Dietary intake of B vitamins and methionine and breast cancer risk. Cancer Causes Control. 2013;24:1555-1563. [PMID: 23686442 DOI: 10.1007/s10552-013-0232-y]

The association between dietary intakes of methionine, choline and betaine and breast cancer risk: A systematic review and meta-analysis

BACKGROUND AND AIM

This study evaluates the associations between dietary intakes and circulating blood levels of methionine, choline or betaine and breast cancer risk, which remains currently unclear.

METHODS

Systematic searches for observational epidemiological studies were performed of the MEDLINE, Embase, and Web of Science databases through July, 2022. Two review authors independently screened titles and abstracts against the eligibility criteria at a first stage, and screened full texts of potentially eligible records at a second stage, followed by data extraction from qualified studies. Quality of evidence was assessed using the Newcastle-Ottawa scale quality assessment tool. Risk estimates were calculated using random-effects meta-analysis.

RESULTS

In total, 21 studies were selected for qualitative analyses and 18 studies were included in the meta-analyses. Random-effects analysis combining prospective cohort (N = 8) or case-control studies (N = 10) showed little evidence of an association between dietary intake of methionine or betaine and the risk of breast cancer. However, inconclusive evidence for a significant inverse association between choline intake and breast cancer risk was found in case-control studies (odds ratio [OR] estimates for highest vs. lowest intakes = 0.38; 95 % CI: 0.16-0.86) but not in prospective cohort studies (hazard ratio [HR] estimates for highest vs. lowest intakes = 1.01; 95 % CI: 0.92-1.12).

CONCLUSION

This study did not suggest an effect of dietary intake of methionine, choline, nor betaine on breast cancer risk, mainly due to the lack of precision of the combined risk estimates as few studies are available. To overcome this uncertainty, more well-designed studies with relevant individual-level covariates are needed.

Comparison of the Index of Nutritional Quality in Breast Cancer Patients With Healthy Women

Background

The index of nutritional quality (INQ) is derived from the food frequency questionnaire (FFQ) and is a method of quantitative and qualitative analysis of diet. This study aimed to compare the INQ for different dietary components between breast cancer (BC) patients and healthy control.

Methods

This case-control study was performed on 180 women with BC and 360 healthy women. Data on general characteristics, medical history, anthropometric indices, physical activity, alcohol consumption, reproductive history, smoking, and dietary intake were collected. A valid FFQ was used to assess the intake of nutrients and the INQ was calculated based on the daily intake of the nutrients.

Results

There was a significant association between BC and INQ of vitamin A (OR = 0.07, 0.01-0.29), vitamin E (OR = 0.43, 0.20-0.93), vitamin B6 (OR = 0.003, 0.000-0.021), riboflavin (OR = 0.25, 0.11-0.59), vitamin K (OR = 0.58, 0.37-0.90), biotin (OR = 0.07, 0.02-0.26), vitamin B12 (OR = 0.32, 0.18-0.56), vitamin C (OR = 0.72, 0.55-0.95), zinc (OR = 0.020, 0.005-0.083), calcium (OR = 0.14, 0.04-0.54) and magnesium (OR = 0.003, 0.000-0.024). Further adjustment for BMI disappeared the association between INQ of vitamin C and BC. The results did not change after further adjustments for waist circumstance and total calorie intake.

Conclusion

A significant association was observed between BC and the INQ of vitamin A, vitamin E, vitamin B6, riboflavin, vitamin K, biotin, vitamin B12, vitamin C, zinc, calcium, and magnesium. The INQ can be used as an indicator in assessing clinical nutrition-related problems. Future longitudinal studies are needed to confirm these results.

Dietary Methyl-Group Donor Intake and Breast Cancer Risk in the European Prospective Investigation into Cancer and Nutrition (EPIC)

(1) Background: Methyl-group donors (MGDs), including folate, choline, betaine, and methionine, may influence breast cancer (BC) risk through their role in one-carbon metabolism; (2) Methods: We studied the relationship between dietary intakes of MGDs and BC risk, adopting data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort; (3) Results: 318,686 pre- and postmenopausal women were followed between enrolment in 1992-2000 and December 2013-December 2015. Dietary MGD intakes were estimated at baseline through food-frequency questionnaires. Multivariable Cox proportional hazards regression models were used to quantify the association between dietary intake of MGDs, measured both as a calculated score based on their sum and individually, and BC risk. Subgroup analyses were performed by hormone receptor status, menopausal status, and level of alcohol intake. During a mean follow-up time of 14.1 years, 13,320 women with malignant BC were identified. No associations were found between dietary intakes of the MGD score or individual MGDs and BC risk. However, a potential U-shaped relationship was observed between dietary folate intake and overall BC risk, suggesting an inverse association for intakes up to 350 µg/day compared to a reference intake of 205 µg/day. No statistically significant differences in the associations were observed by hormone receptor status, menopausal status, or level of alcohol intake; (4) Conclusions: There was no strong evidence for an association between MGDs involved in one-carbon metabolism and BC risk. However, a potential U-shaped trend was suggested for dietary folate intake and BC risk. Further research is needed to clarify this association.

Probiotics for the Chemoprotective Role Against the Toxic Effect of Cancer Chemotherapy

BACKGROUND

The processes of chemo- and radiation therapy-based clinical management of different types of cancers are associated with toxicity and side effects of chemotherapeutic agents. So, there is always an unmet need to explore agents to reduce such risk factors. Among these, natural products have generated much attention because of their potent antioxidant and antitumor effects. In the past, some breakthrough outcomes established that various bacteria in the human intestinal gut are bearing growth-promoting attributes and suppressing the conversion of pro-carcinogens into carcinogens. Hence, probiotics integrated approaches are nowadays being explored as rationalized therapeutics in the clinical management of cancer.

