Folate intake, plasma folate and homocysteine status in a random Finnish population

Exploring the association of hyperhomocysteinemia with early pregnancy losses: A retrospective case-control study in a tertiary clinic in Türkiye

A disturbance in the metabolism of homocysteine in both the mother and the fetus has been implicated in several placental vasculopathy-related disorders, including pregnancy loss. This study aimed to provide insights into the potential role of homocysteine, Vitamin B12, and folic acid in early pregnancy losses, with a specific focus on the Turkish population. The results of 93 pregnant women who experienced miscarriage between 5 and 14 gestational weeks and 93 healthy pregnant women at the same gestational weeks were compared. The demographic and pregnancy characteristics of all pregnant women were recorded. Vitamin B12, folic acid, and homocysteine levels were measured in serum samples obtained from the groups at similar gestational weeks. In addition, any associations between these biomarkers and different types of pregnancy loss, such as spontaneous abortion and missed abortion, were evaluated. Vitamin B12 and folic acid serum levels were significantly lower in women with miscarriages (P = .019, P < .001, respectively). Homocysteine levels were higher in the patient group (P < .001). Logistic regression analysis showed that a higher homocysteine level was the only predictive factor of miscarriage (P = .001, odds ratio = 0.596); however, folic acid and Vitamin B12 were not predictive factors. There was no significant difference in homocysteine and micronutrient levels between women with missed abortions and women with spontaneous abortions (P > .05). Our results support the continuing evidence of a link between maternal homocysteine levels and fetal loss. However, in exploring the shared pathways in the underlying mechanisms causing the 2 forms of pregnancy loss, maternal blood analysis showed no relationship.

Prevalence and Time Trends of Low Serum B12 Levels and Inadequate B12 Dietary Intake in Lebanese Adults amidst the Food Insecurity Situation: Findings from a Nationally Representative Cross-Sectional Study

Rising food insecurity (FI) and the increased prices of animal-based foods could compromise vitamin B12 (B12) intake and serum levels in food-insecure people. Our study aims to determine the prevalence of low levels of serum B12 and its inadequate dietary intake among a nationally representative sample of Lebanese adults aged 18 to 64 years, while exploring the impact of FI and identifying other potential predictors. The B12 intake was assessed using a food frequency questionnaire and the mean of two non-consecutive 24 h recalls. The B12 serum levels were also examined. To examine the time trends in the B12 serum levels and dietary intake, the data from a large representative digitized database of 6290 participants were collected, along with the examination of FAOSTAT food consumption data both before and during the economic crisis period. Our findings revealed that 47.3% of households in Lebanon experienced FI. The inadequate intake of B12 food sources was prevalent in 52.5% of participants, and 61.1% presented with low (23%) or intermediate (38.1%) levels of serum B12. The food-secure households had a higher proportion of B12 intake from meats (p = 0.004), while traditional foods contributed more to food-insecure households (p = 0.000). The participants who were female, unemployed, food-insecure, and had low dietary diversity were about two to three times more likely to have inadequate B12 intake. The predictors of low levels of serum B12 included residing in Beqaa (OR = 2.856 and 95% CI = 1.018-8.01) and having inadequate B12 intake (OR = 1.788 and 95% CI = 1.2-2.65). The findings from observing the time trends in the consumption and the serum levels of B12 indicate a considerable decline in the consumption of most animal-based foods compared to the pre-crisis period, associated with a decline in the serum levels of B12. In conclusion, an alarming prevalence of low dietary intake and low serum levels of B12 was revealed among Lebanese adults, and the indirect effect of FI on B12 serum levels mediated through B12 intake was inferred.

Functional Food Based on Potato

Potato (Solanum tuberosum L.) has gradually become a stable food worldwide since it can be a practical nutritional supplement and antioxidant as well as an energy provider for human beings. Financially and nutritionally, the cultivation and utility of potatoes is worthy of attention from the world. Exploring the functionality and maximizing the utilization of its component parts as well as developing new products based on the potato is still an ongoing issue. To maximize the benefits of potato and induce new high-value products while avoiding unfavorable properties of the crop has been a growing trend in food and medical areas. This review intends to summarize the factors that influence changes in the key functional components of potatoes and to discuss the focus of referenced literature which may require further research efforts. Next, it summarizes the application of the latest commercial products and potential value of components existing in potato. In particular, there are several main tasks for future potato research: preparing starchy foods for special groups of people and developing fiber-rich products to supply dietary fiber intake, manufacturing bio-friendly and specific design films/coatings in the packaging industry, extracting bioactive proteins and potato protease inhibitors with high biological activity, and continuing to build and examine the health benefits of new commercial products based on potato protein. Notably, preservation methods play a key role in the phytochemical content left in foods, and potato performs superiorly to many common vegetables when meeting the demands of daily mineral intake and alleviating mineral deficiencies.

