Why is bowel cancer on the rise in young people?

Experts are calling it a ‘global phenomenon’. Rates of bowel cancer are increasing among younger adults, with some of the steepest rises happening in England. Incidence rates have increased by an average of 3.6% annually over the last decade, making it the fourth-sharpest rise after Chile, New Zealand, and Puerto Rico [1]. Even countries like Japan, renowned for their healthy diet, are seeing the same trend.

So, what’s going on?

In this article, we look at possible explanations, from ultra-processed foods to microplastics and antibiotic use.

Contents

• Background
• 5 reasons bowel cancer rates are rising
  • 1. Ultra-processed foods
  • 2. Excessive antibiotic use
  • 3. Microplastics and PFAS
  • 4. Sedentary lifestyles
  • 5. Not enough fibre
• Reducing your risk
• Bowel cancer screening

How are rates of bowel cancer changing?

Bowel cancer is the third most common cancer in the world, accounting for 10% of all cancers [2]. Every day in the UK, around 120 people are diagnosed with the condition, but perhaps what’s more concerning is that over half of these cases are preventable [3]. Factors like eating processed meat, getting too little fibre, and being overweight can all contribute to your overall risk.

Overall rates of bowel cancer are declining in the UK

Based on the shifts in our diets, you might expect rates of bowel cancer to be increasing, but overall in the UK, figures have remained relatively stable since the 1990s. In fact, the number of new diagnoses has actually decreased by about 6% in the last decade, and experts predict that rates will continue to fall over the next 10 years [3]. This is good news. But the trend isn’t so reassuring for younger adults.

Rates of bowel cancer in young people are increasing

The risk of bowel cancer increases significantly with age because of how the condition develops – the accumulation of cell DNA damage over time. This means it’s rare to develop bowel cancer in your 20s or 30s, but as the Never Too Young campaign highlights, bowel cancer isn’t just a disease of age.

Every year in the UK, about one in 20,000 people in these age brackets is diagnosed with bowel cancer [4]. For comparison, the risk is around one in 250 for people over 80. These low rates in young people have contributed to an age bias, where both patients and clinicians are less likely to consider bowel cancer as a possible diagnosis, which can lead to delayed detection and treatment.

While the absolute number of young people affected is still very low, rates have been increasing. Between the early 1990s and 2019, the number of new diagnoses made in people aged 25 to 49 has increased by 52% (figure 1).

This rise in cases raises an important question: what’s driving this trend?

5 possible reasons bowel cancer rates are climbing

Before delving into possible reasons for this trend, it’s helpful to understand a concept known as the birth cohort effect. This idea suggests that being born in a specific era — and being exposed to unique environmental or lifestyle factors at a young age — can shape how diseases affect us. For example, microplastics and ultra-processed foods are relatively recent phenomena, and early exposure to them could play a role in rising rates of early-onset bowel cancer.

No one can say for certain why rates are rising in younger groups, especially when the absolute number of cases is so low. It likely comes down to a combination of factors, but there are a few potential culprits.

1. A rise in ultra-processed foods

Back in 2000, just over 30% of our calorie intake in the UK came from ultra-processed foods (UPFs) [5]. These days, it’s around 57% [6]. It’s an even bigger problem for young people. A study of over 3,000 adolescents revealed that, on average, 66% of their calorie intake came from UPFs, despite the known harmful effects [7]. 

UPFs are foods made in an industrial setting to be convenient, cheap, and have a long shelf life. They’re often calorie-dense, nutrient-poor, and contain additives like artificial flavours, preservatives, and sweeteners.

When you think of UPFs, you might imagine a Big Mac or a Snickers, but the category also includes:

• Most breads (including multi-seed loaves and supermarket sourdough loaves)
• Breakfast cereals and cereal bars, including instant oats
• Plant-based meat substitutes
• Instant soups
• Margarine
• Sauces and condiments
• Protein bars and powders
• Processed meats
• Flavoured yoghurts
• Soft drinks
• Baby food
• And many more

Some UPFs, like sliced bread or mass-produced cakes, have been around for decades. But the proportion of our diets that contain UPFs has grown substantially [5]. For instance, a study on dietary patterns in Sweden found a 142% increase in UPF consumption between 1960 and 2010 [8].

