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Protect Your Colon Part One

December 6, 2014 Written by JP    [Font too small?]

Nobody wants to get a colonoscopy. But, much like going to the dentist, it’s a preventive care necessity. Unlike most other diagnostic tests, colonoscopies not only detect cancer, but can also prevent it by removing polyps which may develop into cancer. In fact, researchers from the Dana-Farber Cancer Institute and Harvard recently concluded that colonoscopies are by far the most accurate tests to identify and reduce the risk of cancerous growths both in the distal (right) and proximal (left) sides of the colon.

Besides the obvious discomfort associated with a colonoscopy, fear of the results deters some from having the test. However, it’s vitally important to note that most imaging and lab results come back “clear” – i.e. no cancer or pre-cancerous polyps. More importantly, if the analysis of a removed polyp reveals cancerous cells, there are several steps you can take which may lower the risk of developing colon cancer in the future.

According to the latest research, anyone concerned about or at risk for colorectal cancer (CRC) should consider a diet rich in fiber, fruits, magnesium and non-starchy vegetables. This may explain why the so-called “Mediterranean diet” appears to confer protection against CRC. Select berries including black currants and black raspberries may be particularly helpful as they beneficially alter gut bacteria, enzymes and genes that are implicated with colon cancer development. Also interesting is that the berry studies in question have utilized powdered extracts of the fruits. This makes long-term consumption much easier when fresh or frozen berries aren’t available. What else should you eat? A large population study published in the American Journal of Clinical Nutrition goes on to recommend a food plan containing plenty of “fruit and deep-yellow vegetables, dark-green vegetables, onion and garlic” to reduce the “risk of colorectal adenoma, a precursor of colorectal cancer”. In short, the authors are referring to antioxidant-rich, low-glycemic, whole foods.

The role of exercise in colorectal protection cannot be overstated. A classic study appearing in the September 2007 issue of the journal Cancer Epidemiology Biomarkers & Prevention found that a “moderate-to-vigorous” program centered around the use of exercise machines, 60 minutes daily for six days of the week, promoted healthier cell regulation in the colon. Abnormal cell growth or proliferation is pivotal for cancer to take hold and spread. Other research indicates that strength training is, likewise, protective because it reduces several suspected risk factors for colorectal cancer, including high blood sugar, body fat, insulin and IGF-1 (insulin-like growth factor-1). Although exercise isn’t very effective in the promotion of weight loss, it can assist with the prevention of weight gain. Overweight has been consistently linked to colorectal malignancies. All the more reason to stay active and watch your diet.

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

To learn more about the studies referenced in today’s column, please click on the following links:

Study 1 – Study Reinforces Value of Colonoscopy Screening for Colorectal Cancer (link)

Study 2 – Mediterranean Diet and Colorectal Cancer Risk: Results from a European (link)

Study 3 – Evaluation of the Effect of Blackcurrant Products on Gut Microbiota and (link)

Study 4 – Modulation of Genetic and Epigenetic Biomarkers of Colorectal Cancer (link)

Study 5 – Plasma Cytokines as Potential Response Indicators to Dietary Freeze- … (link)

Study 6 – Fruit and Vegetable Intake and Prevalence of Colorectal Adenoma (link)

Study 7 – Dietary Fibre Intake and Risks of Cancers of the Colon and Rectum (link)

Study 8 – The Relation of Magnesium and Calcium Intakes and a Genetic … (link)

Study 9 – Effect of a 12-Month Exercise Intervention on the Apoptotic Regulating (link)

Study 10 – Effects of a 9-Month Strength Training Intervention on Insulin, Insulin- (link)

Diet-Induced Weight Loss Lowers Colorectal Cancer Risk Markers

Source: Am J Clin Nutr. 2011 Feb;93(2):234-42. (link)

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Posted in Exercise, Food and Drink, Nutrition

10 Comments & Updates to “Protect Your Colon Part One”

  1. JP Says:

    Update: Coffee appears to afford protection as well …


    Int J Cancer. 2014 Dec 10. doi: 10.1002/ijc.29390.

    Coffee intake and the risk of colorectal adenoma: The colorectal adenoma study in Tokyo.

