Prospective study on milk products, calcium and cancers of the colon and rectum

Vitamin D and Colorectal Cancer Prevention: Immunological Mechanisms, Inflammatory Pathways, and Nutritional Implications

Vitamin D plays a crucial role in the regulation of the immune system, with immunomodulatory effects that are key in the prevention of colorectal cancer (CRC). Over the past decades, research has shown that this steroid hormone impacts much more than bone health, significantly influencing immune responses. Vitamin D enhances immune organ functions such as the spleen and lymph nodes, and boosts T-cell activity, which is essential in defending the body against tumors. Additionally, vitamin D mitigates inflammatory responses closely linked to cancer development, reducing the inflammation that contributes to CRC. It acts via vitamin D receptors (VDRs) expressed on immune cells, modulating immune responses. Adequate vitamin D levels influence gene expression related to inflammation and cell proliferation, inhibiting tumor development. Vitamin D also activates mechanisms that suppress cancer cell survival, proliferation, migration, and metastasis. Low levels of vitamin D have been associated with an increased risk of CRC, with deficiency correlating with higher disease incidence. Lifestyle factors, such as a diet high in red meat and calories but low in fiber, fruits, and vegetables, as well as physical inactivity, contribute significantly to CRC risk. Insufficient calcium and vitamin D intake are also linked to disease occurrence and poorer clinical outcomes. Maintaining optimal vitamin D levels and adequate dietary intake is crucial in preventing CRC and improving patient prognosis. This review explores the role of vitamin D in immune regulation and summarizes findings from randomized clinical trials assessing the effects of vitamin D supplementation on CRC outcomes.

Calcium Intake and Risk of Colorectal Cancer in the NIH-AARP Diet and Health Study

Importance

Calcium intake is associated with a reduced risk of colorectal cancer (CRC), although it remains unclear whether this association varies by calcium source or tumor site. Moreover, there are disparities in calcium intake by race and ethnicity, but the impact of low calcium consumption on CRC risk in specific racial and ethnic populations is unclear.

Objective

To investigate the association between calcium intake and CRC risk, considering the source of calcium and tumor site and across racial and ethnic groups.

Design, Setting, and Participants

This cohort study analyzed data from the National Institutes of Health-AARP Diet and Health Study. Participants were aged 50 to 71 years at baseline (October 1995 to May 1996), had self-reported good health and neither extremely high nor low caloric or calcium intake, and were followed up until the date of their first primary cancer diagnosis, death, loss to follow-up, or end of follow-up (December 31, 2018). Data were analyzed from April 2022 to April 2024.

Exposure

Calcium intake was estimated from dietary sources (dairy and nondairy), supplements, and total intake.

Main Outcomes and Measures

The primary outcome was CRC incidence. Multivariable-adjusted Cox proportional hazards regression models estimated hazard ratios (HRs) and 95% CIs using the lowest sex-specific quintile of calcium intake as the reference.

Results

Among 471 396 participants who were cancer-free at baseline, mean (SD) baseline age was 62.0 (5.4) years and 59.5% were male. During 7 339 055 person-years of follow-up (median, 18.4 years [IQR, 9.2-22.5 years]), 10 618 first primary CRC cases were identified. Mean (SD) total calcium intake for the lowest quintile (Q1) was 401 mg/d (104 mg/d) for females and 407 mg/d (95 mg/d) for males and for the highest quintile (Q5) was 2056 mg/d (412 mg/d) for females and 1773 mg/d (444 mg/d) for males. Dairy, nondairy, and supplemental sources contributed a mean (SD) of 42.1% (43.5%), 34.2% (24.5%), and 23.7% (38.3%) of total calcium intake, respectively. Higher total calcium intake (Q5 vs Q1) was associated with a lower risk of CRC (hazard ratio [HR], 0.71; 95% CI, 0.65-0.78; P < .001 for trend), with consistent results across calcium sources and tumor sites. Among non-Hispanic Black participants, the mean (SD) calcium intake was 382 mg/d (108 mg/d) for Q1 and 1916 mg/d (466 mg/d) for Q5, with no association of total calcium intake with CRC risk (Q5 vs Q1: HR, 0.60; 95% CI, 0.32-1.13; P = .12 for trend); there was no evidence of effect measure differences by race and ethnicity.

Conclusions and Relevance

In this cohort study, higher calcium intake was consistently associated with reduced CRC risk across tumor sites and sources of calcium. Increasing calcium intake, especially among groups with lower consumption, may be associated with reductions in avoidable differences in CRC risk.

Unlocking the potential of milk whey protein components in colorectal cancer prevention and therapy

Extensive research from large prospective cohort studies and meta-analytical investigations over recent decades have consistently indicated that dairy foods have protective effects, reducing the risk of colorectal cancer. Most of the literature has explored the potential role of milk minerals and vitamins in managing colorectal cancer. Yet, there is a paucity of a comprehensive summary of the anticancer attributes of milk protein components and their underlying mechanisms of action. Recent advancements have spotlighted the potential of whey proteins, including β-lactoglobulin, α-lactalbumin, serum albumin, and lactoferrin, as promising candidates for both the prevention and treatment of colorectal cancer. Notably, whey proteins have demonstrated a more pronounced capacity for suppressing carcinogen-induced tumors when compared to casein. Their strong binding affinity enables them to serve as effective carriers for small molecules or drugs targeting colon cancer therapy. Furthermore, numerous studies have underscored the anti-inflammatory and antioxidant prowess of whey proteins in cancer prevention. Additionally, whey proteins have been shown to trigger apoptosis, hinder tumor cell proliferation, and impede metastasis. This comprehensive review, therefore, not only substantiates the significance of incorporating whey protein components into a balanced daily diet but also underscores their potential in safeguarding against the onset and progression of colorectal cancer.

Cheese consumption and multiple health outcomes: an umbrella review and updated meta-analysis of prospective studies

This umbrella review aims to provide a systematic and comprehensive overview of current evidence from prospective studies on the diverse health effects of cheese consumption. We searched PubMed, Embase, and Cochrane Library to identify meta-analyses/pooled analyses of prospective studies examining the association between cheese consumption and major health outcomes from inception to August 31, 2022. We reanalyzed and updated previous meta-analyses and performed de novo meta-analyses with recently published prospective studies, where appropriate. We calculated the summary effect size, 95% prediction confidence intervals, between-study heterogeneity, small-study effects, and excess significance bias for each health outcome. We identified 54 eligible articles of meta-analyses/pooled analyses. After adding newly published original articles, we performed 35 updated meta-analyses and 4 de novo meta-analyses. Together with 8 previous meta-analyses, we finally included 47 unique health outcomes. Cheese consumption was inversely associated with all-cause mortality (highest compared with lowest category: RR = 0.95; 95% CI: 0.92, 0.99), cardiovascular mortality (RR = 0.93; 95% CI: 0.88, 0.99), incident cardiovascular disease (CVD) (RR = 0.92; 95% CI: 0.89, 0.96), coronary heart disease (CHD) (RR = 0.92; 95% CI: 0.86, 0.98), stroke (RR = 0.93; 95% CI: 0.89, 0.98), estrogen receptor-negative (ER-) breast cancer (RR = 0.89; 95% CI: 0.82, 0.97), type 2 diabetes (RR = 0.93; 95% CI: 0.88, 0.98), total fracture (RR = 0.90; 95% CI: 0.86, 0.95), and dementia (RR = 0.81; 95% CI: 0.66, 0.99). Null associations were found for other outcomes. According to the NutriGrade scoring system, moderate quality of evidence was observed for inverse associations of cheese consumption with all-cause and cardiovascular mortality, incident CVD, CHD, and stroke, and for null associations with cancer mortality, incident hypertension, and prostate cancer. Our findings suggest that cheese consumption has neutral to moderate benefits for human health.

Higher Yogurt Consumption Is Associated With Lower Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Background: Yogurt is known to be nutrient-rich and probiotic content, which gather optimism due to their potential role in preventing and managing cancers. The effect of yogurt consumption on colorectal cancer (CRC) is inconsistent.

Objective: This study aims to investigate the association of yogurt consumption with the risk of CRC.

