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Fried Chicken, Colon Cancer, Kentucky, and Everything In Between

By Parker Lynch

According to the national census data for 2020, Kentucky was found to have the highest incidence of colorectal cancer (CRC) in the country—41.2 new cases of CRC per 100,000 people in the state  that year. This number is concerning, especially when comparing it to other states with significantly lower rates: Utah, Colorado, Delaware, Arizona, and Vermont (about 20 new cases per 100,000 in 2020). 

Why Is CRC Incidence High in Kentucky?

There are several risk factors associated with CRC: tobacco use, poor dietary habits, lack of exercise, genetic predispositions, etc. Unfortunately, the residents of Kentucky exhibit each of these poor lifestyle habits much more than other states. Two-thirds of adults in Kentucky are overweight, less than a tenth eat a sufficient amount of fruits and vegetables, and more than a third are not getting enough exercise. On top of these, family history of CRC is common among many families in the state, making it much more likely for individuals to develop the disease. 

On a national level, Kentucky is known for having some of the poorest diets, which includes a regular consumption of fried foods, meats, and bread. Fried foods and over-processed meats, in particular, can expose one’s body to carcinogens that have been linked to CRC as well as various other cancers. 

Kentucky Culture 

Born out of Corbin, Kentucky, Colonel Sanders’ fried chicken restaurant quickly grew to become a very popular and profitable chain of fast food spots. Known for serving bowls, pot pies, mashed potatoes, and loads of fried chicken, KFC has been a hot-spot since the 1940s. It might seem like an easy fix to tell residents to just “eat healthier”, but unhealthy diets that are deeply ingrained in a state’s culture and history are very hard to just simply eradicate. 

Telling residents of Kentucky to stop eating their fried foods is like telling residents of New York to stop drinking coffee; they may just laugh in your face. Changing the standard American diet and encouraging healthy eating habits remains a challenging endeavor for healthcare workers, researchers, community educators, and the population itself. 

Educating Communities

For starters, access to dietary and lifestyle counseling should be expanded throughout all states in America. In doing so, people would inherently have the opportunity to reflect on their own eating habits, and create plans to maximize their nutrient intake, while also learning how to be financially feasible in doing so. Many people may not even be aware of the significant health consequences of their dietary habits, and they will never know unless people are intentionally educating communities about these crises. 

People don’t need to entirely restrict certain foods in order to avoid CRC, but a gradual decrease of the consumption of fried/heavily processed foods while simultaneously increasing the consumption of vegetables, fruits, and leaner meats will lead to a new culture: one where CRC is not a common disease in one’s community or town. 

 

Parker Lynch is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Picture credit Larry White from Pixabay.

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Gut Microbes Play an Important Role in Colorectal Cancer

By Emmanuel Olaniyan

Colorectal cancer (CRC) is one of the more common types of cancer and is the third largest cause of cancer-related deaths worldwide. According to the American Cancer Society, 153,020 new cases of CRC are expected to be detected throughout the U.S. in 2023, out of which 52,550 people will die from the disease. Considering these figures, it is important to raise public awareness about CRC in order to decrease the number of CRC-related deaths and new cases.

Several studies have researched the causes of CRC, and age, diet, genetics, and the gut microbiota have all been identified as risk factors in various ways. The gut microbiome, in particular, has been shown to play an important role in a number of diseases, and research has begun to focus heavily on its role in CRC. 

What is the Gut Microbiome?

The human gut microbiota refers to the trillions of microbes, such as bacteria, viruses, fungi, and others present in the human digestive tract. The microbiome is the environment they live in. Most microbes in the body are beneficial, but they may become harmful when out of balance.

The gut microbiota is crucial for the overall functioning of a healthy digestive system because it supports the absorption of energy from digested food, guards against pathogens, controls immunological response, and fortifies biochemical barriers of the intestine. However, when harmful bacteria enter the gastrointestinal tract through eating contaminated food or drinking contaminated water and cause infection, all of these advantageous activities could be disrupted.