METHODS

Here, published literature was explored to review chemoprotective roles of probiotics against toxic and side effects of chemotherapeutics.

RESULTS

Apart from excellent anti-cancer abilities, probiotics are bearing and alleviate toxicity and side effects of chemotherapeutics, with a high degree of safety and efficiency.

CONCLUSION

Preclinical and clinical evidence suggested that due to the chemoprotective roles of probiotics against side effects and toxicity of chemotherapeutics, their integration in chemotherapy would be a judicious approach.

Dietary modulations of folic acid affect the development of diethylnitrosamine induced hepatocellular carcinoma in a rat model

The present study evaluated the role of dietary folate modulations in the development of hepatocellular carcinoma (HCC) in a rat model. Male Wistar rats were given diethylnitrosamine (DEN) carcinogen for a period of 18 weeks in addition to different folate modulations. Biochemical parameters were assayed and liver tissues were examined using various histopathological stains viz. Hematoxylin and eosin (H&E), Masson's trichrome, Immunohistochemistry (IHC) staining for arginase-1 and α-smooth muscle actin (SMA). Serum folate and hepatic folate stores were decreased and increased in folate deficiency (FD) and folate oversupplemented (FO) group respectively. Analysis of serum liver function tests revealed deranged liver functioning in all the groups. H&E staining of rat liver demonstrated vague nodularity from 2nd to 8th week, fibrosis from 10th to 15th week, cirrhosis and HCC from 16th to 18th week. Combining the observations of H&E with IHC for arginase-1, 14 (50%), 11 (39.3%) and 17 (58.6%) rats showed HCC positivity in FN (folate normal), FD and FO diets respectively. IHC for α-SMA depicted increased staining with progression of the disease from fibrosis to cirrhosis in all the dietary groups. Collectively, findings of all the histopathological stains, revealed increase in the number of cirrhotic cases and decrease in the number of HCC cases in FD group, indicating delayed progression of HCC with FD. Moreover, FO led to more number of HCC and reduction in the number of cirrhotic cases, signifying early progression of HCC.

Effect of Breast Cancer Treatment on Dietary Vitamin Intake Levels

Breast cancer is the most common tumor among women, representing the second cause of cancer deaths in women. Treatment with chemotherapy negatively interferes with nutritional status. The intake of vitamins before, during and after treatment in a pilot cohort of women with non-invasive breast cancer (type I, II) treated at the Valencian Institute of Oncology (IVO) is evaluated. A 3-day anthropometric and nutritional assessment was performed using the DIAL program. Nutritional intake is compared with the values of Estimated Average Requirements (EAR) and Dietary Reference Intake (DRI) provided by the United States Department of Agriculture (USDA) and the European Food Safety Authority (EFSA). There is an overall decrease in vitamin intake during treatment which worsens at the end of said treatment. The decrease is significant in the case of vitamins B₂ (p = 0.006), B₃ (p = 0.042), B₅ (p = 0.001), and B₈ (p = 0.021). The relative risk during and after treatment increases with respect to the reference timeframe, before treatment. Deficit risks are statistically significant in the case of vitamins B₅ (p = 0.001), B₈ (p = 0.001) and B₁₂ (p = 0.001). Decreased vitamin intake during treatment suggests a negative change in the patients’ dietary behaviors during this time. Nutritional intervention and support may be beneficial to optimize overall dietary intake and maintain compliance with EAR and DRI for patients during a time in which adequate nutrition is important.

Association of folate intake and plasma folate level with the risk of breast cancer: a dose-response meta-analysis of observational studies

Epidemiological studies showing the correlation between folate and the breast cancer risk have revealed inconsistent results. Hence, we conducted a dose-response meta-analysis of observational studies to obtain more reliable conclusions. We searched PubMed and Embase for studies published before April 2019 and identified 39 studies on folate intake and 12 studies on plasma folate level. The combined odds ratios (ORs) and 95% confidence intervals (CIs) were extracted to estimate the breast cancer risk. Folate intake was inversely correlated with the breast cancer risk when the highest and lowest categories (OR = 0.85, 95% CI = 0.79-0.92) were compared, and the dose-response result showed that folate intake had a linear correlation with the breast cancer risk. Moreover, a higher folate intake correlated with a lower breast cancer risk in premenopausal women (OR = 0.80, 95% CI = 0.66-0.97), but not in postmenopausal women (OR = 0.94, 95% CI = 0.83-1.06). However, plasma folate levels were not correlated with the breast cancer risk (OR = 0.98, 95% CI = 0.82-1.17). Folate intake was negatively correlated with the breast cancer risk; however, its practical clinical significance requires further study. Furthermore, additional folate supplements should be considered carefully.

Logistic LASSO Regression for Dietary Intakes and Breast Cancer

A multitude of dietary factors from dietary fat to macro and micronutrients intakes have been associated with breast cancer, yet data are still equivocal. Therefore, utilizing data from the large, multi-year, cross-sectional National Health and Nutrition Examination Survey (NHANES), we applied a novel, modern statistical shrinkage technique, logistic least absolute shrinkage and selection operator (LASSO) regression, to examine the association between dietary intakes in women, ≥50 years, with self-reported breast cancer (n = 286) compared with women without self-reported breast cancer (1144) from the 1999–2010 NHANES cycle. Logistic LASSO regression was used to examine the relationship between twenty-nine variables, including dietary variables from food, as well as well-established/known breast cancer risk factors, and to subsequently identify the most relevant variables associated with self-reported breast cancer. We observed that as the penalty factor (λ) increased in the logistic LASSO regression, well-established breast cancer risk factors, including age (β = 0.83) and parity (β = −0.05) remained in the model. For dietary macro and micronutrient intakes, only vitamin B12 (β = 0.07) was positively associated with self-reported breast cancer. Caffeine (β = −0.01) and alcohol (β = 0.03) use also continued to remain in the model. These data suggest that a diet high in vitamin B12, as well as alcohol use may be associated with self-reported breast cancer. Nonetheless, additional prospective studies should apply more recent statistical techniques to dietary data and cancer outcomes to replicate and confirm the present findings.

