Assessing the Association between Natural Food Folate Intake and Blood Folate Concentrations: A Systematic Review and Bayesian Meta-Analysis of Trials and Observational Studies

Folate is found naturally in foods or as synthetic folic acid in dietary supplements and fortified foods. Adequate periconceptional folic acid intake can prevent neural tube defects. Folate intake impacts blood folate concentration; however, the dose-response between natural food folate and blood folate concentrations has not been well described. We estimated this association among healthy females. A systematic literature review identified studies (1 1992–3 2014) with both natural food folate intake alone and blood folate concentration among females aged 12–49 years. Bayesian methods were used to estimate regression model parameters describing the association between natural food folate intake and subsequent blood folate concentration. Seven controlled trials and 29 observational studies met the inclusion criteria. For the six studies using microbiologic assay (MA) included in the meta-analysis, we estimate that a 6% (95% Credible Interval (CrI): 4%, 9%) increase in red blood cell (RBC) folate concentration and a 7% (95% CrI: 1%, 12%) increase in serum/plasma folate concentration can occur for every 10% increase in natural food folate intake. Using modeled results, we estimate that a natural food folate intake of ≥450 μg dietary folate equivalents (DFE)/day could achieve the lower bound of an RBC folate concentration (~1050 nmol/L) associated with the lowest risk of a neural tube defect. Natural food folate intake affects blood folate concentration and adequate intakes could help women achieve a RBC folate concentration associated with a risk of 6 neural tube defects/10,000 live births.     

Folate intakes and folate biomarker profiles of pregnant Japanese women in the first trimester

OBJECTIVE: To assess the status of dietary folate intake, serum and red blood cell (RBC) folate, and related nutritional biomarkers in healthy Japanese women in early pregnancy. DESIGN: A cross-sectional, observational study. SUBJECTS: Pregnant women in the first trimester, at 7-15 weeks gestation (n=70), who were not consuming any folate supplements or folate fortified foods. METHODS: Three-day dietary records were obtained from each subject to assess dietary folate intake. Blood samples were collected for measurement of biomarkers. Biomarkers and nutrient intake were analyzed in two groups defined by their serum folate concentrations: the low folate group (serum folate < 9 ng/ml) and the high folate group (serum folate > or = 9 ng/ml). RESULT: Mean serum and RBC folate concentrations in all subjects were 10.3 and 519 ng/ml, respectively. These levels were remarkably higher than the reported values from many other countries despite our subjects receiving no folic acids supplements. However, mean folate intake by our subjects from natural foods was 289 microg/day, which is thought to be low according to the Japanese dietary recommendation specified for pregnant women. The intake of spinach and fruits was significantly greater in the high folate group than in the low folate group. CONCLUSION: Folate intake was thought to be adequate to maintain a desirable level of serum folate concentration in Japanese pregnant women in the first trimester, although the intake of folate from natural food was not high enough to meet the recommended daily intake.     

Reduced Kidney Function Is Associated with Increasing Red Blood Cell Folate Concentration and Changes in Folate Form Distributions (NHANES 2011–2018)