    Coffee is a commonly consumed beverage which contains several potential anticarcinogenic and chemopreventive compounds, and has been hypothesized to have protective effects in colorectal neoplasia. However, the limited available data on coffee consumption in relation to colorectal adenoma (CRA), a precursor lesion to most colorectal cancers, remain largely inconsistent. In this study, we evaluated the association of coffee intake with the risk of CRA in a middle-aged Japanese population. Study subjects were selected from examinees who underwent total colonoscopy as part of a cancer screening program and responded to self-administered dietary and lifestyle questionnaires. A total of 738 patients with adenoma and 697 controls were included in the study. Coffee intake was assessed with a food frequency questionnaire, and divided into quartiles based on the distribution among controls. Unconditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) of CRA, with adjustment for potential confounding factors. High coffee consumption was associated with a reduced risk of CRA, with a multivariate-adjusted OR for the highest versus lowest quartile of coffee intake of 0.67 (95% CI=0.48-0.93; Ptrend =0.02). The inverse association of coffee intake was limited to proximal (OR=0.64; 95%CI= 0.44-0.95; Ptrend =0.04) and distal colon adenoma (OR=0.62; 95%CI=0.39-0.99; Ptrend =0.06), and appeared to be more evident with small (OR=0.68; 95%CI=0.49-0.96; Ptrend =0.04) and single adenomas (OR=0.65; 95%CI=0.44-0.95; Ptrend =0.02). Green tea intake was not found to be associated with CRA risk. This study provides support for the protective effect of coffee drinking on colon adenomas, a precursor of colon cancer.

    Be well!


  2. JP Says:

    Update 05/18/15:


    Nutr Cancer. 2015 Apr 14:1-9.

    Effects of a Mediterranean Diet Intervention on Anti- and Pro-Inflammatory Eicosanoids, Epithelial Proliferation, and Nuclear Morphology in Biopsies of Normal Colon Tissue.

    This randomized trial evaluated the effects of intervention with either a Healthy Eating or a Mediterranean diet on colon biomarkers in 120 healthy individuals at increased colon cancer risk. The hypothesis was that eicosanoids and markers of proliferation would be favorably affected by the Mediterranean diet. Colon epithelial biopsy tissues and blood samples were obtained at baseline and after 6 mo of intervention. Colonic eicosanoid concentrations were evaluated by HPLC-MS-MS, and measures of epithelial proliferation and nuclear morphology were evaluated by image analysis of biopsy sections. There was little change in proinflammatory eicosanoids and in plasma cytokine concentrations with either dietary intervention. There was, however, a 50% increase in colonic prostaglandin E3 (PGE3), which is formed from eicosapentanoic acid, in the Mediterranean arm. Unlike PGE2, PGE3, was not significantly affected by regular use of non-steroidal anti-inflammatory drugs at baseline, and normal weight subjects had significantly higher colon PGE3 than overweight or obese subjects. Increased proliferation in the colon at baseline, by Ki67 labeling, was associated with morphological features that defined smaller nuclei in the epithelial cells, lower colon leukotriene concentrations and higher plasma cytokine concentrations. Dietary intervention had little effect on measures of epithelial proliferation or of nuclear morphology. The increase in PGE3 with a Mediterranean diet indicates that in normal colon, diet might affect protective pathways to a greater extent than proinflammatory and proliferative pathways. Hence, biomarkers from cancer models might not be relevant in a true prevention setting.

    Be well!


  3. JP Says:

    Update 07/09/15:


    Alcohol Clin Exp Res. 2015 Jun 25.

    Moderate Alcohol Consumption and Colorectal Cancer Risk.

    BACKGROUND: Heavy alcohol drinking is a risk factor for colorectal cancer (CRC); previous studies have shown a linear dose-dependent association between alcohol intake and CRC. However, some studies suggest that moderate alcohol consumption may have a protective effect, similar to that seen in cardiovascular disease. Other factors may interact with alcohol and contribute additional risk for CRC. We aimed to determine the association between moderate alcohol consumption, limited to 30 g of alcohol per day, by beverage type on CRC risk and to assess the effects of other factors that interact with alcohol to influence CRC risk.

    METHODS: The PubMed database was used to find articles published between 2008 and 2014 related to alcohol and CRC. Twenty-one relevant articles were evaluated and summarized, including 11 articles reporting on CRC risk associated with moderate intake and 10 articles focusing on genetic interactions associated with alcohol and CRC risk.

    RESULTS: The association between alcohol and increased risk for CRC was found when intakes exceeded 30 g/d alcohol. Nonsignificant results were consistently reported for intakes <30 g/d. Additional risks for CRC were found to be related to obesity and folate status for regular alcohol consumers. Some significant results suggest that the development of CRC is dependent on the interaction of gene and environment.