Jaeho Kim and Heung Kyu Lee published a study in 2022 that found a strong association between gut microbiota and CRC. They came to the conclusion that the patients with CRC experienced dysbiosis (an imbalance in bacterial composition, changes in bacterial metabolic activities, or changes in bacteria distribution within the gut) more frequently than healthy individuals. Opportunistic infections were discovered to be more prevalent, and intestinal inflammation has been shown to be reduced along with the percentage of bacteria that produce butyrate, which is an essential component of our digestive system that reduces inflammation in the digestive tract, protects the brain and prevents cancer.

How Can We Maintain a Healthy Gut Microbiome?

Maintaining good hygiene and being mindful of the foods we eat can help keep our gut microbiota healthy. Studies have shown that eating more processed foods and a low intake of dietary fiber increase the risk of CRC. For this reason, it is recommended to consume fermented foods like cheese, soy sauce, vinegar, and yogurt as well as meals high in fiber like whole grains. It has been established that the bacteria present in these fermented foods are similar to those linked to gastrointestinal health. 

Finally, a decrease in processed food consumption and antibiotic use lowers the risk of developing CRC caused by gut microbes. 

 

Emmanuel Olaniyan is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Image source: OpenClipart-Vectors from Pixabay

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Pathways to Nutritional Prevention: an Infographic

Nutrition & Colorectal Cancer Prevention Series: Blog 3

In the previous installments of this blog series, we explored both the molecular pathways behind dietary prevention of colorectal cancer (CRC) as well as the barriers within the built environment that prevent individuals from properly accessing those preventative nutrients. This post will further explore strategies and resources that can aid communities in achieving a balanced diet.

With rising costs of living and barriers in the built environment such as food deserts, reducing CRC through dietary prevention can feel like a daunting task, but there are many resources available that can provide support in this process. 

So how can individuals identify resources that are available to them? This can be done through a multi-pronged approach from accessing fresh food from local organizations to engaging in nutritional education classes. 

Where can you find these resources? Findhelp.org is a database that provides direct links to resources in your zip code. Individuals can input their location and find resources from direct food access, to community gardens, to education. 

Our infographic below provides a snapshot of how integrating dietary pathways can help CRC prevention.

 

Emma Edwards is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Photo credit: Nathan Dumlao on Unsplash

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Tackling Fresh Food Inequality: Navigating the Landscape of Food Deserts and Nutrition

Nutrition & Colorectal Cancer Prevention Series: Blog 2

The first installment of this blog series provided an overview of the molecular pathways that enable dietary interventions to prevent and reduce the spread of colorectal cancer (CRC) cells in the body. These pathways have laid the foundation for this week’s installment: addressing the systemic barriers that prevent individuals from accessing the nutrition they need to reduce CRC risk. 

Connecting the Dots: Access, Healthy Food, and CRC

The link between food deserts (areas with limited access to low-cost yet nutritious food) and health outcomes is well established. Like most health disparities in the U.S., black, brown, and low-income communities are more likely to live in locations with sparse options for fresh, healthy dietary choices. Individuals living in these food deserts often need to drive an extended distance to access fresh fruits and vegetables, as the options near their residences are canned, frozen, or unavailable. Additionally, food swamps are similarly deficient in healthy nutritional options but are marked by a high ratio of fast food to fresh food options. Lack of proximity to fresh and less processed foods contribute to the social determinants of health and make it far more difficult for individuals in these communities to engage in proactive prevention. 

In an article published in May of this year, researchers explored the epidemiologic links between counties with high food desert and food swamp scores and obesity-related cancer mortality rates. Individuals residing in counties with high food swamp scores were found to have significantly (77%) higher odds of obesity-related cancer mortality. The authors similarly identified a positive dose-response relationship between obesity-related cancer mortality and food desert and swamp scores. 

Improving Access to Fresh Foods in These Communities

While individuals living in these geographic locations have substantial barriers, local organizations can help provide services that bridge the gap. Many local food pantries have developed programs to bring fresh foods to communities in need. Volunteers will pack pre-selected boxes of fresh ingredients and set up a free farmer’s market in a community that lacks access to those ingredients, eliminating the transportation barrier and making dietary prevention, or the process of maintaining a balanced and nutritious diet to prevent disease, a more accessible goal. 