Background: Current studies examining the effects of high concentrations of red blood cell (RBC) or serum folates assume that high folate concentrations are an indicator of high folic acid intakes, often ignoring the contributions of other homeostatic and biological processes, such as kidney function. Objective: The current study examined the relative contributions of declining kidney function, as measured by the risk of chronic kidney disease (CKD), and usual total folic acid intake on the concentrations of RBC folate and serum folate (total as well as individual folate forms). Design: Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) collected in 2-year cycles were combined from 2011 to 2018. A total of 18,127 participants aged ≥16 years with available folate measures, kidney biomarker data (operationalized as a categorical CKD risk variable describing the risk of progression), and reliable dietary recall data were analyzed. Results: RBC folate concentrations increased as CKD risk increased: low risk, 1089 (95% CI: 1069, 1110) nmol/L; moderate risk, 1189 (95% CI: 1158, 1220) nmol/L; high risk, 1488 (95% CI: 1419, 1561) nmol/L; and highest risk, 1443 (95% CI: 1302, 1598) nmol/L (p < 0.0001). Similarly, serum total folate concentrations increased as CKD risk increased: low risk: 37.1 (95% CI: 26.3, 38.0) nmol/L; moderate risk: 40.2 (95% CI: 38.8, 41.7) nmol/L; high risk: 48.0 (95% CI: 44.3, 52.1) nmol/L; the highest Risk: 42.8 (95% CI: 37.8, 48.4) nmol/L (p < 0.0001). The modeled usual intake of folic acid showed no difference among CKD risk groups, with a population median of 225 (interquartile range: 108–390) µg/day. Conclusion: Both RBC and serum folate concentrations increased with declining kidney function without increased folic acid intake. When analyzing associations between folate concentrations and disease outcomes, researchers may want to consider the confounding role of kidney function.     

Dietary Intake of Folate and Assessment of the Folate Deficiency Prevalence in Slovenia Using Serum Biomarkers

Folate deficiency is associated with various health issues, including anemia, cardiovascular disease, and birth defects. Low folate intake and suboptimal folate status were found in several countries; however, this topic has not yet been investigated in Slovenia. Dietary folate intake and serum folate status were investigated through the nationally representative food consumption study SI.Menu/Nutrihealth. Folate intake was estimated using a sample of N = 1248 subjects aged 10–74 years, stratified in three age groups (adolescents, adults, elderly population), through two 24 h-dietary recalls and food propensity questionnaire. Data on serum folate and homocysteine was available for 280 participants. Very low folate intake (<300 µg/day) was observed in 59% of adolescents, 58% of adults and 68% of elderlies, and only about 12% achieved the WHO recommended level of 400 µg/day. Major dietary contributors were vegetables and fruit, and cereal products. Living environment, education, employment status and BMI were linked with low folate intake in adults; BMI, and sex in adolescents; and sex in elderlies. Considering low serum folate (<7 nmol/L) and high serum homocysteine (>15 nmol/L), folate deficiency was found in 7.6 and 10.5% in adults and elderlies, respectively. Additional public health strategies should be employed to promote the consumption of folate-rich foods. With current folate intakes, supplementation with folic acid is relevant especially in specific vulnerable populations, particularly in women planning and during pregnancy.     

Associations of Serum Folate and Holotranscobalamin with Cardiometabolic Risk Factors in Rural and Urban Cameroon

A low intake of fruit and vegetables and a high intake of meat are associated with higher cardiometabolic disease risk; however much prior research has relied on subjective methods for dietary assessment and focused on Western populations. We aimed to investigate the association of blood folate as an objective marker of fruit and vegetable intake and holotranscobalamin (holoTC) as a marker of animal-sourced food intake with cardiometabolic risk factors. We conducted a population-based cross-sectional study on 578 adults (mean ± SD age = 38.2 ± 8.6 years; 64% women). The primary outcome was a continuous metabolic syndrome score. The median serum folate was 12.9 (IQR: 8.6–20.5) nmol/L and the mean holoTC was 75 (SD: 34.3) pmol/L. Rural residents demonstrated higher serum folate concentrations (15.9 (9.8–25.9) nmol/L) than urban residents (11.3 (7.9–15.8) nmol/L), but lower holoTC concentrations (rural: 69.8 (32.9) pmol/L; urban: 79.8 (34.9)) pmol/L, p < 0.001 for both comparisons. There was an inverse association between serum folate and metabolic syndrome score by −0.20 in the z-score (95% CI, −0.38 to −0.02) per 10.8 (1 SD) of folate) in a model adjusted for socio-demographic factors, smoking status, alcohol intake, BMI, and physical activity. HoloTC was positively associated with the metabolic syndrome score in unadjusted analysis (0.33 (95% CI, 0.10 to 0.56)) but became non-significant (0.17 (−0.05 to 0.39)) after adjusting for socio-demographic and behavioural characteristics. In conclusion, serum folate and holoTC were associated with the metabolic syndrome score in opposite directions. The positive association between serum holoTC and the metabolic syndrome score was partly dependent on sociodemographic characteristics. These findings suggest that, based on these biomarkers reflecting dietary intakes, public health approaches promoting a higher intake of fruit and vegetables may lower cardiometabolic risk factors in this population.     