    CONCLUSIONS: The association between the amount of alcohol consumed and the incidence of CRC was not significant at moderate intake levels. Moderate alcohol consumption was associated with a reduced CRC risk in study populations with greater adherence to a Mediterranean diet, where wine contributed substantially to the alcoholic beverage consumed. Other factors such as obesity, folate deficiency, and genetic susceptibility may contribute additional CRC risk for those consuming alcohol. To minimize CRC risk, appropriate recommendations should encourage intakes below 30 g of alcohol each day.

    Be well!


  4. JP Says:

    Updated 08/17/15:


    Am J Clin Nutr. 2015 Aug 12.

    Dietary fiber intake and risk of colorectal cancer and incident and recurrent adenoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.

    BACKGROUND: Dietary fiber has been associated with a reduced risk of colorectal cancer. However, it remains unclear at which stage in the carcinogenic pathway fiber may act or which food sources of dietary fiber may be most beneficial against colorectal cancer development.

    OBJECTIVE: The objective was to prospectively evaluate the association between dietary fiber intake and the risk of incident and recurrent colorectal adenoma and incident colorectal cancer.

    DESIGN: Study participants were identified from the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Participants received flexible sigmoidoscopy at baseline and 3 or 5 y after. Dietary fiber intake was measured by using a self-reported dietary questionnaire. The colorectal cancer, incident adenoma, and recurrent adenoma analyses were based on 57,774, 16,980, and 1667 participants, respectively. Unconditional logistic regression was used to assess the risk of incident and recurrent adenoma, and Cox proportional hazards models were used to assess the risk of colorectal cancer across categories of dietary fiber intake, with adjustment for potential confounders.

    RESULTS: Elevated total dietary fiber intake was associated with a significantly reduced risk of incident distal colorectal adenoma (ORhighest vs. lowest tertile of intake: 0.76; 95% CI: 0.63, 0.91; P-trend = 0.003) but not recurrent adenoma (P-trend = 0.67). Although the association was not statistically significant for colorectal cancer overall (HR: 0.85; 95% CI: 0.70, 1.03; P-trend = 0.10), a reduced risk of distal colon cancer was observed with increased total fiber intake (HR: 0.62; 95% CI: 0.41, 0.94; P-trend = 0.03). Protective associations were most notable for fiber originating from cereals or fruit.

    CONCLUSIONS: This large, prospective study within a population-based screening trial suggests that individuals consuming the highest intakes of dietary fiber have reduced risks of incident colorectal adenoma and distal colon cancer and that this effect of dietary fiber, particularly from cereals and fruit, may begin early in colorectal carcinogenesis.

    Be well!


  5. JP Says:

    Updated 12/29/15:


    J Clin Biochem Nutr. 2015 Nov;57(3):217-22.

    Effect of an isocaloric diet containing fiber-enriched flour on
    anthropometric and biochemical parameters in healthy non-obese
    non-diabetic subjects.

    We studied the effect of soluble fiber-enriched products on
    anthropometric and biochemical variables in 30 healthy non-obese,
    non-diabetic subjects. This was a randomized, controlled crossover,
    single-blind, dietary intervention study performed for 8 weeks.
    Subjects received an isocaloric diet with fiber-enriched products for
    the first 4 weeks and with regular flour products for the following 4
    weeks, or vice versa. Weight, height, measures of fat distribution
    (waist, hip circumference), glucose, insulin and triglycerides were
    measured at baseline, after 4 and 8 weeks of intervention. BMI and
    insulin sensitivity indices were calculated. Weight and BMI decreased
    in the first period of isocaloric diet in both groups, regardless of
    the type of flour consumed (weight p<0.01, p<0.001 respectively; BMI p
    = 0.01, p<0.001 respectively). At the end of the 8 weeks, weight and
    BMI further decreased in the group consuming the fiber-enriched diet
    (p<0.01). Insulin resistance, estimated with the Homeostasis Model
    Assessment index and the Lipid Accumulation Product index, improved in
    all subjects after the fiber-enriched flour diet (p = 0.03, p = 0.02,
    respectively). In conclusion, an isocaloric diet supplemented with
    fiber-enriched products may improve measures of fatness and insulin
    sensitivity in healthy non-obese non-diabetic subjects. We might
    hypothesize a similar effect also in subjects with metabolic

    Be well!


  6. JP Says:

    Updated 08/20/16:


    Br J Cancer. 2016 Aug 18.

    Mediterranean diet and colorectal cancer risk: a pooled analysis of three Italian case-control studies.

    BACKGROUND: Adherence to the Mediterranean diet (MD) is associated with a reduced risk of several cancers. However, studies conducted in Mediterranean regions are scanty.