Feeding America has an online tool that locates mobile food pantries with a click and a zip code. Local food pantries may also provide delivery services to elderly or disabled individuals, so check in with your local organization to learn more!

Emma Edwards is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Picture credit OpenClipart-Vectors from Pixabay.

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Enhancing Colorectal Cancer Prevention with Diet: Molecular Pathways and Improved Outcomes

Nutrition & Colorectal Cancer Prevention Series: Blog 1

The link between nutrition and colorectal cancer (CRC)  prevention is well established. Researchers have found that low-inflammation diets, such as Mediterranean diets, are associated with lower risk of CRC. This study also affirmed the link between sugar intake and CRC risk, with individuals who consume beverages high in sugar being more likely to develop rectal adenomas. 

Other studies have explored the links between highly processed foods and development of colorectal adenomas. In addition to highly processed foods, canned foods have also been shown to increase risk of colorectal polyps when measured against fresh fruits and vegetables.

These associations provide evidence that a low-inflammation diet that is low in sugar and processed foods can lower the risk of developing CRC; however, there is limited research on the impact of nutritional interventions on those who are already diagnosed. 

Can Dietary Interventions Improve CRC Outcomes?

A study published earlier this year explored the answers to that very question. 

In accordance with previous research, the authors found that the Mediterranean diet was effective in reducing CRC tumor growth. The mechanisms that are responsible for this inhibited tumor cell growth include the presence of beta-carotene, which is found in a number of fruits, vegetables, and fish. When beta-carotene interacts with fibroblast activation markers, the fibroblasts repress tumor cell growth in the colon. 

Additionally, anti-inflammatory diets can suppress the growth of CRC tumors via immune system pathways. Tea polyphenols, most commonly found in green tea, add diversity to the gut microbiota by often raising short-chain amino acid levels, which in turn promotes the growth of anti-inflammatory gut bacteria. Elevated levels of these “good bacteria” help to modulate the environment within which CRC develops, and aid the immune system in preventing tumor cell growth and spread.

While it is important to understand these pathways, successful, consistent implementation of preventative diets is the key to unlocking the benefits that come from the pathways. The chart below, adapted from this study, provides a framework for workable diet and lifestyle interventions during the various stages of colorectal cancer treatment, from diagnosis to surgery. Key elements of these interventions involve exercise, protein intake, and supplementation of key nutrients such as omega-3 fatty acids. 

 

Blog 2 in this series can be found here: Tackling Fresh Food Inequality.

Emma Edwards is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

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Plant-Based Diets Lower Colorectal Cancer Risk in Men

Colorectal cancer (CRC), the third most common cancer and the third leading cause of cancer-related deaths in the U.S., is preventable with regular screening. In addition to routine screening, other modifiable risk factors, such as diet, play an important role in lowering the risk of CRC. For example, red and processed meats are associated with an increased risk for CRC, while diets rich in dietary fiber reduce the risk of CRC. 

A recent prospective cohort study discovered that plant-based diets rich in healthy plant foods were associated with a lower risk of CRC in men, and varied based on race, ethnicity, and tumor location. These findings signify the importance of incorporating healthy plant foods into diets and reducing meat consumption to lower the risk of CRC. 

The multiethnic cohort study included 79,952 men and 93,475 women. Three plant-based diet scores were investigated to determine the incidence of invasive CRC:

  • Overall plant-based diet index (PDI)
  • Healthful plant-based diet index (hPDI)
  • Unhealthful plant-based diet index (uPDI)

The participants completed a food frequency questionnaire with over 180 food items. PDI, hPDI, and uPDI were calculated based on scoring methods and defined food groups that included:

  • Healthy plant foods, such as whole grains, fruits, vegetables, vegetable oils, nuts, legumes, tea, and coffee.
  • Less healthy plant foods, such as refined grains, fruit juices, potatoes, and added sugars.
  • Animal foods, such as animal fat, dairy, eggs, fish and seafood, and meat. 

