Maternal Dietary Intake of Folate and Vitamins B6 and B12 During Pregnancy and Risk of Childhood Brain Tumors

Childhood brain tumors (CBT) are the second most common childhood cancers, yet their etiology is largely unknown. We investigated whether maternal gestational intake of folate and vitamins B6 and B12 was associated with CBT risk in a nationwide case-control study conducted 2005–2010. Case children 0–14 years were recruited from all 10 Australian pediatric oncology centers. Control children were recruited by national random digit dialing, frequency matched to cases on age, sex, and state of residence. Dietary intake was ascertained using food frequency questionnaires and adjusted for total energy intake. Data from 293 case and 726 control mothers were analyzed using unconditional logistic regression. The odds ratio (OR) for the highest versus lowest tertile of folate intake was 0.70 [95% confidence interval (CI): 0.48, 1.02]. The ORs appeared lower in mothers who drank alcohol during pregnancy (OR = 0.45, 95% CI: 0.22, 0.93), mothers who took folic acid (OR = 0.67, 95% CI: 0.42, 1.06) or B6/B12 supplements (OR = 0.51, 95% CI: 0.25, 1.06) and in children younger than 5 years (OR = 0.50, 95% CI: 0.27, 0.93). These findings are consistent with folate's crucial role in maintenance of genomic integrity and DNA methylation. Dietary intake of B6 and B12 was not associated with risk of CBT.     

Dietary folate, alcohol consumption, and risk of non-Hodgkin lymphoma

Dietary deficiency of folate and other micronutrients involved in the one-carbon metabolism (i.e., vitamins B2, B6, B12, and methionine) have been related to several diseases, including cancers, but results on non-Hodgkin lymphoma (NHL) are controversial. A hospital-based case-control study was conducted in Italy, in 1999-2002. Cases were 190 incident, histologically confirmed NHL aged 18-84 years. Controls were 484 subjects admitted to hospitals for acute, non-neoplastic diseases supposed to be unrelated to alcohol consumption or to diet modification. Dietary habits, including alcohol drinking, were assessed by a validated food-frequency questionnaire. Nutrient intakes were computed using the Italian food composition database. Odds ratios (ORs) and corresponding 95% confidence intervals for tertiles of nutrients' intake were computed using the energy-adjusted residual models. No significant association emerged between NHL risk and intakes of folate (OR=0.9), vitamin B2 (OR=0.9), vitamin B6 (OR=0.8), and methionine (OR=0.7). However, a significant inverse association was observed for all the nutrients examined among abstainers and former drinkers, whereas no relations between one-carbon nutrients and NHL risk emerged among current alcohol drinkers. Our findings support the possibility of an antagonist effect of alcohol on the one-carbon metabolism in NHL etiology. However, the lack of an overall effect for one-carbon nutrients and the small sample size suggested caution in interpreting our results.     

Tea as a Potential Chemopreventive Agent in PhIP Carcinogenesis: Effects of Green Tea and Black Tea on PhIP-DNA Adduct Formation in Female F-344 Rats

Disturbances in DNA methylation have been hypothesized as being involved in carcinogenesis. It has been proposed that dietary factors such as folate, alcohol, and methionine may be associated with colon cancer because of their involvement in DNA methylation processes. Data from a large retrospective population‐based case‐control study of incident colon cancer were used to evaluate whether intake of alcohol and other dietary factors involved in DNA methylation are associated with colon cancer. Dietary data were obtained using a detailed diet history questionnaire. We did not observe strong independent associations between folate, vitamin B6, vitamin B12, methionine, or alcohol and risk of colon cancer after adjusting for body size, physical activity, cigarette smoking patterns, energy intake, and dietary intake of fiber and calcium. However, when assessing the associations between colon cancer and a composite dietary profile based on alcohol intake, methionine, folate, vitamin B12, and vitamin B6 we observed a trend of increasing risk as one moved from a low‐ to a high‐risk group. This trend was modest and most marked in those diagnosed at a younger age [odds ratio (OR) for men = 1.3, 95% confidence interval (CI) = 0.9–1.9; OR for women = 1.6, 95% CI= 1.0–2.6]. We observed that associations with this high‐risk dietary profile were greater among those who took aspirin or nonsteroidal anti‐inflammatory drugs on a regular basis and were younger at the time of diagnosis (men OR = 1.7, 95% CI = 1.0–3.2; women OR = 2.2, 95% CI= 1.0–4.8) and for distal tumors (men OR = 1.4, 95% CI = 0.9–2.3; women OR = 2.0, 95% CI = 1.0–3.8). Findings from this study provide only limited support for previously reported associations between dietary factors involved in DNA methylation and risk of colon cancer.     

