The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies

Cholesterol in colorectal cancer: an essential but tumorigenic precursor?

Colorectal cancer (CRC) is one of the most lethal human malignancies, and with the growth of societies and lifestyle changes, the rate of people suffering from it increases yearly. Important factors such as genetics, family history, nutrition, lifestyle, smoking, and alcohol can play a significant role in increasing susceptibility to this cancer. On the other hand, the metabolism of several macromolecules is also involved in the fate of tumors and immune cells. The evidence discloses that cholesterol and its metabolism can play a role in the pathogenesis of several cancers because there appears to be an association between cholesterol levels and CRC, and cholesterol-lowering drugs may reduce the risk. Furthermore, changes or mutations of some involved genes in cholesterol metabolism, such as CYP7A1 as well as signaling pathways, such as mitogen-activated protein kinase (MAPK), can play a role in CRC pathogenesis. This review summarized and discussed the role of cholesterol in the pathogenesis of CRC as well as available cholesterol-related therapeutic approaches in CRC.

The Potential Prognostic Marker TyG Index Predicts Time to Brain Metastasis at HER2 Positive Breast Cancer

Background

We aimed to investigate the prognostic significance of insulin resistance (IR) markers fasting triglyceride-glucose (TyG) index and triglyceride high-density lipoprotein cholesterol (TG/HDL-C) ratio in HER2-positive breast cancer (BC) patients with brain metastasis (BM).

Methods

In this single-center study, 120 patients who met the criteria were included. TyG and TG/HDL-C at the time of diagnosis were computed retrospectively. For TyG and TG/HDL-C, the median values of 9.32 and 2.95 were taken as the cut-off, respectively. TyG values <9.32 and <2.95 were considered low, and TG/HDL-C values ≥9.32 and ≥2.95 were considered high.

Results

The median overall survival (OS) was 47 months (95% CI: 40.54-53.45). Time to BM was 22 months (95% CI: 17.22-26.73). The median time to BM was 35 months (95% CI: 20.90-49.09) in the low TyG group and 15 months (95% CI: 8.92-21.07) in the high TyG group (p < 0.001). The time to BM was 27 months (95% CI: 20.49-33.50) in the low TG/HDL-C group and 20 months (95% CI: 16.76-23.23) in the high TG/HDL-C group (p=0.084). In the multivariate Cox regression analysis, the TyG index (HR: 20.98, 95% CI: 7.14-61.59, p < 0.001) was an independent risk factor for time to BM.

Conclusion

These findings suggest that the TyG index could be used as a predictive biomarker at the time of diagnosis for risk of time BM in patients with HER2-positive BC. The TyG index can be used as a standard potential marker with prospective studies confirming these data.

Epidemiology beyond its limits

In 1995, journalist Gary Taubes published an article in Science titled "Epidemiology faces its limits," which questioned the utility of nonrandomized epidemiologic research and has since been cited more than 1000 times. He highlighted numerous examples of research topics he viewed as having questionable merit. Studies have since accumulated for these associations. We systematically evaluated current evidence of 53 example associations discussed in the article. Approximately one-quarter of those presented as doubtful are now widely viewed as causal based on current evaluations of the public health consensus. They include associations between alcohol consumption and breast cancer, residential radon exposure and lung cancer, and the use of tanning devices and melanoma. This history should inform current debates about the reproducibility of epidemiologic research results.

Genetic variation associated with childhood and adult stature and risk of MYCN-amplified neuroblastoma

Background

Neuroblastoma is the most common pediatric solid tumor. MYCN‐amplification is an important negative prognostic indicator and inherited genetic contributions to risk are incompletely understood. Genetic determinants of stature increase risk of several adult and childhood cancers, but have not been studied in neuroblastoma despite elevated neuroblastoma incidence in children with congenital overgrowth syndromes.

Methods

We investigated the association between genetic determinants of height and neuroblastoma risk in 1538 neuroblastoma cases, stratified by MYCN‐amplification status, and compared to 3390 European‐ancestry controls using polygenic scores for birth length (five variants), childhood height (six variants), and adult height (413 variants). We further examined the UK Biobank to evaluate the association of known neuroblastoma risk loci and stature.

Results

An increase in the polygenic score for childhood stature, corresponding to a ~0.5 cm increase in pre‐pubertal height, was associated with greater risk of MYCN‐amplified neuroblastoma (OR = 1.14, P = .047). An increase in the polygenic score for adult stature, corresponding to a ~1.7 cm increase in adult height attainment, was associated with decreased risk of MYCN‐amplified neuroblastoma (OR = 0.87, P = .047). These associations persisted in case‐case analyses comparing MYCN‐amplified to MYCN‐unamplified neuroblastoma. No polygenic height scores were associated with MYCN‐unamplified neuroblastoma risk. Previously identified genome‐wide association study hits for neuroblastoma (N = 10) were significantly enriched for association with both childhood (P = 4.0 × 10⁻³) and adult height (P = 8.9 × 10⁻³) in >250 000 UK Biobank study participants.

Conclusions

Genetic propensity to taller childhood height and shorter adult height were associated with MYCN‐amplified neuroblastoma risk, suggesting that biological pathways affecting growth trajectories and pubertal timing may contribute to MYCN‐amplified neuroblastoma etiology.

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.

Dietary protein and fat intake in relation to risk of colorectal adenoma in Korean

Consumption of red meat and alcohol are known risk factors for colorectal cancer, but associations for dietary fat remain unclear. We investigated the associations of dietary fat, protein, and energy intake with prevalence of colorectal adenoma.We performed a prospective cross-sectional study on asymptomatic persons who underwent a screening colonoscopy at a single center during a routine health check-up from May to December 2011. Dietary data were obtained via a validated Food Frequency Questionnaire (FFQ), assisted by a registered dietician. We also obtained information on alcohol consumption and smoking status, and measured metabolic syndrome markers including abdominal circumference, blood pressure, fasting glucose, serum triglyceride and high-density lipoprotein cholesterol. We calculated odds ratio (OR) and 95% confidence interval (CI) to evaluate the associations using the polytomous logistic regression models. As a secondary analysis, we also conducted a matched analysis, matched by age and sex (557 cases and 557 non-cases).The study sample included 557 cases (406 males and 151 females) with histopathologically confirmed colorectal adenoma, and 1157 controls (650 males and 507 females). The proportion of advanced adenoma was 28.1% of men and 18.5% of female, respectively. Although vegetable protein intake was inversely associated with the prevalence of colorectal adenoma, further adjustment for potential confounding factors attenuated the association, resulting in no significant associations. There were no significant associations between dietary fat intake and colorectal adenoma in energy-adjusted models. For vegetable protein in women, the OR for the comparison of those in the highest tertile with those in the lowest tertile was 0.47 (95% CI 0.25-0.91, P for trend = 0.07) after adjustment for total energy intake. However, after controlling for metabolic syndrome markers, body mass index, smoking status, alcohol consumption, and family history of colorectal adenoma, which were all significantly high in the colorectal adenoma patients group, the association became attenuated (OR 0.54, 95% CI 0.27-1.11, P for trend = 0.13).In conclusion, we did not observe the significant associations for intakes of total energy, total, animal and vegetable fats, and total, animal and vegetable proteins in relation to colorectal adenoma prevalence.

