanford University found that people who ate a diet high in fermented foods for 10 weeks had even more diverse microbiomes than those who ate a high-fiber diet.

His go-to's are sourdough bread and kimchi, a Korean fermented cabbage dish.

"My daughter's completely obsessed by kimchi. She makes loads of it. So we've always got a big bucket of it in our house," he said.

"They've got to be part of your regular food consumption, otherwise, the microbes just don't culture and graft into your gut," he said.

• Katie Couric has advocated for colon cancer awareness since losing her husband to the disease in 1998.
• He was diagnosed at 41 years old, with symptoms like fatigue and digestive changes.
• Detecting colon cancer early is key to treatment, and innovations in AI and blood testing could help.

When Katie Couric's husband, Jay Monahan, was diagnosed with colon cancer at 41 years old, it came as a complete shock. By the time he was diagnosed, the cancer was stage 4. He died nine months later, weeks after his 42nd birthday.

"Colon cancer didn't even cross our minds. He of course had symptoms, and in hindsight, I wish we had known what they were," Couric told Business Insider.

Monahan had been tired, but that was understandable — he was a busy lawyer and legal analyst for NBC News and a parent to their two daughters. That fatigue, along with some digestive changes, were vague symptoms of his illness. They're common early signs of colon cancer that can be easy to miss.

At the time of his diagnosis in 1997, the recommended age for having a colonoscopy was 50. Now, it's 45 — changed in 2021 in response to a concerning rise of colon cancer among younger people.

Since his death, Couric said, she's made it her mission to help others catch colon cancer before it was too late.

"Two of the worst words in the English language are 'what if.' You don't want to be wondering, 'What if I had gotten screened?' when it's too late," Couric said. "I hate to be that blunt, but it's true."

Couric spoke to BI during Colorectal Awareness Month as part of her partnership with Cologuard Classic by Exact Sciences, a PGA tournament to support patients and caregivers affected by the disease.

After 27 years of advocacy, Couric shared what she now knows about how to spot colon cancer early and new breakthroughs that could transform how people are diagnosed and treated.

Early warning signs of colon cancer to watch for

There's been a disturbing increase in colon cancer diagnoses in people in their 20s, 30s, and 40s over the past two decades.

Potential factors like diets high in processed foods and red meat, drinking habits, and microplastics could all be driving the rising rates of colon cancer in younger people.

Couric said she's grateful that there's now more awareness of major symptoms of colon cancer, such as:

• Fatigue
• Unintentional weight loss
• Changes in bowel habits
• Blood in stool

One reason colon cancer is misdiagnosed or missed is that symptoms can be vague and attributed to other digestive illnesses.

While the recommended age to start screening for colon cancer was lowered to 45 in 2021, Couric said she finds it "very disturbing" that only about 20% of people between 45 and 49 have been screened.

"If you or someone you know falls into that category, please get your butt to the doctor!" she said.

Before a colonoscopy, you can try an at-home stool test

But don't wait for a blood test or other future innovations if you're worried about your risk now. Colon cancer is very treatable when detected early, so getting screened is crucial.

Colonoscopies are one option, especially for people with known risk factors such as a family history of colon cancer or polyps or digestive diseases such as inflammatory bowel disease.

Another less-invasive option for people with average risk is a stool test, which can be done at home.

"I've learned the best test is the one that gets done, so do your research and figure out what works best for you," Couric said.

She said her advice is to pay attention to anything out of the ordinary, get medical attention, and advocate for yourself at the doctor's office.

"The important thing is to talk to your doctor, and if your doctor isn't taking either your symptoms or desire to get screened seriously, find another doctor, preferably a gastroenterologist," Couric said.

2 scientific breakthroughs could help prevent colon cancer

Major scientific breakthroughs in diagnostic blood tests and innovations driven by artificial intelligence could prevent colon cancer and make it more treatable than ever, Couric said.

"I'm excited to see the capabilities that AI will have on new treatments and screening opportunities," Couric said.

The FDA approved a first-of-its-kind blood test for colon cancer screening in 2024. It works by detecting warning signs in the blood, such as DNA shed by tumors, although it's not a substitute for other screening such as colonoscopies.

AI is already being used to further colon cancer research. It can organize datasets so scientists can better understand the difference between healthy and diseased cells, leading to breakthroughs like the "gut atlas," a map of 1.6 million cells that make up the most comprehensive look at the human digestive system to date.