High-throughput analysis of total homocysteine and methylmalonic acid with the efficiency to separate succinic acid in serum and urine via liquid chromatography tandem mass spectrometry

Vitamin B12 (VB12) deficiency may lead to hyperhomocysteinemia and methylmalonic acidemia development which are risk factors of cardiovascular disease and nervous system impairment, respectively. However, few analytical methods are available to simultaneously quantify total homocysteine (tHcy) and methylmalonic acid (MMA) due to complex analytical requirements, such as sensitivity at nanomolar concentration, separation performance for succinic acid (SA), an endogenous isomer of MMA, and retention properties for polar compounds. Therefore, we developed and validated a simple and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of tHcy and MMA with the efficient separation of SA in human serum and urine. The clinical performance of the assay was validated according to CLSI C62-A guidelines. The recovery for serum tHcy was 95.2-105.8%, urine tHcy was 98.1-111.5%, serum MMA was 94.6-99.4%, and urine MMA was 101.6-105.6%. In addition, the LC-MS/MS method was found to be reliable based on the value of inter-assay imprecision and total imprecision coefficient variation (CV), matrix effect, and carryover. Standards and samples were stable in -20 °C for at least 2 months. The limits of quantifications (LOQs) were 0.074 nmol/mL for tHcy and 0.040 nmol/mL for MMA, which are suitable for detecting tHcy and MMA concentrations in human serum and urine. The concentration of tHcy and MMA in samples collected from 148 subjects were measured using this method. The results suggested that the concentrations of serum tHcy and MMA considerably differed between VB12 sufficient and deficient groups. Serum tHcy and serum MMA concentrations were inversely correlated with VB12 status. Our method represents a rapid technique for estimating tHcy and MMA concentrations in serum and urine samples without the need for derivatization and may be used to assess VB12 status in clinical applications.

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.

Prevention of Neural Tube Defects in Europe: A Public Health Failure

Objective: Thirty years ago it was demonstrated that folic acid taken before pregnancy and in early pregnancy reduced the risk of a neural tube defect (NTD). Despite Public Health Initiatives across Europe recommending that women take 0.4 mg folic acid before becoming pregnant and during the first trimester, the prevalence of NTD pregnancies has not materially decreased in the EU since 1998, in contrast to the dramatic fall observed in the USA. This study aimed to estimate the number of NTD pregnancies that would have been prevented if flour had been fortified with folic acid in Europe from 1998 as it had been in the USA. Design and Setting: The number of NTD pregnancies from 1998 to 2017 that would have been prevented if folic acid fortification had been implemented in the 28 countries who were members of the European Union in 2019 was predicted was predicted using data on NTD prevalence from 35 EUROCAT congenital anomaly registries and literature searches for population serum folate levels and folic acid supplementation. Results: From 1998 to 2017 an estimated 95,213 NTD pregnancies occurred amongst 104 million births in the 28 countries in the EU, a prevalence of 0.92 per 1,000 births. The median serum folate level in Europe over this time period was estimated to be 14.1 μg/L. There is a lack of information about women taking folic acid supplements before becoming pregnant and during the first trimester of pregnancy, with one meta-analysis indicating that around 25% of women did so. An estimated 14,600 NTD pregnancies may have been prevented if the European countries had implemented fortification at the level adopted by the USA in 1998 and 25% of women took folic acid supplements. An estimated 19,500 NTD pregnancies would have been prevented if no women took folic acid supplements. Conclusions: This study suggests that failure to implement mandatory folic acid fortification in the 28 European countries has caused, and continues to cause, neural tube defects to occur in almost 1,000 pregnancies every year.