Methods: Three databases, namely, PubMed, Web of Science, and Embase, were searched for all relevant studies from July 2021 on the association of yogurt consumption with CRC risk. We pooled the odds ratios (ORs) and their 95% CIs using a random-effects meta-analysis to assess the association.

Results: Finally, 16 studies met the inclusion criteria and were chosen in the meta-analysis. Yogurt consumption was significant with lower risk of CRC risk in the overall comparison (OR = 0.87, 95% CI: 0.81–0.94), in the cohort studies (OR = 0.91, 95% CI: 0.86–0.97), and case-control studies (OR = 0.75, 95% CI: 0.65–0.85). With regard to subgroup analyses by study region, cancer type, publication year, and sex, yogurt consumption significantly decreased overall CRC, colon cancer, and distal colon cancer risks. In stratified analyses, we observed significantly decreased CRC risk in Europe and Africa and published after 2010 and overall population. Sensitivity analysis indicated the result is stable and there is no publication bias in the meta-analysis.

Conclusions: Overall, this study indicated that yogurt intake was related to a decreased risk of CRC.

The role of calcium and vitamin D dietary intake on risk of colorectal cancer: systematic review and meta-analysis of case-control studies

PURPOSE

The aim of this study is to analyze the current evidence about the relationships between calcium/vitamin D and CRC based on case-control studies according to sex, tumor location and continental region to complement the information obtained in meta-analyses of other designs.

METHODS

The articles were located in three databases (PUBMED, EMBASE and SCOPUS), they should be written in English language, with a case and control design and published between 1 January 1970 and 31 October 2019.

RESULTS

There were 37 selected studies, 32 for intake of calcium, that involved 24,353 CRC cases and 30,650 controls, and 23 for that of VIT D, with a total of 19,076 cases and 36.746 controls included. For dietary calcium intake, the overall OR was 0.94 (95% CI 0.92-0.97), suggesting a reducing effect with a 6% decrease in CRC risk for every 300 mg of calcium ingested daily. Regarding vitamin D intake a global OR of 0.96 (95% CI 0.93-0.98) was observed, what means a 4% decrease in the risk of CRC per 100 IU/day of vitamin D.

CONCLUSION

Higher dietary intakes of calcium and vitamin D are associated to a decreased risk of CRC.

Enhancement of Anti-Tumoral Immunity by β-Casomorphin-7 Inhibits Cancer Development and Metastasis of Colorectal Cancer

β-Casomorphin-7 (BCM) is a degradation product of β-casein, a milk component, and has been suggested to affect the immune system. However, its effect on mucosal immunity, especially anti-tumor immunity, in cancer-bearing individuals is not clear. We investigated the effects of BCM on lymphocytes using an in vitro system comprising mouse splenocytes, a mouse colorectal carcinogenesis model, and a mouse orthotopic colorectal cancer model. Treatment of mouse splenocytes with BCM in vitro reduced numbers of cluster of differentiation (CD) 20⁺ B cells, CD4⁺ T cells, and regulatory T cells (Tregs), and increased CD8⁺ T cells. Administration of BCM and the CD10 inhibitor thiorphan (TOP) to mice resulted in similar alterations in the lymphocyte subsets in the spleen and intestinal mucosa. BCM was degraded in a concentration- and time-dependent manner by the neutral endopeptidase CD10, and the formed BCM degradation product did not affect the lymphocyte counts. Furthermore, degradation was completely suppressed by TOP. In the azoxymethane mouse colorectal carcinogenesis model, the incidence of aberrant crypt foci, adenoma, and adenocarcinoma was reduced by co-treatment with BCM and TOP. Furthermore, when CT26 mouse colon cancer cells were inoculated into the cecum of syngeneic BALB/c mice and concurrently treated with BCM and TOP, infiltration of CD8⁺ T cells was promoted, and tumor growth and liver metastasis were suppressed. These results suggest that by suppressing the BCM degradation system, the anti-tumor effect of BCM is enhanced and it can suppress the development and progression of colorectal cancer.

The effect of vitamin D on the occurrence and development of colorectal cancer: a systematic review and meta-analysis

PURPOSE

There has been a lot of controversies about the correlation between vitamin D and colorectal cancer (CRC). In this meta-analysis, we purposed to explore the relationship between vitamin D and the incidence of CRC/the prognosis of CRC.

METHODS

A systematic search for articles in databases (Pubmed, Web of Science, EBSCO and Cochrane Library) was terminated in April 2020. The primary outcomes were the incidence rate of CRC and the long-term survival of patients with CRC.

RESULTS

According to the estimated pooled OR from 21 eligible studies, covering 904,152 people, the use of vitamin D was inversely associated with the incidence of CRC [OR = 0.87, (0.82-0.92)]. Among the four studies included in this meta-analysis, covering 7486 patients, compared the overall survival (OS) of CRC between the vitamin D users and the non-users. Based on the estimated pooled HR, vitamin D potentially improved the long-term survival of CRC patients [HR = 0.91, (0.83-0.98)].

CONCLUSION

This meta-analysis demonstrates that vitamin D not only has a positive impact on the incidence of CRC from either the dietary or supplemental sources but also benefits clinical outcomes and improves the long-term survival of CRC patients. However, further studies are recommended to clarify the above phenomena.

Vitamin D Intake and the Risk of Colorectal Cancer: An Updated Meta-Analysis and Systematic Review of Case-Control and Prospective Cohort Studies

Obesity, a sedentary lifestyle, high red meat consumption and alcohol, and tobacco are considered the driving factors behind colorectal cancer (CRC) worldwide. Both diet and lifestyle are recognized to play an important role in the prevention of CRC. Forty years later, the vitamin D-cancer hypothesis is considered consistent. However, the relationship between low vitamin D intake and CRC is still controversial. The aim of this meta-analysis is to determine the associations between Vitamin D intake and CRC. MEDLINE-PubMed and Cochrane databases were searched up to May 2020 for studies evaluating the association between vitamin D intake (from foods and supplements) and CRC. Two reviewers, working independently, screened all titles and abstracts to identify the studies that met the inclusion criteria (case-control or prospective cohort (PC) studies published in English). Data were pooled by the generic inverse variance method using a random or fixed effect model. Heterogeneity was identified using the Cochran Q-test and quantified by the I2 statistic. A total of 31 original studies were included for the quantitative meta-analysis, comprising a total 47.540 cases and 70.567 controls in case-control studies, and a total of 14.676 CRC-incident cases (out of 808.130 subjects in PC studies) from 17 countries. A significant 25% lower risk was reported comparing the highest vs. the lowest dietary vitamin D consumption and CRC risk (odds ratio (95% confidence interval): 0.75 (0.67; 0.85)) in case-control studies, whereas a non-significant association was reported in case of prospective studies (hazard ratio (95% confidence interval): 0.94 (0.79; 1.11). The present meta-analysis demonstrates that high dietary vitamin D is associated to CRC prevention. However, larger and high-quality prospective studies and clinical trials are warranted to confirm this association.

Dairy intake during adolescence and risk of colorectal adenoma later in life

BACKGROUND

Higher dairy intake during adulthood has been associated with lower colorectal cancer risk. As colorectal carcinogenesis spans several decades, we hypothesised that higher dairy intake during adolescence is associated with lower risk of colorectal adenoma, a colorectal cancer precursor.

METHODS

In 27,196 females from the Nurses' Health Study 2, aged 25-42 years at recruitment (1989), who had completed a validated high school diet questionnaire in 1998 and undergone at least one lower bowel endoscopy between 1998 and 2011, logistic regression for clustered data was used to calculate odds ratios (ORs) and 95% confidence intervals (CI).

RESULTS

Colorectal adenomas were diagnosed in 2239 women. Dairy consumption during adolescence was not associated with colorectal adenoma risk (OR highest vs. lowest [≥4 vs. ≤1.42 servings/day] quintile [95% CI] 0.94 [0.80, 1.11]). By anatomical site, higher adolescent dairy intake was associated with lower rectal (0.63 [0.42, 0.95]), but not proximal (1.01 [0.80, 1.28]) or distal (0.97 [0.76, 1.24]) colon adenoma risk. An inverse association was observed with histologically advanced (0.72 [0.51, 1.00]) but not non-advanced (1.07 [0.86, 1.33]) adenoma.

CONCLUSIONS

In this large cohort of younger women, higher adolescent dairy intake was associated with lower rectal and advanced adenoma risk later in life.