The technology could eventually make screenings more accurate by helping doctors spot polyps and other abnormal growths, although more refinements are needed to reduce AI-related false alarms.

• Shannin Desroches was diagnosed with stage 4 colon cancer at 26 years old.
• Desroches, who's active and eats a clean diet, was initially told she likely had a gluten allergy.
• After feeling dismissed, she booked her own scans and was diagnosed with cancer.

A little over a year ago, Shannin Desroches started buckling over in pain after every meal.

She was an active, 26-year-old woman following a clean diet, so her family doctor in Ontario suspected it could be a gluten allergy or celiac disease, ordering bloodwork to confirm.

The tests came back negative. She pushed for more, like a CT scan. Because Canada's healthcare system is public, wait times were longer. The CT scan she was scheduled for was a year out, in October 2024.

In the meantime, she tried to mitigate her extreme abdominal discomfort by eating smaller snacks. Still, she was frequently constipated, had pencil-thin stools, and felt a nagging pain in her left side.

"No matter what I ate, I was in excruciating pain, pretty much yelling for help," Desroches, now 27, told Business Insider. "I knew with my symptoms I wasn't going to make it" to the scan, she said.

Desroches was eventually admitted for an emergency colonoscopy in early 2024, but the procedure couldn't be finished — the tumor in her colon was too big. The GI specialist "couldn't get the camera through," she said.

She was diagnosed with stage 4 colon cancer, given a three-year life expectancy. She's part of the growing demographic of young people developing colorectal cancer, and wishes colonoscopies were more routine for people under 45 — the recommended minimum age.

"If I had a colonoscopy done, I could have caught this even in stage 2 or 3," she said. "That's the most frustrating part to me, knowing that I shouldn't have to be here fighting stage 4."

From dismissal to emergency surgery

Desroches started with an MRI in April 2024, which she managed to book thanks to the help of a family friend. When she left the room, her family friend and a GI surgeon were waiting for her. "They were like, 'I don't want to freak you out, but we need to admit you, you have a blockage,'" she said.

A colonoscopy the next morning confirmed it was a tumor, and she was immediately admitted to a six-hour surgery, which removed part of her large intestine where the tumor was located, her right ovary, 13 lymph nodes, and part of the membrane lining her liver. The surgeon couldn't remove the large tumors on the liver itself without causing liver failure.

When she woke up in the morning with her husband by her side, the surgeon broke the news: she had stage 4 cancer. If they wanted children, the doctor recommended starting egg retrieval from her left ovary right away, because the cancer was likely to spread quickly.

"I remember just almost disassociating," Desroches said. Once the doctors left, she and her husband broke down. "We just had a good cry together and just bawled."

Searching for care options

Desroches decided to pursue immunotherapy, a specialized treatment that trains her immune system to attack the cancer cells in her body, alongside two chemotherapy drugs.

Chemo became complicated. On round 13 of receiving oxaliplatin, a chemotherapy drug, Desroches went into anaphylactic shock, and had to stop taking it.

"It was probably the scariest feeling I've ever felt, knowing that my body is literally shutting down on me," she said.

So far, the results of her treatment make her nervous: her CT scan in January was the first one in which her tumors didn't shrink. She doesn't know what to anticipate for her next one, in April.

In the meantime, Desroches is searching for other options. The surgery she needs, a hepatic arterial infusion pump to deliver chemotherapy drugs directly into her liver, is only available as a clinical trial in Canada — one she doesn't qualify for because she has cancer outside her liver.

The procedure is more routine in the US, but her oncologist said the treatment could cost $500,000 or more when considering testing, a US hospital stay, and treating any complications — something that isn't financially feasible for her.

She's now looking into options in Europe and started a GoFundMe page for her cancer treatments. "It's very overwhelming, but when you're in fight-or-flight mode for your life, it doesn't matter," she said. "You just do it."

Focusing on the future

Since starting treatment in 2024, Desroches and her family are trying to stay optimistic.

In October, Desroches married her husband, Cody Desroches, at a beachside wedding in Jamaica. "I would do anything to go back to that day," she said.

They're planning to have kids, too.

A week after her surgery, Desroches met with a fertility doctor to begin her egg-freezing process immediately. "This was the most pain I've ever been in," she said. She was nauseous from the hormone injections, dry-heaving so hard that she felt her surgical staples would rip open.

After her surgeries, she said she'll never be able to carry her own child, but hopes she and her husband can use a surrogate one day.