Folic acid affects cardiometabolic, oxidative stress, and immunohistochemical parameters in monocrotaline-induced rat heart failure

Heart failure (HF) is one of the major cardiovascular causes of death worldwide. In this study, we explored the effects of folic acid (FA) on cardiometabolic, oxidative stress biomarker changes, and the activity of proliferation marker Ki67 in monocrotaline-induced HF. The research was conducted during a 4 week period using five experimental groups (eight animals per group): blank solution exposed controls (C1: 1 mL/kg physiological saline, 1 day; C2: 1 mL/kg physiological saline, 28 days), monocrotaline (MCT) induced HF (50 mg/kg MCT), FA (5 mg·kg^-1·day^-1 FA), and MCT+FA (50 mg/kg MCT, 5 mg·kg^-1·day^-1 FA). Superoxide dismutase and glutathione peroxidase activities together with total glutathione and parameters of oxidative damage of proteins were determined in cardiac tissue as well as cardiometabolic parameters in plasma or serum. The total glutathionylation was determined by Western blot and proliferation marker Ki67 was assessed by immunohistochemistry. The right ventricular (RV) wall hypertrophy and Ki67 positivity, accompanied by a significant increase of troponin T, has been shown in MCT-induced HF. The antioxidant effect of FA was reflected through superoxide dismutase activity, reduced Ki67 positivity in the RV wall, and a slightly decreased total glutathionylation level.

The influence of subchronic co-application of vitamins B6 and folic acid on cardiac oxidative stress and biochemical markers in monocrotaline-induced heart failure in male Wistar albino rats

The aim of this study was to test the hypothesis that subchronic co-application of vitamins B6 and folic acid (FA) could affect heart failure (HF) induced by monocrotaline (MCT), with the modulation of oxidative stress parameters and cardiometabolic biomarkers. Biochemical and histomorphometric analyses were assessed in blank solution-exposed controls (C1 physiological saline 1 mL/kg, 1 day, n = 8; C2 physiological saline 1 mL/kg, 28 days, n = 8), MCT-induced HF (MCT 50 mg/kg, n = 8), B6+FA (vitamin B6 7 mg·kg–1·day–1, FA 5 mg·kg–1·day–1; n = 8), and MCT+B6+FA (MCT 50 mg/kg, vitamin B6 7 mg·kg–1·day–1, FA 5 mg·kg–1·day–1; n = 8) in male Wistar albino rats (body mass 160 g at the start). Superoxide dismutase and glutathione peroxidase activities, thiol-, carbonyl groups, and nitrotyrosine were determined in cardiac tissue. Echocardiography was performed to confirm MCT-induced HF. The right ventricular wall hypertrophy, accompanied with significant increase of troponin T and preserved renal and liver function, has been shown in MCT-induced HF. However, these effects were not related to antioxidant effects of vitamin B6 and FA, since several parameters of oxidative stress were more pronounced after treatment. In this study, co-application of vitamins B6 and FA did not attenuate hypertrophy of the right ventricle wall but aggravated oxidative stress, which is involved in HF pathogenesis.

Folate and vitamin B12 status and their relation to hematological indices in healthy adults of Iranians: Azar cohort study

BACKGROUND:

Folate and vitamin B₁₂ are essential micronutrients, the deficiency of which can be associated with public health problems worldwide.

AIM:

The aims of this study were to assess the folate and vitamin B₁₂ status of healthy adults and the effect of gender differences on their deficiency using serum folate, vitamin B₁₂ and red blood cell (RBC) folate as biomarkers and their relation to hematological indices.

METHODS:

This study was a part of the Azar cohort study, which is designed as a noncommunicable disease survey in the population of Shabestar, East Azerbaijan, Iran. A total of 95 healthy adults (35 men, 60 women) were chosen according to exclusion criteria and assessed using demographic characteristics and blood sampling.

RESULTS:

Low concentrations of serum folate, vitamin B₁₂ and RBC folate were detected in 16.8%, 61.1% and 40% of all subjects, respectively. Prevalence of low serum folate and vitamin B₁₂ was higher in men than women (25.7% versus 11.7% for serum folate, 77.1% versus 51.7% for serum vitamin B₁₂).A significant positive correlation was found between hemoglobin and serum folate, vitamin B₁₂ and RBC folate concentrations ( r = 0.279, 0.335, 0.228, respectively). No statistically significant correlation between mean corpuscular volume and serum folate, vitamin B₁₂ and RBC folate was seen ( r = -0.049, -0.030, -0.016, respectively).

CONCLUSIONS:

There was a high prevalence of low folate and vitamin B₁₂ concentrations in our community. Regarding the impact of these two vitamins deficiency on overall health, we suggest further investigations with more participants. In addition, monitoring hematological indices could be useful in people with folate and vitamin B₁₂ deficiency.