The link between UPF consumption and bowel cancer isn’t as clear cut as you’d expect — it’s still early days in the world of research. UPFs could unfavourably alter the gut microbiome and some studies suggest they can lead to pre-cancerous changes in the gut [9,10]. Even without conclusive evidence, UPFs tend to be high in salt, sugar, and saturated fats which can lead to weight gain — and we know for sure that being overweight or obese increases the risk of bowel cancer.

So, perhaps it’s time to take a cue from Italy and switch to a Mediterranean diet? Using minimal, high-quality ingredients, Italians have managed to keep UPFs to just 10% of their energy intake [11].

2. Excessive antibiotic use

Since 2013, Public Health England has been actively campaigning to cut down on unnecessary antibiotic use to help fight antibiotic resistance [12]. In the UK, we’ve made good progress over the past decade in limiting antibiotic use to essential cases [13]. But before that, antibiotic consumption was increasing across the globe [14].

Resistance aside, one of the biggest downsides of antibiotics is that they don’t just kill harmful bacteria — they can also wipe out the good ones, particularly in our gut.

Our intestines are home to a thriving ecosystem of around 100 trillion bacteria, constantly shifting in response to our diet, environment, and lifestyle. This microbial city, called the gut microbiome, plays a vital role in digestion, metabolism, mental health, and immunity. But when we take a course of antibiotics — especially broad-spectrum ones — we risk wiping out some of these friendly bugs. This imbalance, known as dysbiosis, can weaken the gut lining and potentially make it more vulnerable to cancer-promoting bacteria [15].

There’s no definitive proof that antibiotics cause bowel cancer, but early research suggests a link, especially with the long-term use of broad-spectrum antibiotics [16,17].

Of course, antibiotics save lives. Avoiding them altogether isn’t the answer, but we should be more mindful and only take them when necessary. After a course of antibiotics, it might also be beneficial to boost your intake of prebiotics to help support the bacteria in your gut.

3. Microplastics and forever chemicals (PFAS)

Since the 1960s, we’ve been polluting the environment with tiny plastic particles (microplastics) from the breakdown of plastic products. When plastic was first developed, its long-term health effects were largely unknown. Today, research suggests that microplastics interfere with various biological processes, potentially affecting hormonal balance, immune function, reproduction, and respiratory health [18–20]. Emerging studies also indicate a possible link between microplastic exposure and an increased risk of certain cancers, including bowel cancer [21–25].

Unfortunately, microplastics are so widespread. They’ve been found pretty much everywhere, from testicles to mountaintops, making them impossible to avoid [26]. So, is there any point in trying?

It’s unlikely to make a big difference (especially if we continue to pollute the environment), but there are certainly ways we can reduce our exposure. It’s up to you how far you go — it’s all about balancing risk with practicality.

Ways to reduce exposure to microplastics:

• Switch food storage containers to glass
• Use reusable bags and bottles instead of single-use plastic
• Don’t heat food in plastic containers
• Choose tap water over bottled water and ideally filter it
• Choose unwrapped produce
• Wear natural fibres like cotton, wool, and linen

Microplastics aren’t the only pollutants raising health concerns. PFAS (per- and polyfluoroalkyl substances), often called forever chemicals, are another group of contaminants found in food packaging, non-stick cookware, waterproof fabrics, and even drinking water. While microplastics are physical particles, PFAS are chemical compounds — but the two often go hand in hand, with plastics acting as carriers for these harmful substances.

Like microplastics, PFAS accumulate in the body over time and have been linked to health problems. There’s no hard evidence that exposure to PFAS causes bowel cancer, but early mice studies show it may increase the expression of cancer-causing proteins [27].