Intake of folate and related nutrients in relation to risk of epithelial ovarian cancer

Assessments of the relation between folate intake and ovarian cancer risk have been limited and inconsistent. Therefore, the authors prospectively examined the association of dietary and supplemental intakes of folate, methionine, and vitamin B(6) with ovarian cancer risk among 80,254 Nurses' Health Study participants. Beginning in 1976, women completed biennial questionnaires assessing ovarian cancer risk factors; starting in 1980, food frequency questionnaires were administered every 2-4 years. During 22 years of follow-up (1980-2002), the authors confirmed 481 incident epithelial ovarian cancers. There were no associations between total folate (top quintile vs. bottom: relative risk (RR) = 1.21, 95% confidence interval (CI): 0.92, 1.60), methionine (RR = 1.00, 95% CI: 0.76, 1.33), dietary vitamin B(6) (RR = 1.09, 95% CI: 0.81, 1.47), or total vitamin B(6) (RR = 1.13, 95% CI: 0.85, 1.51) intake and ovarian cancer risk. Higher dietary folate was associated with a modestly decreased risk after exclusion of cases diagnosed during the 4 follow-up years after dietary assessment (RR = 0.66, 95% CI: 0.43, 1.03) and for the serous subtype (RR = 0.51, 95% CI: 0.31, 0.84). Results did not vary by alcohol intake, multivitamin use, menopausal status, or oral contraceptive use. There was little evidence that folate, methionine, and vitamin B(6) are important in ovarian cancer risk, although dietary folate was inversely associated with risk in some analyses.     

Dietary folate, vitamin B6, vitamin B12 and methionine intake and the risk of breast cancer by oestrogen and progesterone receptor status

Few studies have evaluated the relationship between the consumption of dietary folate and one-carbon metabolism-related nutrients and breast cancer risk defined by oestrogen receptor (ER) and progesterone receptor (PR) status. The objective of the present study was to examine the associations between dietary folate, vitamin B6, vitamin B12, and methionine intake and the risk of breast cancer by ER and PR status among Chinese women in Guangdong. A hospital-based case-control study was conducted from June 2007 to August 2008, with 438 cases and 438 age (5-year interval)- and residence (rural/urban)-matched controls. Dietary intake information was assessed using a validated FFQ administered through a face-to-face interview. Unconditional logistic regression models were used to calculate multivariate-adjusted OR and 95 % CI. A significant inverse association was found between dietary folate and vitamin B6 intake and breast cancer risk. The adjusted OR of the highest v. the lowest quartile were 0·32 (95 % CI 0·21, 0·49; P(trend) < 0·001) for dietary folate and 0·46 (95 % CI 0·30, 0·69; P(trend) < 0·001) for vitamin B6. No associations were observed for vitamin B12 and methionine intake. A significant inverse association between dietary folate intake and breast cancer risk was observed in all subtypes of ER and PR status. These findings suggest that dietary folate and vitamin B6 intakes were inversely associated with breast cancer risk. The inverse association did not differ by ER and/or PR status.     