Is height a risk factor for colorectal adenoma?

BACKGROUND/AIMS

Although it is generally known that the risk for all types of cancer increases with adult height, combined and for several common site-specific cancers (including colon and rectal), evidence is limited for adenomas, which are precursors to colorectal cancer. We evaluated the association between height and risk of colorectal adenoma at various stages of the adenoma-carcinoma pathway.

METHODS

We conducted a retrospective study using data from patients who had undergone a complete colonoscopy as part of a health examination at the Health Promotion Center of Samsung Medical Center between October 13, 2009 and December 31, 2011. A total of 1,347 male subjects were included in our study. Multivariate logistic regression analysis was used to evaluate the association between height and colorectal adenoma.

RESULTS

Each 5-cm increase in height was associated with 1.6% and 5.3% higher risks of advanced colorectal adenoma and high-risk colorectal adenoma, respectively, but associations were not significant after adjusting for age, body mass index, metabolic syndrome, alcohol intake, smoking, family history of colorectal cancer, and regular aspirin use (p = 0.840 and p = 0.472, respectively).

CONCLUSIONS

No clear association was found between colorectal adenoma risk and height. Unlike other site-specific tumors reported to have a consistent relationship with height, the association between colorectal tumor and height remains controversial.

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.

Clinical significance of preoperative serum high density lipoprotein cholesterol levels in soft tissue sarcoma

The prognostic value of lipid profile remains unclear in soft tissue sarcoma. The aim of the present study was to validate the prognostic value of preoperative plasma lipid profile (high density lipoprotein-cholesterol [HDL-C], low density lipoprotein-cholesterol [LDL-C], cholesterol, and triglycerides) levels on disease-free survival (DFS) and overall survival (OS) in soft tissue sarcoma (STS) patients undergoing extensive and radical surgical resection.The preoperative plasma lipid profile levels of 234 STS patients, who were operated on between 2000 with 2010, were retrospectively evaluated. Kaplan-Meier curves and multivariate Cox proportional models were calculated for DFS and OS.In univariate analysis, a decreased HDL-C level was significantly associated with decreased OS (hazard ratio [HR], 3.405; 95% confidence interval (CI), 1.445-8.021, P = 0.005) and remained significant in the multivariate analysis (HR, 5.615; 95% CI, 1.243-25.378, P = 0.025). Patients with HDL-C < 1.475 mmol/L showed a median OS of 71 months. In contrast, patients with HDL-C ≥1.475 mmol/L had a median OS of 101 months. In univariate analysis, a decreased HDL-C level was significantly associated with decreased DFS (HR, 2.085; 95% CI, 1.271-3.422, P = 0.004) and remained significant in the multivariate analysis (HR, 1.808; 95% CI, 1.118-2.924, P = 0.016). Patients with HDL-C <1.475 mmol/L presented with a median DFS of 47 months, whereas patients with HDL-C ≥1.475 mmol/L had a median DFS of 78 months. In univariate analysis and multivariate analyses regarding OS and DFS, there was no significant association between the groups in terms of LDL-C, CHO and TG.Our study investigated the potential prognostic utility of preoperative plasma HDL-C levels as an independent factor in STS patients who had undergone radical surgical resection.

Fatty acid composition of adipose tissue and colorectal cancer: a case-control study

BACKGROUND

Unlike experimental results, epidemiologic studies that used dietary questionnaires were not convincing as regards the relations between dietary fatty acids (FAs) and risk of colorectal cancer (CRC). The FA composition of adipose tissue, which is considered to be an indicator of dietary intake over 2-3 y because of the slow turnover rate, appears promising but has so far been rarely used to explore the relation between CRC and exogenous or endogenously produced FAs.

OBJECTIVE

In this case-control study, we aimed to investigate associations between risk of CRC and the FA composition of subcutaneous adipose tissue and product-to-precursor ratios as indexes of enzymatic activities.

DESIGN

From 2008 to 2011, we recruited 203 cases with newly diagnosed CRC and elective surgery with a curative intent and 223 control subjects with planned abdominal surgery for benign disease and no history of CRC or polyp resection. During surgery, abdominal subcutaneous adipose tissue samples were optimally collected, stored, and analyzed by using high-performance gas chromatography. Multivariate logistic regression was used to estimate ORs for CRC in relation to individual FAs divided into tertiles according to the FA distribution in controls.

RESULTS

After adjustment, significant positive associations with CRC risk were observed in highest compared with lowest tertiles of 16:1n-9 (OR: 1.75; 95% CI: 1.00, 3.06; P-trend = 0.045), 20:3n-6 (OR: 1.79; 95% CI: 1.01, 3.17; P-trend = 0.038), 22:5n-3 (OR: 1.82; 95% CI: 1.06, 3.12; P-trend = 0.023), and the ratio of 18:2n-6 to 18:3n-3 (OR: 2.34; 95% CI: 1.37, 3.98; P-trend = 0.001). Significant inverse associations were observed for 18:3n-3 (OR: 0.48; 95% CI: 0.29, 0.81; P-trend = 0.007). Several product-to-precursor ratios showed significant differences between cases and controls in particular ratios that reflected elongase 2/5 activity.

CONCLUSIONS

CRC patients presented higher concentrations of some FAs but lower concentrations of α-linolenic acid in their subcutaneous adipose tissue than did controls. These results may reflect both dietary patterns and altered FA metabolism but require mechanistic explorations.

Impact of gastrectomy on high-density lipoprotein cholesterol elevation in nonobese patients during a 10-year follow-up

AIM

The role of gastrectomy in glycemic control has been established in the current era of bariatric surgery for obesity. Gastrectomy in obese patients is associated with increased levels of high-density lipoprotein cholesterol (HDL-C). However, limited data on the effects of gastrectomy in nonobese patients are available. We herein investigated the long-term plasma lipid changes in nonobese patients who had undergone gastrectomy.