Intake of vitamin B6, folate, and vitamin B12 and risk of coronary heart disease: a systematic review and dose-response meta-analysis of prospective cohort studies

The objective of this study was to quantify the association of B-vitamins intake with the future risk of coronary heart disease (CHD). A systematic search was performed with the use of PubMed and Scopus from inception to April 30, 2018. Prospective cohort studies evaluating the association of intake of folate, vitamin B6, and vitamin B12 with risk of CHD in the general population were included. A random-effects meta-analysis was performed. Eleven prospective cohort studies (total n = 369,746) with 5133 cases of CHD were included in the analyses. The relative risks were: 0.79 (95%CI: 0.69, 0.89; I² = 67%) for a 250 µg/d increment in folate intake; 0.87 (95%CI: 0.78, 0.96; I² = 80%) for a 0.5 mg/d increment in vitamin B6 intake; and 0.97 (95%CI: 0.80, 1.14: I² = 67%) for a 3 µg/d increment in vitamin B12 intake. The results did not change materially when the analyses were restricted only to dietary vitamins intake. A nonlinear dose-response meta-analysis demonstrated a linear inverse association between folate and vitamin B6 intake and risk of CHD. In conclusion, higher intake of folate and vitamin B6 is associated with a lower risk of CHD in the general population.

Validity of the Food Frequency Questionnaire Assessing the Folate Intake in Women of Reproductive Age Living in a Country without Food Fortification: Application of the Method of Triads

The study aimed to examine the external validity of the Folate Food Frequency Questionnaire (F-FFQ) designed for assessing the folate intake in Serbian women of reproductive age. The F-FFQ was tested against repeated 24 h dietary recalls and correspondent nutritional biomarkers (red blood cells (RBC) and serum folate concentrations) using the method of triads. In a cross sectional study, 503 women aged 18-49 years completed dietary questionnaires and representative validation subsample (n = 50) provided fasting blood samples for biomarker analyses. Correlation coefficients were calculated between each of the dietary methods and three pair-wise correlations were applied for the calculation of validity coefficients. Correlation coefficients observed between F-FFQ and three 24 h recalls were r = 0.56 (p < 0.001) and r = 0.57 (p < 0.001) for total sample and validation group, respectively. Bland-Altman plot and cross-classification analyses indicated good agreement between methods. High validity coefficients were determined between the true intake (I) and dietary assessment methods, F-FFQ (Q) and 24 h dietary recalls (R) (ρQIrbc = 0.871 and ρQIser = 0.814; ρRIrbc = 0.652 and ρRIser = 0.698), and moderate ones for biomarkers (B) (ρBIrbc = 0.428 and ρBIser = 0.421). The F-FFQ is valid instrument for the assessment of dietary folate intake in women living in Serbia, a country without mandatory folic acid food fortification.

Exploring Folate Diversity in Wild and Primitive Potatoes for Modern Crop Improvement

Malnutrition is one of the world’s largest health concerns. Folate (also known as vitamin B₉) is essential in the human diet, and without adequate folate intake, several serious health concerns, such as congenital birth defects and an increased risk of stroke and heart disease, can occur. Most people’s folate intake remains sub-optimal, even in countries that have a folic acid food fortification program in place. Staple crops, such as potatoes, represent an appropriate organism for biofortification through traditional breeding based on their worldwide consumption and the fact that modern cultivars only contain about 6% of the daily recommended intake of folate. To start breeding potatoes with enhanced folate content, high folate potato material must be identified. In this study, 250 individual plants from 77 accessions and 10 Solanum species were screened for their folate content using a tri-enzyme extraction and microbial assay. There was a 10-fold range of folate concentrations among individuals. Certain individuals within the species Solanum tuberosum subsp. andigenum, Solanum vernei and Solanum boliviense have the potential to produce more than double the folate concentrations of commercial cultivars, such as Russet Burbank. Our results show that tapping into the genetic diversity of potato is a promising approach to increase the folate content of this important crop.

Micronutrient status in female university students: iron, zinc, copper, selenium, vitamin B12 and folate

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18-35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 μmol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 μmol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation.

Nutrient intake values for folate during pregnancy and lactation vary widely around the world

Folate is a B-vitamin with particular importance during reproduction due to its role in the synthesis and maintenance of DNA. Folate is well known for its role in preventing neural tube defects (NTDs) during the periconceptional period. There is also an increased need for folate throughout pregnancy to support optimal growth and development of the fetus and blood volume expansion and tissue growth of the mother. During lactation, women are at risk of folate deficiency due to increased demands to accommodate milk folate levels. Nutrient Intake Values (NIVs) for folate have been calculated to take into account additional needs during pregnancy and lactation. However, these values vary widely between countries. For example, the folate requirement that is set to meet the needs of almost all healthy women during pregnancy varies from 300 µg/day in the United Kingdom to 750 µg/day in Mexico. Currently, there is no accepted standardized terminology or framework for establishing NIVs. This article reviews country-specific NIVs for folate during pregnancy and lactation and the basis for setting these reference values.