Relationship between dietary folate intakes,maternal plasma total homocysteine and B-vitamins during pregnancy and fetal growth in Japan

Background Adequate folate status in pregnancy is important for satisfactory pregnancy outcome. Aim of the Study The objective of the present study was to evaluate folate status in healthy pregnant women by assessing dietary folate intakes and measuring changes in folate-related biomarkers including plasma tHcy, serum vitamin B₁₂ (B₁₂), and serum and RBC folate concentrations in each trimester and to examine their relation to fetal growth. Methods From 94 pregnant women, 3-day-dietary records were obtained and blood was collected for plasma total homocysteine (tHcy), serum B₁₂, and serum and red-blood cell (RBC) folate measurements. Infant anthropometric measurements were made immediately after birth. Results Average folate intake was less than 300 μg/day with a mean energy intake of about 1800 kcal. Mean serum and RBC folate concentrations declined significantly during gestation (p < 0.05). Mean serum B₁₂ also significantly decreased (p < 0.01), whereas plasma tHcy increased from 5.1 in the first trimester to 5.9 μmol/l in the third trimester (p < 0.01). Multiple regression analyses, after controlling for maternal age, parity and pre-pregnancy body-mass index indicated that a 1.0 μmol/l increase in plasma tHcy in the third trimester corresponded to a 151 g decrease in birth weight (p < 0.01). Neither B₁₂ nor folate concentrations in all three trimesters showed any significant associations with birthweight. Plasma pyridoxal-5′-phosphate concentrations were markedly low, and were consistent with low intake of vitamin B₆ in our population. Conclusion Our data suggest that higher plasma tHcy in the third trimester is a predictor of lower birth weight. In general, the dietary intake of B-vitamins and energy may be inadequate in our population, suggesting intervention is necessary.     

Supplement use is associated with health status and health-related behaviors in the 1946 British birth cohort

Use of dietary supplements may be one of a number of health-related behaviors that cluster together. The current study investigated the underlying diet, health-related characteristics, and behaviors of users and nonusers of dietary supplements in a longitudinal study of health. Participants (n = 1776) completed a 5-d food diary including information on dietary supplement use (vitamins, minerals, and nutraceuticals) at age 53 y. Sociodemographic information and data on smoking, alcohol, and physical activity were obtained along with anthropometric measurements, blood pressure, and a blood sample (nonfasting subjects). A significantly greater percentage of women reported supplement use compared with men (45.1 vs. 25.2%). Supplement use was associated with lower BMI, lower waist circumference, higher plasma folate and plasma vitamin B-12 concentrations, nonsmoking, participation in physical activity, and nonmanual social class in women and with plasma folate concentrations and participation in physical activity in men. Nonsupplement users tended to be nonconsumers of breakfast cereals, fruit, fruit juice, yogurt, oily fish, and olive oil and had lower dietary intakes of potassium, magnesium, phosphorus, iron, and vitamin C even after adjustment for sociodemographic and behavioral factors. Overall, supplement users tended to differ from nonsupplement users on a range of health-related behaviors and health status indicators, although there were fewer significant associations in men. Similarly, dietary supplements users tended to have underlying diets that, were healthier and those taking supplements may be the least likely to need them. These results support the notion of a clustering of healthy behaviors and cardiovascular risk factors, particularly for women.     