METHODS

Patients were enrolled as part of routine healthcare examinations from 1984 to 2003. Preoperative and postoperative data from patients who had undergone curative gastrectomy were analyzed for up to 10 years postoperatively. Three age- and sex-matched controls were assigned to each case.

RESULTS

Sixty-four nonobese patients without diabetes mellitus or a history of having taken lipid-lowering drugs who underwent curative gastrectomy during the study period were enrolled (60 subtotal gastrectomies, four total gastrectomies). The median follow-up period was 7.6 years. The mean body mass index was 9.6% lower one year after gastrectomy (p < 0.01), then plateaued with a slight recovery. Intriguingly, the preoperative HDL-C level was 21% higher one year after gastrectomy (p < 0.01), increased by another 30% six years after gastrectomy and remained at this level for the rest of the follow-up period. No significant changes in the HDL-C level were observed in the controls. The degree of HDL-C elevation was consistently significant, irrespective of the baseline triglyceride level, HDL-C level or body weight.

CONCLUSIONS

Gastrectomy in nonobese patients was associated with consistent and distinct long-term HDL-C elevations and body mass index reductions.

The association of percentage energy from fat and colon cancer risk among members of the US military

Epidemiologic studies have previously reported an association between high fat intake and colon cancer risk. However, findings have generally been inconclusive. This study aimed to investigate the association between fat as a percentage of energy intake and colon cancer risk. Study subjects included 215 cases and 215 matched controls identified by the Defense Medical Surveillance System. Percentage energy from fat (Pfat) was estimated using a short dietary screener developed by the National Cancer Institute for two time periods: the year before the first blood draw and the year before colon cancer diagnosis. Conditional logistic regression analysis was used to assess the relationship between colon cancer risk and Pfat. Odds ratios and 95% confidence intervals (CIs) were calculated. Compared with the lowest quartile of Pfat, the adjusted odds of having colon cancer were 2.00 (95% CI 0.96-4.18), 2.83 (95% CI 1.41-5.66), and 3.37 (95% CI 1.58-7.17), respectively, for the second, third, and highest quartiles in the year before cancer diagnosis. Similar results were observed for Pfat at an earlier time point. Our findings suggest a positive association between Pfat and colon cancer in the US military population.

Fast food fever: reviewing the impacts of the Western diet on immunity

While numerous changes in human lifestyle constitute modern life, our diet has been gaining attention as a potential contributor to the increase in immune-mediated diseases. The Western diet is characterized by an over consumption and reduced variety of refined sugars, salt, and saturated fat. Herein our objective is to detail the mechanisms for the Western diet's impact on immune function. The manuscript reviews the impacts and mechanisms of harm for our over-indulgence in sugar, salt, and fat, as well as the data outlining the impacts of artificial sweeteners, gluten, and genetically modified foods; attention is given to revealing where the literature on the immune impacts of macronutrients is limited to either animal or in vitro models versus where human trials exist. Detailed attention is given to the dietary impact on the gut microbiome and the mechanisms by which our poor dietary choices are encoded into our gut, our genes, and are passed to our offspring. While today's modern diet may provide beneficial protection from micro- and macronutrient deficiencies, our over abundance of calories and the macronutrients that compose our diet may all lead to increased inflammation, reduced control of infection, increased rates of cancer, and increased risk for allergic and auto-inflammatory disease.

Adipose tissue fatty acid composition and colon cancer: a case-control study

PURPOSE

An increased dietary intake of fat, particularly polyunsaturated fatty acids (PUFAs), has been related to an increased risk of breast, prostate and colon cancers. Patients with and without colon cancer were tested for differences in their fatty stores composition.

METHODS

The fatty acid levels were determined by gas-liquid chromatography in adipose tissue samples, subcutaneous and visceral, obtained intra-operatively from 52 colon cancer and 50 nonneoplastic abdominal disease patients. Statistical analysis was performed using one-way ANOVA, SNK test and Dunnet test. Differences in the composition of saturated, monounsaturated and polyunsaturated fatty acids, in visceral and in subcutaneous samples of colon cancer and nonneoplastic patients, were assessed.

RESULTS

The sum of saturated and monounsaturated fatty acids, respectively, in visceral and in subcutaneous samples, was higher in neoplastic patients (p < 0.001). The sum of some n-6 polyunsaturated fatty acids (PUFAs), the dietary precursor linoleic acid (LA-18:2n-6), and their metabolites, gammalinolenic acid (GLA-18:3n-6) + dihomogammalinolenic acid (DGLA-20:3n-6) + arachidonic acid (AA-22:4n-6), was higher in subcutaneous fat of controls (p < 0.05). The samples from these patients had a fatty acid composition, both subcutaneous and visceral, with a higher content of alphalinolenic acid (ALA-18:3n-3) and stearidonic acid (SDA-18:4n-3) compared to neoplastic patients (p < 0.001). These had subcutaneous and visceral fat stores statistically higher in GLA, DGLA and AA (p < 0.001). Colon cancer patients had subcutaneous adipose stores higher in ALA and LA than visceral sites (p < 0.001).

CONCLUSIONS

Fatty acids may be involved in colon carcinogenesis and there is a depot-specific impact on this process by visceral fat.

Repair kinetics of acrolein- and (E)-4-hydroxy-2-nonenal-derived DNA adducts in human colon cell extracts

ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) play a role in the pathogenesis of colon cancer. Upon oxidation, PUFAs generate α,β-unsaturated aldehydes or enals, such as acrolein (Acr) and (E)-4-hydroxy-2-nonenal (HNE), which can form cyclic adducts of deoxyguanosine (Acr-dG and HNE-dG, respectively) in DNA. Both Acr-dG and HNE-dG adducts have been detected in human and animal tissues and are potentially mutagenic and carcinogenic. In vivo levels of Acr-dG in DNA are at least two orders of magnitude higher than those of HNE-dG. In addition to the facile reaction with Acr, the higher levels of Acr-dG than HNE-dG in vivo may be due to a lower rate of repair. Previous studies have shown that HNE-dG adducts are repaired by the NER pathway (Choudhury et al. [42]). We hypothesize that Acr-dG adducts are repaired at a slower rate than HNE-dG and that HNE-dG in DNA may influence the repair of Acr-dG. In this study, using a DNA repair synthesis assay and a LC-MS/MS method, we showed that Acr-dG in a plasmid DNA is repaired by NER proteins, but it is repaired at a much slower rate than HNE-dG in human colon cell extracts, and the slow repair of Acr-dG is likely due to poor recognition/excision of the lesions in DNA. Furthermore, using a plasmid DNA containing both adducts we found the repair of Acr-dG is significantly inhibited by HNE-dG, however, the repair of HNE-dG is not much affected by Acr-dG. This study demonstrates that the NER repair efficiencies of the two major structurally-related in vivo cyclic DNA adducts from lipid oxidation vary greatly. More importantly, the repair of Acr-dG can be significantly retarded by the presence of HNE-dG in DNA. Therefore, this study provides a mechanistic explanation for the higher levels of Acr-dG than HNE-dG observed in tissue DNA.