Association Between One-carbon Metabolism-related Vitamins and Risk of Breast Cancer: A Systematic Review and Meta-analysis of Prospective Studies

Epidemiologic studies focusing on the association between 1-carbon metabolism-related vitamins (ie, folate, vitamin B₆, vitamin B₂, vitamin B₁₂) and breast cancer risk have reported inconsistent findings. We conducted a systematic search of the reported data and performed a meta-analysis of prospective case-control and cohort studies to derive a more precise evaluation. The PubMed and EMBASE databases were searched to identify eligible studies. A total of 27 studies involving 49,707 cases and 1,274,060 individuals were included in the meta-analysis. The results indicated that a high intake of folate, vitamin B₆, and vitamin B₂ might decrease the risk of breast cancer. The corresponding pooled relative risks (RRs) for the highest intake compared with the lowest were 0.93 (95% confidence interval [CI], 0.88-0.99; P = .018), 0.94 (95% CI, 0.89-1.00; P = .037) and 0.90 (95% CI, 0.82-0.99; P = .026). No significant association between vitamin B₁₂ and breast cancer risk was found (RR, 0.99; 95% CI, 0.94-1.04; P = .604). Further study showed that folate and vitamin B₆ might decrease the risk of estrogen receptor-negative (ER^-)/progesterone receptor-negative (PR^-) breast cancer but not ER⁺/PR⁺ breast cancer. The dose-response meta-analysis indicated a significant linearity relationship between folate intake and a reduced risk of ER^-/PR^- breast cancer. An increment of folate intake (100 μg/d) corresponded to a 7% deceased risk of ER^-/PR^- breast cancer (RR, 0.93; 95% CI, 0.89-0.98; P = .007). In conclusion, a high intake of 1-carbon metabolism-related vitamins might contribute to the prevention of breast cancer, especially ER^-/PR^- breast cancer.

Dietary B-Vitamin Intake and Risk of Breast, Endometrial, Ovarian and Colorectal Cancer among Canadians

Few studies have explored the associations of thiamin, niacin and riboflavin with risk of cancer despite their role in potentially cancer-associated one-carbon metabolism. Using multivariable Cox proportional hazards regression models modified for the case-cohort design, we examined the associations of dietary intake of the above-mentioned B vitamins, as well as folate, and vitamins B6 and B12, with risk of the breast (n = 922), endometrial (n = 180), ovarian (n = 104) and colorectal (n = 266) cancers among age-stratified subcohorts of 3,185 women who were randomly selected from a cohort of 73,909 participants. None of the B-vitamins were associated with risk of breast or colorectal cancers. However, relatively high dietary intake of folate intake was inversely associated with risk of endometrial (HRq4 vs q1: 0.52; 95% CI: 0.29-0.93) and ovarian (HRq3 vs q1: 0.39; 95% CI: 0.19-0.80) cancers while relatively high dietary intake of vitamin B6 was inversely associated with ovarian cancer risk (HRq3 vs q1: 0.49; 95% CI: 0.24-0.98). These findings suggest that dietary intake of folate may reduce risk of endometrial and ovarian cancers and dietary intake of vitamin B6 may reduce risk of ovarian cancer.

The Vitamins Involved in One-Carbon Metabolisms are Associated with Reduced Risk of Breast Cancer in Overall and Subtypes

Background: Some micronutrients like folate, vitamin B12, B6, and B2 are the source of coenzymes, which participate in one-carbon metabolism. Any disruption in this metabolism can interfere with DNA replication, repair and regulation of gene expression and ultimately promote the likelihood of carcinogenesis. This study aimed at investigating the relationship between the intakes of micronutrients involved in one-carbon metabolism with breast cancer (BrCa) and its subtype's odds. Methods: Nutrients' intake from diet and supplements were collected through interviewing 151 cases and 154 controls by a 168-item semiquantitative food frequency questionnaire. Logistic regression was used to determine the relationship between dietary and/or total intake of studied nutrients and odds of BrCa and its subtypes. Results: After adjusting the effects of confounding variables in the models, the odds of BrCa was significantly lower in the highest intake quartile compared with the lowest quartile for total intake of vitamin B2 (OR = 0.17, 95% CI, 0.07-0.39; P_trend < 0.001), vitamin B6 (OR = 0.11, 95% CI, 0.05-0.27; P_trend < 0.001), vitamin B12 (OR = 0.20, 95% CI, 0.09-0.43; P_trend < 0.001) and folate (OR = 0.09, 95% CI, 0.04-0.21; P_trend < 0.001). Also, those with the highest quartile of vitamin B6, B12, B2 and folate intake compared with the lowest quartile were less likely to develop estrogen receptor (ER)+ and progesterone receptor (PR)+ subtypes, ER- status, PR- and human epidermal growth factor receptor 2 (HER2)+ subtypes and HER2- status. Conclusion: High intakes of vitamins B2, B6 and folate are associated with reduced odds of BrCa in overall and all ER, PR and HER2 subtypes. Also, high intakes of vitamin B12 reduced the odds of all subtypes of BrCa except ER- subtype.

Dietary Intake and Weight Changes 5 Years After Laparoscopic Sleeve Gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is becoming a leading primary bariatric surgery but long-term outcome remains unclear. The amount of food eaten is drastically reduced after LSG and may lead to nutritional deficiencies potentially. The aim of this study is to investigate long-term dietary intake and weight status after LSG.

METHODS

Forty patients underwent LSG had more than 5-year follow-up with complete clinical data and food frequency questionnaires were analyzed.