Folate and Nutrients Involved in the 1-Carbon Cycle in the Pretreatment of Patients for Colorectal Cancer

To assess the ingestion of folate and nutrients involved in the 1-carbon cycle in non-treated patients with colorectal adenocarcinoma in a reference center for oncology in southeastern Brazil. In total, 195 new cases with colorectal adenocarcinoma completed a clinical evaluation questionnaire and a Food Frequency Questionnaire (FFQ). Blood samples from 161 patients were drawn for the assessment of serum folate. A moderate correlation was found between serum concentrations of folate, folate intake and the dietary folate equivalent (DFE) of synthetic supplements. Mulatto or black male patients with a primary educational level had a higher intake of dietary folate. Of patients obtaining folate from the diet alone or from dietary supplements, 11.00% and 0.10%, respectively, had intake below the recommended level. Of the patients using dietary supplements, 35% to 50% showed high levels of folic acid intake. There was a prevalence of inadequacy for vitamins B2, B6 and B12, ranging from 12.10% to 20.18%, while 13.76% to 22.55% of patients were likely to have adequate choline intake. The considerable percentage of patients with folate intake above the recommended levels deserves attention because of the harmful effects that this nutrient may have in the presence of established neoplastic lesions.     

Folate status of adults living in the Canary Islands (Spain)

BACKGROUND AND AIM: Human studies support the hypothesized contribution of folate deficiency to carcinogenesis and vascular risk. We assess the nutritional folate status and its relationship to folate intake, smoking, alcohol consumption, oral contraceptive use, and multivitamin supplements. METHODOLOGY: A representative sample of 601 individuals from 18 to 75 years of age was selected from the participants in the Canary Islands Nutrition Survey. A food frequency questionnaire was administered. Serum and erythrocyte levels of folate were determined using a method of automated ionic capturing. RESULTS: Mean serum and red cell folate were 8.2 ng/mL and 214.3 ng/mL, respectively. Only one individual had serum folate below 3 ng/mL, and 21.7% showed moderate deficits (3-6 ng/mL); 10.7% of the sample had erythrocyte folate levels falling below 140 ng/mL, 61.3% between 140 and 240 ng/mL and the remaining 27.9% above 240 ng/mL. A positive significant association was observed between these two folate measurements, as well as between folate intake and each of these biomarkers (p < 0.001). Tobacco consumption was negatively correlated with folate status (p < 0.001). Alcohol consumption, oral contraceptive, and vitamin supplement use were not associated with serum and red cell folate levels. CONCLUSIONS: Even though nutritional folate status can be considered minimally acceptable, it may reflect the low level of fruit and vegetable consumption within the Canary Islands population.     

The Association between Non-Alcoholic Fatty Liver Disease (NAFLD) and Advanced Fibrosis with Serological Vitamin B12 Markers: Results from the NHANES 1999–2004