Relationship of folate,vitamin B-6, vitamin B-12, and methionine intake to incidence of colorectal cancers

It is hypothesized that diets deficient in folate, methionine, and vitamins B-6 and B-12 cause DNA hypomethylation and, as a result, increase risk of colorectal cancers. Furthermore, it is proposed that alcohol, a methyl group antagonist, increases risk of colorectal cancers among those with low intake of folate. Data from the Iowa Women's Health Study, a population-based cohort of incident cancer, were used to examine the relationship of folate, methionine, and vitamins B-6 and B-12 to occurrence of cancers of the colon (n = 598) and rectum (n = 123) over 13 yr of follow-up. There were no independent associations of folate, methionine, or vitamins B-6 and B-12 derived from a food frequency questionnaire with incidence of colon cancer. Adjusted relative risks (RRs) of rectal cancer were similar across categories of folate, vitamin B-12, and methionine intake, but RRs increased progressively with increasing intake of vitamin B-6 [P (for trend) = 0.03]. RRs suggested that incidence of cancer of the proximal colon was lower among those with 1) high folate and high vitamin B-12 intake [RR = 0.59, 95% confidence interval (CI) = 0.39-0.89] and 2) high folate and high vitamin B-6 intake (RR = 0.65, 95% CI = 0.50-0.84) than among those with the lowest intake of these nutrients. Incidence of cancer of the proximal colon was also somewhat lower among those with high folate and low alcohol intake (RR = 0.44, 95% CI = 0.22-0.89). Findings provide limited support for an association between dietary factors involved in DNA methylation and risk of cancers of the colon and rectum.     

Alcohol,smoking, coffee and risk of non-fatal acute myocardial infarction in Italy

Objectives: To assess the relation between cigarette smoking, alcohol, coffee, decaffeinated coffee and tea consumption, and the risk of non-fatal acute myocardial infarction (AMI). Design and setting: Hospital-based case–control study conducted in 1995–1999 in Milan, Italy. Patients: 507 cases with a first episode of non-fatal AMI, and 478 controls admitted to hospital for acute diseases. Methods: Information was collected by interviewer-administered questionnaires. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by multiple logistic regression. Results: Compared to alcohol non-drinkers the OR was 0.6 (95% CI: 0.4–0.9) in drinkers, and 0.5 in drinkers of >3 drinks/day. The OR for >1 drink/day of wine was 0.5, and those for beer, amari, grappa and spirits ranged between 0.4 and 0.6. Compared to never smokers, the OR was 2.2 (95% CI: 1.5–3.1) among current smokers, and 4.6 among current smokers of 25 cigarettes/day. The risk was similar to that of never smokers 5 years after cessation (OR: 1.1 after 5–9 years, 0.7 after 10 years). The OR was 2.3 for low tar cigarettes and 2.0 for high tar ones. The OR for coffee intake (expresso and mocha) was around unity up to 3 cups/day, but rose to 1.9 (95% CI: 1.1–3.3) for 6 cups/day. Moderate decaffeinated coffee and tea intake was not associated with AMI risk. Compared to non-smokers drinking 3 cups of coffee/day, the OR was 1.6 among non-smokers drinking >3 cups of coffee/day and 3.3 (95% CI: 2.1–5.0) among current smokers drinking >3 cups of coffee/day. Compared to alcohol drinkers with a coffee intake of 3 cups/day, alcohol non-drinkers with higher coffee intake had an OR of 2.2, and compared to non-smokers alcohol drinkers, the OR was 3.3 in current smokers alcohol non-drinkers. Conclusions: In this Italian population alcohol intake was inversely associated to AMI risk, while smoking and heavy (but not moderate) coffee drinking increased the risk.     

