Carbohydrates and Cancer: The Science

11.19.2019 0 comments

Author: Trisha Houghton, CNS, ASIST

Carbohydrates account for approximately 50% of the daily intake for adults on a western-style diet, with starch and sucrose being the largest components. And that’s no surprise, considering how cheap and readily available carb-based foods and ingredients are. Plus, when you add salt, table sugar, and oils to them, carbs can quickly become addictive.

The fact that carbohydrates dominate the Western diet is alarming. Why?

Although carbs are necessary for our well-being (they’re the body’s main fuel source), eating a diet rich in carbs can open you up to a myriad of health issues, one of which is colon cancer.

So, it’s critical to learn all you can about dietary carbs and the risks they expose you to. That’s what we’ll address in this article.

Link Between Carbohydrate-Rich Diets and Colon Cancer

Colon cancer is a major health concern – the third leading cause of cancer-related deaths in the United States in men and the fourth in women.

In 2025, it’s estimated that 107,320 people will develop it, and overall, the lifetime risk of developing it is 1 in 24 for men and 1 in 26 for women.

Your diet is one of the most significant risk factors for colon cancer. And according to a growing body of evidence, many foods high in carbohydrates (especially low-quality carbs) can increase your chances of developing the life-threatening condition.

Interestingly enough, a low-carb diet can also drive colon cancer development – this is a newer notion (we’ll cover it further down in this article).

Although many are already aware of the relationship between a carbohydrate-rich diet and colon cancer, the mechanism was not well-understood until now.

Role of Gut Microbes in Cancer Formation

In a recent article published in Cell, scientists used a mouse model prone to colon cancer to show that gut microbes promote tumor growth by supplying metabolites that trigger excessive colon cell proliferation. Uncontrolled cell proliferation is the initial step of cancer.

A 2023 study also highlights the role of gut microbes in cancer. It suggests that the high-carbohydrate diet common in Western countries drives dysbiosis.

Other studies, like this one, note that microbial dysbiosis can be instrumental in carcinogenesis through one or more of these mechanisms:

• Ongoing inflammation that helps to create a pro-cancer environment. Inflammation and colorectal cancer are very closely associated.
• The production of carcinogenic metabolites that inflict damage on epithelial cells, disrupt the mucosal barrier, and lead to cell proliferation.
• DNA damage from dysbiotic microbes (Enterococcus faecalis, for example).
• Immune modulation, where certain bacteria suppress anti-tumor responses and others recruit stem cells that secrete cytokines that promote the growth of tumors.

Note: According to study contributors, more research is needed to solidify the above assumptions surrounding high carb diets, dysbiosis, and carcinogenesis, although they do hold substantial merit.

How Butyrate Stimulates Cell Proliferation

Gut bacteria use carbohydrates to produce a molecule called butyrate that initiates the process of excessive proliferation of the colon epithelial cells.

The major butyrate-producing bacteria belong to the family of Firmicutes and Fusobacterium nucleatum, and it is evident that a diet low in carbohydrates decreases the representative from these two classes of bacteria.

Is butyrate always associated with cancer?The answer is no, only in people carrying a mutation in a gene called MSH2 that predisposes them to acquire colon cancer.

Since we don’t know if we carry the mutation in the gene MSH2 in our genome, it is important to prevent colon cancer by reducing carbohydrates in the diet as well as by having a balanced intestinal microbial community.

Impact of Low-Carb Diets on Gut Bacteria

According to more recent research from just this year, there are situations where a low-carb diet can drive up your cancer risk. And it’s because of its impact on gut bacteria.

In a 2025 study published in Nature Microbiology, three diet types were studied and compared based on their interaction with different types of gut bacteria:

• Low-carb;
• Western-style (high sugar, high fat);
• Normal.

By the conclusion of the study, scientists found that when a strain of E. coli bacteria was combined with the low-carb diet, colon polyps formed. These polyps are known to be a precursor to cancer.

Are All Butyrate Effects Harmful? 

Except in very specific circumstances, butyrate is broadly protective for colon health and your overall well-being.

Here are the many benefits of the short-chain fatty acid, according to several studies: 

• Reduces inflammation to the extent that it can reduce your risk of developing sepsis.
• Brings relief from gastrointestinal conditions like Crohn’s disease, irritable bowel syndrome, and diverticulitis.
• Helps you get more and better NREM sleep.
• Lowers your risk of colon cancer, promotes cancer cell death, and even reduces damage inflicted by cancer or chemotherapy.
• Lowers insulin resistance, which is particularly helpful for those with type 2 diabetes.

Is It Possible To Prevent Colon Cancer Through Diet

Per UCSF Health, around 90% of colorectal cancers are thought to be preventable. 

Still, over a hundred thousand people will fall ill with colon cancer. And this is a shame, given that living a healthy lifestyle, which includes consuming a healthy diet, can help you lower your cancer risk.

Not all forms of cancer are preventable, but colon cancer stands out as one where lifestyle choices make a major difference. Considering the deadly nature of a cancer diagnosis, it only makes sense to do all you can to prevent the condition. Hence, the importance of altering your diet to mitigate the risk.

Get FREE Access!

We are on a mission to change your life by providing you with curated science-backed health tips, nutrition advice and mouth-watering recipes. Sign up to receive your 3 starter gifts and get exclusive access to new weekly content for FREE:

Free eBook

to boost metabolism

4 Shopping Guides

for every diet

22 Free Recipes

to beat sugar addiction

Subscribe now

subscribe

Practical Tips to Reduce Carbohydrates in Your Diet 

If you have been eating a carb-heavy diet for a long time, reducing your carbs may be a lot easier said than done.