Dietary lifestyle and colorectal cancer onset, recurrence, and survival: myth or reality?

BACKGROUND AND PURPOSE

Interest in the possibility that diet might help to reduce the risk of colorectal cancer dates back to 1970 based on both the large variation in rates of specific cancers in different countries and the impressive changes observed in the incidence of cancer in migrants from low- to high-risk areas. Here, we report the state of art of literature data about this topic.

METHODS

Three sections have been separately considered: chemoprevention of first tumor onset, chemoprevention of recurrence after surgery, and chemoprevention of polyp recurrence in the course of the follow-up of subjects with elevated risk. A particular attention has been pointed to dietary factors and survival, whose relevance is showing a growing interest.

RESULTS

The relationship between diet and colorectal cancer has been extensively studied about the onset, sometimes with controversial results. Its influence on recurrence and survival has been examined in only few studies.

CONCLUSIONS

Literature data are convincing for a protective role on the onset of preneoplastic and neoplastic lesions for some foods such as fibers, vitamin A and D, folic acid, calcium, antioxidants, and promising perspectives for some substances such as phyto-estrogens. Less evidence-based data are available on the possibility to avoid the recurrence of the disease or to affect its mortality with dietary habits. Future perspectives will be directed be not only to identify new dietary style able to prevent the onset of neoplastic lesion of the colon but also to realize an effective chemoprevention.

Sustainable sheep production and consumer preference trends: compatibilities, contradictions, and unresolved dilemmas

There are increasing concerns of society towards the consumption of animal products which have been produced and transformed in a sustainable manner. This trend influences consumer purchasing decision making, particularly in developed countries. On the other hand, in the next years, the pressure to increase the volume and efficiency of meat production will be much higher to cope with the expected unsatisfied demand. At least in part, current and future technologies could contribute to solve this challenge. However, the use of some of these innovations could have a negative effect on consumer preferences. There is no consensus in our society about this dilemma. The objective of this paper is to review the scientific evidence related to these topics and to analyze and discuss the effect of some of the extrinsic and intrinsic factors linked with the sheep industry which could affect the acceptability of lamb meat by consumers.

Evaluation of serum high-density lipoprotein cholesterol levels as a prognostic factor in gastric cancer patients

BACKGROUND AND AIM

Although there are some reports of an adverse effect of low serum high-density lipoprotein cholesterol (HDL-C) levels on gastrointestinal cancers, the specific correlation between serum HDL-C levels and gastric cancer remains unknown.

METHODS

Preoperative serum HDL-C levels were retrospectively examined in 184 patients who had undergone gastrectomy. The patients who had undergone gastrectomy were divided into two groups: the normal-HDL-C group and the low-HDL-C group. We examined the characteristics and outcomes of these two groups. Univariate and multivariate analyses were performed to investigate the association between serum HDL-C levels and gastric cancer.

RESULTS

There was no significant difference between the groups in terms of the progression of gastric cancer. In the low-HDL-C group, lymphatic and vascular invasion was significantly increased. The prognosis of the patients in the normal-HDL-C group was significantly better than those in the low-HDL-C group.

CONCLUSIONS

In this study, a positive correlation between low preoperative serum HDL-C levels and prognosis for gastric cancer was demonstrated. Serum HDL-C level may be a clinical prognostic factor for gastric cancer patients.

Diet and nutrient factors in colorectal cancer risk

Diet and nutrition are estimated to explain as much as 30%-50% of the worldwide incidence of colorectal cancer. In 2007, the World Cancer Research Fund (WCRF), in conjunction with the American Institute for Cancer Research (AICR), released the second expert report that summarizes the current scientific evidence linking diet to the prevention of cancer. This text provides an expert summary and level of evidence of the research relating diet/nutrients to factors that influence cancers of multiple organs, including colon and rectum, with an important emphasis on global patterns. Specific examples include dietary fat, red and processed meat, and dairy, as well effects of nutrients such as calcium, folate, and vitamin D. Evidence is obtained from ongoing systematic literature reviews conducted by experts in both the United States and Europe. The expert panel applies standard practices to evaluate the strength and quality of individual studies to draw summary conclusions. In 2011, the report was updated to include findings from a series of meta-analyses published in 2010. To complement the WCRF/AICR report, the authors review the evidence favoring the role for diet and nutrition in the etiology of colorectal cancer. Specifically, they have integrated information gained from more recent meta-analyses and high-quality, prospective study findings, some of which have been included in the 2011 updated WCRF/AICR summary.

Cholesterol metabolism and colorectal cancers

Colorectal cancer (CRC) is primarily a lifestyle disease of the western world. As such it can be likened to cardiovascular disease and indeed it shares many of the same risk factors. It is therefore perhaps unsurprising that cholesterol metabolism and colorectal cancer are also intricately linked. Many of the initial studies suggesting a link between dietary cholesterol, blood cholesterol levels and cholesterol lowering drugs were performed more than a decade ago. The most recent insights in this field are the result of meta-analyses, advances in pharmacogenetics and the new field of molecular pathological epidemiology. This review summarises the current evidence linking cholesterol metabolism with colorectal cancer including the suggested underlying molecular causes and the implications for colorectal cancer prevention.

Identification of colorectal cancer related genes with mRMR and shortest path in protein-protein interaction network

One of the most important and challenging problems in biomedicine and genomics is how to identify the disease genes. In this study, we developed a computational method to identify colorectal cancer-related genes based on (i) the gene expression profiles, and (ii) the shortest path analysis of functional protein association networks. The former has been used to select differentially expressed genes as disease genes for quite a long time, while the latter has been widely used to study the mechanism of diseases. With the existing protein-protein interaction data from STRING (Search Tool for the Retrieval of Interacting Genes), a weighted functional protein association network was constructed. By means of the mRMR (Maximum Relevance Minimum Redundancy) approach, six genes were identified that can distinguish the colorectal tumors and normal adjacent colonic tissues from their gene expression profiles. Meanwhile, according to the shortest path approach, we further found an additional 35 genes, of which some have been reported to be relevant to colorectal cancer and some are very likely to be relevant to it. Interestingly, the genes we identified from both the gene expression profiles and the functional protein association network have more cancer genes than the genes identified from the gene expression profiles alone. Besides, these genes also had greater functional similarity with the reported colorectal cancer genes than the genes identified from the gene expression profiles alone. All these indicate that our method as presented in this paper is quite promising. The method may become a useful tool, or at least plays a complementary role to the existing method, for identifying colorectal cancer genes. It has not escaped our notice that the method can be applied to identify the genes of other diseases as well.