Yogurt consumption and colorectal polyps

Diet modifies the risk of colorectal cancer (CRC), and inconclusive evidence suggests that yogurt may protect against CRC. We analysed the data collected from two separate colonoscopy-based case-control studies. The Tennessee Colorectal Polyp Study (TCPS) and Johns Hopkins Biofilm Study included 5446 and 1061 participants, respectively, diagnosed with hyperplastic polyp (HP), sessile serrated polyp, adenomatous polyp (AP) or without any polyps. Multinomial logistic regression models were used to derive OR and 95 % CI to evaluate comparisons between cases and polyp-free controls and case-case comparisons between different polyp types. We evaluated the association between frequency of yogurt intake and probiotic use with the diagnosis of colorectal polyps. In the TCPS, daily yogurt intake v. no/rare intake was associated with decreased odds of HP (OR 0·54; 95 % CI 0·31, 0·95) and weekly yogurt intake was associated with decreased odds of AP among women (OR 0·73; 95 % CI 0·55, 0·98). In the Biofilm Study, both weekly yogurt intake and probiotic use were associated with a non-significant reduction in odds of overall AP (OR 0·75; 95 % CI 0·54, 1·04) and (OR 0·72; 95 % CI 0·49, 1·06) in comparison with no use, respectively. In summary, yogurt intake may be associated with decreased odds of HP and AP and probiotic use may be associated with decreased odds of AP. Further prospective studies are needed to verify these associations.

Additively protective effects of vitamin D and calcium against colorectal adenoma incidence, malignant transformation and progression: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) exhibits a linear progression from normal colonic epithelium, adenoma initiation, carcinoma transformation and even to metastasis. Diet changes might influence carcinogenesis and prognosis. We aimed to determine the effects of vitamin D and calcium on colorectal adenoma incidence, malignancy development and prognosis.

METHODS

Systematic literature searches (PubMed, Embase, and Cochrane Library databases) and hand searches were performed by September 30, 2019. A random-effects model was adopted to pool relative ratios (RRs) for colorectal tumour incidence or hazard ratios (HRs) for CRC mortality. Stratified analyses were performed by gender, tumour location, calcium intake level and ethnic group.

RESULTS

Total 854,195 cases from 166 studies were included. The colorectal adenoma incidence was inversely correlated with the circulating 25-hydroxyvitamin D [25(OH)D] level (RR: 0.80, 95% CI: 0.71-0.89), vitamin D intake (RR: 0.87, 95% CI: 0.82-0.92) and calcium intake (RR: 0.86, 95% CI: 0.81-0.91). The CRC incidence was decreased by circulating 25(OH)D (RR: 0.67, 95% CI: 0.59-0.77), vitamin D intake (RR: 0.85, 95% CI: 0.78-0.93) and calcium intake (RR: 0.75, 95% CI: 0.70-0.79). High-level circulating 25(OH)D triggered better overall survival (HR: 0.67, 95% CI: 0.57-0.79) and CRC-specific survival (HR: 0.63, 95% CI: 0.53-0.74). Stratified analyses showed that vitamin D and calcium significantly suppressed colorectal tumour incidence among women. Left-sided CRC risk was reversely related to circulating 25(OH)D (RR: 0.60, 95% CI: 0.41-0.88) and vitamin D intake (RR: 0.73, 95% CI: 0.57-0.93). Circulating 25(OH)D decreased colorectal adenoma (RR: 0.63, 95% CI: 0.48-0.82) and CRC (RR: 0.69, 95% CI: 0.56-0.86) risk in populations with higher calcium intake. European and American populations benefited more from vitamin D intake against colorectal tumour. A significant dose-response relationship was observed between intake of vitamin D or calcium and colorectal tumour incidence.

CONCLUSIONS

Vitamin D and calcium play additively chemopreventive roles in colorectal adenoma incidence, malignant transformation and progression, especially for women and left-sided CRC patients.

Association Between Dairy Product Consumption and Colorectal Cancer Risk in Adults: A Systematic Review and Meta-Analysis of Epidemiologic Studies

Dairy product consumption may decrease colorectal cancer (CRC) risk, but very few studies have evaluated the association between different types of dairy products and CRC location. The aim of this systematic review and meta-analysis was to examine the associations between dairy product consumption and CRC incidence. Summary RRs and ORs with 95% CIs were estimated. A total of 15 cohort studies and 14 case-control studies comprising a total of >22,000 cases were included in the quantitative synthesis. The cohort studies showed a consistent significant decrease in CRC risk associated with higher consumption of total dairy products (RR: 0.80; 95% CI: 0.70, 0.91) and total milk (RR: 0.82; 95% CI: 0.76, 0.88) compared with the CRC risk associated with lower consumption. These studies also showed a significant protective association between low-fat milk consumption and CRC (RR: 0.76; 95% CI: 0.66, 0.88), but only for colon cancer (RR: 0.73; 95% CI: 0.61, 0.87). Cheese consumption was inversely associated with the risk of CRC (RR: 0.85; 95% CI: 0.76, 0.96) and proximal colon cancer (RR: 0.74; 95% CI: 0.60, 0.91). No significant associations with CRC were found for the consumption of low-fat dairy products, whole milk, fermented dairy products, or cultured milk. Most of these associations were not supported by the case-control studies. In conclusion, high consumption of total dairy products and total milk was associated with a lower risk of developing CRC at any anatomic location, including the proximal and distal colon and the rectum. Low-fat milk consumption was associated with a lower risk of CRC, but this association was restricted to colon cancer. Cheese consumption was associated with the prevention of CRC, specifically proximal colon cancer. Further studies on larger samples and with longer follow-up periods, along with appropriately designed and executed clinical trials, are warranted to determine whether dairy product consumption affects CRC development.

Probiotic Bacteria: A Promising Tool in Cancer Prevention and Therapy

Gut microbiota is widely considered to be one of the most important components to maintain balanced homeostasis. Looking forward, probiotic bacteria have been shown to play a significant role in immunomodulation and display antitumour properties. Bacterial strains could be responsible for detection and degradation of potential carcinogens and production of short-chain fatty acids, which affect cell death and proliferation and are known as signaling molecules in the immune system. Lactic acid bacteria present in the gut has been shown to have a role in regression of carcinogenesis due to their influence on immunomodulation, which can stand as a proof of interaction between bacterial metabolites and immune and epithelial cells. Probiotic bacteria have the ability to both increase and decrease the production of anti-inflammatory cytokines which play an important role in prevention of carcinogenesis. They are also capable of activating phagocytes in order to eliminate early-stage cancer cells. Application of heat-killed probiotic bacteria coupled with radiation had a positive influence on enhancing immunological recognition of cancer cells. In the absence of active microbiota, murine immunity to carcinogens has been decreased. There are numerous cohort studies showing the correlation between ingestion of dairy products and the risk of colon and colorectal cancer. An idea of using probiotic bacteria as vectors to administer drugs has emerged lately as several papers presenting successful results have been revealed. Within the next few years, probiotic bacteria as well as gut microbiota are likely to become an important component in cancer prevention and treatment.

Milk and risk of colorectal, colon and rectal cancer in the Norwegian Women and Cancer (NOWAC) Cohort Study

According to World Cancer Research Fund International/American Institute for Cancer Research, it is 'probable' that dairy products decrease the risk of colorectal cancer (CRC). However, meta-analyses restricted to women have not shown associations between milk intake and risk of CRC. The aim of this study was to examine the association between milk intake and risk of CRC, colon cancer and rectal cancer among women. Data from 81 675 participants in the Norwegian Women and Cancer Cohort Study were included, and multivariable Cox proportional hazard regression models were used to investigate milk intake using two different analytical approaches: one that included repeated measurements and one that included baseline measurements only (872 and 1084 CRC cases, respectively). A weak inverse association between milk intake and risk of colon cancer may be indicated both in repeated measurements analyses and in baseline data analyses. Hazard ratios (HR) for colon cancer of 0·80 (95 % CI 0·62, 1·03, P trend 0·07) and 0·81 (95 % CI 0·64, 1·01, P trend 0·03) and HR for rectal cancer of 0·97 (95 % CI 0·67, 1·42, P trend 0·92) and 0·71 (95 % CI 0·50, 1·01, P trend 0·03) were found when comparing the high with the no/seldom milk intake group in energy-adjusted multivariable models. Our study indicates that there may be a weak inverse association between milk intake and risk of colon cancer among women. The two analytical approaches yielded different results for rectal cancer and hence CRC. Our study indicates that the use of single or repeated measurements in analyses may influence the results.

