Impact of Weight Loss and Exercise on Colorectal Cancer Risk

Overview of Colorectal Cancer Trends

Recent findings published in the American Journal of Physiology-Endocrinology and Metabolism have examined the relationship between weight loss, subsequent exercise, and colorectal cancer risk. The incidence of colorectal cancer is rising among the young adult demographic in the United States, making it one of the most prevalent cancers globally. Recent studies have highlighted the significant role of bone marrow cells, responsible for blood cell production, in the development of colorectal cancer. However, the effects of weight loss facilitated by diet and exercise on these blood cells and the associated cancer risk have not been extensively studied until now.

Research Collaboration and Methodology

A team of researchers from the University of Ottawa and the University of Illinois at Urbana-Champaign conducted an investigation using a mouse model to assess the effects of weight loss followed by exercise on colorectal cancer risk. Their findings were published in the American Journal of Physiology – Endocrinology and Metabolism.

Findings: Sedentary Mice and Inflammation

All mice involved in the study had cancer and were initially placed on a high-fat diet, leading to obesity. They were later switched to a standard rodent diet for the duration of the study. After two months of weight loss on this normal diet, half of the mice engaged in daily exercise, while the other half remained sedentary. The results indicated that the sedentary mice exhibited higher levels of colon and bone marrow inflammation, as well as increased fat tissue in the bone marrow. Additionally, the lack of physical activity resulted in significant changes to the blood cells.

Results: Benefits of Exercise Post-Weight Loss

In contrast, the exercised mice showed reduced inflammation and tumor formation after weight loss. The researchers noted that the rate of tumor production in the exercise group was comparable to that of control mice exposed to cancerous cells but not obese.

Implications of the Study

The researchers emphasized the long-term alterations in blood cell development and the bone marrow microenvironment induced by obesity, which can persist even after weight loss and improved body composition. These findings suggest that individuals at heightened risk for colorectal cancer, particularly those experiencing obesity, should consider integrating exercise with dietary changes to mitigate their risk.

Conclusion

This research underscores the importance of exercise following weight loss as a potential strategy to lower colorectal cancer risk, particularly for those with obesity.

References

Emmons, R et al. Effects of obesity and exercise on colon cancer induction and hematopoiesis in mice. 2018. American Journal of Physiology-Endocrinology and Metabolism. [Online]. [4 January 2019]. Available from: https://www.physiology.org/doi/abs/10.1152/ajpendo.00237.2018

Eurekalert. 2018. Exercise following weight loss may reduce colorectal cancer risk, study finds. [Online]. [4 January 2019]. Available from: https://www.eurekalert.org/pub_releases/2018-12/aps-efw121218.php