4. Sedentary lifestyles and obesity

Being overweight is now the second biggest cause of cancer in the UK after smoking, and it causes around 11% of bowel cancer cases [3]. And while diet plays a role, so does our modern sedentary lifestyle — we’re simply moving less than ever before.

Back in 1975, only one in ten people in the UK were obese [28]. Today, it’s more than one in four [29]. This rise isn’t just about food; it’s also about how our daily routines have changed. Jobs that once required physical effort are now desk-based, commutes are often spent sitting, and even leisure time is dominated by screens rather than movement.

A lack of physical activity doesn’t just contribute to weight gain — it directly impacts gut health, inflammation, and insulin resistance, all of which can increase the risk of bowel cancer. Exercise, on the other hand, helps keep the digestive system moving, reduces inflammation, and even plays a role in regulating hormone levels linked to cancer growth.

The takeaway? Even small increases in daily movement — whether it's walking more, taking the stairs, or standing up regularly during work — could make a difference in lowering bowel cancer risk.

5. Not enough fibre

Over a quarter of bowel cancer cases in the UK are caused by eating too little fibre [3]. Fibre (or roughage) can be found in plant-based foods like whole grains, fruit, vegetables, and pulses. It keeps everything moving through the gut.

Our ancestors might have consumed as much as 100g of fibre daily [30]. Nowadays, we’ve set a more modest target of 30g a day which can help support the gut microbiome and eliminate cancer-causing chemicals from the gut. It’s not just protective against bowel cancer – getting enough fibre can also reduce the risk of heart disease, stroke, and type 2 diabetes [31]. 

The UK’s National Diet and Nutrition Survey (NDNS) reports that average fibre intake is below recommended levels across all age groups. In particular, children aged 11 to 18 are getting just 16g a day, falling well short of their 25g recommended daily allowance (RDA) [31]. Adults, too, are not reaching their target, so it’s difficult to say whether low-fibre diets are contributing to rising rates of bowel cancer in young people specifically.

Regardless of your age, getting more fibre is generally one of the best ways to keep your gut healthy unless you have specific digestive problems. It’s best to increase your fibre gradually to avoid pain and bloating.

How fibre can reduce bowel cancer risk:

• Increasing fibre intake by 10g per day is associated with a 10% reduction in risk
• Adding three servings (90g) of whole grains to meals every day is linked to a 20% reduction in risk [3]

Reducing your bowel cancer risk

Bowel cancer can affect anyone, regardless of how healthy their lifestyle is — but the good news is that over half of cases are preventable. While some risk factors, like genetics, can’t be changed, there are proactive steps you can take to reduce your risk.

Ways to lower your risk of bowel cancer:

• Up your fibre intake
• Limit processed meat
• Maintain a healthy weight
• Reduce your alcohol intake
• Stop smoking
• Stay physically active

Screening saves lives

Bowel cancer survival is relatively good — almost two-thirds of young people in England survive their disease for ten years or more [3]. Early detection is key. The earlier it’s diagnosed, the better.

In the UK, the NHS offers bowel cancer screening to everyone aged 54 to 74, by checking for blood in the stool with a qFIT test. The qFIT test detects tiny traces of blood in stool, which can be an early warning sign of bowel cancer — even before symptoms appear. The test isn’t perfect, but it can help establish whether someone might need further investigation.

We offer the qFIT Bowel Cancer Screening Test which you can take from home.

Learn more about the pros and cons of the qFIT test.

Young people – don’t be alarmed

While the rates of bowel cancer in young people are rising, it’s still a rare condition for people under 50. But the trend raises questions about how our modern-day dietary patterns and environmental exposures might affect our health. While research is still ongoing, the best thing we can do is take proactive steps to support out gut health.

The good news is that bowel cancer is one of the most preventable cancers and early detection dramatically improves survival rates. Small, consistent changes — like eating more fibre, cutting back on ultra-processed foods, and staying active — can help reduce your overall risk. If you’re experiencing symptoms or worried about your risk of bowel cancer, speak to your doctor.
 

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References
 

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