Olive oil intake is inversely related to cancer prevalence: a systematic review and a meta-analysis of 13,800 patients and 23,340 controls in 19 observational studies

Dietary fat, both in terms of quantity and quality, has been implicated to cancer development, either positively or negatively. The aim of this work was to evaluate whether olive oil or monounsaturated fat intake was associated with the development of cancer. A systematic search of relevant studies, published in English, between 1990 and March 1, 2011, was performed through a computer-assisted literature tool (i.e., Pubmed). In total 38 studies were initially allocated; of them 19 case-control studies were finally studied (13800 cancer patients and 23340 controls were included). Random effects meta-analysis was applied in order to evaluate the research hypothesis. It was found that compared with the lowest, the highest category of olive oil consumption was associated with lower odds of having any type of cancer (log odds ratio = -0.41, 95%CI -0.53, -0.29, Cohran's Q = 47.52, p = 0.0002, I-sq = 62%); the latter was irrespective of the country of origin (Mediterranean or non-Mediterranean). Moreover, olive oil consumption was associated with lower odds of developing breast cancer (logOR = -0,45 95%CI -0.78 to -0.12), and a cancer of the digestive system (logOR = -0,36 95%CI -0.50 to -0.21), compared with the lowest intake. The strength and consistency of the findings states a hypothesis about the protective role of olive oil intake on cancer risk. However, it is still unclear whether olive oil's monounsaturated fatty acid content or its antioxidant components are responsible for its beneficial effects.

Lipid hydroperoxide-induced and hemoglobin-enhanced oxidative damage to colon cancer cells

Epidemiological studies have indicated that Western diets are related to an increase in a series of malignancies. Among the compounds that are credited for this toxic effect are heme and lipid peroxides. We evaluated the effects of hemoglobin (Hb) and linoleic acid hydroperoxides (LAOOH) on a series of toxicological endpoints, such as cytotoxicity, redox status, lipid peroxidation, and DNA damage. We demonstrated that the preincubation of SW480 cells with Hb and its subsequent exposure to LAOOH (Hb + LAOOH) led to an increase in cell death, DCFH oxidation, malonaldehyde formation, and DNA fragmentation and that these effects were related to the peroxide group and the heme present in Hb. Furthermore, Hb and LAOOH alone exerted a toxic effect on the endpoints assayed only at concentrations higher than 100 μM. We were also able to show that SW480 cells presented a higher level of the modified DNA bases 8-oxo-7,8-dihydro-2'-deoxyguanosine and 1,N(2)-etheno-2'-deoxyguanosine compared to the control. Furthermore, incubations with Hb led to an increase in intracellular iron levels, and this high level of iron correlated with DNA oxidation, as measured as EndoIII- and Fpg-sensitive sites. Thus, Hb from either red meat or bowel bleeding could act as an enhancer of fatty acid hydroperoxide genotoxicity, which contributes to the accumulation of DNA lesions in colon cancer cells.

The role of meat fat in the human diet

Food fat plays an important role in the human diet. On the one hand, fats provide the body with energy, contribute to the absorption of fat-soluble vitamins, and act as structural elements of cell walls. On the other hand, a high fat intake is associated with obesity, type 2 diabetes, cancer, and coronary heart disease. Animal fats, which contain a high proportion of saturated fatty acids, are often the focus of attention when it comes to reducing the share of fat in the diet. The present overview of the literature describes the amount of total fat and the percentage of individual fatty acid groups in meat and meat products, documents the contribution of meat and meat products to fat intake, and investigates the connection between meat fat and various diseases. The information given is based mainly on data material from Switzerland; data from other countries have been included for comparison.

Associations of red meat, fat, and protein intake with distal colorectal cancer risk

Studies have suggested that red and processed meat consumption elevate the risk of colon cancer; however, the relationship between red meat, as well as fat and protein, and distal colorectal cancer (CRC) specifically is not clear. We determined the risk of distal CRC associated with red and processed meat, fat, and protein intakes in Whites and African Americans. There were 945 cases (720 White, 225 African American) of distal CRC and 959 controls (800 White, 159 African American). We assessed dietary intake in the previous 12 mo. Multivariate logistic regression analyses were used to obtain odds ratios (OR) and 95% confidence intervals (95% CI). There was no association between total, saturated, or monounsaturated fat and distal CRC risk. In African Americans, the OR of distal CRC for the highest category of polyunsaturated fat intake was 0.28 (95% CI = 0.08-0.96). The percent of energy from protein was associated with a 47% risk reduction in Whites (Q4 OR = 0.53, 95% CI = 0.37-0.77). Red meat consumption in Whites was associated with a marginally significant risk reduction (Q4 OR = 0.66, 95% CI = 0.43-1.00). Our results do not support the hypotheses that fat, protein, and red meat increase the risk of distal CRC.

Intake of dietary fats and colorectal cancer risk: prospective findings from the UK Dietary Cohort Consortium

INTRODUCTION

Epidemiologic evidence for an association between colorectal cancer (CRC) risk and total dietary fat, saturated fat (SF), monounsaturated fat (MUFA) and polyunsaturated fat (PUFA) is inconsistent. Previous studies have used food frequency questionnaires (FFQ) to assess diet, but data from food diaries may be less prone to severe measurement error than data from FFQ.

METHODS

We conducted a case-control study nested within seven prospective UK cohort studies, comprising 579 cases of incident CRC and 1996 matched controls. Standardized dietary data from 4- to 7-day food diaries and from FFQ were used to estimate odds ratios for CRC risk associated with intake of fat and subtypes of fat using conditional logistic regression. We also calculated multivariate measurement error corrected odds ratios for CRC using repeated food diary measurements.

RESULTS

We observed no associations between intakes of total dietary fat or types of fat and CRC risk, irrespective of whether dietary data were obtained using food diaries or FFQ.

CONCLUSION

Our results do not support the hypothesis that intakes of total dietary fat, SF, MUFA or PUFA are linked to risk of CRC.