It's hard to picture her future, she said. "It's just natural when you're at this age — you're always thinking about what's next," whether it's planning a trip, renovating her house, or having kids. At the same time, she never knows if she can commit to a family gathering or if she'll feel too sick to attend.

She savors every moment with her loved ones, a contrast to her "busybody" life as a nurse prior to cancer treatment.

"I try not to focus on that three-year mark because that's just a statistic," she said. "That's not me."

• Colon cancer cases are on the rise, including in people under 45.
• Early symptoms include bloating and abdominal pain, which can be confused with GI disorders.
• Doctors shared why colon cancer can be misdiagnosed, and when to get a colonoscopy.

Years before she was diagnosed with colon cancer at 40, Tracy Robert chalked up her bloating to an IBS diagnosis. She was a personal trainer and nutrition coach who followed a clean diet but felt constantly uncomfortable.

"I remember feeling a sense of heaviness when I would go to the bathroom," Robert, now 50, told Business Insider.

She says she wishes doctors took her "symptoms and concerns seriously." She believes if they had screened her for colon cancer sooner, they might have caught it before it reached stage 2B-3A. By the time Robert was diagnosed, she needed to have part of her large intestine removed, replaced by a colostomy bag.

Robert's story is not uncommon. More people are being diagnosed with colon cancer under the age of 45, the age at which Americans start getting screened for it. In our peer nations, like Canada, screening starts at 50.

Symptoms that might warrant earlier testing can be easily overlooked. Common signs of colon cancer, like constipation or diarrhea, can also be caused by GI-related issues like celiac disease or gluten intolerance.

Take Shannin Desroches, a 27-year-old from Ontario, Canada who buckled in pain after every meal. She was pursuing bloodwork to check for celiac disease, but her symptoms got too severe and she checked into urgent care. Tests revealed multiple tumors throughout her body. At 26, she had stage 4 colon cancer.

For doctors, it's a tricky tightrope to walk when they're diagnosing young patients. About 45% of Americans have digestive issues, many of which have crossover symptoms with colon cancer. Because colonoscopies cost around $2,000 on average, doctors typically won't urge young patients to get a colonoscopy without serious symptoms or a family history of colon cancer.

As colon cancer rates continue to rise worldwide, being able to tell the difference can change the trajectory of a patient's treatment.

Early colon cancer symptoms can be mild

The most common colon cancer symptoms in people under 50 include abdominal pain, altered bowel movements, constipation, bloating, and diarrhea. In many cases, like Desroches', severe symptoms don't show up until later stages.

Depending on where the tumor is, those symptoms might be very mild at first, Dr. David Richards, a gastroenterologist at the MD Anderson Cancer Center, told Business Insider.

If a tumor grows in the center of the colon, it might go undetected or produce mild discomfort. "It hasn't yet gotten big enough or invaded into adjacent structures enough to start really causing symptoms," Richards told BI. On the surface, it might look like a gluten allergy or gastrointestinal issue.

Dietary changes can temporarily improve cancer symptoms

People diagnosed with GI disorders are often advised to make dietary changes.

Desroches started trying to offset her symptoms by eating smaller snacks, but her stools remained thin and she had constant pain in her abdomen. Robert, who was diagnosed with IBS at 20, remembers being told to "eat more fiber."

For some people, diet tweaks can temporarily reduce symptoms of colon cancer, creating "a false-positive response to diet change," Dr. Mohammed Najeeb Al Hallak, an oncologist specializing in GI malignancies at the Karmanos Cancer Institute, told Business Insider.

For example, following a gluten-free diet to treat celiac disease can make stools firmer by reducing inflammation in the small intestine. Less inflammation can also lessen colon cancer symptoms, he said.

If a person has colon cancer, he said these positive changes are temporary — and may delay the diagnosis.

How to spot the difference between colon cancer and digestive issues

The medical community is still debating about the best age to start annual screenings. Research on rising rates changed the recommended screening age from 50 to 45. "Some people argued about lowering it even more because we've been seeing colon cancer popping up more often in younger populations," Richards said.

If you're under 45, there are some "alarm symptoms" to look out for. Anemia, bright red or black stools, unexplained weight loss, trouble swallowing, and fever are all signs to take your symptoms more seriously.

Al Hallak said to always get a second opinion if you feel dismissed by your doctor. For example, celiac disease requires a biopsy and blood tests to confirm the diagnosis — never accept "it's probably celiac" without those tests. See someone who takes your pain seriously, especially if the symptoms don't improve.