Correlation of serum homocysteine and previous history of gestational diabetes mellitus

Background

Gestational diabetes mellitus (GDM) is a common pregnancy condition. In this study, the risk of having a history of previous GDM (pGDM) on serum homocysteine level was assessed

Methods

Biomedical parameters, serum homocysteine, Insulin, homeostatic model assessment (HOMA) in women with (n = 52) and without pGDM (n = 51) were assessed. According to their current status of Oral Glucose Tolerance Test (GTT), the participants in each group were divided into two subgroups of normal or impaired GTT.

Results

Mean serum homocysteine in normal women was 8.56 ± 3.19 vs 11.44 ± 7.34 μmol/L (p < 0.01) in women with pGDM. Two groups had significant differences in respect to serum insulin levels (8.35 ± 5.12 vs 12.48 ± 5.44, p < 0.002), and HOMA-IR (1.90 ± 1.30 vs 2.91 ± 1.30, p < 0.002). In women without pGDM, serum homocysteine in normal and impaired GTT were 7.60 ± 1.69 and 10.52 ± 3.65 μmol/L (p = 0.03), respectively, while in women with pGDM, the figures were 8.38 ± 2.52 and 14.00 ± 10.17 (p < 0.01), respectively. In multi regression analysis an association between history of GDM and homocysteine levels was presented (OR: 7.71, 95% CI: 1.67-35.42, p < 0.001).

Conclusion

A trend of elevation of homocysteine is presented in women with pGDM, that is more prominent in women with impaired GTT, and shows a significant correlation with history of GDM. Further studies with larger sample size are suggested.

Monitoring diet and diet-related chronic disease risk factors in Finland

Health and dietary monitoring has a long history in Finland. The aim of this review is to summarise the main sources of Finnish dietary information including food balance sheets, household budget survey data, questionnaires related to dietary behaviour and risk factors of main chronic diseases as well as dietary surveys. According to these sources, dietary behaviour and food choices have changed considerably during the last decades. For example, the total fat intake (E %) has decreased remarkably from nearly 40 % in the late 1960s to close to 30 % in 2007. Furthermore, the type of fat consumed has changed noticeably due to the increased popularity of oil used in cooking and the large variety of softer spreads available. There has also been a notable decrease in intake of salt, and a multiple increase in the consumption of fruits and vegetables since the 1970s. The future challenges of dietary monitoring include keeping the participation rates in dietary surveys at acceptable levels, controlling under/over-reporting of diet, developing a national monitoring system for children and adapting to international changes and requirements to harmonise dietary monitoring in Europe.

A prospective study of one-carbon metabolism biomarkers and risk of renal cell carcinoma

OBJECTIVE

Previous studies have found associations between one-carbon metabolism factors and risk of several cancers, but little is known regarding renal cell carcinoma (RCC). We conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a prospective study of Finnish male smokers aged 50-69 at baseline.

METHODS

Prediagnostic folate, vitamin B(6), vitamin B(12), cysteine, riboflavin, and homocysteine concentrations were measured in fasting serum from 224 incident RCC cases and 224 controls (matched on age and date of serum collection). Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for potential confounders.

RESULTS

Serum folate tended to be inversely associated with RCC, compared to the first quartile, the odds ratios (95% CI) for subsequent quartiles were 0.62 (0.35-1.08), 0.52 (0.29-0.93), and 0.67 (0.37-1.20) (P-trend = 0.19). When modeled as a threshold effect, subjects in the lowest serum folate quartile (<or=6.64 nmol/l), which corresponds to deficient folate status, had a significant increased RCC risk (OR = 1.68, 95% CI 1.06-2.65) compared to those with higher serum folate. The other one-carbon metabolism biomarkers were not associated with RCC.

CONCLUSIONS

This study in male smokers suggests that deficient folate status may increase risk of RCC, but confirmation is needed in other epidemiologic studies that include women and non-smokers.

