Cancer research has come a long way in the last few decades. Although progress is often slow, taxing, and challenging to generate clinical relevance, the studies you read about today may be the tipping point for future therapies. Similarly, some studies have shown the microbiome may play a pivotal role in how cancerous conditions occur, creating a field of research that has left many scientists excited to explore.
This connection with the human microbiome helps pave the way to more possibilities for better outcomes. The first is, of course, the best outcome of cancer prevention by keeping the body healthy and balanced through personalized nutrition and lifestyle. There are also growing avenues for much earlier detection of cancers where there were little or none before, as well as new and surprising connections with certain microbes on the effect of cancer treatments. All from the power of the microbiome.
Prevention
The Immune System and Inflammation: A Gut Issue
One of the key factors that may influence our immune system is our gut microbiome. When healthy and balanced, the gut microbiome helps regulate our immune system's response. However, when imbalanced, an unhealthy gut microbiome may increase the exposure of inflammation.
Despite all the negative connotations typical of hearing the word "inflammation," it's an integral part of how we heal ourselves. Inflammation is simply our body rapidly flushing a hurt area or pathogen invasion with white blood cells to clear out harmed cells or infection. Without it, we would die prematurely from sepsis, and our wounds would never heal. It is only when inflammation becomes dysregulated, and our body becomes flooded with macrophages that they begin to turn on healthy tissue.
Macrophages are a type of white blood cell and our most savage defenders against pathogens and decaying cells.1 Their name – macrophage – means "large eater" and refers to their ability to devour and digest their target. Inside macrophages are an extremely acidic environment full of chemicals like hydrogen peroxide that is used to rapidly degrade and break down whatever it consumes.2 Macrophages are essential to our immune response and work hard to fight off harmful microbes.
This is why preventing any inflammatory response can be just as detrimental as allowing it to overwhelm the body. Instead, identifying ways to reduce how many immunity soldiers are produced excessively - especially when unnecessary - is a prominent focus for various diseases, including cancer.
But why wouldn't we want to flood our bodies with these cancer-eating macrophages? It seems counterintuitive - yet scientists have shown inflammation can play a critical role in how cancer develops and progresses.
From Immune Response to Immune Offense
Our GALT – the gut-associated lymphoid system – is an essential part of our digestive tract that houses upwards of 70% of our immune system.1 In cancer, the immune system plays an integral role in whether we can adequately defend against cancer cell progression. Usually, when an organ or tissue in our body experiences an increase in mutations that can prove cancerous, our body defends against it and eliminates those cells from growing. However, several types of mutations can hide cancerous cells from our immune system and allow them to grow and spread. Additionally, when a cancerous tumor becomes mature enough, it can actually recruit our immune system to work for it, "hypnotizing" soldiers to help break down walls in our body that allow the cancer to spread.
In cancer, when the tumor has exceeded its environment and prepares to metastasize, cancer cells begin recruiting circulating macrophages - with their impressive digesting powers - to help them break down the surrounding boundaries that prevent the tumor from moving toward other tissues.2 If we are experiencing a large amount of inflammation, the tumor has access to even more soldiers to recruit.
Keeping the Microbiome (and the body) In a Healthy Balance
The question arises from the information above–how do we keep our immune system from heading into overdrive or stalling completely out? How can we cultivate that happy medium? One way to heavily support the GALT is to keep your gut microbes happy, healthy, and balanced.
Eat the foods that are right for you right now
Ensure you're eating foods that are beneficial for your body and your microbiome. Superfoods are only super if they contain nutrients that your gut microbes thrive with. And those nutrients may not always be the requisite kale and blueberries. Guessing may not always be your best bet here (hint: you'll need to test).
And please, stay away from foods you know are problematic for you right now. Letting those opportunistic microbes have a feast with foods that may be an issue for you, no matter how healthy they are, and you're creating that imbalance in your microbiome that we need to keep at a minimum for a good balance.
Make sure to fill in those nutrient gaps
Just because your diet is made up of healthy, whole foods and low in processed foods and sugars doesn't mean you may not have nutritional gaps. Make sure your nutritional program has everything you need, even ensuring you get nutrients from foods you're currently avoiding (if you need them) to rebalance your microbiome.
