Dietary and biomarker estimates of fatty acids and risk of colorectal cancer

The associations between intake of or circulating fatty acids and risk of colorectal cancer (CRC) are unclear. We examined prospectively the associations between dietary or biomarker fatty acids and CRC. For 41,514 men and women, aged 40–69 years, baseline (1990–94) dietary intakes of fatty acids were estimated using a food frequency questionnaire and plasma phospholipid (PPL) fatty acids were measured for 4,205 participants including 395 CRC cases, according to a case‐cohort design. Hazard ratios were computed using Cox regression adjusting for education, alcohol intake, smoking status, physical activity and total energy intake; and stratified for gender, ethnicity and family history of cancer, with age as the time scale. We assessed the heterogeneity of associations with colon and rectal cancers. PPL saturated fatty acids (SFAs) were positively associated with CRC risk, while total n‐3 polyunsaturated fatty acids (PUFA) and long chain marine n‐3 PUFAs showed inverse associations, significant only for 22:5 n‐3. No significant associations were observed for dietary fatty acid intakes but positive associations with CRC of borderline significance were seen for both dietary and PPL linoleic acid. Positive associations with dietary palmitic acid (16:0), MUFAs and n‐6 PUFAs were seen for rectal but not colon cancers. PPL 22:6 n‐3 was inversely associated with rectal cancer. Limiting intakes of SFAs and MUFAs could be assisted by following existing guidelines to limit red and processed meats which are important sources in the Australian diet. Our observations regarding linoleic acid should be examined further.     

Attributable risks for colorectal cancer in Northern Italy

Using data from a case-control study conducted between 1985 and 1992 in northern Italy on 828 cases of colon cancer, 498 cases of rectal cancer and 2,024 controls in hospital for acute, non-neoplastic, non-digestive tract disorders, we estimated the percent population attributable risk (PAR) for colorectal cancer in relation to β-carotene, vitamin C (as markers of a diet rich in fruit and vegetables), red meat and seasoning fat intake, daily meal frequency and family history of the disease. On the basis of multivariate odds ratios, adjusted for total calorie intake, a low intake of β-carotene accounted for 39% of all the cases and a low intake of vitamin C for 14%. These two micronutrients together explained 43% of all colorectal cancer cases in this population. A high frequency of intake of red meat consumption explained 17% of all cases, and a high score of seasoning fats 4%. A higher daily meal frequency was responsable for 13% of the cases, and these 5 dietary factors together explained 63% of colorectal cancer cases in this population. Family history of colorectal cancer accounted for 4% of all cases. These estimates were similar for colon and rectal cancers separately, in males and females, and in younger and elderly subjects, except for seasoning fats and family history, whose PARs were apparently greater for colon cancer and at younger age. Thus, even though available dietary data were limited in several aspects, and the PAR estimates were based on somewhat arbitrary assumptions regarding the exposure distribution, about two-thirds of all colorectal cancers in this population could be explained in terms of a few risk factors or risk indicators considered. This would correspond to the avoidance of a large proportion of the over 18,000 deaths from colorectal cancer registered per year in the whole of Italy. © 1996 Wiley-Liss, Inc.     

Specific fatty acids and human colorectal cancer: an overview

BACKGROUND: Evidence suggests that dietary fats are associated with risk of colorectal cancer. The effect of fats depends not only on the quantity, but also on their composition in specific fatty acids. Moreover, fats are peroxidizable, and peroxidation products as well as antioxidants play a role in the pathogenic process of colorectal cancer. METHODS: The published literature was reviewed for the relationship between dietary intake or concentration of specific fatty acids in adipose tissue, erythrocytes, plasma or feces in relation to colorectal cancer. RESULTS: Increased concentrations of short-chain fatty acids (SCFAs) and eicosanopentaenoic acid (EPA) seem to protect against colorectal cancer. Increased concentrations of medium-chain fatty acids (MCFAs) and arachidonic acid (AA) might be associated with increased risk. Long-chain saturated fatty acids (LCSFAs) seem unrelated to colorectal cancer, while the associations between monounsaturated fatty acids (MUFAs), trans fatty acids, polyunsaturated fatty acids (PUFAs) such as linoleic acid (LA), alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), omega-3/omega-6 ratio and colorectal cancer are unconvincing. CONCLUSIONS: It is suggested that the substitution of food with high MCFAs and AA content by a SCFAs- and EPA-rich diet may contribute to reduced risk of colorectal cancer.     