• Increasingly, young people with clean diets and healthy lifestyles are getting colon cancer.
• Doctors say diet plays a role in the rising risk, but doesn't tell the whole story.
• We are learning more about ways microplastics, sleep cycles, and our environment may play a role.

At 30, Chris Lopez was hitting his stride. He was attending culinary arts school in Dallas. He was meal prepping and hitting the gym regularly, focused on getting a degree and setting up his life right.

His symptoms were easy to dismiss, at least at first. "I had a real bad stomach ache that was going on for about a month," he told Business Insider. "I thought, 'Oh, maybe I ate some sushi, some fish or something that was undercooked.'"

Except food poisoning doesn't typically last for weeks on end, and doesn't leave blood in your stool. He rapidly lost weight, from 175 pounds to 145 in a single summer — without eating less. "I was pretty much like a skeleton," he said.

Lopez went to his doctor, who eventually decided to do a colonoscopy to learn more. That's when they discovered a "grapefruit-sized" tumor in his colon, he said. Lopez saw the scan and couldn't believe his eyes. Colon cancer? He was so young, healthy, and fit.

Stories like Lopez's are increasingly common. Colon cancer rates are rocketing among athletic young people in their 20s, 30s, and 40s, and survival rates are dropping.

Take Chris Rodriguez, a 37-year-old improv actor and CrossFit enthusiast who adheres to a high-fiber, high-protein diet, with plenty of veggies. He was 35 when he was diagnosed with stage 3 rectal cancer.

"The question pops in your mind, 'What else was I supposed to do?'," Rodriguez told BI. "That's really the unfortunate thing with a diagnosis like this, is there isn't really much else that you're supposed to do, outside of looking for symptoms."

The most convenient explanations for the rise in young colon cancer are diet and weight. We know diet can influence colorectal cancer risk, and it's something people can fix, to a degree. Plus, our diets have changed. These days we all consume more sugar, more ultra-processed foods, more oil and butter, while moving less.

Still, doctors say the trend we're seeing now defies neat categories of genetics or lifestyle, and it's baffling. Other factors are clearly messing with our digestive systems, but they're tough to pinpoint. Pollution, microplastics, and artificial light — all are pervasive in society, yet very tricky to study.

Thanks to recent research, we are starting to get a better picture of why young colon cancer cases are rising, and we're on the cusp of some pretty big results that may uncover better ways to prevent and treat it.

Young colon cancer is getting deadlier and more common

Something shifted in the 1960s. Everyone born after 1960 has a higher colon cancer risk than previous generations. This phenomenon is known as the "birth cohort effect."

"The rise that we're seeing cannot just be accounted for by inherited differences," Dana Farber colon cancer researcher Dr. Marios Giannakis told BI.

In the US, young colon cancer rates have been rising about 3% every year since the early 1990s, according to National Cancer Institute data.

"We do think since genetics haven't changed, the cancers that are increasing are environmentally based," Dr. William Dahut, the chief science officer at the American Cancer Society, said during a recent briefing to reporters. "Exactly what's doing it is really — more research is needed."

The biggest cancer centers in the US are opening units to investigate this trend. In 2018, Memorial Sloan Kettering in New York opened a first-of-its-kind center for "young-onset" colorectal cancer patients. Dana Farber in Boston, Mass General, MD Anderson Cancer Center, and Columbia University Irving Medical Center followed close behind, all opening special programs for young colon cancer cases.

In 2021, the CDC took action, lowering the age of recommended colon cancer screening from 50 to 45. It's an effort to catch more young colon cancer cases sooner, upping the odds of people surviving.

It isn't a uniquely American issue. Wealthy countries, in particular, are seeing similar spikes. New Zealand, Chile, Norway, and Turkey are among 27 countries recording record-high rates of young colon cancer.

Diets matter — to an extent

It's hard to dismiss the role our changing food landscape has played. We are undoubtedly eating worse than our grandparents did 100 years ago.

Take fiber, for example. Found in abundance in whole plant foods like beans, it is a nutrient clearly associated with lower risk of cancer.

Some of the most popular foods in US supermarkets — prepackaged for our convenience — tend to have fiber stripped out during processing, and extra salt, sugar, and oils added in to make them more palatable and shelf-stable.

It started in the aftermath of World War II, when industrial processing and factory farming took hold nationwide.

"Essentially we redeployed what had allowed the United States and allies to prevail in that war to non-military applications, and it completely transformed agriculture," Dr. David Katz, a leading expert in chronic disease prevention and nutrition, told BI.

