Exciting research carried out at the Institute of Food Research at Newcastle University has revealed that ‘epigenetic’ changes to genes (known as DNA methylation) affected in cancer are caused mainly by aging, but are also influenced by diet.
Researchers examined DNA from cells lining the gut wall in volunteers attending colonoscopy clinic, who were free from bowel cancer or inflammatory bowel disease and who simply kept on consuming their usual diet without any supplements.
The researchers looked for specific epigenetic changes in genes associated with onset of bowel cancer, which is an age-related disease. Epigenetic changes don’t alter the genetic code but affect how and when genes are expressed as proteins. Further, DNA methylation is transmitted to daughter cells when cells divide, and some of these DNA changes are believed to be associated with cancer development.
The researchers examined the possible relationship between DNA methylation and various risk factors such as age, sex, body size and levels of specific nutrients in blood. The strongest influence on gene methylation was age. This fits with the known fact that the biggest risk factor for bowel cancer is age, with risk increasing exponentially at over 50 years of age.
Further, men tend to more of these changes to their DNA than women, which is also consistent with men being at a relatively greater risk of bowel cancer. Volunteers with higher vitamin D and selenium status showed lower levels of harmful DNA methylation. Again, it is known that higher vitamin D and selenium status is linked to reduced risk of bowel cancer.
The B vitamin folate is essential for health. However, in this study, high folate status was associated with epigenetic changes linked with bowel cancer. This finding is consistent with previous population suggesting that excessive folate consumption may increase cancer risk in some people and emphasizes the need for further research on optimal folate status.
Obesity is also a risk factor for bowel cancer. This study found a connection between body height, weight and waist circumference and epigenetic changes to DNA. How excess body weight induces these epigenetic changes, and what exactly their consequences are for gut health, are currently being investigated.
This study makes it clear that growing older increases the harmful epigenetic status of genes linked to bowel cancer; these changes can also be modulated by nutrients and vitamins in your diet as well as body shape, especially obesity.