RESULTS

The mean age of subjects is 33.5 years old with mean body mass index (BMI) 37.9 kg/m². Mean BMI loss at 5 years after LSG is 10.6 kg/m². Weight regain appeared in 20% of patients. Dietary composition analysis at 5 years showed mean calorie intake of 1230 kcal/day, protein 70 g/day (22.5% of calorie), fat 50 g/day (36.1%), carbohydrate 126 g (41.4%), iron 7.5 mg/day, calcium 536.2 mg/day, and fiber 11.7 g/day. Calorie intake at 5 years after LSG is correlated with weight loss but weight regain is not related to a higher calorie intake. All comorbidities were significantly improved after LSG but hemoglobin and parathyroid hormone significantly changed. Incidence of iron deficiency anemia increased from 7.5% at pre-operation to 41.2% after LSG. Incidence of secondary hyperparathyroidism increased from 17.5 to 60.7%.

CONCLUSION

LSG is an effective and durable bariatric procedure but with significant changes in nutritional status. Dietary instruction for LSG should include foods rich in protein, iron, calcium, and fiber.

Dietary intake of nutrients involved in one-carbon metabolism and risk of urothelial cell carcinoma: A prospective cohort study

Nutrients involved in one-carbon metabolism may play a role in carcinogenesis through DNA replication, repair and methylation mechanisms. Most studies on urothelial cell carcinoma (UCC) have focused on folate. We sought to examine the association between B-group vitamins and methionine intake and UCC risk, overall and by subtype, and to test whether these associations are different for population subgroups whose nutritional status may be compromised. We followed participants in the Melbourne Collaborative Cohort Study (N = 41,513) for over 20 years and observed 500 UCC cases (89% originating in the bladder; superficial: 279, invasive: 221). Energy-adjusted dietary intakes of B vitamins (B1, B2, B3, B5, B6, B8, B9 and B12) and methionine were estimated from a 121-item food frequency questionnaire administered at baseline (1990-1994), using the residuals method. We used Cox regression models to compute hazard ratios (HRs) of UCC risk per standard deviation (SD) of log-transformed nutrient intakes and 95% confidence intervals, adjusted for potential confounders. We investigated associations by tumor subtype, and tested interactions with sex, country of birth, smoking and alcohol drinking. The risk of UCC appeared not to be associated with intake of B-group vitamins or methionine, and findings were consistent across tumor subtypes and across demographic and lifestyle characteristics of the participants. A potential interaction between vitamin B1 and alcohol drinking was observed (all participants: HR per 1 SD = 0.99 (0.91-1.09), never drinkers: HR = 0.81 (0.69-0.97), p-interaction = 0.02), which needs to be confirmed by other studies. Our findings do not indicate that dietary intake of nutrients involved in one-carbon metabolism are associated with UCC risk.

Comparison of Anionic, Cationic and Nonionic Surfactants as Dispersing Agents for Graphene Based on the Fluorescence of Riboflavin

Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate (SDS), and cationic hexadecyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB). The influence of the surfactant type, chain length and concentration, G total concentration and G/surfactant weight ratio on the fluorescence intensity of vitamin B₂ (riboflavin) was investigated. The quality of the different G dispersions was assessed by scanning and transmission electron microscopies (SEM and TEM). A quenching phenomenon of the fluorescence of riboflavin was found for G dispersions in all the surfactants, which generally becomes stronger with increasing G/surfactant weight ratio. For dispersions in the ionic surfactants, the quenching is more pronounced as the surfactant concentration raises, whilst the non-ionic one remains merely unchanged for the different G/Brij L23 weight ratios. More importantly, results indicate that DTAB solutions are the optimum media for dispersing G sheets, leading to an up to 16-fold drop in the fluorescence intensity. Understanding the mechanism in fluorescence quenching of G dispersions in surfactants could be useful for several optical applications.

Novel associations between blood DNA methylation and body mass index in middle-aged and older adults

BACKGROUND/OBJECTIVES

There is increasing evidence of a relationship between blood DNA methylation and body mass index (BMI). We aimed to assess associations of BMI with individual methylation measures (CpGs) through a cross-sectional genome-wide DNA methylation association study and a longitudinal analysis of repeated measurements over time.

SUBJECTS/METHODS

Using the Illumina Infinium HumanMethylation450 BeadChip, DNA methylation measures were determined in baseline peripheral blood samples from 5361 adults recruited to the Melbourne Collaborative Cohort Study (MCCS) and selected for nested case-control studies, 2586 because they were subsequently diagnosed with cancer (cases) and 2775 as controls. For a subset of 1088 controls, these measures were repeated using blood samples collected at wave 2 follow-up, a median of 11 years later; weight was measured at both time points. Associations between BMI and blood DNA methylation were assessed using linear mixed-effects regression models adjusted for batch effects and potential confounders. These were applied to cases and controls separately, with results combined through fixed-effects meta-analysis.

RESULTS

Cross-sectional analysis identified 310 CpGs associated with BMI with P<1.0 × 10^-7, 225 of which had not been reported previously. Of these 225 novel associations, 172 were replicated (P<0.05) using the Atherosclerosis Risk in Communities (ARIC) study. We also replicated using MCCS data (P<0.05) 335 of 392 associations previously reported with P<1.0 × 10^-7, including 60 that had not been replicated before. Associations between change in BMI and change in methylation were observed for 34 of the 310 strongest signals in our cross-sectional analysis, including 7 that had not been replicated using the ARIC study.

CONCLUSIONS

Together, these findings suggest that BMI is associated with blood DNA methylation at a large number of CpGs across the genome, several of which are located in or near genes involved in ATP-binding cassette transportation, tumour necrosis factor signalling, insulin resistance and lipid metabolism.