"You only have a certain total number of calories you can eat per day, and if a higher percentage of those is made up of hamburgers and Pop-Tarts, then a lower percentage ipso facto is made up of lentils and all the other good stuff."

Ultra-processed foods now account for a significant proportion of what we eat. Excess sugar, salt, and chemicals lurk in pasta sauce, breakfast cereals, and salad dressing. Brown bread labeled "heart healthy" can have a higher sugar content than white Wonderbread.

Upsetting the balance of nutrients in our guts has consequences. Compounds that aren't necessarily harmful in moderation, like omega-6 fatty acids from seed oils, take up a disproportionate part of our diets. That can lead to inflammation, infection, and diseases like diabetes, heart disease, and, yes, colon cancer.

Your microbiome is not just about what you eat. It's influenced by myriad factors, from how you were born to your work schedule.

What else is going on?

Doctors and lab scientists who spoke to BI for this story all said the rise in millennials getting colon cancer likely won't be attributed to one single thing.

Shuji Ogino, an epidemiology professor at Harvard Medical School, has been studying young colon cancer cases across the world. He published a study in Nature that showed the early life "exposome" — diet, lifestyle, environment, exposures — has changed dramatically, becoming conducive to cancer.

We've introduced lots of new things to our environment without knowing the ramifications. Now, we're starting to see the long-term effects.

Something as simple as artificial light could play a role. "That's something no human being experienced 200 years ago," Ogino said. Lights allow us to work and socialize at all hours, impacting how our body clocks regulate hormones and metabolism.

Dr. Heinz-Josef Lenz, co-lead of the gastrointestinal cancer program at the University of Southern California cancer center, is also studying how the environment may be damaging our DNA in ways we don't yet understand.

His data so far suggests the trend of more younger folks developing colon cancer isn't genetic, but our genes may affect how we respond to our exposures — the processed food we eat, the antibiotics we take, and the polluted air we breathe.

"When you are 16 years old or 20 years old, you cannot blame it on diet or exercise or obesity — it's just too short," he said. "We're just scratching the surface on better understanding the impact of the parents, particularly in the young onset: was their exposure part of it, or not?"

Here are five things we're learning:

1. Sleep cycle

We can't separate gut health from our internal clock.

Gut bacteria help regulate sleep, which cuts cancer risk.

Emerging evidence suggests that disrupting the circadian rhythm creates problems in the gut that can contribute to colon cancer, according to studies in mice and data in humans. Our sleep can be derailed by late schedules and artificial light from our homes and phones, which may be one factor in rising colon cancer cases.

2. Microplastics in air and water

Increasingly, researchers are finding evidence that microplastics play a negative role in fertility.

They can also be pro-inflammatory, driving diseases like cancer and obesity, hurting lungs, and possibly helping cancer to thrive in the body.

A new evidence roundup from researchers at UCSF analyzed 22 studies that compared microplastic exposure to health problems in mice and people, and found that all of them showed some harm.

"We basically saw this continuous effect that the more you get exposed to it, so in our environment, the more it gets produced, the greater the health harm," Nicholas Chartres, one of the study's authors and a former head of the science and policy team at UCSF's program on reproductive health and the environment, told BI.

Chartres says the time is now to act to reduce our microplastic exposure, and it must be done at a policy level. At home, Chartres runs around the house throwing out his kids' plastic toys, but he knows he's playing a losing game of environmental whack-a-mole.

"We don't need to have specific quantification of the level of harm, there's enough here to show that they're certainly contributing," he said.

3. What your parents were exposed to

Lenz is conducting research that aims to unravel why so many Hispanic patients in Southern California seem to be especially at risk of developing early colon cancer.

His team is studying cancer patients' blood, DNA damage, lifestyles, and ZIP codes to pinpoint where their exposure risks might be coming from, whether it be overuse of antibiotics, pollution that families are exposed to, or something else.

"It could be an epigenetic event, not only from the patient itself but from the family, from the parents and their exposure," he said. "Epigenetics can be influenced by lifestyle and by exposure to chemicals, or whatever it is that will actually react."

4. Antibiotics

It is well established that antibiotics disrupt the gut microbiome, killing off some beneficial bacteria. And humans aren't the only antibiotic consumers.

Most of the antibiotics (73%) in use worldwide are for meat production, recent research suggests. Some meat advertised as antibiotic-free has failed independent testing.