Folate status of Ghanaian populations in London and Accra

Migration to the UK is associated with higher incidence of stroke in African populations. A low folate status has been associated with increased risk of stroke, likely to be mediated through raised plasma homocysteine concentrations. We conducted a cross-sectional study to compare blood folate and homocysteine concentrations in eighty healthy Ghanaian migrants living in London matched by sex, age and occupation to 160 individuals from an urban population in Accra, Ghana. Folate intake was determined using three 24 h recalls. Fasting blood samples were collected for the determination of serum and erythrocyte folate and plasma homocysteine concentrations and the methylenetetrahydrofolate reductase (MTHFR) 677C → T polymorphism. Reported mean folate intake was 20 % lower in London compared with Accra (P < 0·001). However, serum folate was 44 % higher, erythrocyte folate 30 % higher and plasma homocysteine was 26 % lower in subjects from London compared with those from Accra (P < 0·001). These differences persisted after adjusting for confounders including the MTHFR 677C → T mutation, which was rare in both populations. Although there were no associations between dietary folate intake and blood folates (P>0·05), folic acid supplement use, which was more prevalent in London than Accra (25 and 10 %, respectively,P = 0·004) was associated with erythrocyte folate in both populations (P < 0·01). The main predictors of plasma homocysteine concentrations were erythrocyte folate and male sex (P < 0·001). Findings from the present study suggest that migration from Ghana to the UK results in improvement of biomarkers of folate status despite the fact that reported dietary intake of folate was apparently lower in subjects from London.

Quantitation of serum angiopoietin-like proteins 3 and 4 in a Finnish population sample

We have developed and validated quantitative ELISAs for human angiopoietin-like (ANGPTL)3 and 4 and correlated their serum levels with parameters of lipid and carbohydrate metabolism. For this study, we used a random subsample of the Health 2000 Health Examination Survey consisting of 125 men and 125 women, aged 30-94 years. The anthropometric and biochemical parameters of subjects were characterized in detail. ANGPTL 3 and 4 levels were determined using the developed ELISAs. The intra- and inter-assay coefficients of variation for the assays were less than 15%. The average serum concentration of ANGPTL3 was 368 +/- 168 ng/ml (mean +/- SD) and for ANGPTL4 it was 18 +/- 23 ng/ml (mean +/- SD). ANGPTL4 serum levels displayed high variability between individuals ranging from 2 to 158 ng/ml. In post-heparin plasma, both ANGPTL 3 and 4 were increased. Low levels of ANGPTL3 were associated with decreased HDL-cholesterol and increased triglyceride levels. ANGPTL4 levels were positively correlated with FFAs (P = 0.044) and waist-hip ratio (P = 0.016). The developed ELISAs will be important tools to clarify the role of ANGPTL 3 and 4 in human energy metabolism and partitioning of triglycerides between sites of storage (adipose tissue) and oxidation (skeletal and cardiac muscle).

Examination of selected national policies towards mandatory folic acid fortification

The purpose of this paper is to present an examination of the contrasting policies towards mandatory folic acid fortification in six countries from different regions of the world. Three questions are addressed: 1) What is the policy of the country? 2) Why was the policy adopted? 3) What lessons have been learned? Policy contrasts among countries were assessed as reflecting different interpretations of the potential risks and benefits associated with folic acid fortification. Although commonalities were identified, it was considered unlikely that there could be a standard policy response for all countries. Instead, a country-by-country policy response based on national circumstances is indicated.

MTHFR C677T Polymorphism is Not Associated with Placental Abruption or Preeclampsia in Finnish Women

OBJECTIVE

The aim of our study was to examine genetic variability in the gene encoding methylenetetrahydrofolate reductase (MTHFR) and individual susceptibility to the placental abruption or preeclampsia.

METHODS

362 women (133 with preeclampsia, 117 with placental abruption, and 112 healthy controls) were genotyped for C677T polymorphism in the MTHFR gene.

RESULTS

Similar genotype distributions were observed in the frequencies of C/C homozygotes (58.6%, 64.1%, and 57.1% for the three groups, respectively) and mutant homozygotes T/T (9.0%, 5.1% and 5.4%). No significant differences were detected in T allele frequencies (25.2%, 20.5%, and 24.1% for the three groups, respectively).

CONCLUSIONS

MTHFR C677T polymorphism does not have a major role in the development of preeclampsia or placental abruption in the Finnish population.

