Impact of Diet-Induced Inflammation on Colorectal Cancer

Overview of Colorectal Cancer

Colorectal cancer ranks as the third most prevalent cancer globally, predominantly affecting older men. Key lifestyle risk factors contributing to its development include diet, obesity, smoking, and levels of physical activity. Diagnosis typically involves endoscopic analysis, enabling physicians to visualize the colon’s interior, followed by a biopsy of any abnormal tissue growths known as polyps.

Inflammation’s Role in Colorectal Cancer

Research indicates a significant connection between inflammation and colorectal cancer. Inflammatory disorders, such as irritable bowel syndrome, have been linked to this cancer’s incidence. Additionally, lifestyle factors like obesity and smoking are known to exacerbate inflammation. Medications that alleviate inflammation, such as aspirin, have been recommended for colorectal cancer prevention in adults aged 40 and older.

New Research on Diet and Cancer Risk

A recent study published in JAMA Oncology explores whether inflammatory diets contribute to colorectal cancer risk in the general population. Researchers utilized dietary data from The Nurses’ Health Study (NHS), which includes registered female nurses aged 30 to 55, and the Health Professionals Follow-up Study (HPFS), comprising 51,529 male healthcare professionals aged 40 to 75. Participants in both cohorts completed food frequency questionnaires (FFQs) every four years, alongside biennial surveys covering various medical and lifestyle factors.

Methodology of the Study

The inflammatory potential of participants’ diets was assessed using the empirical dietary inflammatory pattern (EDIP) score. This validated scoring system categorizes food groups based on their inflammatory properties, distinguishing between anti-inflammatory foods (e.g., beer, wine, vegetables, and fruit juice) and pro-inflammatory foods (e.g., processed meats and sugary drinks). The researchers tracked dietary data until participants’ deaths, cancer diagnoses (excluding non-melanoma skin cancer), or the study’s conclusion in 2012, allowing for an analysis of any causal links between colorectal cancer and inflammatory diets.

Findings on Diet-Induced Inflammation and Cancer Incidence

Colorectal Cancer Rates among Participants

The study identified colorectal cancer in 2,699 participants (1,441 women and 1,258 men). Among men, those with the most pro-inflammatory diets exhibited a colorectal cancer incidence rate of 151 per 100,000 years, compared to 115 per 100,000 years for those with anti-inflammatory diets. Similarly, in women, the incidence rate was 92 per 100,000 years for pro-inflammatory diets versus 81 per 100,000 years for anti-inflammatory diets.

Influence of Additional Factors

Further analysis revealed that obese men experienced a 48% heightened risk of colorectal cancer when adhering to pro-inflammatory diets. Conversely, lean women showed a greater risk in this category. Alcohol consumption also influenced cancer rates, with non-drinkers facing a higher risk—62% for men and 33% for women.

Study Limitations and Strengths

Limitations

A limitation noted in the study is the reliance on Body Mass Index (BMI) as a measure of obesity, which has been criticized for its inability to accurately reflect individual health. Additionally, the researchers acknowledged instances of missing FFQ data but justified their findings by highlighting the consistency of responses among participants.

Strengths of the Study

A significant advantage of this research is the validated EDIP scoring method, which demonstrated high predictive quality in previous studies. The large sample size and comprehensive participant data minimized potential confounding variables, strengthening the results.

Implications of the Research

The findings suggest that pro-inflammatory diets may elevate the risk of colorectal cancer in both men and women. This underscores the potential benefit of dietary strategies aimed at reducing inflammation to mitigate cancer risk. The insights gained from this research are particularly relevant for individuals with a family history of colorectal cancer or those undergoing treatment for the disease.

Reference

Tabung, F. K., et al. (2018). “Association of Dietary Inflammatory Potential With Colorectal Cancer Risk in Men and Women.” JAMA Oncol.