Red meat consumption ups a person's colon cancer risk, and so does antibiotic use, but these two factors aren't necessarily separate.

5. C-section

Newborns are exposed to trillions of their mother's microbes as they travel through the birth canal, giving an infant's microbiome an initial boost. Kids who are delivered through the abdomen via cesarean section don't get those same health benefits.

Recent research from Sweden suggests girls who are born via c-section have a higher risk of developing young colon cancer than those born vaginally.

Major colon cancer discoveries coming in 2025-2026

In 2024, a group of international researchers mapped 1.6 million cells in the gut to create the most comprehensive picture to date — the "gut atlas."

"It's rare that any one study squeezes out all the relevant biological insights," Ivan Vujkovic-Cvijin, a professor of medicine at Cedars-Sinai Medical Center, who was not involved in the study, told Business Insider.

"By identifying which components of tissue function are dysregulated in disease, the scientific community can design drugs to restore those functions," he said.

There's more to come. Multiple big, well-funded multinational studies are underway, including a US-UK collaboration that's giving out interdisciplinary cancer grants to teams around the world. The studies are expected to release results this year and next.

2 ways to reduce your risk today

Until we know better what's going on, researchers and clinicians say there are two steps you can take to reduce colon cancer risk.

First, control what you can control.

"Let's focus on the stuff we can change," Dr. Cassandra Fritz, a gastroenterologist and colon cancer researcher at the Washington University School of Medicine in St. Louis, tells her patients.

That means no smoking, regular exercise, less alcohol, reducing your intake of ultra-processed snacks and processed meats, and no sugary beverages — factors directly linked with colon cancer risk. You could also consider microwaving food in glass or ceramic instead of plastic.

Second, know the signs of colon cancer and do not be complacent about them. Many young cases are diagnosed too late, making treatment complicated.

These four symptoms can occur up to 18 months before a colon cancer diagnosis:

• Abnormal diarrhea that lasts for weeks
• Persistent abdominal pain
• Bloody stool (red, magenta, or black)
• Iron deficiency anemia (determined by a blood test)

Don't fear the process of getting checked, experts told BI. Anyone dealing with these persistent symptoms can ask their doctor for a fecal immunochemical test (FIT) that is noninvasive and costs just a few dollars.

"If there are symptoms which could be associated with colon cancer, make sure you get the screening and don't just accept that they're saying 'It's unlikely' or 'I've never seen it,'" Lenz said.

When it's spotted early, colon cancer is a very survivable disease.

• The amount of calcium in a glass of milk could lower the risk of colorectal cancer, a study on women found.
• Many foods, including seeds, canned sardines, and figs, are high in calcium.
• The studies comes as cases of colorectal cancer in people under 50 rise in the US.

Consuming the amount of calcium found in a glass of milk could reduce the risk of colorectal cancer, according to a new study involving women.

That was regardless of whether the calcium came from dairy or non-dairy sources. Foods such as figs, leafy greens, and tofu are among the non-dairy sources of calcium.

In the study published on Wednesday in Nature Communications, the authors said this suggests calcium itself, rather than milk, was the main factor responsible for cutting the risk.

Using dietary and health data provided by more than 542,000 women with an average age of 59 over for around 16 years, researchers from Oxford University studied whether 97 foods affected colorectal cancer risk. They found that consuming an extra 300mg of calcium a day was associated with a 17% lower colorectal risk from the baseline. In the US, the lifetime risk of developing the disease is approximately 4.4% for men and 4.1% for women.

Calcium is commonly known as a mineral the body needs to build and maintain strong bones. But calcium may have a protective effect against colorectal cancer because it binds to bile acids and free fatty acids in the colon, which helps reduce their cancer-causing potential, the study said.

Colorectal cancer is the third-leading cause of cancer-related death in US men and the forth-leading cause in US women, according to The American Cancer Society. The rate of people being diagnosed with the condition has fallen since the mid-1980s, but in people under 55, rates have been increasing by 1% to 2% a year since the mid-1990s.

The link between colorectal cancer risk and diet is well-established, and experts recommending people cut down on ultra-processed foods and red meat, and instead eat plenty of fruits, vegetables, and whole grains. But the new findings could help provide even more targeted dietary guidance.

The study was observational, meaning the researchers didn't intervene in any way, and more research is needed to confirm a link between calcium intake and cancer risk.

"It is difficult to separate the effects of individual nutrients from an effect of milk per se," Tom Sanders, professor emeritus of nutrition and dietetics at King's College London, said.

