It is estimated that just over 15,500 people per year, in Australia alone, will develop bowel cancer. Bowel cancer accounts for 11% of all deaths from cancer making it the second most common cause of cancer deaths in Australia. Despite the reduction in smoking to around 13% of the adult population in Australia, lung cancer still sits at number one.
Therefore, any new research suggesting simple preventative measures to prevent bowel cancer is certainly most welcome. A study from Texas published in the Journal “Gut Microbes” has suggested that consuming spinach on a regular basis appears to reduce bowel cancer risk. Spinach has a variety of excellent nutrients that appear to inhibit the growth of polyps. This appears to be the case with genetic or non-genetic bowel cancer.
The other interesting findings from this study suggests the significant contribution from the colony of bacteria living in our colon known as the gut microbiota.
It is interesting to note that only 10 to 15% of cases of bowel cancer appear to be the hereditary, familial type. Also, only somewhere between 5–10% of polyps develop into bowel cancer.
In this study from Texas, particular rats who were genetically primed to develop familial adenomatous polyps (a well-known precursor for bowel cancer) were fed spinach for a period of 26 weeks. This study demonstrated that the regular consumption of spinach could delay the growth of polyps.
When the researchers delved deeper into why this was the case, it appeared to be due to the variety of gut bacteria living in the colon along with the positive metabolites produced during the interaction between these gut bacteria and the colon, itself. The study of this process is known as metabolomics. It is suggested that the rich source of several nutrients in spinach contribute to this positive effect. The healthy gut bacteria metabolise these nutrients & release certain substances such as linoleic acid & short chain fatty acids which have a positive effect in maintaining good health in general & reduce the formation of pre-cancerous, adenomatous polyps. The nutrients in spinach include vitamin K, glutathione and folate as part of this protective effect.
Simply, the modern western diet which involves a variety of processed carbohydrates and synthetic fats tends to promote the generation of bowel cancer, probably by favouring the growth of pathogenic bacteria which promote colonic polyps by forming toxic chemicals within the colonic environment. It appears the regular consumption of fruit and vegetables and, in particular, leafy greens such as spinach seems to be associated with a positive benefit in reducing bowel cancer risk by encouraging healthy bacteria to produce healthy metabolites.
Over the past decade, the evidence has grown that many simple lifestyle factors not only reduce bowel cancer risk, but the risk for all our common killers. If you follow the principles detailed below, you may reduce your risk for all modern diseases by anywhere between 70–80%.
Ying-Shiuan Chen et al, Dietary spinach reshapes the gut microbiome in an Apc-mutant genetic background: mechanistic insights from integrated multi-omics, Gut Microbes (2021)