Each food group was associated with specific scores. 

  • High PDI scores demonstrated greater consumption of all types of plant foods. 
  • High hPDI foods showed greater consumption of healthy plant foods and lower consumption of less healthy plant foods. 
  • Higher uPDI scores demonstrated lower consumption of healthy plant foods and greater consumption of less healthy plant foods. 

The study found that a plant-based diet that includes natural, rather than processed, plant-based foods is associated with a reduced risk of CRC in men. For women, however, none of the plant-based diets were significantly associated with CRC risk. For both men and women, the average scores of PDI and hPDI were highest among Japanese Americans and lowest among Native Hawaiians. The mean uPDI was highest in Native Hawaiian men and lowest in African American men and white women. Men with higher scores for PDI and hPDI had a 24% and 21% lower risk of CRC than men with lower scores for those diets, respectively. Furthermore, no significant association was found between risk for CRC and uPDI for men.

These analyses highlight the potential significance of plant-based diets in preventing CRC and suggest that the benefits of plant-based diets can vary based on sex and race/ethnicity. The findings underscore the importance of increasing healthy and less-processed plant foods in our diet and reducing meat consumption to lower the risk of CRC.

 

Sahar Alam is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

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In Conversation With Dr. Alessandro Mannucci: Understanding the Relation Between Lynch Syndrome and the Oral and Fecal Microbiota

Image Credit: CDC on Unsplash

The Colon Cancer Foundation (CCF) spoke with Alessandro Mannucci, MD, who received the 2022 Colon Cancer Foundation and CGA Colorectal Cancer Research Scholar Award to present his work at the 2022 CGA-IGC Annual Meeting in Nashville, TN, November 11-13. Dr. Mannucci, a medical resident in gastroenterology and gastrointestinal endoscopy at the San Raffael Hospital, Milan, Italy, will be presenting his work titled ‘Lynch Syndrome is Associated with Fecal and Salivary Dysbiosis’.

CCF: What is the importance of the gut and the microbial flora in the human body, and how do they influence our well-being?

Dr. Mannucci: Broadly speaking, the microbiota is made up of many different cell types, including bacteria, viruses, fungi, and other kinds of microorganisms. However, our study specifically focused on bacteria because it is known that we have way more bacteria in our body than human cells. That alone indicates the significant impact of the microbiome on different phases of our life—from childhood to adulthood. 

The disruption of a healthy microbiome equilibrium causes the components of the microbiome to converge toward a proinflammatory environment in several ways. Certain species increase the risk of colorectal cancer [CRC]. Organisms that increase in numbers in the presence of CRC are generally proinflammatory. This understanding has come simultaneously with the realization that inflammation is one of the new pillars of cancer. The inflammatory environment is a disruption that is particularly important when studying the colon because the colon is the first organ in direct contact with the microbiome. 

CCF: Can you tell us the importance of this fact in your research? 

Dr. Mannucci: In our study, we had a suspect: the microbiome. While the microbiome is known to play a role in turning a normal cell cancerous, this association had not been investigated in the context of the hereditary Lynch syndrome [LS]. Mutations in one of five genes can lead to LS. 

There is a spectrum of manifestations of LS, the most important of which is CRC, although developing the cancer is determined by penetrance. We were interested in knowing if the microbiome has a role in this process.We wanted to know if the microbiome in individuals with LS who had not yet developed cancer, differed from those without LS. While it may be difficult to explain a cause-and-effect relationship, it is important to understand why a difference exists. Germline pathogenic variants may influence the formation, conformation, and diversity of the microbiome, or vice versa. Interestingly, we found that the fecal microbiota was significantly different among those with LS, but we need more data.

CCF: What is the relevance of microorganisms in the oral cavity? 

Dr. Mannucci: In individuals with LS, the cells within their mouth are also mutated. So we decided to test the differ

 Alessandro Mannucci, MD

ence between the fecal and oral microbiota among those with and without LS and found that not only is the fecal microbiota different, which you would expect because LS is associated with an increased risk of CRC, but we also observed a proinflammatory change in the oral microbiota. We now know that the oral microbiota of patients with LS differs from that of healthy individuals, which raises the question that pathogenic variants inside the mouth may interact with microbiota species that cause a proinflammatory shift. 