Case-control analysis of dietary folate and risk of bladder cancer

Dietary folate, a water-soluble B vitamin found in a variety of fruits and vegetables, is of particular interest as a chemopreventive agent due to its role in DNA methylation and DNA synthesis and repair. We hypothesized that individuals with low folate intake would be at an increased risk for bladder cancer. Using an ongoing case-control study we assessed dietary folate in 409 incident bladder cancer patients and 451 healthy control subjects. A food-frequency questionnaire was used to estimate naturally occurring food folate (microg/kcal/day), dietary folate equivalents (DFE) from food sources (microg DFE/kcal/day), and DFE from all sources (microg DFE/kcal/day). Unconditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Bladder cancer patients reported a statistically significant lower intake of folate than control subjects for food folate and DFE from food sources (P < 0.001) but not for DFE from all sources (P = 0.061). In the highest quartile of food folate intake there was a 54% reduced risk for bladder cancer (OR = 0.46; 95% CI = 0.29-0.73) after adjusting for age, gender, ethnicity, smoking, and total energy intake. Similarly, the highest quartile of intake was associated with a 59% reduced risk for DFE from food sources (OR = 0.41; 95% CI = 0.26-0.65) and a 35% reduced risk for DFE from all sources (OR = 0.65; 95% CI = 0.42-1.00). In the joint-effects analyses using never smokers with high folate intake as the reference group (OR = 1.0), heavy smokers with low food folate intake had a 2.31-fold (95% CI = 1.11-4.82) increased risk, whereas heavy smokers with high folate intake had a reduced OR of 1.31 (95% CI = 0.53-3.26). Although the ORs were not statistically significant, light smokers and high folate intake exhibited a protective effect (OR = 0.62; 95% CI = 0.20-1.94), whereas an increased risk was observed for light smoking and low folate intake (OR = 1.41; 95% CI = 0.57-3.45). These patterns were consistent for the joint effects of smoking and DFE from food sources and DFE from all sources. In summary, high intake of dietary folate was associated with an overall decrease in bladder cancer risk. These data may have important implications for cancer prevention; however, large, hypothesis-driven, population-based clinical trials will be required to confirm these findings.     

Dietary Folate,Alcohol Consumption,and Risk of Non-Hodgkin Lymphoma

Dietary deficiency of folate and other micronutrients involved in the one-carbon metabolism (i.e., vitamins B ₂ , B ₆ , B ₁₂ , and methionine) have been related to several diseases, including cancers, but results on non-Hodgkin lymphoma (NHL) are controversial. A hospital-based case-control study was conducted in Italy, in 1999–2002. Cases were 190 incident, histologically confirmed NHL aged 18–84 years. Controls were 484 subjects admitted to hospitals for acute, non-neoplastic diseases supposed to be unrelated to alcohol consumption or to diet modification. Dietary habits, including alcohol drinking, were assessed by a validated food-frequency questionnaire. Nutrient intakes were computed using the Italian food composition database. Odds ratios (ORs) and corresponding 95% confidence intervals for tertiles of nutrients' intake were computed using the energy-adjusted residual models. No significant association emerged between NHL risk and intakes of folate (OR = 0.9), vitamin B ₂ (OR = 0.9), vitamin B ₆ (OR = 0.8), and methionine (OR = 0.7). However, a significant inverse association was observed for all the nutrients examined among abstainers and former drinkers, whereas no relations between one-carbon nutrients and NHL risk emerged among current alcohol drinkers. Our findings support the possibility of an antagonist effect of alcohol on the one-carbon metabolism in NHL etiology. However, the lack of an overall effect for one-carbon nutrients and the small sample size suggested caution in interpreting our results.     

Polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, intakes of folate and related B vitamins and colorectal cancer: a case-control study in a population with relatively low folate intake