Dietary fat, cholesterol and colorectal cancer in a prospective study

The relationships between consumption of total fat, major dietary fatty acids, cholesterol, consumption of meat and eggs, and the incidence of colorectal cancers were studied in a cohort based on the Finnish Mobile Clinic Health Examination Survey. Baseline (1967-1972) information on habitual food consumption over the preceding year was collected from 9959 men and women free of diagnosed cancer. A total of 109 new colorectal cancer cases were ascertained late 1999. High cholesterol intake was associated with increased risk for colorectal cancers. The relative risk between the highest and lowest quartiles of dietary cholesterol was 3.26 (95% confidence interval 1.54-6.88) after adjusting for age, sex, body mass index, occupation, smoking, geographic region, energy intake and consumption of vegetables, fruits and cereals. Consumption of total fat and intake of saturated, monounsaturated, or polyunsaturated fatty acids were not significantly associated with colorectal cancer risk. Nonsignificant associations were found between consumption of meat and eggs and colorectal cancer risk. The results of the present study indicate that high cholesterol intake may increase colorectal cancer risk, but do not suggest the presence of significant effects of dietary fat intake on colorectal cancer incidence.     

Fat and K-ras mutations in sporadic colorectal cancer in The Netherlands Cohort Study

Associations between dietary intake of various fats and specific K-ras mutations in colorectal cancer (CRC) were investigated within the framework of The Netherlands Cohort Study on diet and cancer (NLCS). After 7.3 years of follow-up and with exclusion of the first 2.3 years, 448 colon and 160 rectal cancer patients and 2948 subcohort members (55-69 years at baseline) were available for data-analyses. Mutation analysis of the K-ras gene was performed on all archival colon and rectal adenocarcinoma specimens. Case-cohort analyses were used to compute adjusted incidence rate ratios (RR) and 95% confidence intervals (CI) for colon and rectal cancer cases and for K-ras mutation subgroups. The intake of total, saturated and monounsaturated fat was not significantly associated with colon or rectal cancer. High intake of dietary polyunsaturated fat and, specifically, linoleic acid is associated with an increased risk of mutated K-ras colon tumours. The RRs for 1 SD of increase of polyunsaturated fat and linoleic acid were 1.21 (95% CI 1.05-1.41) and 1.22 (95% CI 1.05-1.42), respectively, and similar associations were observed for both G > A transitions and G > T or G > C transversions in the colon. In contrast, no significant associations were observed with rectal cancer risk, overall nor with specific K-ras mutation status. A high intake of polyunsaturated fat, in particular linoleic acid, may be an important dietary risk factor for K-ras mutated colon tumours, possibly by generating G > A transitions or G > T or G > C transversions in the K-ras oncogene.     

Fermented dairy products,dietary calcium and colon cancer: A case-control study in the netherlands

To examine whether the consumption of fermented dairy products or the dietary intake of calcium decreases colon cancer risk, a case-control study was conducted in The Netherlands. Dietary patterns were assessed in detail (for cases before diagnosis or symptoms occurred) using a structured dietary history questionnaire. After adjustment for potential confounding variables, consumption of fermented dairy products, hard cheese and unfermented dairy products was not significantly associated with risk of colon cancer: an odds ratio (OR) of I. I was found for individuals consuming more than one serving of fermented dairy products per day as compared to those consuming less than 10% of one serving a day. Adjustment for dietary calcium attenuated the associations. Total dietary calcium was positively but non-significantly associated with colon cancer risk after adjustment for age, gender, urbanization level and total energy intake. Additional adjustment for a positive family history of colorectal cancer, cholecystectomy and energy-adjusted intake of total fat, dietary fibre, vitamin C and alcohol increased the association. No differences were observed between calcium from fermented and from unfermented dairy sources. The observed associations for fermented dairy products and dietary calcium differed between men and women: positive significant associations were observed in men, while in women non-significant inverse associations were found. Our results do not support the hypothesis that an increased intake of commercially available, commonly used fermented dairy products or dietary calcium decreases the risk of colon cancer.     