High lactose whey cheese consumption and risk of colorectal cancer - The Norwegian Women and Cancer Study

The incidence of colorectal cancer (CRC) has increased among Norwegian women, and is among the highest in the world. In order to understand this increase, country specific dietary exposures have been investigated. The aim of this study was to quantify the association between consumption of brown cheese, a common bread topping in Norway, and colorectal, colon, and rectal cancer in the prospective Norwegian Women and Cancer (NOWAC) Study. Data on brown cheese consumption and adjustment factors was available for 82 527 women. During a mean of 14.6 years of follow-up (1.2 million person-years), there were 1360 cases of colorectal cancer (907 colon; 453 rectal). Multivariable Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for colorectal, colon, and rectal cancer sites. We modelled restricted cubic splines with 4 knots, to assess a possible non-linear relationship between brown cheese intake and the investigated cancer sites. In the age-adjusted model, consumption of more than 2 slices (>16 grams) of brown cheese per day was associated with 13% reduced risk of colon cancer (95% CI 4%-21%) compared to women who did not consume brown cheese. The multivariable-adjusted model, however, showed no association between brown cheese consumption and the risk of colorectal, colon, or rectal cancer (colorectal: HR = 0.93, 95% CI 0.76–1.13, p-trend 0.37; colon: HR = 0.83, 95% CI 0.65–1.06; p-trend = 0.10; rectal: HR = 1.16, 95% CI 0.84–1.1.61, p-trend = 0.41). In this large, prospective cohort study of women, consumption of brown cheese was suggestively protective against colon cancer. However, adjustment attenuated the inverse risk association. Brown cheese consumption was not associated with rectal cancer, or colorectal cancer overall.

The Effects of UVB and Vitamin D on Decreasing Risk of Colorectal Cancer Incidence and Mortality: A Review of the Epidemiology, Clinical Trials, and Mechanisms

The solar ultraviolet B-vitamin D-cancer hypothesis was first suggested in 1980 based on a geographical ecological study. Since then, several ecological and observational studies, as well as researches of mechanisms have supported the hypothesis. Also, the association between vitamin D condition and cancer risk has been assessed in a number of epidemiologic studies, while data from interventional studies remain scant. In regard of cancer locations, the body of evidence is most substantial for colorectal cancer, for which support comes from studies of 25(OH)D, vitamin D intake, and region of residence in a sunny weather. Collectively evidence demonstrates that vitamin D has a potent and beneficial effect at antagonizing and blocking several mitogenic mechanisms related to tumorigenesis. Taken together with the epidemiological studies and limited clinical trials, individuals may need to consider elevating 25(OH)D levels via sun exposure and/or vitamin D supplementation to decrease risk of colorectal cancer, in addition to standard care, treat cancer.

Foods and beverages and colorectal cancer risk: a systematic review and meta-analysis of cohort studies, an update of the evidence of the WCRF-AICR Continuous Update Project

Objective

As part of the World Cancer Research Fund International Continuous Update Project, we updated the systematic review and meta-analysis of prospective studies to quantify the dose-response between foods and beverages intake and colorectal cancer risk.

Data sources

PubMed and several databases up to 31 May 2015.

Study selection

Prospective studies reporting adjusted relative risk estimates for the association of specific food groups and beverages and risk of colorectal, colon and rectal cancer.

Data synthesis

Dose-response meta-analyses using random effect models to estimate summary relative risks (RRs).

Results

About 400 individual study estimates from 111 unique cohort studies were included. Overall, the risk increase of colorectal cancer is 12% for each 100 g/day increase of red and processed meat intake (95% CI = 4-21%, I2=70%, pheterogeneity (ph)<0.01) and 7% for 10 g/day increase of ethanol intake in alcoholic drinks (95% CI = 5-9%, I2=25%, ph = 0.21). Colorectal cancer risk decrease in 17% for each 90g/day increase of whole grains (95% CI = 11-21%, I2 = 0%, ph = 0.30, 6 studies) and 13% for each 400 g/day increase of dairy products intake (95% CI = 10-17%, I2 = 18%, ph = 0.27, 10 studies). Inverse associations were also observed for vegetables intake (RR per 100 g/day =0.98 (95% CI = 0.96-0.99, I2=0%, ph = 0.48, 11 studies) and for fish intake (RR for 100 g/day = 0.89 (95% CI = 0.80-0.99, I2=0%, ph = 0.52, 11 studies), that were weak for vegetables and driven by one study for fish. Intakes of fruits, coffee, tea, cheese, poultry and legumes were not associated with colorectal cancer risk.

Conclusions

Our results reinforce the evidence that high intake of red and processed meat and alcohol increase the risk of colorectal cancer. Milk and whole grains may have a protective role against colorectal cancer. The evidence for vegetables and fish was less convincing.

The association of diet, gut microbiota and colorectal cancer: what we eat may imply what we get

Despite the success of colonoscopy screening and recent advances in cancer treatment, colorectal cancer (CRC) still remains one of the most commonly diagnosed and deadly cancers, with a significantly increased incidence in developing countries where people are adapting to Western lifestyle. Diet has an important impact on risk of CRC. Multiple epidemiological studies have suggested that excessive animal protein and fat intake, especially red meat and processed meat, could increase the risk of developing CRC while fiber could protect against colorectal tumorigenesis. Mechanisms have been investigated by animal studies. Diet could re-shape the community structure of gut microbiota and influence its function by modulating the production of metabolites. Butyrate, one of the short-chain fatty acids (SCFAs), which act as a favorable source for colonocytes, could protect colonic epithelial cells from tumorigenesis via anti-inflammatory and antineoplastic properties through cell metabolism, microbiota homeostasis, antiproliferative, immunomodulatory and genetic/epigenetic regulation ways. In contrast, protein fermentation and bile acid deconjugation, which cause damage to colonic cells through proinflammatory and proneoplastic ways, lead to increased risk of developing CRC. In conclusion, a balanced diet with an increased abundance of fiber should be adopted to reduce the risk and prevent CRC.

Independent associations of dairy and calcium intakes with colorectal cancers in the Adventist Health Study-2 cohort

OBJECTIVE

Results associating dairy and Ca intakes with colorectal cancer (CRC) risk have been mixed. Most previous analyses have suffered from confounding between dairy and Ca intakes. We examined independent associations between these variables, also dairy foods, and CRC incidence in a population with a large range of dairy intakes.

DESIGN

Adventist Health Study-2 is a cohort study where subjects were enrolled 2002-2007. Proportional hazard regression analyses were performed to estimate hazard ratios (HR). Regression calibration was used to correct for dietary measurement error.

SETTING

The population lived in all states of the USA.

SUBJECTS

There were 77712 analytic subjects, all of whom were Seventh-day Adventists. Much of their dietary Ca came from non-dairy sources.

SUBJECTS

During a mean follow-up of 7·8 years, 380 incident colon cancer and 111 incident rectal cancer cases were observed.

RESULTS

Comparing extreme quintiles of intake in measurement error-corrected analyses, dairy intake (HR=0·31; 95 % CI 0·09, 0·88), independent of total Ca, was inversely related with risk of rectal cancer but gave little indication of association with colon cancer. However, total Ca intake (independent of dairy) was associated with risk of colon cancer (HR=0·55; 95 % CI 0·28, 0·98) and there was little indication of association with rectal cancer. Traditional regression analyses and associations with macronutrients from dairy generally supported these results. Milk intake was also negatively associated with CRC (HR=0·63; 95 % CI 0·43, 0·89).

CONCLUSIONS

Dairy intake may decrease the risk of rectal cancer, and Ca may reduce risk of colon cancer and CRC.