Folate is key in one-carbon metabolism, disruption of which can interfere with DNA synthesis, repair, and methylation. Efficient one-carbon metabolism requires other B vitamins and the optimal activity of enzymes including 5,10-methylenetetrahydrofolate reductase (MTHFR). We report a population-based case-control study of folate intake, related dietary factors and MTHFR polymorphisms (C677T, A1298C) and colorectal cancer in a population with relatively high colorectal cancer incidence and relatively low folate intake. A total of 264 cases with histologically confirmed incident colorectal cancer and 408 controls participated. There was no clear trend in risk with reported intakes of total, or dietary, folate, riboflavin, vitamin B12 or vitamin B6, nor were there interactions between folate intake and the other B vitamins or alcohol. For C677T, risk decreased with increasing variant alleles (multivariate OR for CT v. CC = 0.77 (95 % CI 0.52, 1.16); OR for TT v. CC = 0.62 (95 % CI 0.31, 1.24)), which, although not statistically significant, was consistent with previous studies. For A1298C, compared with AA subjects, CC subjects had modest, non-significant, reduced risk (multivariate OR = 0.81 (95 % CI 0.45, 1.49)). There were significant interactions between total folate and C677T (P = 0.029) and A1298C (P = 0.025), and total vitamin B6 and both polymorphisms (C677T, P = 0.016; A1298C, P = 0.033), although the patterns observed differed from previous studies. Seen against the setting of low folate intake, the results suggest that the role of folate metabolism in colorectal cancer aetiology may be more complex than previously thought. Investigation of particular folate vitamers (for example, tetrahydrofolate, 5,10-methylenetetrahydrofolate) may help clarify carcinogenesis pathways.     

Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification

BACKGROUND: Historic reports on the treatment of pernicious anemia with folic acid suggest that high-level folic acid fortification delays the diagnosis of or exacerbates the effects of vitamin B-12 deficiency, which affects many seniors. This idea is controversial, however, because observational data are few and inconclusive. Furthermore, experimental investigation is unethical. OBJECTIVE: We examined the relations between serum folate and vitamin B-12 status relative to anemia, macrocytosis, and cognitive impairment (ie, Digit Symbol-Coding score < 34) in senior participants in the 1999-2002 US National Health and Nutrition Examination Survey. DESIGN: The subjects had normal serum creatinine concentrations and reported no history of stroke, alcoholism, recent anemia therapy, or diseases of the liver, thyroid, or coronary arteries (n = 1459). We defined low vitamin B-12 status as a serum vitamin B-12 concentration < 148 pmol/L or a serum methylmalonic acid concentration > 210 nmol/L-the maximum of the reference range for serum vitamin B-12-replete participants with normal creatinine. RESULTS: After control for demographic characteristics, cancer, smoking, alcohol intake, serum ferritin, and serum creatinine, low versus normal vitamin B-12 status was associated with anemia [odds ratio (OR): 2.7; 95% CI: 1.7, 4.2], macrocytosis (OR: 1.8; 95% CI: 1.01, 3.3), and cognitive impairment (OR: 2.5; 95% CI: 1.6, 3.8). In the group with a low vitamin B-12 status, serum folate > 59 nmol/L (80th percentile), as opposed to < or = 59 nmol/L, was associated with anemia (OR: 3.1; 95% CI: 1.5, 6.6) and cognitive impairment (OR: 2.6; 95% CI: 1.1, 6.1). In the normal vitamin B-12 group, ORs relating high versus normal serum folate to these outcomes were < 1.0 (P(interaction) < 0.05), but significantly < 1.0 only for cognitive impairment (0.4; 95% CI: 0.2, 0.9). CONCLUSION: In seniors with low vitamin B-12 status, high serum folate was associated with anemia and cognitive impairment. When vitamin B-12 status was normal, however, high serum folate was associated with protection against cognitive impairment.     