"We already know that around half of all bowel cancers could be prevented by having a healthier lifestyle, and this new research supports this, with a particular focus on dairy," Lisa Wilde, director of research and external affairs at the charity Bowel Cancer UK, said. If you don't drink dairy milk, there are other ways you can get calcium and still reduce your bowel cancer risk, she added.

Americans should consume around 1,000mg of calcium a day, according to the Office for Dietary Supplements.

Here are six foods that are high in calcium, including some that might surprise you.

Seeds

Some seeds pack a punch when it comes to calcium content.

One tablespoon of sesame seeds, for example, contains 100mg of calcium, while one tablespoon of poppy seeds contains 127mg or around 10% of the daily recommended amount.

They are also high in other nutrients such as fiber and healthy fats.

Whey protein

As well as being high in protein and helping to promote muscle growth, whey protein powder is very high in calcium.

A 1.2-ounce scoop of whey protein powder isolate contains about 160 mg or 12% of the daily recommended amount.

Leafy greens

Leafy greens are rich in many nutrients, including calcium.

One cup of cooked collard greens has 268 mg of calcium, or about 21% of the amount the average person needs in a day. And kale has around 250 mg of calcium per 100g, which is more than the 110mg in 100g of whole milk.

Spinach and chard contain lots of calcium, but they also contain a group of molecules called oxalates that bind to calcium and make it unavailable to our bodies.

Tofu

Whether it's firm, soft, or silken, tofu is also a good source of calcium. 120g of the plant-based protein steamed or fried contains 200mg of calcium.

Edamame beans, which are young soybeans, also contain the mineral.

Canned fish

Canned fish is higher in calcium than fresh fish because it contains bones that have become soft through cooking and can be eaten.

Canned sardines and salmon are particularly rich in calcium, with 60g of canned sardines in oil containing 240 mg, while 85 grams of canned salmon with bones contains 19% of the daily recommended amount.

Figs

Dried figs contain more calcium than any other dried fruit. Just two figs have 100 mg or 10% of the calcium we need each day.

They are also high in fiber, copper, potassium, manganese, magnesium, and vitamin K.

• Colon cancer rates for people under age 50 are going up across countries both rich and poor.
• In the US, rates for older adults are declining, while early-onset colon cancer is on the rise.
• Scientists are starting to uncover clues about how modern diets and lifestyles play a role.

Colon cancer is quickly becoming a young person's disease in countries around the world.

A new study released Wednesday in the Lancet Oncology documents rising rates of early-onset colorectal cancer across rich, highly-industralized parts of North America and Europe, and in middle-income areas worldwide.

"We found this trend is not just about high-income, Western countries," lead study author and cancer researcher Hyuna Sung told Business Insider. "It reaches the parts we didn't see before, such as South America and Asia."

During the 5-year period from 2013 to 2017, colon cancer rates in young people went up in 27 of 50 countries Sung's team examined worldwide. Though the study only includes one country in Africa (Uganda), it is still some of the most recent, comprehensive data available on colon cancer rates around the globe. And it shows colon cancer rates spiking in young people living in countries like Turkey, Ecuador, and Chile.

The trend is not hitting all countries equally, though. While in the US, early-onset colon cancer rates continue to rise to unprecedented levels, there are outliers in the data, like Italy, Spain, and Latvia, where the rates appear relatively unchanged year over year.

"This study is quite expected," associate professor Ganesh Halade from USF Heart Health Institute, who was not involved in this study, told BI, while poring over the new data, and noting the rising rates across several continents. "Fundamentally, our diet is changed"

Halade's own colon cancer research, published earlier this week, identified how ultra-processed foods can fuel colon cancer, wreaking havoc on the immune system, and worsening inflammation.

"It's very obvious the way that this disease trend is going on right now," he said. "We need to go back and consider our diet, sleep, and exercise."

Why colon cancer is striking younger people in richer countries

It still seems to be the case that the richer a country gets, the more young people are at risk of developing colon cancer. Countries with some of the steepest gains in under 50 colon cancer cases in recent years include Australia, New Zealand, the US, South Korea and Japan.

"Children and adolescents in these highly industrialized and urbanized countries were probably among the earliest to uptake detrimental dietary exposures and sedentary lifestyles associated with economic wealth," the study authors wrote.

In other words, driving around in a car, sitting at a desk, and eating more convenience food every day for decades on end may not be great for our overall health, and might have some connections to these cancer trends. Once inflammation skyrockets, Halade said, cancer has an easier time both sprouting and thriving. His anecdotes? More sleep, movement, and home-cooked food.