Background: There is evidence that vitamin B12 and associated metabolite levels are changed in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH); however, their association has been in dispute. Methods: We included 8397 individuals without previous liver condition or excess alcohol intake from the National Health and Nutrition Examination Survey (NHANES) 1999–2004. NAFLD was diagnosed with Fatty Liver Index (FLI) ≥ 60 or USFLI ≥ 30, and participants with advanced fibrosis risks were identified with elevated non-alcoholic fatty liver disease fibrosis score (NFS), fibrosis 4 index (FIB-4), or aspartate aminotransferase (AST)/platelet ratio index (APRI). Step-wide logistic regression adjusting for confounders was used to detect the association between NAFLD or advanced fibrosis with serum vitamin B12, folate, red blood cell folate (RBC folate), homocysteine (HCY), and methylmalonic acid (MMA). Results: The weighted prevalence of NAFLD was 44.2%. Compared with non-NAFLD participants, patients with NAFLD showed significantly increased RBC folate level and RBC counts, decreased serum vitamin B12 and folate, and similar HCY and MMA levels. NAFLD with advanced fibrosis risk had higher MMA and HCY, reduced serum vitamin B12, and similar serum folate and RBC folate levels than NAFLD with low fibrosis risk. Only RBC folate was independently associated with an increased risk of NAFLD (OR (95% CI): 2.24 (1.58, 3.18)). In all participants, MMA (OR: 1.41 (1.10, 1.80)) and HCY (OR: 2.76 (1.49, 5.11)) were independently associated with increased risk for advanced fibrosis. In participants with NAFLD, this independent association still existed (OR: 1.39 (1.04, 1.85) for MMA and 1.95 (1.09, 3.46) for HCY). In all participants, the area under the receiver operating characteristic curve (ROC AUC) on fibrosis was 0.6829 (0.6828, 0.6831) for MMA and 0.7319 (0.7318, 0.7320) for HCY; in participants with NAFLD, the corresponding ROC AUC was 0.6819 (0.6817, 0.6821) for MMA and 0.6926 (0.6925, 0.6928) for HCY. Conclusion: Among vitamin B12-associated biomarkers, RBC folate was independently associated with elevated NAFLD risk, whereas MMA and HCY were associated with increased risk for advanced fibrosis in the total population and NAFLD participants. Our study highlighted the clinical diagnostic value of vitamin B12 metabolites and the possibility that vitamin B12 metabolism could be a therapeutic target for NASH. Further studies using recent perspective data with biopsy proven NASH could be conducted to validate our results.     

Evaluation of folate status by serum and erythrocyte folate levels and dietary folate intake in Taiwanese schoolchildren

The folate status and dietary folate intake of Taiwanese schoolchildren was investigated by analysis of both serum and red blood cell (RBC) folate levels and dietary folate intake in 1105 boys and 958 girls aged 6-13 years sampled from the Nutrition and Health Survey in Taiwan Elementary School Children 2001-2002 (NAHSIT Children 2001-2002). Mean serum folate levels were 18.3+/-8.8 nmol/L (8.1+/-3.9 ng/mL) in boys and 20.3+/-9.7 nmol/L (9.0+/-4.3 ng/mL) in girls. Mean RBC folate levels were 700+/-320 nmol/L (308+/-141 ng/mL) in boys and 751+/-347 nmol/L (331+/-153 ng/mL) in girls. The prevalence of serum folate deficiency was 1.4% in boys and girls, and the prevalence of marginal serum folate deficiency (7-14 nmol/L) was 31.1% in boys and 25.8% in girls. In addition, 8.5% of boys and 7.4% girls had RBC folate deficiency (RBC folate < 318 nmol/L), and 17% of children had marginal RBC folate deficiency (RBC folate of 318-454 nmol/L). Our results suggesting that Taiwanese schoolchildren have poor folate status especially during periods of rapid growth and development such as the transition from childhood to early adolescence (boys at age 12-12.9, girls at age 11-12.9). The average estimated folate intakes were 269+/-9 microg/d in boys and 259+/-9 microg/d in girls, and 42% of Taiwanese schoolchildren had a dietary folate intake below 2/3 of the RDA, indicating a poor dietary folate intake in this population. This study shows that the folate status of Taiwanese schoolchildren is currently inadequate and strategies are needed for improvement.     

Sex-specific relationships between alcohol consumption and vitamin D levels: The Korea National Health and Nutrition Examination Survey 2009

This study assessed the association between vitamin D sufficiency (serum 25(OH)D ≥30 ng/mL) and alcohol consumption using data from the Korea National Health and Nutrition Examination Survey conducted in 2009. The following characteristics were obtained in 7,010 Korean participants ≥19-years-of-age: serum 25(OH)D level, alcohol consumption (drinking frequency, drinking number of alcoholic beverages on a typical occasion, average daily-alcohol intake), and potential confounders (age, residence, housing status, occupation, total fat and lean mass, smoking, physical activity, history of liver diseases, liver function, and daily intake of energy, protein, and calcium). After adjusting for confounders, vitamin D sufficiency in men was significantly associated with drinking frequency, number of alcoholic drinks consumed, and average daily alcohol intake; odds ratio of 1.21-1.72, 2.17-3.04, and 2.27-3.09, respectively. Increase in the three alcohol drinking-related behaviors was also linearly associated with increase in serum 25(OH)D level in men. By comparison, there was no significant association between alcohol intake and serum 25(OH)D level in women. The positive association between vitamin D sufficiency and alcohol consumption was evident only in Korean men.     