Folate and colorectal neoplasia: relation between plasma and dietary markers of folate and adenoma recurrence

BACKGROUND: The results of epidemiologic studies indicate that higher intakes or blood concentrations of folate are associated with a lower risk of colorectal neoplasia; however, only one study assessed the role of homocysteine. OBJECTIVE: We assessed the relation between biochemical and dietary markers of folate status and colorectal adenoma recurrence. DESIGN: Analyses were conducted in 1014 men and women aged 40-80 y who had undergone removal of all colorectal polyps. Diet and supplement use were ascertained through a food-frequency questionnaire administered at study entry. Blood collected at baseline was used to measure plasma folate and homocysteine concentrations. Unconditional logistic regression was used to assess the odds of recurrence associated with the intakes of folate, methionine, and vitamins B-6 and B-12 and with plasma folate and homocysteine. RESULTS: Relative to subjects in the highest quartile of plasma homocysteine, those in the lowest quartile had an odds ratio (OR) of adenoma recurrence of 0.69 (95% CI: 0.47, 1.02; P for trend = 0.02) after adjustment for confounding factors. Lower odds of recurrence were shown for higher plasma folate (OR: 0.66; 95% CI: 0.46, 0.97) and higher total intakes (dietary plus supplemental) of folate (OR: 0.61; 0.42, 0.89) and vitamin B-6 (OR: 0.65; 0.45, 0.94). Slightly weaker and nonsignificant associations were shown for dietary folate, methionine, and total vitamin B-12. CONCLUSIONS: A lower recurrence of colorectal adenomas was shown in subjects with higher intakes and plasma concentrations of folate. Additional markers involved in folate metabolism, including lower homocysteine and higher vitamin B-6 intake, were also associated with lower odds of recurrence.     

Association between B vitamin intake and plasma homocysteine concentration in the general Dutch population aged 20-65 y

BACKGROUND: An elevated plasma total homocysteine (tHcy) concentration is associated with an increased risk of cardiovascular diseases. Folate, riboflavin, vitamin B-6, and vitamin B-12 are essential in homocysteine metabolism. OBJECTIVE: The objective was to describe the association between dietary intakes of folate, riboflavin, vitamin B-6, and vitamin B-12 and the nonfasting plasma tHcy concentration. DESIGN: A random sample of 2435 men and women aged 20-65 y from a population-based Dutch cohort examined in 1993-1996 was analyzed cross-sectionally. RESULTS: Univariately, intakes of all B vitamins were inversely related to the plasma tHcy concentration. In multivariate models, only folate intake remained inversely associated with the plasma tHcy concentration. Mean plasma tHcy concentrations (adjusted for intakes of riboflavin, vitamin B-6, vitamin B-12, and methionine and for age, smoking, and alcohol consumption) in men with low (first quintile: 161 microg/d) and high (fifth quintile: 254 microg/d) folate intakes were 15.4 and 13.2 micromol/L, respectively; in women, plasma tHcy concentrations were 13.7 and 12.4 micromol/L at folate intakes of 160 and 262 microg/d, respectively. In men, the difference in the mean plasma tHcy concentration between men with low and high folate intakes was greater in smokers than in nonsmokers (2.8 compared with 1.6 micromol/L) and greater in nondrinkers than in drinkers of >2 alcoholic drinks/d (3.5 compared with 1.4 micromol/L). In women, the association between folate intake and plasma tHcy was not modified by smoking or alcohol consumption. CONCLUSIONS: In this Dutch population, folate was the only B vitamin independently inversely associated with the plasma tHcy concentration. Changing dietary habits may substantially influence the plasma tHcy concentration in the general population.     

Nutrients in folate-mediated, one-carbon metabolism and the risk of rectal tumors in men and women

In an investigation of rectal tumors characterized by CpG island methylator phenotype (CIMP), KRAS2 mutation, and TP53 mutation, we examined associations with dietary and supplemental folate, riboflavin, vitamins B(6) and B(12), and methionine, nutrients involved in folate-mediated 1-carbon metabolism. We also examined folate intake and common MTHFR polymorphisms in relation to CIMP. Data from a population-based study of 951 cases (750 with tumor markers) and 1,205 controls were evaluated using multiple logistic regression models and generalized estimating equations. Reduced risk of methylated tumors was suggested in women with the upper tertile of folate intake (≥0.42 mg/day) vs. the lower tertile: OR = 0.6, 95%CI = 0.3-1.2. In men, a significant 3-fold increased risk of CIMP+ tumor was observed for the upper tertile of folate (≥0.75 mg/day) vs. the lower tertile (<0.44 mg/day): OR = 3.2, 95%CI = 1.5-6.7. These men consumed a greater proportion of folic acid fortified foods relative to natural, primarily plant-based sources (52% vs. 48%) than women with CIMP+ tumors (22% vs. 78%). MTHFR 1298A>C influenced folate in male CIMP+ risk (P interaction < 0.01). Our findings suggest folate supplementation effects may differ between genders, perhaps due to variation in MTHFR and/or endogenous/exogenous hormones, and may be important in the initiation and progression of methylated rectal tumors in men.     