But don’t worry – with the below carb-busting tips, you can make smart tweaks that make a big difference:

• Always check the amount of sugar in the products you buy at the grocery store (sweetened yogurt, cereal, and almond milk, for example). Choose unsweetened or a maximum of 2g sugar per serving portion.
• Try not to eat as many refined carbs (like white bread), and opt instead for whole foods, like grain breads/whole wheat bread. You can also reduce your overall bread-based carbohydrate intake.
• Look at every nutrition facts label when grocery shopping – keep an eye out for low-carb snacks, like certain dairy products (cheese and yogurt), nuts, and eggs.
• Switch out fruit juice for whole fruits. Juice contains a lot of fructose (one of the most common simple sugars) in most cases.
• Pay attention to breakfast foods, as they tend to be high-carb options (think granola, bagels, or breakfast cereals). Instead of those, go for egg-centric dishes for low-carb diets.
• Plan out and prep your meals in advance so you never find yourself stressed or in a rush come breakfast, lunch, or dinner. Don’t forget to keep healthy, quick-grab snack foods in the house as well.
• Swap out added sugars for alternatives like stevia or xylitol, especially if you want to lose weight or are trying not to gain weight.

Benefits of Probiotics for Gut Health

Another great thing you can do for yourself is to start a probiotic supplement to support your gut health. It contains “good” gut bacteria that are known to support the health of your digestive tract.

One excellent source of healthy and friendly bacteria and yeast is Kefir. Kefir helps strengthen the intestines and resists the growth of bad bacteria and pathogens.

Other health benefits of probiotics include:

• Mental health improvements made possible via the brain/gut connection.
• Clear, moisturized, youthful-looking skin due to reduced inflammation.
• Boosted immunity, given that up to 80% of immune cells are located in the gut.
• And more.

Key Takeaways for a Balanced Diet 

So what’s the key to reducing colon cancer risk? It’s not eliminating all carbohydrates. It’s making smarter choices and consuming a balanced, microbiome-friendly diet with fruits, vegetables, and key nutrients.

And this means: 

• Prioritizing complex carbohydrates from fiber-rich vegetables, legumes, and whole grains over refined grains and sugars or highly processed foods/packaged foods.
• Remembering that a balanced diet should also include moderate amounts of protein, healthy fats (skip saturated fat and go for monounsaturated, polyunsaturated, or unsaturated fats), and probiotic-rich foods like kefir or yogurt to promote microbial diversity. It should also have a variety of beneficial vitamins and minerals to support your ongoing vitality.
• Knowing that carbohydrate quality matters over quantity: not all carbs are harmful. Low-quality ones (like french fries and soda) are where the real danger lies.
• Aiming for consistency, variety, and minimally processed or whole ingredients.
• Avoiding added sugar as much as possible.

If you follow the above dietary guidelines, you’ll give your gut (and your colon) the best possible defense. You might also be able to stave off weight gain, accomplish your weight loss goals, avoid heart disease, and more!

While adjusting your carbohydrate intake is a powerful first step toward protecting your colon and improving your gut microbiome, true long-term health goes even deeper—down to your cells. Supporting cellular repair and reducing inflammation at the root level is essential for disease prevention and healthy aging. That’s where Restore Life can help.

Our Restore Life formula supports boosting your longevity and restoring your youthful glow, both inside and out. It is the only product in the world that is specifically designed to “switch off your aging button.”

Click here to learn more about Restore Life and its 7 multi-purpose ingredients that have antioxidant properties, boost your collagen production, make your skin look more youthful and wrinkle-free, and help reduce the biological age of your cells.

Frequently Asked Questions

What are 7 examples of carbohydrate foods?

White bread, white and brown rice, pasta, potatoes, sugary breakfast cereals, juice (orange juice and other fruit juice), bananas, and lentils are seven examples of high-carb foods.

Which food has no carbs?

Many healthy foods have no carbs: hard-boiled eggs, pickles, olives, tuna, string cheese, and salmon. Eating foods like these can help you build a winning low-carb diet. And don’t forget to skip the fruit drinks.

What vegetables have the most carbs?

Not all carbs are unhealthy. Those looking for healthy carbohydrates should reach for: corn, carrots, beets, sweet potatoes, zucchini, pumpkin, parsnips, brussels sprouts, and squash. They all have lots of healthy carbs.

Sources

Gut Microbial Metabolism Drive Transformation of MSH-Deficient Colon Epithelial Cells

The Burden of Carbohydrates in Health and Disease

Carbohydrates: How carbs fit into a healthy diet

Key Statistics for Colorectal Cancer

A meta-analysis between dietary carbohydrate intake and colorectal cancer risk: evidence from 17 observational studies

Study uncovers how low-carb diet drives colorectal cancer development

Understanding the role of the gut microbiome in gastrointestinal cancer: A review

Role of microbial dysbiosis in carcinogenesis & cancer therapies

Dietary fibre counters the oncogenic potential of colibactin-producing Escherichia coli in colorectal cancer

The Health Benefits and Side Effects of Butyrate

Carbs 101

Colorectal Cancer Prevention and Screening

We created ZONIA because we believe that everyone deserves to be empowered with the education and tools to be healthy and happy. Zonia's original videos and personalized transformation programs by our health & wellness experts will help you achieve this mission. Click on the button below to get started today:

start my 7 day free membership