Advances in understanding the relationship between dietary factors and risk of colorectal cancer

The purpose of this paper is to summarize the relationship between dietary factors and risk of colorectal cancer. There is evidence that meat, high-fat diet and drinking increase the chance of developing colorectal cancer, while whole grains, dietary fiber, folacin, selenium, zinc and calcium reduce the risk of colorectal cancer. Therefore, an inadequate diet may contribute to the development of colorectal cancer. These viewpoints provide a basis for prevention of colorectal cancer in terms of diet control.

Associations between trans fatty acid consumption and colon cancer among Whites and African Americans in the North Carolina colon cancer study I

Disparities in incidence and mortality rates of colon cancer exist between Whites and African Americans. Prior studies examined the association between trans fatty acid consumption and colorectal cancer, but none assessed this possible relationship within a large study population of African Americans and Whites. Using data from a population-based, case-control study in North Carolina, we investigated this association with attention to possible racial differences. Cases and matched controls were queried on demographic characteristics, lifestyle factors, medical history, and diet. Cases reported higher daily consumption (g/day) of trans fatty acids (mean = 5.9, SD = 2.9, median = 5.5, IQR = 3.8-7.5) compared to controls (mean = 5.2, SD = 2.4, median = 4.7, IQR = 3.5-6.4). Energy-adjusted trans fatty acid consumption was not associated with colon cancer. Compared to participants in the lowest quartile of consumption, those in the highest quartile had an adjusted odds ratio of 1.01 (95% confidence interval 0.69, 1.49) for Whites and 0.99 (95% confidence interval 0.61, 1.62) for African Americans. No association was found between increased consumption of trans fatty acid and specific tumor location (proximal or distal colon). In conclusion, trans fatty acid consumption is not associated with colon cancer and does not contribute to disparities in colon cancer rates.

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.

Animal origin foods and colorectal cancer risk: a report from the Shanghai Women's Health Study

The association of animal-origin food consumption and cooking patterns with colorectal cancer (CRC) risk was evaluated in a cohort of 73,224 participants of the Shanghai Women's Health Study. After a mean follow-up time of 7.4 yr, 394 incident cases of CRC (colon = 236; rectal = 158) were diagnosed. Overall, no association was found between the risk of CRC and intake of total meat and total fish. Eel (P(trend) = 0.01), shrimp (P(trend) = 0.06), and shellfish (P(trend) = 0.04) consumption were positively associated with CRC risk. High egg intake and high intake of total cholesterol were also related to risk of CRC (RR for the highest vs. lowest quintiles of intake were 1.4 (95% CI = 1.1-2.0) for eggs and 1.6 (95% CI = 1.1-2.3) for cholesterol). Milk intake was inversely associated with the risk of colon cancer (P(trend) = 0.05). Common Chinese cooking practices except the smoking method of cooking were not related to CRC risk. The latter was positively associated with colon cancer (RR = 1.4 for ever vs. never, 95% CI = 1.1-1.9). A possible role of cholesterol and environmental pollution in the etiology of CRC was suggested.

Meta-analysis of animal fat or animal protein intake and colorectal cancer

BACKGROUND

In the recent World Cancer Research Fund/American Institute for Cancer Research report of diet and cancer, it was concluded that there is limited but suggestive evidence that animal fat intake increases the risk of colorectal cancer.

OBJECTIVE

To clarify this potential relation, we conducted meta-analyses across a variety of subgroups, incorporating data from additional studies.

DESIGN

Analyses of high compared with low animal fat intakes and categorical dose-response evaluations were conducted. Subgroup analyses, consisting of evaluations by study design, sex, and tumor site were also performed.

RESULTS

Six prospective cohort studies with comprehensive dietary assessments, contributing 1070 cases of colorectal cancer and approximately 1.5 million person-years of follow-up, were identified. The summary relative risk estimate (SRRE) for these studies was 1.04 (95% CI: 0.83, 1.31; P for heterogeneity = 0.221) on the basis of high compared with low intakes. When data from case-control studies were combined with the cohort data, the resulting SRRE was 1.15 (95% CI: 0.93, 1.42) with increased variability (P for heterogeneity = 0.015). In our dose-response analysis of the cohort studies, no association between a 20-g/d increment in animal fat intake and colorectal cancer was observed (SRRE: 1.02; 95% CI: 0.95, 1.09). In a separate analysis of 3 prospective cohort studies that reported data for animal protein or meat protein, no significant association with colorectal cancer was observed (SRRE: 0.90; 95% CI: 0.70, 1.15).

CONCLUSION

On the basis of the results of this quantitative assessment, the available epidemiologic evidence does not appear to support an independent association between animal fat intake or animal protein intake and colorectal cancer.

Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence

Energy intake, physical activity, and obesity are modifiable lifestyle factors. This chapter reviews and summarizes the epidemiologic evidence on the relation of energy intake, physical activity, and obesity to cancer. High energy intake may increase the risk of cancers of colon-rectum, prostate (especially advanced prostate cancer), and breast. However, because physical activity, body size, and metabolic efficiency are highly related to total energy intake and expenditure, it is difficult to assess the independent effect of energy intake on cancer risk. There are sufficient evidences to support a role of physical activity in preventing cancers of the colon and breast, whereas the association is stronger in men than in women for colon cancer and in postmenopausal than in premenopausal women for breast cancer. The evidence also suggests that physical activity likely reduces the risk of cancers of endometrium, lung, and prostate (to a lesser extent). On the other hand, there is little or no evidence that the risk of rectal cancer is related to physical activity, whereas the results have been inconsistent regarding the association between physical activity and the risks of cancers of pancreas, ovary and kidney. Epidemiologic studies provide sufficient evidence that obesity is a risk factor for both cancer incidence and mortality. The evidence supports strong links of obesity with the risk of cancers of the colon, rectum, breast (in postmenopausal women), endometrium, kidney (renal cell), and adenocarcinoma of the esophagus. Epidemiologic evidence also indicates that obesity is probably related to cancers of the pancreas, liver, and gallbladder, and aggressive prostate cancer, while it seems that obesity is not associated with lung cancer. The role of obesity in other cancer risks is unclear.