Another hypothesis is that individuals with this particular hereditary predisposition to CRC may also have a predisposition to orthodontic diseases. While we currently have limited understanding of this association and are testing the hypothesis, our discovery of the unexpected difference of a proinflammatory environment led us to suppose that maybe something else was at play.

What is interesting when we talk about scientific studies is not only what you are interested in, but also what you compare it to. In our case, we compared LS patients without cancer diagnosis to unrelated, healthy patients. So we did not have within-family control, which other investigators might want to look at–within the family or individuals with LS in different age groups.

CCF: How long will the subjects in your study be followed?

Dr. Mannucci: While we usually follow patients throughout their lives, five to ten years of follow-up will give us more insight. The idea is that if there is a proinflammatory environment within that patient, it could trigger cancer at an earlier age. To test that hypothesis, we are collecting samples of relatively young individuals, and we want to follow them and see if they develop cancer. The mean age of patients with LS was 48 years plus or minus 16 years.

CCF: Does diet influence microbial flora and the balance of pro- versus anti-inflammatory microbial flora in the oral cavity and the gut?

Dr. Mannucci: You raise a very, very interesting point! The microbiota is adaptable, and it can change very rapidly. There is some robustness to it, meaning you shape the health of your microbiome during your youth and by the time you reach adolescence or young adulthood, your microbiota is pretty much set. However, it can change based on your diet. 

One of our study limitations is that we could not control for diet. We could control other factors that can influence the changes within the microbiota itself, such as age, sex, smoking, the presence of cancer, or chemotherapy treatment—factors that can modify the shape, overall biodiversity, and the general composition of the microbiota.

However, we could not control the overall dietary composition. In the future, we may control our patients’ diet and place them either on a Western diet as opposed to a Mediterranean diet or a modern diet. 

Assuming that individuals with a higher risk of CRC follow an anti-inflammatory diet, you would expect to see an anti-inflammatory microbiota. We found the opposite; we found a proinflammatory change within the microbiota. While we are planning to control for participant diets in future studies, an alternative approach would be to include individuals with different genetic backgrounds and eating similar diets to investigate the differences in their microbiota. 

But remember, this is currently a hypothesis. What we know now is that these genetic predispositions are associated with a difference in the microbiota composition, and that difference itself is a proinflammatory environment. We don’t know the cause-effect relationship or how that can be altered, yet.

CCF: What would be a key takeaway from your study findings?

Dr. Mannucci: A key takeaway is that we’re developing a tool to better understand who does or does not get cancer. Hopefully, it will become a tool or a target to reduce the risk of cancer. I completely agree that diet can be a big influence. So maybe in the near future, we will be able to tell our patients that if they stop smoking, regularly exercise, reduce the intake of fatty foods, and if they have a specific kind of diet, they can reduce their risk of CRC. The microbiota has the potential to become an instrument for reducing the risk of cancer, but we are not there yet.

Thank you to Sahar Alam, CCF’s Colorectal Cancer Prevention Intern, for her assistance with this post.

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Ultra-Processed Foods a Risk Factor for Colorectal Cancer

Diet has been recognized as an important modifiable risk factor for colorectal cancer (CRC). In particular, diets consisting of high fats and carbohydrates, such as red and processed meats, are considered high-risk. Now, a large-scale cohort study among U.S. residents has revealed that high consumption of ultra-processed foods might increase CRC risk in men—the third most diagnosed cancer in the U.S.. 

For the past two decades, researchers have witnessed a significant increase in the consumption of ultra-processed foods, industrial ready-to-eat or ready-to-heat products high in refined sugars, refined starch, and trans fats. Ultra-processed foods currently contribute to 57% of the total daily calories consumed by American adults. A growing pool of evidence suggests that ultra-processed foods increase CRC risk by altering the composition and diversity of gut microbiota and increasing the risk of obesity.  Some examples of these foods include bread and rolls, breakfast bars and cereals, hotdogs and other processed meats, packaged sweet snacks and desserts, jams and jellies, and condiments, among other things.