Review of the magnitude of folate and vitamin B12 deficiencies worldwide

Human deficiencies of folate and vitamin B12 result in adverse effects which may be of public health significance, but the magnitude of these deficiencies is unknown. Therefore, we examine the prevalence data currently available, assess global coverage of surveys, determine the frequency with which vitamin status assessment methods are used, and identify patterns of status related to geographical distribution and human development. Surveys were identified through PubMed and the Vitamin and Mineral Nutrition Information System at the World Health Organization (WHO). Since different thresholds were frequently used to define deficiency, measures of central tendency were used to compare blood vitamin concentrations among countries. The percentage of countries with at least one survey is highest in the WHO Regions of South-East Asia and Europe. Folate and vitamin B12 status were most frequently assessed in women of reproductive age (34 countries), and in all adults (27 countries), respectively. Folate status assessment surveys assessed plasma or serum concentrations (55%), erythrocyte folate concentrations (21%), or both (23%). Homocysteine was assessed in one-third of the surveys of folate and vitamin B12 status (31% and 34% respectively), while methylmalonic acid was assessed in fewer surveys of vitamin B12 status (13%). No relationship between vitamin concentrations and geographical distribution, level of development, or population groups could be identified, but nationally representative data were few. More representative data and more consistent use of thresholds to define deficiency are needed in order to assess whether folate and vitamin B12 deficiencies are a public health problem.

Laying hens can convert high doses of folic acid added to the feed into natural folates in eggs providing a novel source of food folate

There are few good sources of natural food folates apart from green leafy vegetables and these may have a limited potential to increase folate status because of substantial losses that can occur during cooking. Fortified foods can overcome this but are controversial because of safety concerns regarding chronic exposure to high-dose folic acid (FA; the synthetic form). The aim of the present study was to develop eggs with an enriched natural folate content and minimal unmetabolised FA. Forty-eight, 30-week-old laying hens were randomised to receive the basal feed (formulated to provide 1 mg folate/kg feed) to which had been added one of the following FA levels (0, 2, 4, 8, 16, 32 mg/kg feed). Total folate was measured in eggs collected throughout the 12-week study period and the FA content estimated at 12 weeks. Results showed that the maximal egg folate content was achieved by adding 16 mg FA/kg feed. At this optimal dose, the total folate content per egg was 75 μg (compared with 32 μg in a regular egg) of which FA represented at most 10 %, a level which would probably be converted into natural folates by humans after ingestion. The results demonstrate that it is possible to use synthetic FA at high doses to produce novel animal foods enriched with natural folates in a cost-efficient process. Such foods may be particularly relevant to European populations without access to FA fortification and therefore dependent on natural food folate sources for the primary prevention of folate-related disease.

Dietary intake and status of folate and vitamin B12 and their association with homocysteine and cardiovascular disease in European populations

BACKGROUND/OBJECTIVES

Folate and vitamin B12 have been suggested to play a role in chronic diseases like cardiovascular diseases. The objectives are to give an overview of the actual intake and status of folate and vitamin B12 in general populations in Europe, and to evaluate these in view of the current vitamin recommendations and the homocysteine concentration.

METHODS

Searches in Medline with 'folic acid', 'folate' and 'vitamin B12', 'B12' or 'cobalamin' as key words were combined with the names of the European countries. Populations between 18 and 65 years were included.

RESULTS

Sixty-three articles reporting on studies from 15 European countries were selected. Low folate intakes were observed in Norway, Sweden, Denmark and the Netherlands. Low intakes of vitamin B12 were not common and only seen in one small Greek study. In the countries with a low intake of folate, the recommended levels were generally not achieved, which was also reflected in the folate status. Vitamin B12 intake was not strongly associated with the vitamin B12 status, which can explain why in the Netherlands and Germany the vitamin B12 status was inadequate, despite sufficient intake levels. In countries with a low folate intake in particular, the Hcy concentration was higher than ideal.

CONCLUSIONS

Populations from the Nordic countries, the Netherlands, Germany and Greece may need to improve their intakes of folic acid, B12 or both to either meet the recommendations or to optimize their statuses. This could be achieved via a food-based approach, food fortification or supplements.

Determination of folate concentrations in diverse potato germplasm using a trienzyme extraction and a microbiological assay

Folate deficiency is a leading cause of birth defects and is implicated in several other diseases. We are interested in how much folate concentrations vary among potato germplasm. We determined total folate concentrations of potato tubers from 67 cultivars, advanced breeding lines, or wild species. Folates were extracted by a tri-enzyme treatment and analyzed by using a Lactobacillus rhamnosus microbiological assay. Folate concentrations varied from 521 +/- 96 to 1373 +/- 230 ng/g dry weight and were genotype and location dependent. The highest folate concentrations were mostly found in color-fleshed potatoes. Variations of folate concentrations within either color- or white-fleshed tubers were similar ( approximately 2-fold). Skin contained approximately 30% higher folate concentrations than flesh. Storage of tubers for 7 months generally led to an increase in folate contents. Semiquantitative RT-PCR analyses showed that higher folate contents were correlated with lower mRNA expression of some folate genes.

