Well it certainly feels good to write again. In the midst of fellowship applications and a tough July at work, blogging has been the last thing on my mind.. but as usual I start to miss it! A while back I asked for suggestions of new blog topics, and was so pleased to get a few questions regarding colon cancer & healthy colons in general. How cool is that?! Love you guys. I absolutely love writing about med school, residency etc., but it's truly a JOY to talk about anything related to health/prevention and if it's involving the GI tract? Yes please.
Referring to colon health, I'm mainly speaking about the prevention and screening for colon cancer. However much of what I'll discuss is doubly applicable to other conditions such as diverticulosis (outpouchings of the colon prone to bleeding and infection) as well as the general maintenance of having regular bowel movements (I could write an entire book on the management of constipation, but that's for another day.)
We care about colon cancer because it's the second most common kind of cancer and the third leading cause of cancer deaths. The majority of cases occurs in industrialized nations with a "western lifestyle" which already clues you in to what puts you at risk. When it comes to prevention, there are factors that are out of our control. Random genetic mutations and familial syndromes exist that put a person at risk for developing cancer regardless of prevention and screening. However, there are modifiable risk factors for which we CAN control; namely these are diet, physical activity, weight management, & tobacco/ alcohol use (you know, the usual important things.)
There have been hundreds upon hundreds of studies trying to pin down *specific* aspects of a diet that may increase the risk of colon cancer, but with poor reproducibility and consistency in results. Examples of these concepts include the following: high fiber diet, diet with low meat consumption, calcium supplementation, vitamin B6 supplementation, and antioxidants. Comparing these specific nuances to their counter-diets didn't seem to yield a major effect of the incidence of and mortality related to colon cancer. What DOES prove to be consistently true is dietary patterns, meaning avoidance of the Western Diet in general [source]. It isn't simply cutting out meat, or taking a calcium supplement that mitigates your risk of colon cancer but rather the interconnected advantage of moving towards a whole foods/unrefined/lower sugar/high micronutrient content diet. The small specifics of moving away from the Western diet will look different for everyone (not necessarily vegan, or paleo, or whatever..) but the further we move away from processed and/or fast food likely the lower our risk for colon cancer. (Ya don't say!)
In much of my constant reading in preventive medicine, diet almost always trumps exercise as the most important factor in preventing any disease. When it comes to colon cancer however, it appears that more studies have consistently linked higher levels of physical activity with a reduced risk. Interestingly, one meta analysis finds a dose-response relationship for this-- meaning that the more exercise you do the less your risk [source.] This does NOT mean that moderate exercise (e.g., walking 30-40 minutes 4x/week) doesn't reduce your risk.. so if this is what you can do, DO IT! The specific pathways for HOW exercise does this is unclear, but likely related to its affect on insulin resistance (reducing insulin-like growth factor which is involved in tumor growth), and reducing systemic inflammation. COOL- now i feel like going for a run :-)
I'm always hesitant to discuss body weight as a risk factor because of the emotions it stirs regarding body image. Truthfully, I share information here objectively and in doing so, it can't possibly be viewed as "body shaming" because it is my professional responsibility to explain the risks associated with excess body weight. As a disclaimer I always feel its important to share the notion that overweight does NOT equal unhealthy, just as "normal" weight does not equate to healthy. There are a myriad of other components that make up an ideal health profile and body weight is just one (albeit an important one.) Furthermore, it's essential we talk about body composition compared to total body weight. Unfortunately almost all studies look at BMI (Body Mass Index) that does not take into consideration lean body mass versus fat mass. So while the majority of studies can link an elevated BMI to increased risk of colon cancer, I'd expect a very physically active person who ends up with an increased weight due to muscle mass to have a lower risk for colon cancer compared to the "normal weight/poor lifestyle" individual. As always, I still support the notion of changing the lifestyle habits WITHOUT a weight loss goal in mind. Weight loss should simply be a side effect-- NOT the goal.
TOBACCO & ALCOHOL
I shouldn't even have to write that tobacco increases the risk for cancer. The single most IMPORTANT thing a smoker can do for their health is to quit. Forget about diet, working out, sleeping, stress, etc... all your energy should be toward the single goal of giving up cigarettes or other tobacco products, end of story. Specifically for colon cancer, 15-20% of cases are DIRECTLY related to smoking, let alone the interplay it likely has for many other risk factors. If people stopped smoking, there would be 15-20% LESS cases of death from colon cancer (let alone all the other diseases it ultimately affects which is basically all of them.) STOP SMOKING OK?
For alcohol, most of the studies we have available examine the consumption of 2+ more drinks per day, which not surprisingly there is an associated increased risk. The affects of very moderate to minimal consumption is unclear, but I would venture to say that no drinks is better than some (but if the occasional social drink makes the rest of your life better.. I'm not one to stop you.)
While eating plants, moving your body, and avoiding tobacco/alcohol are essential aspects of colon health and in my preventive minded practice I support these changes 100%, I want you to know that truly the MOST important thing you can do (ok except maybe besides not smoking. Seriously don't smoke, it sucks) is to comply with colorectal cancer screening. You know, a colonoscopy. (Or other screening modalities, but colonoscopy is still the most highly regarded tool for cancer screening.) If you are completely averse to the idea of a colonoscopy (drinking a wonderful delicious laxative resulting in pooping water, and then allowing a gastroenterologist examine your colon by sticking a camera up your rectum, what do you mean that doesn't sound appealing? Please talk to your doctor about other options including a newer screening modality called a FIT test, which basically looks at a small sample of your poop for DNA seen in blood. If this test is positive, you would THEN be highly advised to get a colonoscopy for diagnostic purposes.
When do you need to start screening? If you are of "average risk" meaning without family history and without symptoms (no blood in your stool, anemia, unintentional weight loss, no inflammatory bowel disease, no family history of colon cancer) your screening should start at the age of 50. Many gastroenterologists and internists will also recommend that African Americans start screening at age 45 due to the increased incidence at an earlier age.
What about with family history? In that case, you would start 10 years BEFORE the age of diagnosis of your first degree relative. For example- if your father was diagnosed with colon cancer at age 56, you would be recommended to get your first colonoscopy at age 46 to reduce your risk of presenting with an invasive tumor compared to the early development of a polyp or pre-cancerous lesion. As always I advise you speak to your own doctor directly regarding when and how you will be screened.
I hope this brief blog provides some reminders of what we already know-- that living a well balanced, healthy lifestyle in general benefits every aspect of our wellness, including that of our colon! Please share with friends/family ready to take charge of their health <3