Glycomacropeptide Sustains Microbiota Diversity and Promotes Specific Taxa in an Artificial Colon Model of Elderly Gut Microbiota

The potential of milk-derived glycomacropeptide (GMP) and lactose for modulating the human gut microbiota of older people, in whom loss of diversity correlates with inferior health, was investigated. We used an in vitro batch fermentation (artificial colon model) to simulate colonic fermentation processes of two GMP products, i.e., a commercially available GMP concentrate and a semipurified GMP concentrate, and lactose. Faecal samples were collected from healthy and frail older people. Samples were analyzed by Illumina Miseq sequencing of rRNA gene amplicons. The commercial GMP preparation had a positive effect on the growth of Coprococcus and Clostridium cluster XIVb and sustained a higher faecal microbiota diversity compared to control substrates or lactose. Lactose fermentation promoted the growth of Proteobacteria including Escherichia/Shigella. This work provides an in-depth insight on the potential of GMP and lactose for modulating the gut microbiota and contributes more evidence confirming the prebiotic activity of GMP.

Vitamin D supplementation and quality of life following diagnosis in stage II colorectal cancer patients: a 24-month prospective study

PURPOSE

Research suggests patients are motivated to supplement standard cancer care with healthy lifestyle changes. However, few studies have prospectively investigated whether these changes result in positive outcomes. In this study, our objective was to examine the associations between vitamin D supplementation and quality of life (QoL), cancer recurrence, and all-cause mortality in stage II CRC patients following diagnosis.

METHODS

A total of 453 newly diagnosed patients were enrolled from the North Carolina Central Cancer Registry. Data on demographic variables, treatment, and health behaviors were collected by interview at diagnosis, 12, and 24 months post-diagnosis. QoL was measured using the FACT-C and SF-12 questionnaires.

RESULTS

After adjustment for potential confounders, the survivors who used vitamin D supplements had a better CCS score (subscale of FACT-C) over 24 months compared to non-users (β = 1.28; 95 % CI 0.07-2.48). This association persisted among calcium users (β = 2.41; 95 % CI 1.01-3.82), but not in non-users (β = 0.34; 95 % CI -1.45-2.13) (P interaction = 0.09). No association was observed with risk of recurrence or mortality.

CONCLUSIONS

This suggests that vitamin D supplementation may jointly influence QoL with calcium following diagnosis in CRC survivors. These results also support the notion that clinicians should recommend positive lifestyle changes in conjunction with the standard of care.

Nutrients, foods, and colorectal cancer prevention

Diet has an important role in the development of colorectal cancer. In the past few decades, findings from extensive epidemiologic and experimental investigations have linked consumption of several foods and nutrients to the risk of colorectal neoplasia. Calcium, fiber, milk, and whole grains have been associated with a lower risk of colorectal cancer, and red meat and processed meat have been associated with an increased risk. There is substantial evidence for the potential chemopreventive effects of vitamin D, folate, fruits, and vegetables. Nutrients and foods also may interact, as a dietary pattern, to influence colorectal cancer risk. Diet likely influences colorectal carcinogenesis through several interacting mechanisms. These include the direct effects on immune responsiveness and inflammation, and the indirect effects of overnutrition and obesity-risk factors for colorectal cancer. Emerging evidence also implicates the gut microbiota as an important effector in the relationship between diet and cancer. Dietary modification therefore has the promise of reducing colorectal cancer incidence.

Iranian dietary patterns and risk of colorectal cancer

BACKGROUND

Role of diet on colorectal cancer (CRC) has been considered in terms of single foods and nutrients, but less frequently in terms of dietary patterns in Iran. The objective of this study was to determine the association between Iranian dietary patterns and CRC.

METHODS

This case-control study was conducted in four hospitals in Tabriz City of Iran including 414 participants aged 35-75 years:207 cases with CRC confirmed by pathology and colonoscopy findings were selected and 207 controls free of neoplastic conditions and diet-related chronic diseases (from the same hospital at the same period for the cases). Dietary data were assessed using a 123-item semi-quantitative food frequency questionnaire. Two dietary patterns were found by using of Principal Component Analysis (PCA) method;"Healthy pattern"and "Iranian pattern". Multivariate logistic regression analysis was used to estimate adjusted odds ratios (OR) for relationship between dietary patterns and colorectal cancer.

RESULTS

After adjusting for confounding factors, the Iranian dietary pattern was significantly associated with an increased odds of colorectal cancer (OR= 1.46; 95% Confidenec Interval (CI)=1.05-2.19) while a reduced odds of colorectal cancer was observed with the Healthy dietary pattern (OR=0.18; 95% CI= 0.091-0.47).

CONCLUSION

Iranian dietary pattern (IDP) seems to increase the odds of colorectal cancer and protective effect of Healthy dietary pattern.

Vitamin and multiple-vitamin supplement intake and incidence of colorectal cancer: a meta-analysis of cohort studies

This paper systematically evaluated the association of intake of different vitamins and multiple-vitamin supplements and the incidence of colorectal cancer. Relevant studies were identified in MEDLINE via PubMed (published up to April 2014). We extracted data from articles on vitamins A, C, D, E, B9 (folate), B2, B3, B6, and B12 and multiple-vitamin supplements. We used multivariable-adjusted relative risks (RRs) and a random-effects model for analysis and random effects. With heterogeneity, we looked for the source of heterogeneity or performed sensitivity and stratified analyses. We found 47 articles meeting the inclusion criteria. The multivariable-adjusted RR for pooled studies for the association between the highest versus lowest vitamin B9 (folate) intake and colorectal cancer was 0.88 [95 % confidence interval (95 % CI) 0.81-0.95]. Vitamin D was 0.87 (95 % CI 0.77-0.99); vitamin B6, 0.88 (95 % CI 0.79-0.99); vitamin B2, 0.86 (95 % CI, 0.76-0.97); vitamin A, 0.87 (95 % CI, 0.75-1.03); vitamin C, 0.92 (95 % CI, 0.80-1.06); vitamin E, 0.94 (95 % CI, 0.82-1.07); vitamin B12, 1.10 (95 % CI, 0.92-1.32); vitamin B3, 1.18 (95 % CI, 0.76-1.84). Vitamin B9 (folate), D, B6, and B2 intake was inversely associated with risk of colorectal cancer, but further study is needed. Our study featured unacceptable heterogeneity for studies of multiple-vitamin supplements, so findings were inconclusive.

Dietary supplement use and colorectal cancer risk: a systematic review and meta-analyses of prospective cohort studies

Use of dietary supplements is rising in countries where colorectal cancer is prevalent. We conducted a systematic literature review and meta-analyses of prospective cohort studies on dietary supplement use and colorectal cancer risk. We identified relevant studies in Medline, Embase and Cochrane up to January 2013. Original and peer-reviewed papers on dietary supplement use and colorectal cancer, colon cancer, or rectal cancer incidence were included. "Use-no use"(U-NU), "highest-lowest"(H-L) and "dose-response"(DR) meta-analyses were performed. Random-effects models were used to estimate summary estimates. In total, 24 papers were included in the meta-analyses. We observed inverse associations for colorectal cancer risk and multivitamin (U-NU: RR = 0.92; 95% CI: 0.87,0.97) and calcium supplements (U-NU: RR = 0.86; 95% CI: 0.79,0.95; H-L: RR = 0.80; 95% CI: 0.70,0.92; DR: for an increase of 100 mg/day, RR = 0.96; 95% CI: 0.94,0.99). Inconsistent associations were found for colon cancer risk and supplemental vitamin A and vitamin C, and for colorectal cancer risk and supplemental vitamin D, vitamin E, garlic and folic acid. Meta-analyses of observational studies suggest a beneficial role for multivitamins and calcium supplements on colorectal cancer risk, while the association with other supplements and colorectal cancer risk is inconsistent. Residual confounding of lifestyle factors might be present. Before recommendations can be made, an extensive assessment of dietary supplement use and a better understanding of underlying mechanisms is needed.