Folate intake estimated with an updated database and its association to blood folate and homocysteine in Korean college students

OBJECTIVE: To measure folate content in cooked foods commonly consumed in Korea for evaluating its relation to folate nutriture of college students. DESIGN: Folate content in 32 raw and cooked foods was measured by microbiological assay after trienzyme extraction. These values and the previously published values of 110 raw foods commonly consumed in Korea were used to update the currently available food tables to estimate dietary folate intake of 106 students based on a 3-day 24-h recall. The association of folate intake with blood folate and homocysteine concentrations was evaluated. SETTING: Cheongju, Korea. SUBJECTS: Healthy college students aged 18 to 27 y old (44 males and 62 females). RESULTS: The average folate loss in 32 foods caused by cooking was 29%. The mean daily dietary folate intakes estimated with an updated database were 406 and 305 mug in males and females, respectively. About 10% of both male and female students showed low serum folate (<6.8 nmol/l). Folate intake was positively correlated with serum and erythrocyte folate concentrations in female students (r=0.27 and 0.29, respectively, P<0.05), and negatively correlated with serum homocysteine in male students (r=-0.41, P<0.05). CONCLUSIONS: Mean dietary folate intake was higher than those of previous studies since the database was updated using values obtained with trienzyme extraction. Folate intake for the general population should be re-evaluated using reliable food folate values obtained with trienzyme extraction.     

Elevated maternal serum folate in the third trimester and reduced fetal growth: a longitudinal study

This study aimed to examine the association of fetal growth and elevated third trimester maternal serum folate due to folic acid (FA) supplement intake. Dietary intake, use of FA supplements, weight, and blood biomarkers of B-vitamins (serum folate, pyridoxal, vitamin B(12), and plasma total homocysteine) were observed in 33 healthy pregnant women at the third trimester (average gestational age 35 wk). Birth outcomes were assessed through hospital birth records. Infant anthropometry and maternal blood biomarkers were followed up at 1 mo postpartum. Fourteen women were taking FA supplements at the third trimester. Dietary intake was similar among FA users and non-users, but serum folate and pyridoxal were significantly higher in users (11.6±6.7 vs. 6.1±3.2 ng/mL, and 13.8±21.7 vs. 3.2±1.4 ng/mL, respectively). Plasma total homocystein (tHcy) was higher in non-users compared to users, but not significantly. Nine FA users and eight non-users had low serum vitamin B(12) values (<203 pg/mL). Nine FA users and all non-users had low serum pyridoxal values (<7.0 ng/mL). Infant birthweight was significantly lower in users compared to non-users (2,894±318 vs. 3,154±230 g). At 1 mo postpartum, infant weight and length were similar between FA users and non-users, but infant weight gain was larger in users. Higher serum folate values due to FA use in the third trimester was related to reduced fetal size. Excess FA under low vitamin B(6) and B(12) status may affect fetal growth.     