The above-mentioned study analyzed responses from over 200,000 participants—159,907 women from the Nurses’ Health Study (1986-2015) and 46,341 men from the Health Professionals Follow-up Study (1986-2014)—across three large prospective studies in the U.S. that assessed dietary intake. The follow-up period was between 24-28 years. At the time of study enrollment, none of the participants had any cancer diagnoses. Information on dietary intake, demographic characteristics, lifestyle factors, and medical conditions of the participants was obtained through food frequency questionnaires every four years. 

Of the 206,000 participants who were followed for more than 25 years, the research team documented 1,294 cases of CRC among men and 1,922 cases among women. The study findings indicated that those who consumed the highest amount of ultra-processed foods had a 29% higher risk of CRC compared to those with the lowest consumption. However, this was not observed among women. Among women, the risk of CRC was positively associated with higher consumption of ready-to-eat or ready-to-heat mixed dishes. In contrast, higher consumption of yogurt and dairy-based desserts was linked to a reduced risk of CRC among women. 

These findings support the importance of limiting certain types of ultra-processed foods for better health outcomes. Here are some additional resources on diet and lifestyle and how they can influence your colon health and overall wellness:

  1. Healthy Inside and Out: How Diet and Lifestyle Impact Colorectal Cancer
  2. Dietary Mindfulness Can Reduce the Risk of Colorectal Cancer
  3. Diet and Nutrition to Prevent Colon Cancer

 

Kitty Chiu is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Image credit: Tim Toomey on Unsplash

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Improving Colorectal Cancer Screening Rates in Mississippi

In past years, the rate of colorectal cancer (CRC) has become a serious public health problem in Mississippi. A study conducted in 2020 showed that Mississippi had one of the highest mortality rates from CRC as well as one of the CRC lowest screening rates between 2015 and 2019. The state also leads the nation in cardiovascular disease mortality rates as well as diabetes mortality. These are both known comorbidities for many types of cancers, including CRC. 

One theory as to why the screening rates are so low in Mississippi is that about 55% of the state’s population resides in rural locations, which may make it hard for some individuals to access regular medical care. The rural population in Mississippi has a high rate of uninsured individuals making it hard for this population to afford regular screenings. In 2016, 14% of the population under 65 were uninsured. 

Another theory as to why CRC rates are so prevalent in Mississippi is that the diet of many of the residents is high in red meat and low in fiber. This is in part due to a culture that relies on red meat and processed foods. This diet is also more prevalent in areas that have a low socioeconomic background, as it can be difficult to obtain healthy food if one lives in a food desert. 

Colorectal cancer-related mortality in those over 50 (2014-2018).
Data source: https://statecancerprofiles.cancer.gov/map/map.noimage.php.

Fortunately, the Mississippi government recognized the issue and has developed a plan to help increase the screening rate of residents in Mississippi and decrease mortality rates —70X2020 was initiated in 2014. Since the start of the program, there has been an increase in individuals who got screened, specifically in minority communities. So far, screening rates have improved from 55% in 2014 to 69.9% in 2020. For white individuals there was a compliance rate of just under 70% and for black individuals there was a compliance rate of just above 70% in 2020. 

From this case study, we are able to theorize that screening and diet play a crucial role in the development of CRC. We are also able to see that there is a strong correlation between screening rates and CRC mortality rates. 

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Dr. Cynthia Sears Explains the Connection Between Our Diet, The Gut Microbiome and Colorectal Cancer

The Colon Cancer Foundation recently had the opportunity to speak with Dr. Cynthia Sears, Professor of Medicine and Oncology, Johns Hopkins University School of Medicine; Professor of Molecular Microbiology and Immunology at the Bloomberg School of Public Health. She is also the leader of the Bloomberg-Kimmel Institute for Cancer Immunotherapy at Johns Hopkins. Her current research focus is on the microbiome and how specific bacteria can contribute to colon cancer.