Phytotherapy and Nutritional Supplements on Breast Cancer

Breast cancer is the most frequent type of nonskin malignancy among women worldwide. In general, conventional cancer treatment options (i.e., surgery, radiotherapy, chemotherapy, biological therapy, and hormone therapy) are not completely effective. Recurrence and other pathologic situations are still an issue in breast cancer patients due to side effects, toxicity of drugs in normal cells, and aggressive behaviour of the tumours. From this point of view, breast cancer therapy and adjuvant methods represent a promising and challenging field for researchers. In the last few years, the use of some types of complementary medicines by women with a history of breast cancer has significantly increased such as phytotherapeutic products and nutritional supplements. Despite this, the use of such approaches in oncologic processes may be problematic and patient's health risks can arise such as interference with the efficacy of standard cancer treatment. The present review gives an overview of the most usual phytotherapeutic products and nutritional supplements with application in breast cancer patients as adjuvant approach. Regardless of the contradictory results of scientific evidence, we demonstrated the need to perform additional investigation, mainly well-designed clinical trials in order to establish correlations and allow for further validated outcomes concerning the efficacy, safety, and clinical evidence-based recommendation of these products.

Dietary Reference Values for riboflavin

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives dietary reference values (DRVs) for riboflavin. The Panel considers that the inflection point in the urinary riboflavin excretion curve in relation to riboflavin intake reflects body saturation and can be used as a biomarker of adequate riboflavin status. The Panel also considers that erythrocyte glutathione reductase activation coefficient is a useful biomarker, but has limitations. For adults, the Panel considers that average requirements (ARs) and population reference intakes (PRIs) can be determined from the weighted mean of riboflavin intake associated with the inflection point in the urinary riboflavin excretion curve reported in four intervention studies. PRIs are derived for adults and children assuming a coefficient of variation of 10%, in the absence of information on the variability in the requirement and to account for the potential effect of physical activity and the methylenetetrahydrofolate reductase 677TT genotype. For adults, the AR and PRI are set at 1.3 and 1.6 mg/day. For infants aged 7-11 months, an adequate intake of 0.4 mg/day is set by upward extrapolation from the riboflavin intake of exclusively breastfed infants aged 0-6 months. For children, ARs are derived by downward extrapolation from the adult AR, applying allometric scaling and growth factors and considering differences in reference body weight. For children of both sexes aged 1-17 years, ARs range between 0.5 and 1.4 mg/day, and PRIs between 0.6 and 1.6 mg/day. For pregnant or lactating women, additional requirements are considered, to account for fetal uptake and riboflavin accretion in the placenta during pregnancy or the losses through breast milk, and PRIs of 1.9 and 2.0 mg/day, respectively, are derived.

Biomarkers of folate and vitamin B12 and breast cancer risk: report from the EPIC cohort

Epidemiological studies have reported inconsistent findings for the association between B vitamins and breast cancer (BC) risk. We investigated the relationship between biomarkers of folate and vitamin B12 and the risk of BC in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Plasma concentrations of folate and vitamin B12 were determined in 2,491 BC cases individually matched to 2,521 controls among women who provided baseline blood samples. Multivariable logistic regression models were used to estimate odds ratios by quartiles of either plasma B vitamin. Subgroup analyses by menopausal status, hormone receptor status of breast tumors (estrogen receptor [ER], progesterone receptor [PR] and human epidermal growth factor receptor 2 [HER2]), alcohol intake and MTHFR polymorphisms (677C > T and 1298A > C) were also performed. Plasma levels of folate and vitamin B12 were not significantly associated with the overall risk of BC or by hormone receptor status. A marginally positive association was found between vitamin B12 status and BC risk in women consuming above the median level of alcohol (ORQ4-Q1  = 1.26; 95% CI 1.00-1.58; Ptrend  = 0.05). Vitamin B12 status was also positively associated with BC risk in women with plasma folate levels below the median value (ORQ4-Q1  = 1.29; 95% CI 1.02-1.62; Ptrend  = 0.03). Overall, folate and vitamin B12 status was not clearly associated with BC risk in this prospective cohort study. However, potential interactions between vitamin B12 and alcohol or folate on the risk of BC deserve further investigation.

Plasma Riboflavin Level is Associated with Risk, Relapse, and Survival of Esophageal Squamous Cell Carcinoma

Riboflavin is an essential micronutrient for normal cellular activity, and deficiency may result in disease, such as cancer. We performed a case-control study to explore the association of riboflavin levels with risk and prognosis of esophageal squamous cell carcinoma (ESCC). Plasma riboflavin levels, as measured by enzyme-linked immunosorbent assay (ELISA), in ESCC patients were significantly lower than in those of healthy controls (7.04 ± 6.34 ng/ml vs. 9.32 ± 12.40 ng/ml; P < 0.05). Moreover, there was an inverse relationship between riboflavin level and risk of ESCC (odds ratio (OR) = 0.97, 95% confidence interval (CI) = 0.95-0.99, P =  0.02). The 5-year relapse-free and overall survival rates were significantly lower when riboflavin levels were ≤0.8 ng/ml than >0.8 ng/ml (relapse-free survival rate: 29.4% vs. 54.8%; overall survival rate: 28.6% vs. 55.6%). Plasma riboflavin level was an independent protective factor for both relapse-free (hazard ratio (HR) = 0.325, 95% CI = 0.161-0.657, P = 0.002) and overall survival of ESCC patients (HR = 0.382, 95% CI = 0.190-0.768, P = 0.007). In conclusion, plasma riboflavin levels are significantly related to risk and prognosis of ESCC patients, suggesting that moderate supplementation of riboflavin will decrease risk and prevent recurrence of ESCC and also improve prognosis of ESCC patients.