Serum homocysteine concentration as a marker of nutritional status of healthy subjects in Crete, Greece

BACKGROUND: Dietary habits are an important determinant of serum homocysteine (tHcy), which may be a marker rather than a cause of progression of the atherosclerotic process. The aim of the present study was to evaluate the nutritional status, and to determine the serum tHcy concentrations in healthy subjects who live in rural areas of Crete, and who theoretically follow a contemporary Mediterranean-style diet. METHODS: Serum tHcy, folate, vitamin B(12), creatinine, glucose, and the lipid profile, were measured in 203 (141 men and 62 women) healthy subjects, aged 33-78 years. The major risk factors for cardiovascular disease such as age, gender, cigarette smoking, obesity were recorded and dietary data were assessed using a 3-day weighed food intake record. RESULTS: Our population had high serum tHcy, low serum folate concentrations and lower than the traditional Cretan dietary folate intake [median (range): 12.0 (3.6-44.7) micromol L(-1), 7.9 (1.9-15.5) ng mL(-1) and 241 (68-1106) microg, respectively]. Dietary intake of fibre, omega-3, and mono- or/ polyunsaturated fatty acids was also low. An inverse relation was observed between serum tHcy concentrations and serum folate (r = -0.28; P < 0.01) and vitamin B(12) levels (r = -0.33; P < 0.001). CONCLUSIONS: Nowadays, the Cretan diet has changed towards a more westernized eating pattern. Given the analytic difficulties in determining the amount of folate in food and the inverse correlation between serum tHcy and folate levels, serum tHcy concentrations may be a useful marker for nutritional status, especially folate deficiency, in healthy subjects.     

Biological Variability and Impact of Oral Contraceptives on Vitamins B6, B12 and Folate Status in Women of Reproductive Age

Vitamins B₆, B₁₂ and folate play crucial metabolic roles especially during the reproductive years for women. There is limited reporting of within-subject variability of these vitamins. This study aimed to determine the within and between subject variability in serum vitamins B₆, B₁₂, folate and erythrocyte folate concentrations in young women; identify factors that contribute to variability; and determine dietary intakes and sources of these vitamins. Data were obtained from the control group of a trial aimed at investigating the effect of iron on the nutritional status of young women (age 25.2 ± 4.2 year; BMI 21.9 ± 2.2 kg/m²). The coefficients of variability within-subject (CV_I) and between-subject (CV_G) for serum vitamins B₆, B₁₂ and folate, and erythrocyte folate were calculated. Food frequency questionnaires provided dietary data. CV_I and CV_G were in the range 16.1%–25.7% and 31.7%–62.2%, respectively. Oral contraceptive pill (OCP) use was associated (P = 0.042) with lower serum vitamin B₁₂ concentrations. Initial values were 172 ± 16 pmol/L and 318 ± 51 pmol/L for OCP and non-OCP users, respectively; with differences maintained at four time points over 12 weeks. BMI, age, physical activity, alcohol intake and haematological variables did not affect serum or erythrocyte vitamin concentrations. Vitamin B₁₂ intakes were derived from traditional and unexpected sources including commercial energy drinks. Young women using OCP had significantly lower serum vitamin B₁₂ concentrations. This should be considered in clinical decision making and requires further investigation.     

中学生饮酒行为与危害健康行为相互影响的研究

为探讨中学生饮酒行为与其他危害健康行为以及情绪问题的相互关系 ,作者对1 358名中学男生和 1 1 0 9名女生饮酒行为、焦虑和抑郁症状、其他危害健康行为进行无记名问卷调查。结果显示 ,男生饮酒率显著高于女生 ,非条件Logistic回归分析表明 ,吸烟、不健康的减肥行为、焦虑、经常骑车带人、打架、年级高为男生饮酒显著性影响因素 ;不良的减肥行为、打架、焦虑和自杀念头与女生饮酒关联。提示中学男、女生饮酒行为与情绪问题以及其他危害健康行为可能相互影响     

Covariation of cigarette smoking and other health-risk behaviors among Japanese high school students: a preliminary study