Macronutrients and colorectal cancer: a Swiss case-control study.

BACKGROUND: A role of energy and various nutrients, including protein, sugar, saturated and unsaturated fats, in colorectal cancer risk has been suggested, but should be better defined. PATIENTS AND METHODS: The association between dietary intake of various macronutrients and colorectal cancer risk was analysed using data from a case-control study conducted between 1992 and 2000 in the Swiss Canton of Vaud. The study comprised 286 case subjects (174 males, 112 females; median age 65 years) with incident, histologically confirmed colon (n = 149) or rectal (n = 137) cancer, and 550 control subjects (269 males, 281 females; median age 59 years) admitted to the same University Hospital for a wide spectrum of acute non-neoplastic conditions. Dietary habits were investigated using a validated food frequency questionnaire, including questions on 79 foods or recipes and on individual fat intake pattern. Multivariate odds ratios (OR) were obtained after allowance for age, sex, education, physical activity and energy intake. RESULTS: The risk of colon and rectal cancer increased with total energy intake (OR in highest and lowest tertile, 2.0 and 2.2, respectively). There was no significant relation with starches or proteins, a significant inverse relation with sugars (OR for the highest tertile, 0.5), a direct trend in risk of borderline significance for saturated fats (OR = 1.4 for the highest tertile), and significant inverse trends for monounsaturated (OR = 0.6) and polyunsaturated fats (OR = 0.6). CONCLUSIONS: These findings confirm that energy intake is directly related to colorectal cancer risk, and that different types of fat may have different roles in colorectal carcinogenesis.     

Dietary marine n-3 fatty acids in relation to risk of distal colorectal adenoma in women.

Epidemiologic studies of dietary marine n-3 fatty acids and risk of colorectal cancer have been inconsistent, and their relation to risk of colorectal adenoma has not been evaluated in detail. We examined dietary marine n-3 fatty acids and the ratio of marine n-3 to total n-6 fatty acids (n-3/n-6 ratio) in relation to risk of adenoma of the distal colon or rectum among 34,451 U.S. women who were initially free of colorectal cancer or polyps, who completed a semiquantitative food frequency questionnaire in 1980, and who underwent endoscopy from 1980 to 1998. We documented 1,719 distal colorectal adenoma cases (705 large adenomas, 897 small adenomas, 1,280 distal colon adenomas, and 505 rectal adenomas) during 18 years of follow-up. Neither dietary marine n-3 fatty acids nor n-3/n-6 ratio were associated with risk of total distal colorectal adenoma after adjustment for age and established risk factors [multivariable relative risk (RR) for extreme quintiles of dietary marine n-3 fatty acids = 1.04; 95% confidence interval (95% CI), 0.84-1.27, P(trend) = 0.66; RR for extreme quintiles of n-3/n-6 ratio = 1.02; 95% CI, 0.83-1.25; P(trend) = 0.86]. Similarly, no significant associations were observed separately for distal colon or rectal adenoma. However, higher intake of dietary marine n-3 fatty acids was nonsignificantly but suggestively inversely associated with large adenoma (RR, 0.74; 95% CI, 0.54-1.01; P(trend) = 0.16) but directly associated with small adenoma (RR, 1.36; 95% CI, 1.02-1.81; P(trend) = 0.09). Our findings do not support the hypothesis that a higher intake of marine n-3 fatty acids or a higher n-3/n-6 ratio reduces the risk of distal colorectal adenoma but are suggestive that higher intake may reduce the progression of small adenomas to large adenomas.     

The influence of folate and multivitamin use on the familial risk of colon cancer in women.