Antiserum detection of reactive carbonyl species-modified DNA in human colonocytes

Polyunsaturated fats have been linked to occurrences of sporadic colon cancer. One possible cause may be degradation of polyunsaturated fats during cooking, resulting in multiple reactive carbonyl species (RCS) that can damage nuclear DNA and proteins, particularly in rapidly dividing colon crypt cells. This study describes a novel antiserum against RCS-modified DNA, with apparent order of reactivity to DNA modified with 4-hydroxy-trans-2-nonenal > glyoxal > acrolein > crotonaldehyde > malondialdehyde; some reactivity was also observed against conjugated Schiff base-type structures. Anti-(RCS-DNA) antiserum was successfully utilised to demonstrate formation of RCS-DNA in a human colon cell model, exposed to RCS insult derived from endogenous and exogenous lipid peroxidation sources. Further utilisation of the antiserum for immunohistochemical analysis confirmed RCS-modified DNA in crypt areas of 'normal' colon tissue. These results fully support a potential role for dietary lipid peroxidation products in the development of sporadic colon cancer.

Induction of apoptosis by linoleic acid is associated with the modulation of Bcl-2 family and Fas/FasL system and activation of caspases in AGS human gastric adenocarcinoma cells

In this study, we investigated the effects of linoleic acid (LA), a polyunsaturated fatty acid found in most vegetable oils and certain food products, on the growth of AGS human gastric adenocarcinoma cells. LA treatment resulted in a concentration-dependent growth inhibition of AGS cells by inducing apoptosis, as evidenced by the formation of apoptotic bodies, chromatin condensation, and the accumulation cells in the sub-G1 phase. LA treatment induced cyclin-dependent kinase inhibitor p21 in a p53-independent manner; however, this compound did not affect the cell cycle distribution. Reverse transcription-polymerase chain reaction and western blot analyses showed that treating the cells with LA caused the up-regulation of pro-apoptotic Bax expression and the down-regulation of anti-apoptotic Bcl-2 expression. The apoptosis of AGS cells by LA was found to be associated with an elevated Fas and Fas ligand expression in a concentration-dependent manner. Furthermore, a proteolytic activation of caspases (3, 8, and 9), and degradation/cleavage of poly(ADP-ribose) polymerase and phospholipase C-gamma 1 protein were noted in LA-treated AGS cells. The present results indicate that the Fas/Fas ligand pathway might be involved in LA-induced apoptosis of AGS cells.

The women's health initiative: lessons learned

The Women's Health Initiative (WHI) was initiated in 1992 as a major disease-prevention research program among postmenopausal women. The program includes a randomized controlled intervention trial involving 68,132 women and four distinct interventions: conjugated equine estrogens, alone or in combination with medroxyprogesterone acetate, for coronary heart disease prevention with breast cancer as an anticipated adverse effect; a low-fat eating pattern for breast and colorectal cancer prevention; and calcium and vitamin D supplementation for hip fracture prevention. Results from this multifaceted trial have made a substantial impact in clinical practice. A companion cohort study among 93,676 women serves as a source for new risk factor information and provides a comparative observational assessment of the clinical trial interventions. A specimen repository and quality-controlled outcome data for a range of diseases are among the resources that support the ongoing research program. WHI clinical trial contributions and challenges are reviewed and discussed.

Significance of alterations in plasma lipid profile levels in breast cancer

HYPOTHESES

The relationship between lipids and breast cancer is obscure. Until now, conflicting results have been reported on the association between lipids and risk of breast cancer in women. Therefore, the major aim of this study is to examine the role of alterations in lipid profile in breast cancer.

STUDY DESIGN

Plasma lipids (ie, total cholesterol [TC], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very-low-density lipoprotein [VLDL], and triglycerides [TG]) were analyzed from 70 controls, 30 patients with benign breast disease (BBD), 125 untreated breast cancer patients, and 93 posttreatment follow-up samples.

METHODS

Samples were analyzed using highly sensitive and specific spectrophotometric methods.

RESULTS

Plasma TC, LDL, VLDL, and TG were significantly lower (p = .042, p = .003, p = .024, p = .014, respectively) in patients with BBD compared with controls. Plasma TC and HDL were significantly lower (p = .026, p = .0001, respectively), and VLDL and TG were significantly higher (p = .009, p = .05) in breast cancer patients as compared with controls. Plasma VLDL and TG were significantly higher in breast cancer patients as compared with patients with BBD. The receiver-operating characteristic curve showed that plasma TC, LDL, VLDL, and TG levels could significantly discriminate (p = .001, p = .005, p = .005, p = .005, respectively) between controls and patients with BBD. Plasma levels of TC, HDL, VLDL, and TG could significantly distinguish (p = .01, p = .002, p = .001, p = .002, respectively) between controls and breast cancer patients. Plasma levels of VLDL and TG could significantly discriminate (p = .000, p = .000, respectively) between patients with BBD and breast cancer patients. Odds ratio analysis revealed that higher levels of TC and HDL were significantly associated with a reduction in breast cancer risk (p = .01 and p = .0001, respectively), whereas higher levels of VLDL and TG were significantly associated with increased breast cancer risk (p = .001 and p = .002, respectively). Plasma VLDL and TG levels were significantly lower in complete responders as compared with pretreatment levels (p = .000, p = .000, respectively), and plasma TC and LDL levels were significantly lower in nonresponders as compared with pretreatment levels (p = .015, p = .009, respectively).

CONCLUSION

The alterations in lipid profile levels showed a significant correlation with breast cancer risk, disease status, and treatment outcome.

Effect of orlistat on fecal fat, fecal biliary acids, and colonic cell proliferation in obese subjects

BACKGROUND & AIMS

Orlistat is a weight management agent that selectively inhibits gastrointestinal lipase activity. Because of orlistat's mode of action, increased fecal fat is presented to the colonic mucosa, and fecal bile acid and free fatty acid composition may be altered during treatment. Our aim was to assess the effect of treatment of obese subjects with orlistat 120 mg 3 times a day for 6 weeks on fecal lipid and bile acid parameters and colonic mucosal cell proliferation.

METHODS

Twenty-four obese (body mass index, 30-40 kg/m2) but otherwise healthy male and female subjects were enrolled in a single-center, randomized, double-blind, placebo-controlled, parallel-group study. Participants were hospitalized during days 1-3 and 33-42 of treatment and were treated as outpatients for the remaining days.

RESULTS

Treatment with orlistat for 6 weeks resulted in significantly greater increases in fecal weight, total fecal fat, and fecal free fatty acids than placebo. Total fecal bile acid amounts decreased slightly with orlistat, and increased significantly with placebo treatment (P < .05 between-group difference). Orlistat did not alter colonic cell proliferation as assessed by the 3 proliferative indices (5-bromo-2-deoxyuridine, whole crypt mitotic count, and proliferating cell nuclear antigen).

CONCLUSIONS

Biochemical changes in fecal composition related to the pharmacodynamic mode of action of orlistat are not accompanied by altered colonic cell proliferation, a putative biomarker of colon cancer risk.

