The Role of Insulin, Infection, and Inflammation in Cancer Risk

Chronic ConditionsLifestyleMetabolic Health

Sep 7

ESTIMATED READ TIME:  4–5 MINS

Throughout my years of studying nutrition, working alongside physicians and researchers, and walking through my own battle with cancer, I've found that the experts I trust most consider the root causes of cancer to be the "three I's":

Insulin.
Infection.
Inflammation.

Cancer is undoubtedly a very complex disease with no single cause, but these three factors can help explain why certain environments and behaviors are more favorable for cancer to develop and grow.

This doesn't mean every person with elevated insulin, a chronic infection, or inflammation will develop cancer. Nor does it mean cancer can be prevented or cured by addressing these three factors alone.

But growing evidence suggests these causes deserve our attention—not only for cancer prevention, but for overall health. Let's take a closer look.

1. Insulin: Feeding More Than Your Cells

Cancer research has shifted significantly over the past decades, focusing more on how metabolic function can drive tumor growth.

Healthy cells are flexible, fueling themselves with either glucose or fats. Cancer cells, however, typically rely on glucose to fuel rapid growth—a process called the Warburg effect.

Even when oxygen is available, many tumors ferment glucose instead of using it efficiently, a discovery that supports the metabolic theory of cancer.

Rather than viewing cancer only as a genetic disease, this theory suggests abnormalities in cellular metabolism and mitochondrial function can influence how cancer develops and progresses.

Researchers have also found that elevated insulin levels can create an environment that encourages cell growth.

In fact, obesity and metabolic issues are among the leading causes of cancer worldwide, according to the World Health Organization (WHO). "Nearly a quarter of deaths from cancer are due to tobacco use, alcohol consumption, high body mass index, low fruit and vegetable intake, lack of physical activity, and air pollution," WHO reports.

Insulin is an anabolic hormone, meaning one of its primary jobs is to signal cells to grow and store nutrients. Chronically elevated insulin can raise levels of insulin-like growth factor-1 (IGF-1), another hormone involved in cell growth and division.

Large studies have linked insulin resistance, obesity, metabolic syndrome, and type 2 diabetes with an increased risk of several cancers, including colorectal, breast, pancreatic, liver, and endometrial cancers.

The relationship between insulin and cancer is so significant that some integrative physicians use a technique called insulin-potentiated therapy (IPT), in which a controlled dose of insulin is given before chemotherapy to potentially increase cancer cells' uptake of the drugs.

Although IPT remains controversial and is not considered standard cancer care at this time, it shows just how closely insulin and cancer cell metabolism are connected.

You can see why it's essential to prioritize metabolic health not only for diabetes prevention but for long-term wellness. Simple ways to support healthy insulin levels include:

Eating adequate protein with every meal (25+ grams).
Limiting sugary beverages and refined carbohydrates.
Building and maintaining muscle through resistance training.
Walking after meals.
Prioritizing restorative sleep.

2. Infections and Viruses: When the Immune System Faces a Long-Term Threat

Infections likely don't come to mind when you think about the causes of cancer. But scientists have known for decades that certain infections and viruses can increase cancer risk.

In fact, WHO estimates that approximately 13% of cancers worldwide are linked to infectious agents, and this number rises to 30% of cancer cases in low- and lower-middle-income countries. Some of the best-known examples include:

Human papillomavirus (HPV), which can contribute to cervical and several other cancers (in fact, it's the cause of 99% of cervical cancer cases).
Helicobacter pylori, a bacterium associated with stomach ulcers and gastric cancer.
Hepatitis B and hepatitis C viruses, which significantly increase the risk of liver cancer.
Epstein-Barr virus (EBV), which has been linked to several lymphomas and nasopharyngeal cancer.

It's believed that infections can contribute to cancer in several ways, including by directly damaging DNA and interfering with normal cell repair. Many also trigger chronic inflammation or weaken the immune system's ability to recognize and eliminate abnormal cells.

Some integrative practitioners have also found that fungal overgrowth, parasites, or imbalances in the microbiome may contribute to certain cancers. While these remain active areas of research, the strongest evidence currently supports the infectious agents listed above.

Supporting your immune system doesn't guarantee protection from cancer, but maintaining healthy sleep, good nutrition, regular exercise, stress management, and appropriate vaccinations when recommended can all help your body respond the best way it can to pathogens it may come across.

3. Inflammation: A Fire That Never Goes Out

Inflammation is framed as being dangerous, but in the right amount, it's one of our built-in healing tools. When you cut your finger or fight off an infection, inflammation helps your body repair damaged tissue and eliminate harmful invaders.

The problem isn't inflammation itself, but chronic inflammation that never completely turns off.

Chronic low-grade inflammation has been linked to heart disease, diabetes, Alzheimer's disease, autoimmune conditions, and many forms of cancer.

Researchers now recognize that inflammatory cells and signaling molecules are present throughout the tumor microenvironment, where they can influence how cancers develop, grow, recruit blood vessels, and spread.

As one review puts it, "Tumor-promoting inflammation is considered one of the enabling characteristics of cancer development."

Cancer isn't necessarily an "inflammatory disease." But persistent inflammation appears to create conditions that make it easier for abnormal cells to survive and multiply.

What's especially important is that insulin, infection, and inflammation often work together.

Poor metabolic health can increase inflammation.
Chronic infections can trigger inflammation.
Inflammation itself can worsen insulin resistance.

It becomes a vicious cycle that places extra stress on the body. Fortunately, many of the same daily habits support healthy inflammatory responses, strengthen immune defenses against viruses and infections, and support metabolic health.

I encourage people to:

Eat quality proteins and colorful fruits and vegetables rich in antioxidants.
Choose healthy fats like extra virgin olive oil, avocado, and omega-3-rich fish.
Eliminate smoking and minimize alcohol.
Maintain a healthy weight.
Exercise regularly.
Prioritize restorative sleep.
Avoid vitamin D deficiency, including by getting enough sunlight exposure and/or supplementing.
Spend time in prayer and reduce chronic stress.

The Bottom Line: Create an Environment That Supports Health, Not Cancer

Cancer is one of the most complex diseases we face, and no single factor explains why it develops. Still, I believe one of the best questions we can ask is this:

"What kind of environment am I creating inside my body?"

Is it one that promotes healthy metabolism?
Is it one that supports a resilient immune system?
Is it one that encourages balanced inflammatory responses?

These are factors we can help influence through our choices.

When I was diagnosed with cancer, I realized that healing wasn't simply about fighting a disease. It was also about strengthening the body God had given me through nourishing foods, regular movement, quality sleep, healthy relationships, gratitude, and faith.

While none of these habits guarantee freedom from cancer, they can help create a stronger foundation for long-term health and resilience.

References:

https://pmc.ncbi.nlm.nih.gov/articles/PMC7062568/

https://www.iarc.who.int/news-events/global-burden-of-cancer-attributable-to-infections-in-2018-a-worldwide-incidence-analysis/

https://www.who.int/news-room/fact-sheets/detail/cancer

https://pmc.ncbi.nlm.nih.gov/articles/PMC4783224/

https://www.mskcc.org/announcements/warburg-effect-what-turns-cells

https://pmc.ncbi.nlm.nih.gov/articles/PMC12468734/

https://pmc.ncbi.nlm.nih.gov/articles/PMC7884814/

https://www.mskcc.org/cancer-care/integrative-medicine/herbs/insulin-potentiation-therapy

https://linkinghub.elsevier.com/retrieve/pii/S2214-109X(19)30488-7

https://pubmed.ncbi.nlm.nih.gov/36834525/