Low intake of folate and methionine and heavy alcohol consumption have been associated with an increased overall risk of colon cancer, possibly related to their role in methylation pathways. We estimated the relative risk (RR) of colon cancer according to a history of colorectal cancer in a first-degree relative and categories of folate, methionine, and alcohol intake in a prospective cohort study of 88,758 women who completed family history and detailed food frequency questionnaires. During 16 years of follow-up, colon cancer was diagnosed in 535 women. The inverse association of folic acid with colon cancer risk was greater in women with a family history. Compared with women who consumed 200 microg or less of folic acid/day, the age-adjusted RR of colon cancer for those who consumed >400 microg/day was 0.81 (95% confidence interval, 0.62-1.07) in women without a family history of colorectal cancer and 0.48 (95% confidence interval, 0.28-0.83) in women with a family history (P for interaction = 0.02). The influence of family history was markedly diminished by use of multivitamins containing folic acid (P for interaction = 0.04). High levels of dietary methionine also reduced the effect of family history (P for interaction = 0.05), whereas moderate to heavy alcohol consumption increased the risk associated with family history (P for interaction = 0.004). Other risk factors for colorectal cancer did not significantly modify the influence of family history. Our results suggest that higher intake of folate and methionine, regular use of multivitamins containing folate, and avoidance of moderate to heavy alcohol consumption may diminish the excess risk of colon cancer associated with a family history of the disease.     

Diet and premenopausal bilateral breast cancer: A case-control study

We investigated associations between diet and premenopausal bilateral breast cancer in a familial matched case-control study. We studied 140 cases from population-based registries in Los Angeles County (California) and Connecticut, and from the major hospitals in the southern parts of the Province of Quebec. Unaffected sisters of the cases served as matched controls (222 total). Dietary intake were assessed with a food frequency questionnaire. Total fat, monounsaturated fat, polyunsaturated fat, oleic acid, and linoleic acid intake was inversely associated with premenopausal bilateral breast cancer risk. Consumption of carbohydrates (and sweetened beverages) was associated with an increased risk. We observed no associations for dietary fiber, antioxidants, or major food groupings, but we did observe inverse associations for intake of low fat dairy products and tofu. These findings suggest that monounsaturated and polyunsaturated fats, as well as soy foods, might reduce the risk of premenopausal bilateral breast cancer.     

Inhibition of experimental colorectal carcinogenesis by dietary N-6 polyunsaturated fats

The influence of dietary fats on azoxymethane-induced colorectal carcinogenesis and erythrocyte, adipose, colon mucosa and tumour tissue fatty acids was investigated in 228 Wistar rats. The two main diets compared were beef suet rich in saturated fatty acids and corn oil rich in a linoleic acid, an N-6 polyunsaturated fatty acid. The animals were placed in one of four dietary groups: A = 5% saturated fat, B = 20% saturated fat, C = 5% N-6 fat and D = 20% N-6 fat. There was no difference in the number of adenomas between any of the dietary groups. The mean (+/- SEM) carcinoma yield per rat was A = 0.93 +/- 0.28, B = 1.93 +/- 0.50, C = 0.70 +/- 0.07, D = 0.13 +/- 0.04; the tumour yields in rats fed the saturated fat diets were significantly different from each other and from those fed the N-6 fat diets. The fatty acid profiles in all tissues were dependent upon the type and level of dietary fat and the tissue type. Arachidonate was higher in tumours compared to normal mucosa. Significant correlations were found between adipose linoleate (reflecting dietary intake) and tumour oleate and tumour arachidonate but not with the colorectal mucosa of control animals. This is the first in vivo study to show reduced colorectal carcinogenesis by N-6 polyunsaturated fatty acids.     

Dietary fatty acids and colorectal cancer risk in men: A report from the Shanghai Men's Health Study and a meta‐analysis

Evidence from animal models suggests that dietary fatty acids have both anticancer and tumor‐promoting effects. Whether dietary fatty acids are associated with colorectal cancer (CRC) in humans remains inconclusive. We investigated associations between dietary fatty acids and risk of CRC among 59 986 men who participated in the Shanghai Men's Health Study (SMHS), an ongoing population‐based prospective cohort study. We identified 876 incident CRC cases in the SMHS during a mean follow‐up of 9.8 years. Associations between dietary fatty acid intake and CRC risk were evaluated by Cox proportional hazard regression analyses. Consumption of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) was not significantly associated with CRC risk. Multivariate hazard ratios (HRs) and respective 95% confidence intervals (CIs) for Quartile 4 vs Quartile 1 were 0.92 (0.74‐1.14; P_trend = 0.47) for SFA, 0.95 (0.79‐1.16; P_trend = 0.74) for MUFA and 1.18 (0.95‐1.46; P_trend = 0.21) for PUFA. No significant associations were found for total n‐6 PUFA or total n‐3 PUFA. Additionally, we performed a meta‐analysis to summarize results from the present study and 28 reports from 26 additional cohorts, which supported the overall null association between dietary fatty acid intake and CRC risk among men. Docosahexanoic acid and eicosapentaenoic acid were associated with 11% to 12% reduced risk, and linoleic acid a 19% increased risk, of CRC in the meta‐analysis of combined sexes. In conclusion, this population‐based prospective study and meta‐analysis of cohort studies found little evidence that dietary fatty acid intake was associated with risk of CRC in men.     