Le tabac et l'alcool augmentent le risque d'adénomes et de cancers colorectaux

OBJECTIVE

To analyze the associations between lifestyle factors and colorectal adenomas or cancers in a population 50-74 years old.

METHOD

The study population underwent colonoscopy after positive fecal occult blood test in Health examination centers of the French general health insurance. The two sets of cases (n= 674 cancers, n=2618 adenomas) were compared with controls (n=5456). Associations between risk of colorectal disease and health data (mainly tobacco and alcohol consumption, physical activity, obesity, and laboratory test results) were analyzed with logistic regression models to estimate odds ratios.

RESULTS

The probability of colorectal cancer or adenoma was statistically associated with age (60 years or older in men and women). A significant relation between these diseases was observed with smoking (in both smokers and ex-smokers) and with alcohol consumption, with odds ratios above 1.30. The other risk factors studied were not significantly associated with these colorectal diseases.

CONCLUSION

This result provides still more evidence of the need for actions against these risk behaviors.

Diet, gender, and colorectal neoplasia

The association between diet and colorectal cancer has been studied in depth for many decades, with equivocal results. It has been hypothesized that cancers arising in the distal and proximal colon have different pathologies, and therefore different risk factors. As such, it is possible that diet-related factors might influence colorectal neoplasia differently depending on the subsite. Recent evidence indicates that women may be more likely to develop proximal cancers than men. Additionally, the link between certain dietary factors and colorectal neoplasia in women seems to vary by menopausal status. Given these observations, women may be affected differently than men by diet-related factors. The objective of this article was therefore to review the data for diet and colorectal adenomas and cancer, and then attempt to address the potential differences in the association of diet-related factors and colorectal neoplasia in men and women. For total energy intake, selenium, and fiber, it seems that there may be slightly stronger effects in men as compared with women, whereas calcium and folate seem to affect both sexes similarly. With regard to vitamin D and colorectal cancer, women may exhibit stronger associations than men. Perhaps the most evidence for a sex-specific effect is observed for obesity, where more substantial direct relationships between body size and colorectal neoplasia have been reported for men than for women. However, this observation may be influenced by the differential effects in women by menopausal status. Further research on sex-specific dietary effects is warranted.

Dietary fatty acids and colorectal cancer: a case-control study

Fatty acid effects on colorectal cancer risk were examined in a national prospective case-control study in Scotland (1999-2006), including 1,455 incident cases and 1,455 matched controls. Three conditional logistic regression models adjusted for energy (residual method) and for other risk factors were applied in the whole sample and were stratified by sex, cancer site, age, and tumor staging. Total and trans-monounsaturated fatty acids and palmitic, stearic, and oleic acids were dose-dependently associated with colorectal cancer risk, but these effects did not persist after further energy adjustment. Significant dose-dependent reductions in risk were associated with increased consumption of omega-3 polyunsaturated fatty acids (highest vs. lowest quartile of intake: odds ratio = 0.63, 95% confidence interval: 0.50, 0.80; p < 0.0005 for trend) and of eicosapentaenoic (odds ratio = 0.59, 95% confidence interval: 0.47, 0.75; p < 0.0005 for trend) and docosahexaenoic (odds ratio = 0.63, 95% confidence interval: 0.50, 0.80; p < 0.0005 for trend) acids. These associations persisted after including energy with the nutrient-energy-adjusted term or total fatty acid intake (energy adjusted). The observed different effects of different types of fatty acids underline the importance of type of fat in the etiology and prevention of colorectal cancer.

Review article: nutrition, obesity and colorectal cancer

BACKGROUND

The age-adjusted incidence of colorectal cancer is higher in prosperous industrialized countries than elsewhere. Dietary factors may account for 75% of sporadic colorectal cancer in the west, but the mechanisms remain obscure.

AIM

To review evidence for the effects of overweight and obesity, physical activity and specific dietary components on colorectal neoplasia.

METHODS

English language papers cited on MEDLINE, obtained using search terms related to colorectal cancer, physical activity and body mass and specific food components were reviewed.

RESULTS

There is evidence for adverse effects of overweight and obesity and protective effects of high physical activity against colon, but not for rectal cancer. These effects may reflect metabolic stress and chronic low-grade inflammation. There are also modest adverse effects of red and processed meat. There is evidence for protective effects of dietary fibre, but for fruits and vegetables the evidence remains weak and inconclusive. There is some evidence for protective effects of n-3 polyunsaturated fatty acids from fish, some micronutrients and possibly phytochemicals. The effects of many dietary constituents may depend upon genetic polymorphisms affecting a variety of genes.

CONCLUSION

Further research should focus particularly on the effects of insulin-resistance, impaired glucose tolerance and chronic low-grade inflammation on the colonic mucosa.

Serum HDL-C as a potential biomarker for nodal stages in gastric cancer

BACKGROUND

Although changes in lipid profile have been documented in gastrointestinal cancers, the specific relationship between serum lipid levels and lymph node (N) stages in gastric cancer remains uncertain.

METHODS

Preoperative serum lipid concentrations were retrospectively examined in 501 patients who underwent curative resection for primary gastric cancer. Univariate and multivariate analyses were carried out to investigate the association of serum lipid levels with nodal stages.

RESULTS

The serum high-density lipoprotein cholesterol (HDL-C) levels in gastric cancer patients correlated well with N stages. Cases with low HDL-C (< 40 mg/dl) presented more advanced pN(2-3) disease (57.6%, 83/144) than those with normal HDL-C (36.4%, 130/357; P < 0.05). The observed elevation of the TC/HDL-C ratio for patients with pN(2-3) disease was statistically significant when compared with that for patients with pN(0-1 )disease (mean values 3.57 vs. 3.31, P < 0.05). By receiver operating characteristic analysis, the combination of serum HDL-C concentration and TC/HDL-C ratio led to a sensitivity of 70.0% and a specificity of 51.0% in predicting stage pN(2-3). A logistic regression model revealed that both low HDL-C (< 40 mg/dl) and high TC/HDL-C ratio (> or =3.32) had an independent association with advanced pN(2-3 )stages. When patients' lipid levels were stratified by means of histological differentiation, the significant correlation of serum HDL-C levels with nodal stages was only detected in differentiated gastric cancer.

CONCLUSIONS

For gastric cancer patients, preoperative low serum HDL-C concentration or high TC/HDL-C ratio might be a potential biomarker of advanced pN(2-3) stages, especially for those with the histologically differentiated type.