    METHODS: To investigate the relation between MD and colorectal cancer risk in Italy, we pooled data from three case-control studies, including a total of 3745 colorectal cancer cases and 6804 hospital controls. Adherence to the MD was assessed using an a priori Mediterranean Diet Score (MDS), based on nine components.

    RESULTS: Compared with the lowest adherence to the MD (0-2 MDS), the odds ratio (OR) was 0.52 (95% confidence interval (CI) 0.43-0.62) for the highest adherence (7-9 MDS), with a significant inverse trend in risk (P<0.0001). The OR for a 1-point increment in the MDS was 0.89 (95% CI 0.86-0.91). The inverse association was consistent across studies, cancer anatomical subsites and strata of selected covariates.

    CONCLUSIONS: This Italian study confirms a favourable role of MD on colorectal cancer risk.

    Be well!


  7. JP Says:

    Updated 10/03/16:


    Br J Nutr. 2016 Oct;116(7):1275-1287.

    Flavonoid intake from vegetables and fruits is inversely associated with colorectal cancer risk: a case-control study in China.

    Flavonoids may play an important role in the protective effects of vegetables, fruits and tea against colorectal cancer. However, associations between flavonoids and colorectal cancer risk are inconsistent, and a few studies have evaluated the effect of flavonoids from different dietary sources separately. This study aimed to evaluate associations of flavonoids intake from different dietary sources with colorectal cancer risk in a Chinese population. From July 2010 to December 2015, 1632 eligible colorectal cancer cases and 1632 frequency-matched controls (age and sex) completed in-person interviews. A validated FFQ was used to estimate dietary flavonoids intake. Multivariate logistical regression models were used to calculate the OR and 95 % CI of colorectal cancer risk after adjusting for various confounders. No significant association was found between total flavonoids and colorectal cancer risk, with an adjusted OR of 1·06 (95 % CI 0·85, 1·32) comparing the highest with the lowest quartile. Anthocyanidins, flavanones and flavones intakes from total diet were found to be inversely associated with colorectal cancer risk. Compared with the lowest quartile, the adjusted OR for the highest quartile were 0·80 (95 % CI 0·64, 1·00) for anthocyanidins, 0·28 (95 % CI 0·22, 0·36) for flavanones and 0·54 (95 % CI 0·43, 0·67) for flavones. All subclasses of flavonoids from vegetables and fruits were inversely associated with colorectal cancer. However, no significant association was found between tea flavonoids and colorectal cancer risk. These data indicate that specific flavonoids, specifically flavonoids from vegetables and fruits, may be linked with the reduced risk of colorectal cancer.

    Be well!


  8. JP Says:

    Updated 09/11/17:


    J Epidemiol Community Health. 2017 Oct;71(10):961-969.

    Intake of dietary fibre and lifetime non-steroidal anti-inflammatory drug (NSAID) use and the incidence of colorectal polyps in a population screened for colorectal cancer.

    BACKGROUND: There is suggestive evidence that increased intake of dietary fibre and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are generally associated with decreased colorectal cancer risk. However, the effects on precursors of colorectal cancer, such as adenomatous polyps, are mixed. We present the associations between dietary fibre intake and NSAID use on the presence and type of colorectal polyps in a screening population.

    METHODS: A cross-sectional study of 2548 individuals undergoing colonoscopy at the Forzani & MacPhail Colon Cancer Screening Centre (Calgary, Canada) was conducted. Dietary fibre intake and NSAID use were assessed using the Diet History Questionnaire I or II and the Health and Lifestyle Questionnaire. Colorectal outcomes were documented as a polyp or high-risk adenomatous polyp (HRAP; villous histology, high-grade dysplasia, ≥10 mm or ≥3 adenomas). Crude and ORs and 95% CIs were estimated using unconditional logistic regression.

    RESULTS: There were 1450 negative colonoscopies and 1098 patients with polyps, of which 189 patients had HRAPs. Total dietary fibre intake was associated with a decreased presence of HRAPs (OR=0.50, 95% CI: 0.29 to 0.86) when comparing the highest to lowest quartiles and was observed with both soluble (OR=0.51, 95% CI: 0.30 to 0.88) and insoluble (OR=0.51, 95% CI: 0.30 to 0.86) fibres. Ever use of NSAIDs was also inversely associated with HRAPs (OR=0.65, 95% CI: 0.47 to 0.89), observed with monthly (OR=0.60, 95% CI: 0.37 to 0.95) and daily (OR=0.53, 95% CI: 0.32 to 0.86) use.

    CONCLUSIONS: Dietary fibre intake and NSAID use were associated with a decreased risk of having a HRAP at screening.

    Be well!