Adipose fatty acids and cancers of the breast,prostate and colon: An ecological study

Animal and ecological studies suggest that linoleic acid intake is related to breast-cancer incidence. Analytical epidemiologic studies, however, do not support such findings. The primary objective of our ecological study was to investigate the association between breast-cancer incidence and linoleic acid status across European countries. In addition, other fatty acids and cancer sites were studied. Mean fatty acid composition of adipose tissue samples in 11 centres from 8 European countries and Israel served as indicators of exposure of the population. Figures on cancer incidence for the respective or comparable regions were obtained from published data. N-6 fatty acids in adipose tissue ranged from 10.4 in Helsinki to 24.6 g/100 g fatty acids in Jerusalem. N-6 fatty acids were not associated significantly with breast, colon or prostate cancer. Cancers of the breast and colon were associated negatively with cis-mono-unsaturated fatty acids and positively with trans fatty acids. Despite a large range in intake, we found no evidence of a positive association between n-6 fatty acid status and breast cancer, but associations were observed between other fatty acids and cancer. Differences in linoleic acid intake cannot explain risk differences in breast-cancer incidence between affluent countries, while associations of other fatty acids with cancer rates may reflect cultural differences. Int. J. Cancer 72:587–591, 1997. © 1997 Wiley-Liss, Inc.     

Dietary fatty acids,luminal modifiers,and risk of colorectal cancer

Inconsistent observations in epidemiologic studies on the association between total fat intake and colorectal cancer may be ascribed to opposing effects of individual fatty acids and the presence of other dietary constituents that modify luminal or systemic lipid exposure. We analyzed the data from a population‐based case‐control study that included 1,163 cases and 1,501 controls to examine the effects of individual fatty acid groups on colorectal cancer risk as well as their interactions with calcium and fiber intake. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression model according to quartile levels of energy‐adjusted fatty acid intake. In the bivariable analyses, the risk of colorectal cancer increased with trans fatty acid (TFA) intake (OR for top vs. bottom quartile =1.46, 95% CI 1.17–1.59, p‐value for a trend <0.001), but the associations was substantially attenuated in multivariable analyses (p value for a trend = 0.176). However, a significant linear trend in the multivariable OR (p = 0.029) for TFA was present for subjects with lower calcium intake. Furthermore, multivariable ORs progressively decreased with increasing both omega‐3 and omega‐6 poly‐ unsaturated fatty acid intake (p‐values for linear trend: 0.033 and 0.011, respectively) for subjects with lower dietary fiber intake. These interactions were also significant or marginally significant (p = 0.085 for TFA, 0.029 for omega‐3 and 0.068 for omega‐6). Our results suggest that populations with lower intake of luminal modifiers, i.e., calcium and fiber, may have differential risks of colorectal cancer associated with dietary fatty acid intake.     