Colorectal cancer and nonfermented milk, solid cheese, and fermented milk consumption: a systematic review and meta-analysis of prospective studies

Colorectal cancer is the second most prevalent cancer worldwide. A systematic review and meta-analysis of prospective studies was conducted to examine the association between intake of different types of dairy foods during adulthood and the development of colorectal cancer, specifically comparing nonfermented milk, solid cheese, and fermented milk. Seven databases were systematically searched and 15 cohort studies selected for inclusion, involving over 900,000 subjects and over 5200 colorectal cancer cases. Meta-analysis resulted in an overall relative risk of colon cancer of 0.74 (95% confidence interval 0.60-0.91) in men consuming nonfermented milk (highest intake category averaging 525 g/day). No association was found between consumption of nonfermented milk and rectal cancer in men or nonfermented milk and colon or rectal cancer in women. No protective association was found between consumption of solid cheese or fermented milk and colorectal cancer. Reasons for the differences in the impact of nonfermented milk, solid cheese, and fermented milk in the colon are discussed. This meta-analysis supports the inverse association between nonfermented milk consumption and risk of colon cancer in men, and provides an evidence base to assist in the formulation of dietary guidelines involving dairy foods.

Calcium intake and colorectal cancer risk: dose-response meta-analysis of prospective observational studies

Mechanistic and epidemiologic studies provide considerable evidence for a protective association between calcium intake and incident colorectal cancer (CRC). While the relationship has not been substantiated by short-duration randomized controlled trials (RCTs) of CRC, trials do show a benefit on adenomas, a precursor to CRC. To address some of this inconsistency, we conducted dose-response meta-analyses by sources of calcium intake, based on prospective observational studies published up to December 2013 identified from PubMed, Embase, and BIOSIS. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. For total calcium intake, each 300 mg/day increase was associated with an approximately 8% reduced risk of CRC (summary RR = 0.92, 95% CI = 0.89-0.95, I(2)  = 47%, 15 studies with 12,305 cases, intake = 250-1,900 mg/day, follow-up = 3.3-16 years). While the risk decreased less steeply in higher range of total calcium intake (P(non-linearity)  = 0.04), the degree of curvature was mild and statistical significance of non-linearity was sensitive to one study. For supplementary calcium, each 300 mg/day increase was associated with an approximately 9% reduced risk of CRC (summary RR = 0.91, 95% CI = 0.86-0.98, I(2)  = 67%, six studies with 8,839 cases, intake = 0-1,150 mg/day, follow-up = 5-10 years). The test for non-linearity was not statistically significant (P(non-linearity)  = 0.11). In conclusion, both dietary and supplementary calcium intake may continue to decrease CRC risk beyond 1,000 mg/day. Calcium supplements and non-dairy products fortified with calcium may serve as additional targets in the prevention of CRC. RCTs of calcium supplements with at least 10 years of follow-up are warranted to confirm a benefit of calcium supplements on CRC risk.

Consumption of dairy products and colorectal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Background

Prospective studies have consistently reported lower colorectal cancer risks associated with higher intakes of total dairy products, total milk and dietary calcium. However, less is known about whether the inverse associations vary for individual dairy products with differing fat contents.

Materials and Methods

In the European Prospective Investigation into Cancer and Nutrition (EPIC), we investigated the associations between intakes of total milk and milk subtypes (whole-fat, semi-skimmed and skimmed), yoghurt, cheese, and dietary calcium with colorectal cancer risk amongst 477,122 men and women. Dietary questionnaires were administered at baseline. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, adjusted for relevant confounding variables.

Results

During the mean 11 years of follow-up, 4,513 incident cases of colorectal cancer occurred. After multivariable adjustments, total milk consumption was inversely associated with colorectal cancer risk (HR per 200 g/day 0.93, 95% CI: 0.89–0.98). Similar inverse associations were observed for whole-fat (HR per 200 g/day 0.90, 95% CI: 0.82–0.99) and skimmed milk (HR per 200 g/day 0.90, 95% CI: 0.79–1.02) in the multivariable models. Inverse associations were observed for cheese and yoghurt in the categorical models; although in the linear models, these associations were non-significant. Dietary calcium was inversely associated with colorectal cancer risk (HR per 200 mg/day 0.95, 95% CI: 0.91–0.99); this association was limited to dairy sources of calcium only (HR per 200 mg/day 0.95, 95% CI: 0.91–0.99), with no association observed for non-dairy calcium sources (HR per 200 mg/day 1.00, 95% CI: 0.81–1.24).

Conclusions

Our results strengthen the evidence for a possible protective role of dairy products on colorectal cancer risk. The inverse associations we observed did not differ by the fat content of the dairy products considered.

Dietary patterns and risk of colorectal cancer in Tehran Province: a case-control study

Background

Colorectal cancer is the third and fourth leading cause of cancer incidence and mortality among men and women, respectively in Iran. However, the role of dietary factors that could contribute to this high cancer incidence remains unclear. The aim of this study was to determine major dietary patterns and its relationship with colorectal cancer.

Methods

This case–control study was conducted in four hospitals in Tehran city of Iran. A total of 71 patients (35 men and 36 women, aged 40–75 years) with incident clinically confirmed colorectal cancer (CRC) and 142 controls (70 men and 72 women, aged 40–75 years) admitted to hospital for acute, non-neoplastic diseases were recruited and interviewed. Dietary data were assessed by 125-item semi-quantitative food frequency questionnaire. Multivariate logistic regression was used to estimate the relationship between dietary patterns and risk of colorectal cancer.

Results

Two major dietary patterns (Healthy pattern and Western pattern) were derived using principal component analysis. Each dietary pattern explained 11.9% (Healthy pattern) and 10.3% (Western pattern) of the variation in food intake, respectively. After adjusting for confounding factors, the Healthy dietary pattern was significantly associated with a decreased risk of colorectal cancer (OR= 0.227; 95% CI=0.108–0.478) while an increased risk of colorectal cancer was observed with the Western dietary pattern (OR=2.616; 95% CI= 1.361-5.030).

Conclusion

Specific dietary patterns, which include healthy and western patterns, may be associated with the risk of colorectal cancer. This diet-disease relationship can be used for developing interventions that aim to promote healthy eating for the prevention of chronic disease, particularly colorectal cancer in the Iranian population.

A meta-analysis of the effects of energy intake on risk of digestive cancers

AIM: To quantitatively assess the relationship between energy intake and the incidence of digestive cancers in a meta-analysis of cohort studies.

METHODS: We searched MEDLINE, EMBASE, Science Citation Index Expanded, and the bibliographies of retrieved articles. Studies were included if they reported relative risks (RRs) and corresponding 95% CIs of digestive cancers with respect to total energy intake. When RRs were not available in the published article, they were computed from the exposure distributions. Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator. We performed fixed-effects meta-analyses and meta-regressions to compute the summary RR for highest versus lowest category of energy intake and for per unit energy intake and digestive cancer incidence by giving each study-specific RR a weight that was proportional to its precision.

RESULTS: Nineteen studies consisting of 13 independent cohorts met the inclusion criteria. The studies included 995 577 participants and 5620 incident cases of digestive cancer with an average follow-up of 11.1 years. A significant inverse association was observed between energy intake and the incidence of digestive cancers. The RR of digestive cancers for the highest compared to the lowest caloric intake category was 0.90 (95% CI 0.81-0.98, P < 0.05). The RR for an increment of 239 kcal/d energy intake was 0.97 (95% CI 0.95-0.99, P < 0.05) in the fixed model. In subgroup analyses, we noted that energy intake was associated with a reduced risk of colorectal cancer (RR 0.90, 95% CI 0.81-0.99, P < 0.05) and an increased risk of gastric cancer (RR 1.19, 95% CI 1.08-1.31, P < 0.01). There appeared to be no association with esophageal (RR 0.96, 95% CI 0.86-1.07, P > 0.05) or pancreatic (RR 0.79, 95% CI 0.49-1.09, P > 0.05) cancer. Associations were also similar in studies from North America and Europe. The RR was 1.02 (95% CI 0.79-1.25, P > 0.05) when considering the six studies conducted in North America and 0.87 (95% CI 0.77-0.98, P < 0.05) for the five studies from Europe.

CONCLUSION: Our findings suggest that high energy intake may reduce the total digestive cancer incidence and has a preventive effect on colorectal cancer.

Dietary, endocrine, and metabolic factors in the development of colorectal cancer

INTRODUCTION

Colorectal cancer is the third cause of death in industrialized countries. Genetic susceptibility and diet are determinant of cancer risk and tumor behavior. Variation in cancer incidence among and within populations with similar dietary patterns suggests that an individual response may reflect interactions with genetic factors, which may modify gene, protein, and metabolite expression patterns. Nutrigenomics, defined as the interaction between nutrition and an individual genome, will likely provide important clues about responders and non-responders to nutritional intervention.