This study aims to determine if cigarette smoking is associated with engaging in other health-risk behaviors among high school students in Japan. Self-administered anonymous questionnaires were conducted in 1999 using a sample of 1,466 students (male: 50.5%, female: 49.5%) in grades 10 through 12 at seven public senior high schools in urban areas of Okinawa, Japan. Health-risk behaviors studiedal included cigarette smoking, alcohol drinking, thinner use, sexual intercourse, suicidal ideation, nonuse of seat belts, physical inactivity, and weight loss practices. In the logistic regression models, controlled for sociodemographic variables, smoking was significantly associated with all health-risk behaviors except physical inactivity. In particular, associations of alcohol drinking and sexual intercourse with smoking were strong. Among male students, statistically significant odds ratios existed for alcohol drinking, sexual intercourse, and nonuse of seat belts. Among female students, all of the odds ratios for health-risk behaviors were statistically significant, except for physical inactivity. Generally, the odds ratios of female students were higher than those of male students. In conclusion, high school students who smoked cigarettes in this study may be at higher risk for engaging in other health-risk behaviors. Particularly, alcohol drinking and sexual intercourse are more likely to co-occur with smoking. These findings suggest that smoking prevention programs should be integrated with other health-risk behaviors.     

Association of folate intake and serum homocysteine in elderly persons according to vitamin supplementation and alcohol use

BACKGROUND: The serum total homocysteine concentration (tHcy), an indicator of folate status and a possible risk factor for vascular disease, is elevated with impaired renal function and poor vitamin B-12 status, which are common in the elderly. OBJECTIVE: Our objective was to determine the association between tHcy, folate intake, alcohol consumption, and other lifestyle factors in elderly persons. DESIGN: This cross-sectional study used linear regression to model changes in tHcy. Subjects were 278 men and women aged 66-94 y studied in 1993. RESULTS: Total folate intake was negatively associated with tHcy in models adjusted for age, sex, serum creatinine, and serum albumin. We found an interaction between food folate intake and supplement use. Food folate intake had an inverse dose-response relation with tHcy that was limited to nonusers of supplements. Predicted tHcy was 1.5 micromol/L lower in users of supplements containing folate and vitamin B-12 than in nonusers and was independent of food folate intake. We found a positive dose-response relation of coffee and tea intake with tHcy, a positive association for alcohol intake of > or = 60 drinks/mo compared with low intake, and an interaction of alcohol use with folate intake and supplement use. Compared with alcohol users, nonusers had higher predicted tHcy and a lower inverse dose-response relation of food folate intake with tHcy. CONCLUSIONS: The inverse association between folate intake and tHcy was strongest among nonusers of supplements and among alcohol drinkers. Identifying modifiable factors related to tHcy, a possible risk factor for vascular disease, is especially important in elderly persons.     

The Association of Acculturation Factors with Biochemical Indices of Folate Status Among Mexican Americans 60 Years of Age or Older in the Post-Fortification Era: National Health and Nutrition Examination Survey (NHANES) 2001–2006

Acculturation factors have been found to affect dietary intakes of folate among older Mexican Americans (MAs) (≥60 years). The association of acculturation with folate biomarkers is unknown. We determined whether acculturation factors were associated with folate biomarkers (e.g., serum folate, red blood cell [RBC] folate, and total homocysteine concentrations) and whether this association could be explained by dietary folate. Using data from the National Health and Nutrition Examination Survey (NHANES) 2001–2006, we estimated that 42.8% and 40.1% of older MAs reported speaking Spanish all or most of the time or being born in Mexico, respectively (lower acculturation factors). Lower acculturation factors were not associated with total homocysteine concentrations but were, in general, associated with lower serum folate and RBC folate concentrations, but these associations were not always independent of factors such as sex, education, and poverty, and possibly were mediated by dietary and supplemental folate. Thus, the lower folate status observed among older MA with lower acculturation factors may be modifiable by changes in the intake of folic acid.

[Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Nutrition in Gerontology and Geriatrics for the following free supplemental resource: a table of the predictors of serum folate or red blood cell folate concentrations among Mexican Americans 60 years of age or older using country of origin or language preference, respectively, as acculturation factors, from the National Health and Nutrition Examination Survey 2001–2006.]