Plasma Folate and Vitamin B12 Levels in Patients with Hepatocellular Carcinoma

Folate and vitamin B12 involved in the one-carbon metabolism may play a key role in carcinogenesis and progression of hepatocellular carcinoma (HCC) through influencing DNA integrity. The purpose of this study is to evaluate the association of plasma folate and vitamin B12 levels with HCC in a case-control study on 312 HCC patients and 325 cancer-free controls. Plasma concentrations of folate and vitamin B12 in all the subjects were measured by electrochemiluminescence immunoassay. Meanwhile, the information of HCC patients' clinical characteristics including tumor-node-metastasis (TNM) stage, tumor size and tumor markers were collected. The patients of HCC had significantly lower folate levels than those of controls; there was no significant difference in the mean of plasma vitamin B12 levels. We also observed an inverse association between the levels of plasma folate and HCC: the adjusted odds ratios (OR) (95% confidence intervals (CI)) of HCC from the highest to lowest quartile of folate were 0.30 (0.15-0.60), 0.33 (0.17-0.65), and 0.19 (0.09-0.38). Compared to the subjects in the lowest quartile of plasma vitamin B12, only the subjects in the highest quartile of vitamin B12 exhibited a significant positive relationship with HCC, the adjusted OR was 2.01 (95% CI, 1.02-3.98). HCC patients with Stage III and IV or bigger tumor size had lower folate and higher vitamin B12 levels. There was no significant difference in the mean plasma folate levels of the HCC cases in tumor markers status (AFP, CEA and CA19-9 levels), whereas patients with higher CEA or CA19-9 levels retained significantly more plasma vitamin B12 than those with normal-CEA or CA19-9 level. In conclusion, plasma folate and vitamin B12 levels could be associated with HCC, and might be used as predictors of clinical characteristics of HCC patients. However, further prospective studies are essential to confirm the observed results.

Determination of riboflavin based on fluorescence quenching by graphene dispersions in polyethylene glycol

A quenching phenomenon of riboflavin fluorescence was found in graphene dispersions in PEG ascribed to π–π stacking and H-bonding interactions.

Targeted DNA Methylation Screen in the Mouse Mammary Genome Reveals a Parity-Induced Hypermethylation of Igf1r That Persists Long after Parturition

The most effective natural prevention against breast cancer is an early first full-term pregnancy. Understanding how the protective effect is elicited will inform the development of new prevention strategies. To better understand the role of epigenetics in long-term protection, we investigated parity-induced DNA methylation in the mammary gland. FVB mice were bred or remained nulliparous and mammary glands harvested immediately after involution (early) or 6.5 months following involution (late), allowing identification of both transient and persistent changes. Targeted DNA methylation (109 Mb of Ensemble regulatory features) analysis was performed using the SureSelectXT Mouse Methyl-seq assay and massively parallel sequencing. Two hundred sixty-nine genes were hypermethylated and 128 hypomethylated persistently at both the early and late time points. Pathway analysis of the persistently differentially methylated genes revealed Igf1r to be central to one of the top identified signaling networks, and Igf1r itself was one of the most significantly hypermethylated genes. Hypermethylation of Igf1r in the parous mammary gland was associated with a reduction of Igf1r mRNA expression. These data suggest that the IGF pathway is regulated at multiple levels during pregnancy and that its modification might be critical in the protective role of pregnancy. This supports the approach of lowering IGF action for prevention of breast cancer, a concept that is currently being tested clinically.

Micronutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer Subtypes

Background

Vitamins involved in one-carbon metabolism are hypothesized to influence breast cancer (BC) risk. However, epidemiologic studies that examined associations between B vitamin intake and BC risk have provided inconsistent results. We prospectively examined, in the Italian ORDET cohort, whether B vitamin consumption was associated with risk of BC and BC subtypes.

Methods

After a mean follow-up of 16.5 years, 391 BCs were diagnosed among 10,786 cohort women. B vitamin intakes were estimated from food frequency questionnaires. Cox proportional hazard models adjusted for energy intake and confounders, estimated hazard ratios (HR) with 95% confidence intervals (CIs) for BC according to intake.

Results

RRs were 0.61 (95% CI 0.38–0.97 highest vs. lowest quartile; P trend 0.025) for thiamine; 0.48 (95% CI 0.32–0.71; P trend <0.001) for riboflavin; 0.59 (95% CI 0.39–0.90; P trend 0.008) for vitamin B6, and 0.65 (95% CI 0.44–0.95; P trend 0.021) for folate. As regards risk of BC subtypes, high riboflavin and folate were significantly associated with lower risk of estrogen receptor positive (ER+) and progesterone receptor positive (PR+) cancers, and high thiamine was associated with lower risk of ER-PR- cancers. High riboflavin was associated with lower risk of both HER2+ and HER2- cancers, high folate with lower risk of HER2- disease, and high thiamine with HER2+ disease.

Conclusions

These findings support protective effects of thiamine and one-carbon metabolism vitamins (folate, riboflavin, and vitamin B6) against BC in general; while folate may also protect against ER+PR+ and HER2- disease; and thiamine against ER-PR-, and HER2+ disease.

Lack of effects of dietary folate intake on risk of breast cancer: an updated meta-analysis of prospective studies

BACKGROUND

Epidemiological findings are controversial relating to the relationship between dietary folate intake and the risk of breast cancer. We therefore conducted a meta-analysis of prospective cohort studies to clarify this association.

MATERIALS AND METHODS

PUPMED, EMBASE, and MEDLINE databases were searched for all relevant literature published in English from January 1, 1966 to August 2013. Summary relative risk (RR) and 95% confidence intervals (CIs) were calculated using a fixed or random effects model.