DISCUSSION

Epidemiological and experimental studies suggest a protective role of some normal components of daily diet (fish oil, milk, and vegetables), estrogens, and phytoestrogens in colorectal cancer. The effect of estrogen seems to be mediated by their binding to estrogen receptor beta (ER-β), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-β in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-β agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen agonists in mammals. They are characterized by a higher binding affinity to ER-β as compared to estrogen receptor alpha (ER-α), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardiovascular accidents, higher incidence of endometrial and breast cancer) and makes these substances potential candidates for colorectal cancer prevention.

Calcium and vitamin D and risk of colorectal cancer: results from a large population-based case-control study in Newfoundland and Labrador and Ontario

BACKGROUND

Previous epidemiological studies have been suggestive but inconclusive in demonstrating inverse associations of calcium, vitamin D, dairy product intakes with risk of colorectal cancer (CRC). We conducted a large population-based comparison of such associations in Newfoundland and Labrador (NL) and Ontario (ON).

METHODS

A case control study design was used. Colorectal cancer cases were new CRC patients aged 20-74 years. Controls were a sex and age-group matched random sample of the population in each province. 1760 cases and 2481 controls from NL and ON were analyzed. Information on dietary intake and lifestyle was collected using self-administered food frequency and personal history questionnaires.

RESULTS

Controls reported higher mean daily intakes of total calcium and total vitamin D than cases in both provinces. In ON, significant reduced CRC risk was associated with intakes of total calcium (OR of highest vs. lowest quintiles was 0.57, 95% CI 0.42-0.77, p(trend) = 0.03), total vitamin D (OR = 0.73, 95% CI 0.54-1.00), dietary calcium (OR = 0.76, 95% CI 0.60-0.97), dietary vitamin D (OR = 0.77, 95% CI 0.61-0.99), total dairy products and milk (OR = 0.78, 95% CI 0.60-1.00), calcium-containing supplements use (OR = 0.76). In NL, the inverse associations of calcium, vitamin D with CRC risk were most pronounced among calcium- or vitamin D-containing supplement users (OR = 0.67, 0.68, respectively).

CONCLUSIONS

Results of this study add to the evidence that total calcium, dietary calcium, total vitamin D, dietary vitamin D, calcium- or vitamin D-containing supplement use may reduce the risk of CRC. The inverse associations of CRC risk with intakes of total dairy products and milk may be largely due to calcium and vitamin D.

Dairy products and colorectal cancer risk: a systematic review and meta-analysis of cohort studies

BACKGROUND

Previous studies of the association between intake of dairy products and colorectal cancer risk have indicated an inverse association with milk, however, the evidence for cheese or other dairy products is inconsistent.

METHODS

We conducted a systematic review and meta-analysis to clarify the shape of the dose-response relationship between dairy products and colorectal cancer risk. We searched the PubMed database for prospective studies published up to May 2010. Summary relative risks (RRs) were estimated using a random effects model.

RESULTS

Nineteen cohort studies were included. The summary RR was 0.83 (95% CI [confidence interval]: 0.78-0.88, I2=25%) per 400 g/day of total dairy products, 0.91 (95% CI: 0.85-0.94, I2=0%) per 200 g/day of milk intake and 0.96 (95% CI: 0.83-1.12, I2=28%) per 50 g/day of cheese. Inverse associations were observed in both men and women but were restricted to colon cancer. There was evidence of a nonlinear association between milk and total dairy products and colorectal cancer risk, P<0.001, and the inverse associations appeared to be the strongest at the higher range of intake.

CONCLUSION

This meta-analysis shows that milk and total dairy products, but not cheese or other dairy products, are associated with a reduction in colorectal cancer risk.

Yogurt consumption and risk of colorectal cancer in the Italian European prospective investigation into cancer and nutrition cohort

Fermented dairy products like yogurt have been suggested to protect against colorectal cancer (CRC). We conducted a prospective study on 45,241 (14,178 men; 31,063 women) volunteers of the EPIC-Italy cohort who completed a dietary questionnaire including specific questions on yogurt intake. During 12 years of follow-up, 289 volunteers were diagnosed with CRC. Hazard ratios (HRs) for the disease and 95% confidence intervals (CIs) were estimated by Cox proportional hazard models, stratified by dietary questionnaire and adjusted for energy intake and other potential confounders. Yogurt intake was inversely associated with CRC risk. For the energy-adjusted model, HR for CRC in the highest versus lowest tertile of yogurt intake was 0.62 (95% CI, 0.46-0.83). In the full model adjusted for energy, simple sugar, calcium, fiber, animal fat, alcohol and red meat intake, as well as body mass index, smoking, education and physical activity, HR was 0.65 (95% CI, 0.48-0.89) in the highest versus lowest tertile. The protective effect of yogurt was evident in the entire cohort, but was stronger in men, although there was no interaction of sex with the yogurt-CRC association (p(interaction) 0.20, fully adjusted model). In our prospective study, high yogurt intake was significantly associated with decreased CRC risk, suggesting that yogurt should be part of a diet to prevent the disease. Investigation of larger cohorts is necessary to reveal any residual confounding of the association of yogurt intake with CRC risk.

Calcium, vitamin D and colorectal cancer chemoprevention

Identifying modifiable risk factors, particularly dietary factors, which have been hypothesized to play an important role in colorectal carcinogenesis, remains crucial in developing primary prevention strategies. Calcium and vitamin D have been shown consistently in experimental studies to have anti-cancerous properties including but not limited to stimulating differentiation, reducing proliferation, and inducing apoptosis. The majority of epidemiologic studies consistently support an approximately 20-30% reduction in risk of colorectal cancer and adenomas comparing high to low intake categories of both calcium and vitamin D, although independent effects may not be adequately separated. Less consistency exists on the dose-response relation for both nutrients. Intake of calcium of not more than 1000 mg/d and intake of vitamin D of 1000-2000 IU/d, achieving a level of at least 30 ng/mL, appear important for colorectal cancer prevention. More study is warranted to determine the optimal intake levels and duration to reduce the colorectal cancer risk.

Dietary cholesterol intake and cancer

BACKGROUND

This study assesses the association between dietary cholesterol intake and the risk of various cancers.

PATIENTS AND METHODS

Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces by 1182 incident histologically confirmed cases of the stomach, 1727 of the colon, 1447 of the rectum, 628 of the pancreas, 3341 of the lung, 2362 of the breast, 442 of the ovary, 1799 of the prostate, 686 of the testis, 1345 of the kidney, 1029 of the bladder, 1009 of the brain, 1666 non-Hodgkin's lymphomas (NHL), 1069 leukemia and 5039 population controls. Information on dietary habits and nutrition intake were obtained using a food frequency questionnaire, which provided data on eating habits 2 years before the study. Odds ratios (ORs) were derived by unconditional logistic regression to adjust for total energy intake and other potential confounding factors.

RESULTS

Dietary cholesterol was positively associated with the risk of cancers of the stomach, colon, rectum, pancreas, lung, breast (mainly postmenopausal), kidney, bladder and NHL: the ORs for the highest versus the lowest quartile ranged from 1.4 to 1.7. In contrast, cholesterol intake was inversely associated with prostate cancer.

CONCLUSIONS

Our findings add to the evidence that high cholesterol intake is linked to increased risk of various cancers. A diet low in cholesterol may play a role in the prevention of several cancers.

Meta-analyses of vitamin D intake, 25-hydroxyvitamin D status, vitamin D receptor polymorphisms, and colorectal cancer risk

BACKGROUND

Our objective was to conduct a systematic review and meta-analysis of prospective studies on colorectal cancer (CRC) and vitamin D intake and 25-hydroxyvitamin D status, as part of the World Cancer Research Fund Continuous Update Project. We also aimed at conducting meta-analysis of all studies on CRC and vitamin D receptor (VDR) single-nucleotide polymorphisms.

METHODS

Relevant studies were identified in PubMed (up to June 2010). Inclusion criteria were original and peer-reviewed publications with a prospective design (for studies on vitamin D intake or status). Random effects of dose-response meta-analyses were performed on cancer incidence.

