Every day, our immune system identifies and destroys pre-cancerous and cancerous cells1. These are cancer cells that we are oblivious to. When our immune system is down and underperforming, cancer cells that usually would be routinely destroyed by our body, are sometimes instead free to circulate and then proliferate.
This is perhaps what happened to me. When undergoing chemotherapy for breast cancer, the chemotherapy drugs wiped out my fast-growing cells, including possibly, any rogue cancer cells. As a side effect of action against cancer cells, chemotherapy also caused my immune system to plummet. Later, as my immune system was in recovery, it’s cancer surveillance capacity was still not at peak performance. For the first time in many decades, it failed to seek out and destroy melanoma cells that began to grow from a skin imperfection on the top of my scalp. Since a child, I was overexposed to the cancer-causing ultra-violet rays of the harsh Australian sun. I have always used sunscreen and protective clothing but while swimming and surfing in the ocean, my scalp was totally unprotected and repeatedly burnt.
Our immune systems and our digestive systems are directly linked, and intestinal microbial balance is important to maintaining a healthy immune system. This is possibly the key to immunotherapy. Immunotherapy works by upregulating and enhancing our immune system function to allow it to work well at identifying and destroying cancer cells.
What does alcohol do to the microbiome?
I’ve been wondering what happens when I drink that sometimes, glass of wine at the dinner table. (For more about alcohol and cancer, see my article; Is Chardonnay Okay?)
The 2015 issue of Alcohol Research: Current Reviews (ARCR) summarizes the evidence that alcohol disrupts immune pathways:
“The gastrointestinal (GI) system is typically the first point of contact for alcohol as it passes through the body and is where alcohol is absorbed into the bloodstream. One of the most significant immediate effects of alcohol is that it affects the structure and integrity of the GI tract. For example, alcohol alters the numbers and relative abundances of microbes in the gut microbiome (see the article by Engen and colleagues2), an extensive community of microorganisms in the intestine that aid in normal gut function. These organisms affect the maturation and function of the immune system. Alcohol disrupts communication between these organisms and the intestinal immune system. Alcohol consumption also damages epithelial cells, T cells, and neutrophils in the GI system, disrupting gut barrier function and facilitating leakage of microbes into the circulation (see the article by Hammer and colleagues3).”4
Alcohol alters the microbial population in the digestive tract. One study of alcoholics showed microbial community was significantly altered—containing a lower abundance of Bacteroidetes and a higher abundance of Proteobacteria5. Similar to other findings, a study of alcohol-fed mice demonstrated a decrease in the abundance of Bacteriodetes and Firmicutes and an increase in Proteobacteria and Actinobacteria6. This imbalance is known as dysbiosis.
Dysbiosis: Dysbiosis is a term used to describe a microbial imbalance on or inside the body, commonly within the digestive tract where it has been associated with illness.
(The class Bacteroidia was formerly called Bacteroidetes.)
A Solution is to Increase Dietary Soluble Fiber
To counter this possible adverse effect of dysbiosis from drinking alcohol, growing and feeding more Bacteroidetes and Firmicutes, may assist the microbiome rebalance and support the immune system.
For instance, the commensal bacteria Bacteroides fragilis produce a particular glycan (chain like structure of single sugar molecules), polysaccharide A, which has strong anti-inflammatory effects7. A soluble fiber diet increases Bacteroides fragilis group abundance and Immunoglobulin A production in the gut8. Immunoglobulin A (IgA) is essential for defense of the intestinal mucosa against harmful pathogens8.
Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium. The word ‘soluble’ means ‘dissolve’. So soluble fiber is fiber that dissolves in water. Short-chain fatty acids produced by soluble fiber fermentation feed the good bacteria in your gut, improving gastrointestinal health. Short-chain fatty acids are the main source of nutrition for the cells in your colon.
A good source of Bacteriodetes is beans. With the aim to feed your internal population of bacteroides, adding daily beans such as black beans or lima beans to your diet may counteract any depletion caused by consumption of alcohol. (It may take a little time for your microbiota to develop sufficiently to digest beans if you are not accustomed to eating them).
A healthy immune system is better equipped than an unhealthy one, for both surveillance of new pre-cancerous and cancerous cells in the body, and for destroying already existing malignant cells.
My conclusion is, besides eating more soluble fiber to increase the good bacteria and assist my immune system, reducing and better still, removing alcohol from my diet, is the best way to support my immune system, to help it help me, kill off cancer cells.
Other factors to consider
Diet affects the immune system, and the immune system has an effect on the microbiota. The innate immune system is another factor that probably influences the composition of the intestinal microbiota. Besides diet, other factors are – host genetics- maternal transfer and early colonization- antibiotics and medications- infection- inflammation- stress- hygiene and age7.
For more about using food to combat cancer CLICK HERE.
REFERENCES
1. Afshar-Sterle S, Zotos D, Bernard NJ, et al. Fas ligand–mediated immune surveillance by T cells is essential for the control of spontaneous B cell lymphomas. Nat Med. 2014;20(3):283-290.
2. Engen PA, Green SJ, Voigt RM, Forsyth CB, Keshavarzian A. The Gastrointestinal Microbiome: Alcohol Effects on the Composition of Intestinal Microbiota. Alcohol Res. 2015;37(2):223-236.
3. Hammer AM, Morris NL, Earley ZM, Choudhry MA. The First Line of Defense: The Effects of Alcohol on Post-Burn Intestinal Barrier, Immune Cells, and Microbiome. Alcohol Res. 2015;37(2):209-222.
4. Sarkar D, Jung MK, Wang HJ. Alcohol and the Immune System. Alcohol Res. 2015;37(2):153-155.
5. Mutlu EA, Gillevet PM, Rangwala H, et al. Colonic microbiome is altered in alcoholism. American Journal of Physiology-Gastrointestinal and Liver Physiology. 2012;302(9):G966-G978.
6. Bull-Otterson L, Feng W, Kirpich I, et al. Metagenomic analyses of alcohol induced pathogenic alterations in the intestinal microbiome and the effect of Lactobacillus rhamnosus GG treatment. PLoS One. 2013;8(1):e53028-e53028.
7. Maslowski KM, Mackay CR. Diet, gut microbiota and immune responses. Nat Immunol. 2011;12(1):5-9.
8. Nakajima A, Sasaki T, Itoh K, et al. A Soluble Fiber Diet Increases Bacteroides fragilis Group Abundance and Immunoglobulin A Production in the Gut. Appl Environ Microbiol. 2020;86(13):e00405-00420.