RESULTS

Dietary folate intake was not significantly associated with the risk of breast cancer. The combined PR with 95% CI for the highest vs. lowest category dietary intake of folate [fifteen studies; 1,836,566 participants and 24,083 patients with breast cancer] was 0.98 (0.90-1.05). Among subgroup analysis by menstrual status, hormonal status and the consumption of alcohol, methionine and vitamin B12, no significant association was observed for the dietary intake of folate and the risk of breast cancer. Dose-response analysis showed that a 220 μg/day increment in dietary folate intake was not associated with the risk of breast cancer.

CONCLUSIONS

Our findings indicate that dietary folate intake has no significant effect on the risk of breast cancer.

Paternal intake of folate and vitamins B6 and B12 before conception and risk of childhood acute lymphoblastic leukemia

PURPOSE

We investigated whether paternal dietary intake of folate before conception is associated with the risk of childhood acute lymphoblastic leukemia (ALL) in a nationwide case-control study.

METHODS

Data on dietary folate intake during the 6 months before the child's conception were collected from 285 case fathers and 595 control fathers using a dietary questionnaire. Nutrient intake was quantified using a customized computer software package based on Australian food composition databases. Data on folate intake were analyzed using unconditional logistic regression, adjusting for study-matching variables, total energy, and potentially confounding variables. In a subset of 229 cases and 420 controls, data on vitamin B6 and vitamin B12 intake were also analyzed.

RESULTS

No consistent associations were seen with paternal dietary intake of folate or vitamin B6. Higher levels of paternal dietary vitamin B12 were appeared to be associated with an increased risk of childhood ALL, with those in the highest tertile of consumption having an OR of 1.51 (0.97, 2.36). The use of supplements containing folate and vitamins B6 or B12 was rare.

CONCLUSIONS

We did not find any biologically plausible evidence that paternal nutrition in the period leading up to conception was associated with childhood ALL. Our finding for vitamin B12 may be a chance finding, given the number of analyses performed, or be attributable to participation bias because parents with a tertiary education had the lowest level of B12 intake and tertiary education was more common among control than case parents.

Alcohol and risk of breast cancer in postmenopausal women: an analysis of etiological heterogeneity by multiple tumor characteristics

Alcohol consumption is an established risk factor for breast cancer. Whether associations vary by specific tumor characteristics independent of other characteristics is unclear. We evaluated the association between alcohol consumption and breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort (54,562 women aged 55-74 years recruited at 10 US screening centers between 1993 and 2001; median follow-up, 8.9 years; 1,905 invasive breast cancer cases). Hazard ratios and 95% confidence intervals for subtypes defined by histological type and estrogen receptor (ER)/progesterone receptor (PR) status were calculated with standard Cox models. A novel 2-stage Cox model assessed heterogeneity in risk for individual tumor characteristics while adjusting for others. Significant trends across categories of alcohol consumption were observed, with hazard ratios for those consuming 7 or more drinks per week versus never drinkers as follows: for estrogen receptor-positive (ER+) cancer, 1.48 (95% confidence interval (CI): 1.19, 1.83); for progesterone receptor-positive (PR+) cancer, 1.64 (95% CI: 1.31, 2.06); for ER+/PR+ cancer, 1.63 (95% CI: 1.30, 2.05); and for mixed ductal/lobular cancer, 2.51 (95% CI: 1.20, 5.24). For ER+ and PR+ cancers, trends were significant for ductal and mixed ductal/lobular types. PR status explained the positive association with ER status (for ER status, Pheterogeneity=0.70 after adjustment for PR status). Alcohol consumption was not associated with all breast cancer subtypes. Future work should emphasize large collaborative studies, precise definition of subtypes, and adjustment for correlated tumor characteristics.

Epigenetic reprogramming in breast cancer: from new targets to new therapies

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer death among women in the United States. Recently, interest has grown in the role of epigenetics in breast cancer development and progression. Epigenetic changes such as DNA methylation, histone modifications, and abnormal expression of non-coding RNAs emerged as novel biomarkers in breast cancer diagnosis, therapy, and prevention. This review focuses on the most recent mechanistic findings underlying epigenetic changes in breast cancer development and their role as predictors of breast cancer risk. The rapid progress in our understanding of epigenetic findings in breast cancer has opened new avenues for potential therapeutic approaches via identification of epigenetic targets. We highlight the development of novel epigenetically targeted drugs, relevant clinical trials in breast cancer patients, and recent approaches combining epigenetic agents with chemotherapy and/or endocrine therapy that may incrementally improve long-term outcomes in appropriately selected breast cancer patients. Biomarkers of response are needed, however, to identify patient subsets that are most likely to benefit from epigenetic treatment strategies.

Modification in the diet can induce beneficial effects against breast cancer

The population tends to consume foods that in addition to their nutritional values can offer some benefits to their health. There are many epidemiological evidences and research studies in animal models suggesting that diet plays an important role in breast cancer prevention or progression. This review summarized some of the relevant researches about nutrition and cancer during the last years, especially in breast cancer. The analysis of probiotics and fermented products containing lactic acid bacteria in cancer prevention and/or treatment was especially discussed. It was observed that a balance of fatty acids similar to those of traditional Mediterranean diet, the consumption of fruits and vegetables, dietary fiber intake, vitamin supplementation are, along with the intake of probiotic products, the most extensively studied by the negative association to breast cancer risk. The consumption of probiotics and fermented products containing lactic acid bacteria was associated to reduce breast cancer risk in some epidemiological studies. The use of animal models showed the modulation of the host’s immune response as one of the important effects associated to the benefices observed with most probiotics. However; future assays in human are very important before the medical community can accept the addition of probiotic or fermented milks containing lactic acid bacteria as supplements for cancer patients.

Folate intake and the risk of breast cancer: a dose-response meta-analysis of prospective studies

BACKGROUND

Previous observational studies regarding the existence of an association between folate intake and the risk of breast cancer have been inconsistent. This study aimed to summarize the evidence regarding this relationship using a dose-response meta-analytic approach.