RESULTS

We observed inverse associations of CRC risk with dietary vitamin D [summary relative risk (RR) per 100 IU/day = 0.95, 95% CI: 0.93-0.98; 10 studies; range of intake (midpoints) = 39-719 IU/day] and serum/plasma 25-hydroxyvitamin D (RR per 100 IU/L = 0.96, 0.94-0.97; 6 studies; range = 200-1,800 IU/L), but not with total vitamin D (5 studies). Supplemental (2 studies; range = 0-600 IU/day) and total (4 studies; range = 79-732 IU/day) vitamin D intake and 25-hydroxyvitamin D status (6 studies; range = 200-1,800 IU/L) were inversely associated with colon cancer risk. We did not observe statistically significant associations between FokI, PolyA, TaqI, Cdx2, and ApaI VDR polymorphisms and CRC risk. The BsmI polymorphism was associated with a lower CRC risk (RR = 0.57, 0.36-0.89 for BB versus bb, 8 studies).

CONCLUSIONS

These meta-analyses support the evidence of an inverse association between vitamin D intake, 25-hydroxyvitamin D status, and the BsmI VDR polymorphism and CRC risk.

IMPACT

Improving vitamin D status could be potentially beneficial against CRC incidence.

Vitamin D and colon cancer

A wealth of scientific evidence supports a role for vitamin D in decreasing colorectal cancer incidence, and possibly mortality. This reduction in risk is related to inhibition of cellular proliferation and stimulation of differentiation. The minimal amount and duration needed to bring about these effects necessitate additional studies. Furthermore, a critical evaluation of physiologically relevant biomarkers of vitamin D status, including 25-hydroxyvitamin D, is needed. Several dietary components and the balance between energy intake and expenditure influence vitamin D metabolism. Scientists need to identify confounders and modifiers of the biological response to vitamin D, including dietary factors, lifestyle factors such as exercise, race or ethnicity, and genetic background.

Prevention of colorectal cancer with vitamin D

The fact that colorectal cancer (CRC) is the second leading cause of cancer mortality in the United States emphasizes the need for more effective preventive and therapeutic modalities. There is growing evidence that vitamin D may reduce the incidence of CRC. Results of epidemiologic, in vitro, in vivo animal and clinical studies suggest that a low serum vitamin D level may be a serious risk factor for CRC and a high serum vitamin D level may reduce the risk of CRC. On a molecular level, vitamin D suppresses CRC development and growth by affecting cell proliferation, differentiation, apoptosis, and angiogenesis. Vitamin D insufficiency and CRC are common in the elderly population. Vitamin D insufficiency is simple to screen for and treatable with vitamin D supplementation. Serum 25-hydroxyvitamin D (calcidiol) is the best measure of vitamin D status and should be checked routinely for individuals with risk factors for CRC. Maintaining serum concentrations of calcidiol above 32 ng/ml (80 nmol/l) in individuals whose serum calcidiol level is low may help prevent CRC as well as osteoporosis, fractures, infections, and cardiovascular disease. Daily calcidiol intake of 1000 International Units can increase serum vitamin D to sufficient levels in most elderly persons and, based on available data, may substantially lower the incidence of CRC with minimal risks.

Epidemiology of vitamin D and colorectal cancer: casual or causal link?

INTRODUCTION

Since Garland and Garland hypothesized that better vitamin D status lowered risk of colorectal cancer in 1980, the relation between vitamin D status and colorectal cancer risk has been investigated in epidemiologic studies. These studies are reviewed.

MATERIALS AND METHODS

Various approaches have been used to estimate vitamin D status, including direct measures of circulating 25(OH)vitamin D levels, surrogates or determinants of vitamin D (including region of residence, intake, and sun exposure estimates, or a combination of these). These measures of vitamin D status have been studied in relation to colorectal adenoma, cancer incidence and mortality.

RESULTS

In general, all lines of inquiry from observational studies indicate that an association between better vitamin D status and lower colorectal cancer risk exists. While most of the studies have examined vitamin D status in relation to risk of cancer, some evidence suggests that vitamin D may be additionally important for colorectal cancer progression and mortality.

DISCUSSION

Although confounding factors cannot be entirely excluded, the consistency of the association using various approaches to measure vitamin D, for diverse endpoints and in diverse populations shows high consistency and is suggestive of a causal association. Thus, improving vitamin D status could be potentially beneficial against colorectal cancer incidence and mortality.

Evaluation of epidemiological studies of intestinal bacteria that affected occurrence of colorectal cancer: studies of prevention of colorectal tumors by dairy products and lactic acid bacteria

Enviromental factors have been consistently associated with colon cancer risk. In particular, consumption of Western-style diet including red meat is the most widely accepted etiologic risk factor. It has been reported that dietary factors change the proportion of intestinal flora, and it also affects the composition of fecal bile acids and the intestinal activity of some mutagens. In addition, it was suggested that modulating the composition of intestinal flora may reduce the occurrence of colorectal cancer. In this review, we present the clinical studies on the association between intestinal flora and the risk of colorectal cancer that have been carried out to date. The clinical studies of intestinal bacteria related to colorectal cancer risk have not shown consistent results so far, compared with the accomplishments of some basic studies. On the other hand, it was suggested in some clinical studies that lactic acid bacteria reduce the occurrence of colorectal cancer.

Molecular mechanisms triggered by low-calcium diets

Ca is not only essential for bone mineralisation, but also for regulation of extracellular and intracellular processes. When the Ca2+ intake is low, the efficiency of intestinal Ca2+ absorption and renal Ca2+ reabsorption is increased. This adaptive mechanism involves calcitriol enhancement via parathyroid hormone stimulation. Bone is also highly affected. Low Ca2+ intake is considered a risk factor for osteoporosis. Patients with renal lithiasis may be at higher risk of recurrence of stone formation when they have low Ca2+ intake. The role of dietary Ca2+ on the regulation of lipid metabolism and lipogenic genes in adipocytes might explain an inverse relationship between dairy intake and BMI. Dietary Ca2+ restriction produces impairment of the adipocyte apoptosis and dysregulation of glucocorticosteroid metabolism in the adipose tissue. An inverse relationship between hypertension and a low-Ca2+ diet has been described. Ca2+ facilitates weight loss and stimulates insulin sensitivity, which contributes to the decrease in the blood pressure. There is also evidence that dietary Ca2+ is associated with colorectal cancer. Dietary Ca2+ could alter the ratio of faecal bile acids, reducing the cytotoxicity of faecal water, or it could activate Ca2+-sensing receptors, triggering intracellular signalling pathways. Also it could bind luminal antigens, transporting them into mucosal mononuclear cells as a mechanism of immunosurveillance and promotion of tolerance. Data relative to nutritional Ca2+ and incidences of other human cancers are controversial. Health professionals should be aware of these nutritional complications and reinforce the dairy intakes to ensure the recommended Ca2+ requirements and prevent diseases.

trans-Fatty acid consumption and its association with distal colorectal cancer in the North Carolina Colon Cancer Study II

Recently, the potential health effects of trans-fatty acid consumption have raised concerns. A few studies have examined the risk of colorectal cancer with increasing consumption of trans-fatty acids, but none investigated the risk of rectal cancer, which may have different risk factors than colon cancer. Our objective was to explore the relationship between trans-fatty acid consumption and distal colorectal (sigmoid, rectosigmoid, and rectal) cancer using a case-control study of Whites (n = 1,516) and African Americans (n = 392) in North Carolina from 2001 to 2006. Matched cases and controls were interviewed about demographic information, lifestyle factors, and diet. White cases reported higher mean consumption of trans-fatty acid than White controls, but mean consumption was similar for African American cases and controls. Relative to the lowest quartile, the highest quartiles of energy-adjusted trans-fatty acid consumption were positively associated with distal colorectal cancer for Whites [adjusted ORs for the third and fourth quartiles are 1.54 (95%CI: 1.12, 2.13) and 1.45 (95%CI: 1.04, 2.03), respectively]. Consumption was not associated with distal colorectal cancer in African Americans [adjusted ORs for the third and fourth quartiles are 0.98 (95%CI: 0.47, 2.05) and 0.87 (95%CI 0.42, 1.81), respectively]. In conclusion, high consumption of trans-fatty acids was positively associated with distal colorectal cancer among Whites.