Scientists have long known that obesity increases the risk of developing many types of cancer. However, the reasons behind this link have remained unclear. Now, researchers are uncovering how changes in metabolism may create an environment in the body that allows cancer to develop and thrive.
Recent reviews by researchers at the University of Bristol and others examine the latest evidence on how obesity, diabetes, and related metabolic changes influence cancer. Their findings suggest that addressing these metabolic issues could be vital to preventing many common cancers.
“We’ve seen obesity rates climb dramatically in recent decades, and cancer rates have risen along with them,” says lead author Dr. Jeff Holly. “Our review indicates that the metabolic changes associated with obesity may be creating fertile ground for cancer to develop.”
The researchers explain that as we gain excess weight, we alter the levels of essential hormones and growth factors, especially insulin and insulin-like growth factors (IGFs). These act as signals telling cells when to grow and divide. In obesity, these signals often become overactive.
“It’s like the accelerator pedal for cell growth gets stuck down,” Holly explains. “This revved-up metabolism can allow cancer cells that may be present to grow and spread when they otherwise might have remained dormant.”
This metabolic perspective on cancer is supported by several key findings:
- Cancer cells exhibit altered metabolism, including increased glucose uptake and fermentation of glucose to lactate, even in the presence of oxygen (the Warburg effect). This metabolic shift appears to be a fundamental characteristic of cancer cells.
- Obesity and type 2 diabetes are associated with metabolic changes that create an internal environment more conducive to cancer growth. This includes increased insulin levels, IGFs, inflammatory cytokines, and altered availability of metabolic fuels.
- Many genes commonly mutated in cancer affect metabolic pathways, suggesting that both genetic and lifestyle factors may converge to reset metabolism in ways that promote cancer.
- Interventions that improve metabolic health, such as calorie restriction, exercise, and certain diabetes medications like metformin, have shown promise in reducing cancer risk or improving outcomes.
The good news is that these metabolic changes appear to be reversible. Studies have found that weight loss, improved diet, increased physical activity, and even certain diabetes medications can help normalize metabolic factors linked to cancer risk.
“This presents an opportunity for cancer prevention,” says Holly. “By addressing the root metabolic issues, we may make the body less hospitable for cancer to develop in the first place.”
The researchers stress that more studies are still needed to understand these connections fully. However, they believe focusing on metabolism could lead to new cancer prevention and treatment strategies.
“We’ve made great strides in early detection and treatment of many cancers,” Holly notes. “But prevention is still the ultimate goal. Understanding how obesity and metabolism influence cancer risk brings us closer to that goal.”
This metabolic perspective on cancer suggests that many common cancers may be preventable through lifestyle changes and interventions that target metabolic health. It also opens up new avenues for cancer treatment by targeting the unique metabolic features of cancer cells.
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