Get your body moving
It's essential to get in movement every single day if you can. Not only for cardiovascular health but also for a balanced microbiome. Studies show that low to moderate-intensity activity can support healthy digestion and increase the diversity and population of a healthy microbiome.7,8
What does moderate-intensity activity look like?
Brisk walking (or light jogging)
Yoga
Water aerobics
Bike riding
Ballroom dancing
Shooting hoops
Hiking
Keep those regular appointments
Make sure you make and keep those regular checkups with your doctor, including wellness visits, dental checkups, and cleanings. Listen to your body regularly, take notes on things that seem out of the ordinary, and talk them over with your doctor. They may want to do some screenings with you.
Take time for yourself
While stress has not been shown to cause cancer, it has been shown to weaken the immune system and make it harder for you to feel healthy consistently, especially if you are undergoing long periods of stress.
Give yourself time to rest, regenerate, and decompress. That's when the parasympathetic nervous system can take over your "rest and digest" functions and tame those fight-or-flight instincts you may have so you can destress. A simple mindfulness practice can help with this, done on a regular basis.
Deep Breathing: Find a comfortable, quiet place to sit or lie down. Close your eyes and take deep, slow breaths. Focus on the sensation of your breath entering and leaving your body. This helps calm the nervous system and reduce stress.
Body Scan: Start at the top of your head and slowly move your attention down through your body, noticing any areas of tension or discomfort. As you identify these areas, consciously relax them. This practice can help you release physical tension.
Mindful Walking: Take a short walk and pay attention to each step. Feel the ground beneath your feet, notice the movement in your legs, and take in your surroundings. This can help you become more present in the moment.
Gratitude Journaling: Write down three things you're grateful for every day. This practice can shift your focus to positive aspects of your life and help you relax.
Progressive Muscle Relaxation: Tense and then relax different muscle groups in your body, starting from your toes and working your way up to your head. This practice can release physical tension and promote relaxation.
Strengthen healthy habits
A healthy lifestyle with good hygiene habits is an excellent practice for overall health and wellness and can significantly help reduce the risk of cancer and other health challenges. As mentioned above, simple practices like eating a nutrient-rich diet, regular physical activity, and consistent quality of sleep matter, but it's also important to reduce other risk factors such as avoiding tobacco, limiting alcohol intake, and minimizing sun exposure.
Maintaining proper daily hygiene, like showering, brushing teeth, washing hands, and grooming, can also help prevent infections. Though genetics and other factors affect cancer risk, making positive lifestyle choices and hygiene practices part of your daily routine is a practical, proactive way to lower the chances of this disease. Over time, small, consistent healthy habits can go a long way to preserve and protect your health.
Earlier Detection
Just like keeping those yearly wellness visits with your doctor, take those annual tests your physician orders for you. For people of a certain age, usually beginning at 40 (depending on how at risk the individual is for the specific type of cancer), this includes starting regular, yearly testing for early detection of cancers. Here are a few screening options, some available through your physician and others over the counter.
Breast Cancer:
Early detection for breast cancer options include mammograms, breast ultrasounds and MRIs, and new experimental imaging like 3D mammography. Even self-examinations can help when done correctly and reported immediately to your physician if anything is found.
Colorectal Cancer:
Early detection for colorectal cancer (CRC) includes non-invasive options such as a fecal occult blood test (FOBT) to detect hidden blood in stool samples, a fecal immunochemical test (FIT) to detect human hemoglobin, or an sDNA stool test. All of these are done at home by the patient and test for biomarkers of colorectal cancer, with a follow-up for a diagnostic test if these tests turn a positive result. Colonoscopy tests are also available with a doctor's prescription as an invasive screening test for CRC and are done as an outpatient medical process.
Oral Cancer:
Sometimes identified as head and neck cancer, oral cancers are often screened for by your dentist visually during regular 6-month cleanings (so it's important to keep these visits on your calendar as well). Your dentist will usually look at and feel the inside of your mouth for any abnormal patches or lumps, as well as your throat and neck.