Meat, fish and fat intake in relation to subsite-specific risk of colorectal cancer: The Fukuoka Colorectal Cancer Study

High intake of red meat has been associated with increased risk of colorectal cancer in Western countries. There has been much interest in the role of n-3 polyunsaturated fatty acids (PUFA) in colorectal cancer prevention, but epidemiological findings are limited and inconsistent. The objective of our study was to examine associations of meat, fish and fat intake with risk of colorectal cancer, paying particular attention to the subsite within the colorectum. Data were from the Fukuoka Colorectal Cancer Study, a population-based case-control study, covering 782 cases and 793 controls. Diet was assessed by interview, using newly developed personal-computer software for registering semiquantitative food frequencies. The intake of beef/pork, processed meat, total fat, saturated fat or n-6 PUFA showed no clear association with the overall or subsite-specific risk of colorectal cancer. There was an almost significant inverse association between n-3 PUFA and the risk of colorectal cancer; the covariate-adjusted odds ratio for the highest (median 3.94 g/day) versus lowest (median 1.99 g/day) quintile of energy-adjusted intake was 0.74 (95% confidence interval 0.52-1.06, trend P=0.050). The consumption of fish and fish products was similarly inversely related to the risk although the association was not statistically significant. These associations were more evident for distal colon cancer; adjusted odds ratio for the highest versus lowest quintile of n-3 PUFA intake was 0.56 (95% confidence interval 0.34-0.92, trend P=0.02). Our findings do not support the hypothesis that consumption of red meat increases colorectal cancer risk but do suggest that high intake of fish may decrease the risk, particularly of distal colon cancer.     

Associations of energy, fat, calcium, and vitamin D with prostate cancer risk.

This population-based, case-control study in King County,Washington examined associations of energy, fat, vitamin D, and calcium with risk of prostate cancer in 605 incident cases (ages 40-64 years) identified from the Seattle-Puget Sound Surveillance Epidemiology and End Results registry and 592 controls recruited from the same underlying population using random-digit telephone sampling. Self-administered food frequency questionnaires were used to assess diet over the 3-5-year period before diagnosis or interview date. Total energy was associated with increased risk for both local and regional/distant stage disease. The adjusted odds ratios [95% confidence intervals (CIs)] contrasting highest to lowest quintile of energy intake were 2.15 (95% CI, 1.35-3.43) for local and 1.96 (95% CI, 1.08-3.56) for regional/distant disease. Fat was associated with regional/distant disease only. Adjusted odds ratios comparing the highest to lowest quintiles of percentage energy from total, saturated, and monounsaturated fats were 2.01 (1.03-3.92), 1.82 (0.93-3.56), and 2.00 (1.03-3.87), respectively. For calcium, adjusted odds ratios contrasting the highest to lowest quartiles were 1.07 (0.63-1.84) for local and 2.12 (1.02-4.38) for regional/distant disease. There were no associations of vitamin D, total polyunsaturated fatty acids, or the highly unsaturated, long-chain eicosapentainoic and docosahexaenoic fatty acids with prostate cancer risk. These results suggest that high energy intake is a risk factor for both localized and nonlocalized prostate cancer, whereas dietary fat and calcium increase the risk of regional/distant disease only. These results are consistent with general dietary guidelines to moderate consumption of total energy and fat, and they motivate further research to consider the potential benefits and risks of high calcium intake.     

Dietary total fat and fatty acids intake,serum fatty acids and risk of breast cancer: A meta‐analysis of prospective cohort studies

Results from prospective cohort studies on the association between dietary total fat and fatty acids intake and risk of breast cancer remain controversial. Pertinent prospective cohort studies were identified by a search of Embase and PubMed from inception to September 2015. Study‐specific relative risks (RRs) with 95% confidence intervals were pooled using a random‐effect model. Between‐study heterogeneity and publication bias were assessed, and sensitivity analysis was conducted. Twenty‐four independent studies on dietary total fat and fatty acids intake and seven studies on serum fatty acids were included. The pooled RR of breast cancer for the highest vs. lowest category of dietary total fat intake was 1.10 (1.02–1.19); however, no association was observed in studies adjusting for traditional risk factors of breast cancer. No association was observed between animal fat, vegetable fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n‐3 PUFA, n‐6 PUFA, eicosapentaenoic acid, docosahexaenoic acid, alpha‐linolenic acid, oleic acid, linoleic acid and arachidonic acid and risk of breast cancer. The pooled RRs of breast cancer for the highest vs. lowest category of serum SFA, MUFA, PUFA, n‐3 PUFA and n‐6 PUFA were 1.00 (0.78–1.28), 1.41 (0.99–2.03), 0.59 (0.27–1.30), 0.81 (0.60–1.10) and 0.84 (0.60–1.18), respectively. Results from this meta‐analysis suggested that dietary total fat and fatty acids might be not associated with risk of breast cancer.     