Nutrients contributing to one-carbon metabolism and risk of non-Hodgkin lymphoma subtypes

Because little is known about the etiology of non-Hodgkin lymphoma (NHL), a heterogeneous disease, and because dietary factors are modifiable, the authors examined the associations between nutrients related to one-carbon metabolism and risk of NHL in a population-based case-control study of Connecticut women diagnosed between 1996 and 2000. A total of 594 cases and 710 controls completed a food frequency questionnaire for determination of intakes of folate, vitamins B(2), B(6), and B(12), and methionine. Through unconditional logistic regression, the authors estimated the risk of NHL associated with intake of each nutrient. Comparing the highest quartile of intake with the lowest, the authors found lower risks of all NHL associated with increasing intakes of folate and methionine. Analysis by NHL subtype indicated lower risks of diffuse large B-cell lymphoma (highest quartile vs. lowest: odds ratio (OR) = 0.54, 95% confidence interval (CI): 0.30, 0.98; p-trend = 0.02) and marginal zone lymphoma (highest quartile vs. lowest: OR = 0.08, 95% CI: 0.02, 0.26; p-trend < 0.0001) associated with folate. Vitamin B(6) intake was also associated with lower risk of NHL overall and of marginal zone lymphoma (highest quartile vs. lowest: OR = 0.23, 95% CI: 0.08, 0.65; p-trend = 0.002). These findings suggest that these nutrients may be important for susceptibility to NHL.     

Dietary factors related to hypertension risk in Korean adults-data from the Korean national health and nutrition examination survey III

Regional differences between large cities and rural areas are observed in the Korean National Health and Nutrition Examination Survey (KNHANES). This present study was conducted to evaluate the effect of dietary factors on hypertension risk in Korean populations, especially residents of the Chungcheong province which was not in metropolitan area, using KNHANES III. A total of 544 adults aged ≥ 19 years were placed into either the normotensive or the hypertensive group. Subject characteristics, BMI, blood pressure, and nutrient intakes were compared between the two groups using a chi-square test and t-test. We estimated odds ratios (ORs) using multiple logistic regression, adjusted for energy intake and selected covariates. There were significant differences in age, education level, alcohol consumption, and BMI between the normotensive and hypertensive groups. We found decreased ORs for the medium versus lowest tertile of calcium intake (multivariate OR = 0.43, 95% CI: 0.21-0.88), for the highest versus lowest tertile of calcium intake (multivariate OR = 0.43, 95% CI: 0.20-0.90) with significant trends in risk (P = 0.040), and for the medium versus lowest tertile of potassium intake (multivariate OR = 0.43, 95% CI: 0.20-0.89). Subjects with the highest sodium/calcium ratio had a 2.10-fold greater risk of hypertension compared to the subject with the lowest, with significant trends in risk (P = 0.002). Adequate calcium and potassium intake should be encouraged and regional differences should be considered in making a healthy plan for hypertension management.     

Dietary folate intake, alcohol, and risk of breast cancer in a prospective study of postmenopausal women.