Dr. Sears, received her medical degree at Thomas Jefferson Medical College and completed her training in internal medicine at the Cornell Medical School, and trained in infectious diseases at The Memorial Sloan Kettering Cancer Institute and the University of Virginia. Over the past 20 years, Dr. Sears has conducted research on colonic microbiota and colon cancer, making her an expert in this field.

Q. What enticed you to start studying bacteria and the microbiome in relation to colon cancer.  

Dr. Sears: I am an infectious disease doctor who got into internal medicine because of previous work I conducted. I conduct research on how the microbiome is impacted by organisms and bacteria. I am also looking at improving immunotherapy response among colon cancer patients, since, unfortunately, only 20% to 30% of colon cancer patients respond to immunotherapy—a majority of patients do not respond. I am currently working to help improve treatments for cancer patients.

Dr. Cynthia Sears

Q. Can you help us improve our understanding of the interaction between a person’s dietary habits and the gut microbiome and how it relates to colorectal cancer?

Dr. Sears: There’s been substantial research showing that diet is a major driver of the composition and function of the microbiome. Individuals who shifted from a meat based diet to a vegetarian diet can see a shift in their microbiome in the first 24 to 48 hours. This shows that we have the ability to impact our microbiome based on the foods we eat. It also shows that we all have the capacity to have a “good” microbiome. It is also important to note that each person is different in their response to a particular diet. For example, some individuals can eat ice cream and pizza and have no change in their physiology, while others may have a terrible response.

Q. Talking about the “ideal” diet, is there really an “ideal” diet? What impact does an individual’s genetics or environmental factors have on the gut microbiome?

Dr. Sears: We are not very good at targeting the individual level. As a society we can’t afford the type of testing it would require to figure out exactly what each individual should and should not be eating. We really must rely on public health and what’s best for most people. In relation to genetics, it’s published that less than 10% of the effect in our microbiome is related to our genetic makeup. There’s a lot of redundancy in the microbiome. We can have three perfectly healthy individuals and when we sequence their microbiomes, they would all look totally different. In one person a certain bug may be taking up a niche and promoting the production of short-chain fatty acids and in another individual, a totally different bug could be doing the exact same thing.

Q. There has been a lot of research comparing the Mediterranean diet with the Western Diet, with the Mediterranean diet being rich in grains, fiber, fruit, vegetables, and fish meanwhile the Western diet is high in fat and red meat. Do you have any advice for individuals on what diet they should follow?

Dr. Sears: People should try and follow a Mediterranean diet or the DASH [Dietary Approach to Stop Hypertension] diet. I’m a big fan of the idea that food is medicine.

Q. What would you like the public to know about the gut microbiome?

Dr. Sears: We are at least as many microbes as we are human cells but the microbes are just much smaller so the human cells are more evident. Microbes are critical to our overall health. Individual’s should strive to foster a good microbiome whether it’s on your skin, your mouth, or in your colon. There is also literature about the impact that exercise and physical activity can have on your gut microbiome as well as brain health and vascular health. The more an individual is focused on healthy living, the better they will be overall.

Q. What do you think is the future of this field?

Dr. Sears: The future direction in this field is immunotherapy, where we can use the microbiome as a biomarker. When you do a stool test or a plasma test the doctors will be able to tell you if you are more or less likely to respond to this therapy based on a microbial signal. This can relate to colorectal cancer because early-age onset colorectal cancer [EAO-CRC] is becoming frighteningly common but it is still rare enough that we are not doing colonoscopies on everyone under the age of 50. We can hopefully do something to see if a person is at a higher risk and then we can focus our care and try to prevent EAO-CRC. 

 

Here are some additional resources on diet and lifestyle and how they can influence your colon health and overall wellness:

  1. Healthy Inside and Out: How Diet and Lifestyle Impact Colorectal Cancer
  2. Dietary Mindfulness Can Reduce the Risk of Colorectal Cancer
  3. Could the Western Diet Be a Risk Factor for EAO-CRC?
  4. Have You Had Your Fiber Yet? Food Habits and the Risk of Colorectal Cancer
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