There seems to be a pronounced uptick in the incidence of early-onset colon cancer among people born after 1950, suggesting that there are lifestyle and environmental exposures impacting Gen X, millennials, and Gen Z in ways their baby boomer parents and predecessors like the Greatest Generation didn't experience.

At the same time, thanks to more cancer screenings and less smoking, colon cancer rates in older adults are going down in many rich countries around the world, including the US, Canada, Australia, New Zealand, the UK, South Korea, and Israel.

What we eat and how we live matters, it seems

Scientists are still endeavoring to untangle exactly what is driving the early-onset colon cancer risk, but there seem to be some clear signals in the data about the food system we live in. Another new study released earlier this week suggested that our modern diets, filled with candy, sugary drinks, and processed foods, don't have enough of the healthy fats and nutrients our bodies need to keep cancer-driving inflammation in check.

Foods rich in omega-3, like leafy greens, fatty fish, nuts and seeds can help prevent the inflammatory processes that over time lead to cancer. But sweets, chips, sausages, and packaged cakes seem to fuel tumors, while also crowding out more unprocessed, healthier choices in our diets.

Still, food can't be the whole story. It's clear that a family history of colon cancer, as well as the unique dance your genetics and your environment play, have key roles in your personal level of colon cancer risk. Experts are looking into environmental factors like air pollution, microplastics, and more sedentary lifestyles for clues about what else may be driving the increase in young colon cancer.

• A new study offers more evidence linking cancer to inflammation from diets high in processed foods.
• Analysis found tumors were fueled by inflammatory compounds and a lack of compounds linked to healing.
• Researchers are looking to foods like leafy greens and fish to pinpoint disease-fighting molecules.

Ultra-processed foods may be fueling a rise in colon cancer cases — but healthy foods could unlock new ways to prevent or treat the disease, new research suggests.

Researchers from the University of South Florida and Tampa General Hospital Cancer Institute analyzed more than 100 tumor samples from patients. They were looking for compounds called bioactive lipids, molecules that can increase or decrease inflammation in the body.

The research team found that tumor samples contained a high proportion of these inflammation-causing compounds compared to healthy tissue.

Previous evidence has linked increased inflammation to diets high in processed food like chips, sausages, packaged desserts, and refined carbs.

Processed food shows up almost everywhere in our diets, and evidence increasingly suggests it's a factor in worsening health. At the same time, colon cancer cases are on the rise in younger people, and it's now the second-leading cause of cancer-related death in the US.

The researcher team also noted that the tumors were lacking in molecules associated with healing and lowering inflammation.

The inside look at the tumors could give scientists the tools to fight cancer by trying to balancing the body's immune response, slowing or stopping tumor growth by cutting back on inflammatory compounds and boosting healthy ones.

One source of these kinds of molecules is our diet, from foods like leafy greens and seafood rich in omega-3 fatty acids.

"If the molecules are coming from processed food products, they directly imbalance the immune system and drive chronic inflammation," Ganesh Halade, co-author of the study and professor at the University of South Florida Health Heart Institute said in a press release. "Our bodies are designed to actively resolve inflammation through bioactive lipid compounds derived from the healthy fats, like avocados, that we consume."

Fighting cancer with fish oil

The study, published December 10 in the journal Gut, is the first from a project funded by a five-year, $3.1 million grant from the National Institutes of Health.

The results are helping researchers better understand how food may influence cancer risk, Dr. Timothy Yeatman, senior author of the study and professor of surgery at the University of South Florida, said in a press release.

Cancer is like a "chronic wound that won't heal," and a daily diet of ultra-processed foods can make it harder for the body to fight off tumors because of the increased inflammation, Yeatman said.

While it's not news that spinach and seafood is better for you than doughnuts and soda, pinpointing the link between food and inflammation unlocks more effective strategies to stave off disease in the future.

For example, the Tampa General Hospital Cancer Institute has conducted early trials of a modified form of fish oil with promising results for reducing inflammation, according to the press release.

"This has the potential to revolutionize cancer treatment, moving beyond drugs to harness natural healing processes," Yeatman said. "It's a vital step toward addressing chronic inflammation and preventing diseases before they start."

In the meantime, there's evidence that your best bet for a longer, healthier life is sticking to a diet of mostly whole, unprocessed foods like veggies, fruits, legumes, lean proteins, and whole grains.