Low B-vitamin intake may increase risk of breast cancer through decreased DNA repair capacity. Alcohol intake increases risk for breast cancer, with evidence from prospective studies of an interaction between alcohol and folate. We explored dietary intake of folate and other B vitamins with risk of breast cancer in a cohort study of 34,387 postmenopausal women. To measure diet, we mailed a food frequency questionnaire; we estimated nutrient intakes and categorized them into four levels: <10th, 11th-30th, 31st-50th, and >50th percentiles. Through 12 years of follow-up, we identified 1,586 cases of breast cancer in the cohort at risk. We estimated relative risks (RRs) and 95% confidence intervals (CIs) through Cox regression models adjusted for age, energy, and other risk factors. Women in the lowest 10th percentile of folate intake from diet alone were at modestly increased risk of breast cancer relative to those above the 50th percentile: RR = 1.21 (95% CI = 0.91--1.61). We examined the joint association of folate intake and alcohol use on risk of breast cancer, with the reference group defined as women with high folate (>50th percentile) and no alcohol use. The RRs of breast cancer associated with low dietary folate intake were 1.08 (95% CI = 0.78--1.49) among nondrinkers, 1.33 (95% CI = 0.86--2.05) among drinkers of < or = 4 gm per day, and 1.59 (95% CI = 1.05--2.41) among drinkers of > 4 gm per day. These results suggest that the risks of postmenopausal breast cancer may be increased among women with low intakes of folate if they consume alcohol-containing beverages.     

Dietary factors of one-carbon metabolism and prostate cancer risk

BACKGROUND: Folate is hypothesized to be inversely associated with the risk of several cancers, but such a potential association has not been well studied for prostate cancer. Vitamin B-6, vitamin B-12, methionine, and alcohol can influence folate-related metabolism. OBJECTIVE: The objective was to investigate the associations between dietary factors of one-carbon metabolism and prostate cancer risk within the alpha-Tocopherol, beta-Carotene Cancer Prevention Study. DESIGN: Of the cohort's 27 111 Finnish male smokers aged 50-69 y who had complete dietary data, 1270 had a diagnosis of incident prostate cancer between 1985 and 2002. Folate, vitamin B-6, vitamin B-12, methionine, and alcohol intakes were estimated from a 276-item modified dietary history questionnaire. Cox proportional hazard models, adjusted for age and vitamin supplement use, estimated relative risks (RR) and 95% CIs. RESULTS: Vitamin B-6 intake was inversely associated with prostate cancer risk (RR for highest versus lowest quintile: 0.88; 95% CI: 0.72, 1.07; P for trend = 0.045), whereas vitamin B-12 intake was associated with significantly increased risk (RR = 1.36; 95% CI: 1.14, 1.96; P for trend = 0.01). No association between folate or alcohol intake and prostate cancer risk was observed. No differences were found in the above associations according to stage of disease or subgroups of several potential effect modifiers. CONCLUSIONS: We found no convincing evidence for a protective role of one-carbon metabolism against prostate cancer, although these observations can be generalized only to smokers. The possible modest protective association with vitamin B-6 and the significantly elevated risk with vitamin B-12 intake warrant further investigation.     

Folate, vitamin B6, vitamin B12, and methionine intakes and risk of stroke subtypes in male smokers

The associations of dietary folate, vitamin B(6), vitamin B(12), and methionine intakes with risk of stroke subtypes were examined among 26,556 male Finnish smokers, aged 50-69 years, enrolled in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Dietary intake was assessed at baseline by using a validated food frequency questionnaire. During a mean follow-up of 13.6 years, from 1985 through 2004, 2,702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were identified from national registers. In analyses adjusting for age and cardiovascular risk factors, a high folate intake was associated with a statistically significant lower risk of cerebral infarction but not intracerebral or subarachnoid hemorrhages. The multivariate relative risk of cerebral infarction was 0.80 (95% confidence interval: 0.70, 0.91; p(trend) = 0.001) for men in the highest versus lowest quintile of folate intake. Vitamin B(6), vitamin B(12), and methionine intakes were not significantly associated with any subtype of stroke. These findings in men suggest that a high dietary folate intake may reduce the risk of cerebral infarction.