  9. JP Says:

    Updated 11/04/17:


    JAMA Oncol. 2017 Nov 2.

    Fiber Intake and Survival After Colorectal Cancer Diagnosis.

    Importance: Although high dietary fiber intake has been associated with a lower risk of colorectal cancer (CRC), it remains unknown whether fiber benefits CRC survivors.

    Objective: To assess the association of postdiagnostic fiber intake with mortality.

    Design, Setting, and Participants: A total of 1575 health care professionals with stage I to III CRC were evaluated in 2 prospective cohorts, Nurses’ Health Study and Health Professionals Follow-up Study. Colorectal cancer-specific and overall mortality were determined after adjusting for other potential predictors for cancer survival. The study was conducted from December 23, 2016, to August 23, 2017.

    Exposures: Consumption of total fiber and different sources of fiber and whole grains assessed by a validated food frequency questionnaire between 6 months and 4 years after CRC diagnosis.

    Main Outcomes and Measures: Hazard ratios (HRs) and 95% CIs of CRC-specific and overall mortality after adjusting for other potential predictors for cancer survival.

    Results: Of the 1575 participants, 963 (61.1%) were women; mean (SD) age was 68.6 (8.9) years. During a median of 8 years of follow-up, 773 deaths were documented, including 174 from CRC. High intake of total fiber after diagnosis was associated with lower mortality. The multivariable HR per each 5-g increment in intake per day was 0.78 (95% CI, 0.65-0.93; P = .006) for CRC-specific mortality and 0.86 (95% CI, 0.79-0.93; P < .001) for all-cause mortality. Patients who increased their fiber intake after diagnosis from levels before diagnosis had a lower mortality, and each 5-g/d increase in intake was associated with 18% lower CRC-specific mortality (95% CI, 7%-28%; P = .002) and 14% lower all-cause mortality (95% CI, 8%-19%; P < .001). According to the source of fiber, cereal fiber was associated with lower CRC-specific mortality (HR per 5-g/d increment, 0.67; 95% CI, 0.50-0.90; P = .007) and all-cause mortality (HR, 0.78; 95% CI, 0.68-0.90; P < .001); vegetable fiber was associated with lower all-cause mortality (HR, 0.83; 95% CI, 0.72-0.96; P = .009) but not CRC-specific mortality (HR, 0.82; 95% CI, 0.60-1.13; P = .22); no association was found for fruit fiber. Whole grain intake was associated with lower CRC-specific mortality (HR per 20-g/d increment, 0.72; 95% CI, 0.59-0.88; P = .002), and this beneficial association was attenuated after adjusting for fiber intake (HR, 0.77; 95% CI, 0.62-0.96; P = .02). Conclusions and Relevance: Higher fiber intake after the diagnosis of nonmetastatic CRC is associated with lower CRC-specific and overall mortality. Increasing fiber consumption after diagnosis may confer additional benefits to patients with CRC. Be well! JP

  10. JP Says:

    Updated 12/03/17:


    Obesity, 25: S95–S101

    The Impact of Diet-Induced Weight Loss on Biomarkers for Colorectal Cancer: An Exploratory Study (INTERCEPT)

    Objective: The aim of this study was to explore the potential effects of diet-induced weight loss on molecular biomarkers of colorectal cancer risk in serum and colorectal tissue.

    Methods: This single-arm exploratory study included 20 adults with BMI ≥ 30 kg/m2 completing an 8-week, complete, low-energy liquid diet. Pre- and postintervention anthropometric measurements, fasting blood draws, and endoscopic examinations to procure colorectal biopsies were performed. Fasting insulin, glucose, insulinlike growth factor 1 (IGF-1), C-reactive protein (CRP), and blood lipids were measured in serum, and tissue markers of apoptosis (M30), colonocyte proliferation (Ki-67), and insulin signaling (phospho-mTOR) were assessed using immunohistochemical staining.

    Results: Participants achieved substantial weight loss (mean = 13.56%). Mean concentrations of insulin, glucose, and cholesterol were significantly reduced (P < 0.05), but IGF-1 and CRP were not. Colorectal tissue expression of Ki-67 was significantly reduced (preintervention mean score = 7, postintervention mean score = 3.9, mean % change −43.8; P = 0.027). There were no significant changes in M30 or phospho-mTOR. Conclusions: Weight loss in individuals with obesity was associated with improvements in insulin sensitivity and blood lipid profiles and a significant reduction in tissue Ki-67 expression. This is one of the first studies to demonstrate potential cancer-relevant changes in colorectal tissue following weight loss achieved through diet. Be well! JP

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