METHODOLOGY AND PRINCIPAL FINDINGS

We performed electronic searches of the PubMed, EmBase, and Cochrane Library databases to identify studies published through June 2013. Only prospective observational studies that reported breast cancer effect estimates with 95% confidence intervals (CIs) for more than 2 folate intake categories were included. We excluded traditional case-control studies because of possible bias from various confounding factors. Overall, we included 14 prospective studies that reported data on 677,858 individuals. Folate intake had little effect on the breast cancer risk (relative risk (RR) for highest versus lowest category = 0.97; 95% CI, 0.90-1.05; P = 0.451). Dose-response meta-analysis also suggested that a 100 µg/day increase in folate intake had no significant effect on the risk of breast cancer (RR = 0.99; 95% CI, 0.98-1.01; P = 0.361). Furthermore, we used restricted cubic splines to evaluate the nonlinear relationship between folate intake and the risk of breast cancer, and discovered a potential J-shaped correlation between folate intake and breast cancer risk (P = 0.007) and revealed that a daily folate intake of 200-320 µg was associated with a lower breast cancer risk; however, the breast cancer risk increased significantly with a daily folate intake >400 µg.

CONCLUSION/SIGNIFICANCE

Our study revealed that folate intake had little or no effect on the risk of breast cancer; moreover, a dose-response meta-analysis suggested a J-shaped association between folate intake and breast cancer.

Folate intake and the risk of breast cancer: a systematic review and meta-analysis

There is conflicting epidemiological evidence on the role of folate and breast cancer risk. We conducted a systematic review and quantitative meta-analysis of folate intake and folate blood levels and the risk of breast cancer. Four electronic databases (Medline, PubMed, Embase, and Current Contents Connect) were searched to April 11, 2014, with no language restrictions for observational studies that measured folate intake or blood levels and the risk of breast cancer. The meta-analysis of dietary folate intake comprising 36 studies with 34,602 cases, and a total sample size of 608,265 showed a decreased risk of breast cancer, with an odds ratio (OR) of 0.84 [95 % confidence interval (CI) 0.77-0.91]. When stratified by menopausal status and by study design, none of the meta-analyses of prospective studies showed any statistically significant decrease in the risk of breast cancer. The meta-analysis of total folate showed no statistically significant association with breast cancer OR of 0.98 (95 % CI 0.91-1.07). There was no significant association between either dietary or total folate intake and breast cancer when stratified by hormonal receptor status. The meta-analysis of blood folate levels found no significant association with the risk of breast cancer, with an OR of 0.86 (95 % CI 0.60-1.25). Breast cancer does not appear to be associated with folate intake, and this did not vary by menopausal status or hormonal receptor status. Folate blood levels also do not appear to be associated with breast cancer risk.

Higher dietary folate intake reduces the breast cancer risk: a systematic review and meta-analysis

Background:

Many epidemiological studies have investigated the association between folate intake, circulating folate level and risk of breast cancer; however, the findings were inconsistent between the studies.

Methods:

We searched the PubMed and MEDLINE databases updated to January, 2014 and performed the systematic review and meta-analysis of the published epidemiological studies to assess the associations between folate intake level, circulating folate level and the overall risk of breast cancer.

Results:

In all, 16 eligible prospective studies with a total of 744 068 participants and 26 205 breast cancer patients and 26 case–control studies with a total of 16 826 cases and 21 820 controls that have evaluated the association between folate intake and breast cancer risk were identified. Pooled analysis of the prospective studies and case–control studies suggested a potential nonlinearity relationship for dietary folate intake and breast cancer risk. Prospective studies indicated a U-shaped relationship for the dietary folate intake and breast cancer risk. Women with daily dietary folate intake between 153 and 400 μg showed a significant reduced breast cancer risk compared with those <153 μg, but not for those >400 μg. The case–control studies also suggested a significantly negative correlation between the dietary folate intake level and the breast cancer risk. Increased dietary folate intake reduced breast cancer risk for women with higher alcohol intake level, but not for those with lower alcohol intake. No significant association between circulating folate level and breast cancer risk was found when the results of 8 identified studies with 5924 participants were pooled.

Conclusions:

Our studies suggested that folate may have preventive effects against breast cancer risk, especially for those with higher alcohol consumption level; however, the dose and timing are critical and more studies are warranted to further elucidate the questions.

Association of vitamin B6, vitamin B12 and methionine with risk of breast cancer: a dose-response meta-analysis

Background:

Epidemiological studies evaluating the association of vitamin B₆, vitamin B₁₂ and methionine with breast cancer risk have produced inconsistent results.

Methods:

Pertinent studies were identified by a search in PubMed and Web of Knowledge. Random-effect model was used. Dose–response relationship was assessed by restricted cubic spline.

Results:

The combined relative risk (95% confidence interval) of breast cancer for the highest vs lowest category of serum pyridoxal 5′-phosphate (PLP, active form of vitamin B₆) levels and dietary methionine intake was 0.80 (0.66–0.98, P=0.03) and 0.94 (0.89–0.99, P=0.03), respectively, and the associations of breast cancer with higher serum PLP levels and dietary methionine intake were significant among post-menopausal women, but not among pre-menopausal women. The inverse association between breast cancer risk and dietary vitamin B₆ intake, serum vitamin B₁₂ levels and dietary vitamin B₁₂ intake was not significant overall. Linear dose–response relationship was found, and the risk of breast cancer decreased by 23% (P<0.00) for every 100 pmol ml⁻¹ increment in PLP levels and 4% (P=0.05) for every 1 g per day increment in dietary methionine intake, respectively.

Conclusion:

Serum PLP levels and methionine intake might be inversely associated with breast cancer risk, especially among postmenopausal women, which need to be confirmed.