Vitamins, minerals, essential fatty acids and colorectal cancer risk in the United Kingdom Dietary Cohort Consortium

The risk for colorectal cancer may be influenced by the dietary intake of various vitamins, minerals and essential fatty acids. We conducted a pooled analysis of dietary data collected using food diaries in seven prospective studies in the United Kingdom Dietary Cohort Consortium. Five hundred sixty-five cases of colorectal cancer were matched with 1,951 controls on study centre, age, sex and recruitment date. Dietary intakes of retinol, vitamin A, thiamin, riboflavin, vitamin B6, folate, vitamin B12, vitamin D, calcium, iron, magnesium, potassium, n - 6 fatty acids, n - 3 fatty acids and the ratio of n - 6 to n - 3 fatty acids were estimated and their associations with colorectal cancer examined using conditional logistic regression models, adjusting for exact age, height, weight, energy intake, alcohol intake, fiber intake, smoking, education, social class and physical activity. There were no statistically significant associations between colorectal cancer risk and dietary intake of any of the vitamins, minerals or essential fatty acids examined.     

Dietary fat intake and risk of skin cancer: A prospective study in Australian adults

Although intakes of dietary fat have been associated with both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin, the evidence is sparse and inconsistent. This study prospectively investigated the association between total dietary fat; saturated, polyunsaturated and monounsaturated fatty acids; and percent energy from fat in relation to BCC and SCC of the skin. At baseline in 1992, total fat intake and intake of fatty acids were assessed in an Australian community‐based longitudinal study, using a validated semi‐quantitative food frequency questionnaire in 1,057 adult residents (aged 25–75 years) in Nambour, Queensland. Information on demography, sun‐sensitivity history and sun exposure factors were obtained using self‐administered questionnaires. Associations with BCC and SCC in terms of persons newly affected and of tumor counts were assessed using Poisson and negative binomial regression models, respectively, based on incident, histologically‐confirmed tumors occurring between 1992 and 2002. No significant linear trends were observed in overall risk of BCC or SCC of the skin with increasing total fat intake. However, in participants with a history of skin cancer, total fat intake (multivariable adjusted RR = 2.42, 95% CI = 1.20–4.88; p for trend = 0.01) was associated with increased numbers of SCC tumors comparing the highest to lowest tertile. In conclusion, SCC tumor risk increased as total fat intake increased in people with a history of skin cancer. Dietary fats were not associated with BCC occurrence. © 2009 UICC     

A 22-year Prospective Study of Fish, n-3 Fatty Acid Intake, and Colorectal Cancer Risk in Men.

BACKGROUND: Fish is the main dietary source of long-chain n-3 fatty acids, which have been suggested to play a protective role in colorectal cancer development in laboratory and animal studies. Human studies have not shown consistent results. We examined the association between intakes of fish and n-3 fatty acids from fish and colorectal cancer risk in men enrolled in the Physicians' Health Study. METHODS: The Physicians' Health Study began as a randomized trial to examine the effect of aspirin and beta-carotene supplementation on cancer and cardiovascular disease. Fish intake was assessed at the 12-month follow-up with an abbreviated food-frequency questionnaire. Cox proportional hazards models were used to estimate multivariate relative risks for colorectal cancer for the categories of fish intake and quartiles of n-3 fatty acid intake. RESULTS: During 22 years of follow-up, 500 men had a confirmed diagnosis of colorectal cancer. Fish intake was inversely associated with colorectal cancer risk [multivariate relative risk (95% confidence interval) for highest versus lowest category, 0.60 (0.40-0.91); P trend = 0.01]. The inverse association was observed for both colon and rectal cancers. Our findings for n-3 fatty acids were similar to those for fish; the multivariate relative risk (95% confidence interval) of total colorectal cancer for the highest versus lowest quartile of n-3 fatty acids was 0.74 (0.57-0.95; P trend = 0.01). CONCLUSIONS: Our results from this long-term prospective study suggest that intakes of fish and long-chain n-3 fatty acids from fish may decrease the risk for colorectal cancer.