Early detection screening tests are available for at-home use, which require only a saliva sample. Tests like these screen for specific biomarkers of oral cancer†. Dentists are now discovering early detection tests like this and prescribing them for their patients as they can help detect the possibility of oral cancer much earlier than visual examination.
Cervical Cancer:
For cervical cancer, the pap test for identifying abnormal cells is done at regular gynecological visits, and an HPV test is used to detect the high-risk human papillomavirus (HPV) DNA, which can contribute to cervical cancer.
Prostate Cancer:
Prostate-specific antigen (PSA) tests measure levels of antigens in the blood, which may indicate prostate issues. Physical examinations are also done regularly through healthcare providers.
Skin Cancer (Melanoma):
A dermatologist or healthcare provider conducts visual examinations of the skin, with small skin samples taken for biopsy if abnormal growths are seen.
Cancer Treatment Response
Emerging research has shown that the composition and activity of the microorganisms in the gut can influence a patient's response to various cancer therapies. This includes immunotherapy, a type of cancer treatment that harnesses the immune system to target and destroy cancer cells.
However, only patients with certain kinds of gut bacteria have been associated with better responses to the immunotherapy drugs called checkpoint inhibitors that can help shrink tumors. When only small groups of patients responded positively to this immunotherapy, researchers wanted to discover why.9
It was found that patients with certain types of bacteria responded positively to the immunotherapy, and those with different kinds of bacteria did not respond to the immunotherapy. Certain species of bacteria can enhance the immune system's ability to recognize and attack cancer cells.10
As studies like this are still in their infancy, more research should be done on identifying microbial species for this type of cancer therapy. But this is a promising frontier to continue.
Your Microbiome Takeaway
Although there is no one cause for cancer, and certainly no one-size-fits-all cure (at least yet), a considerable amount of cancer research has illuminated one thing clearly: each and every day, we are getting a clearer look at how complicated cancer is, but there is hope.
We are moving further away from simplified and generalized ideas of how we should treat cancer patients and identifying how they differ. We can find better treatments by shifting our perspective to treating people at their unique disease status. Ultimately, what we can take away from these studies, and others like them, is how essential a true holistic approach is to our health. By focusing on the multifaceted role of inflammation and our gut and exploring how interlinked the health of our microbiome is to the health of each of us, researchers may mark a fundamental change in how we view cancer therapies.
Published Oct. 2019
Updated Oct. 2023
†CancerDetect™ test is not an FDA-approved or cleared test.
Resources:
1 Wynn TA, Chawla A, Pollard JW. Nature. 2013;496:445-455.
2 https://www.cancer.net/cancer-types/breast-cancer/statistics
3 Buchta Rosean C, Bostic RR, Ferey JCM, et al. (2019). Cancer Res. 2019;79:3662-3675.
4 Francescone R, Hou V, Grivennikov SI. (2014). Cancer J. 2014;20:181-189.
5 Siegel RL, Miller KD, Fedewa SA, et al. Colorectal cancer statistics, 2017. CA Cancer J Clin. 2017;67:177-193.
6 Saus E, Iraola-Guzman S, Willis JR, Brunet-Vega A, Gabaldon T. (2019). Mol Aspects Med. 2019;69:93-106.
7 Monda, Vincenzo, Ines Villano, Antonietta Messina, Anna Valenzano, Teresa Esposito, Fiorenzo Moscatelli, Andrea Viggiano, et al. (2017). Oxidative Medicine and Cellular Longevity 2017 (March): 3831972.
8 Allen JM, Mailing LJ, Niemiro GM, Moore R, Cook MD, White BA, et al. Med Sci Sports Exerc. (2018) 50:747–57. doi: 10.1249/MSS.000000000000
9 NCI Staff. (2018, Feb 5). Cancer Currents Blog, National Cancer Institute. online - cancer.gov
10 Zeriouh M, Raskov H, Kvich L, Gögenur I, Bennedsen ALB. (2023). Neoplasia. 2023 Sep;43:100923. doi: 10.1016/j.neo.2023.100923. Epub 2023 Aug 19. PMID: 37603952; PMCID: PMC10465958.