The effect of low doses of betaine on plasma homocysteine in healthy volunteers

Homocysteine is a risk factor for vascular diseases, and lowering of plasma total homocysteine (tHcy) may be beneficial for health. Homocysteine can be remethylated to methionine by betaine–homocysteine methyltransferase using betaine (2(N,N,N-trimethyl)glycine) as methyl donor. A dose of 6 g betaine/d has been used in the treatment of homocystinuria, but data on the dose–response are scarce. Thirty-four healthy men and women were supplied with doses of 1, 3 and 6 g betaine and then with 6 g betaine + 1 mg folic acid for four consecutive 1-week periods. The mean plasma tHcy concentration decreased by 1·1 (NS), 10·0 and 14·0 % (P<0·001) after supplementation with 1, 3 and 6 g betaine respectively. A further decrease in plasma tHcy by 5 % (P<0·01) was achieved by combining 1 mg folic acid with the 6 g betaine dose. Plasma betaine increased from 31 (SD 13) to 255 (SD 136) μmol/l in a dose-dependent manner (R20·97). We conclude that plasma tHcy is lowered rapidly and significantly by 3 or 6 g betaine/d in healthy men and women.

Testing of variants of the MTHFR and ESR1 genes in 1798 Finnish individuals fails to confirm the association with migraine with aura

Among the few independently replicated genetic associations in migraine are polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) and oestrogen receptor (ESR1) genes. We studied the contribution of these genes to migraine susceptibility by genotyping six MTHFR and 26 ESR1 polymorphisms in 898 unrelated migraine with aura (MA) patients and in 900 unrelated healthy controls. There were no differences in the genotype distributions of the previously migraine-associated SNPs C677T (MTHFR) and G2014A (ESR1) between cases and controls (P-values 0.83 and 0.55, respectively). Thus, we were not able to replicate the previous findings, although our study had considerable power. However, five of the ESR1 SNPs (rs6557170, rs2347867, rs6557171, rs4870062 and rs1801132) that were in strong linkage disequilibrium were nominally associated with MA (uncorrected P-values 0.007-0.034). These results did not, however, remain significant after taking multiple testing into account. Thus it seems unlikely that the studied genes are involved in migraine susceptibility, at least in this sample.

Greater Fish, Fruit, and Vegetable Intakes Are Related to Lower Incidence of Venous Thromboembolism

Background— Little is known about the role of dietary intake in the development of deep vein thrombosis or pulmonary embolus (venous thromboembolism [VTE]). Homocysteine, factor VIII, and von Willebrand factor levels, risk factors for VTE, are influenced by dietary intake. We tested the hypothesis that foods rich in B vitamins and ω-3 fatty acids are negatively associated and meat intake is positively associated with incidence of VTE.

Methods and Results— In a prospective study over 12 years, 14 962 middle-aged adults participating in the Atherosclerosis Risk in Communities study were followed up for incident VTE. All hospitalizations were identified, and 196 VTEs were validated by chart review. A food frequency questionnaire assessed dietary intake at baseline and year 6. In separate proportional hazards regression analyses, risk of developing VTE was computed across quintiles of selected nutrients, major food groups, and the Western diet pattern, with adjustment for demographic and lifestyle factors, body mass index, and diabetes. Hazard ratios and 95% confidence intervals of VTE incidence across quintiles of fruit and vegetable intake were 1.0 (reference), 0.73 (0.48 to 1.11), 0.57 (0.37 to 0.90), 0.47 (0.29 to 0.77), and 0.59 (0.36 to 0.99) ( P trend =0.03). Eating fish 1 or more times per week was associated with 30% to 45% lower incidence of VTE for quintiles 2 to 5 compared with quintile 1, suggestive of a threshold effect. Hazard ratios of VTE across quintiles of red and processed meat intake were 1.0, 1.24 (0.78 to 1.98), 1.21 (0.74 to 1.98), 1.09 (0.64 to 1.87), and 2.01 (1.15 to 3.53) ( P trend =0.02). Hazard ratios were attenuated only slightly after adjustment for factors VIIc and VIIIc and von Willebrand factor.

Conclusions— A diet including more plant food and fish and less red and processed meat is associated with a lower incidence of VTE.

Nutritional determinants of plasma total homocysteine distribution in the Canary Islands

OBJECTIVE

We sought to define plasma homocysteine reference values in healthy individuals in the Canary Islands and to determine its relations to folate and vitamin B12 intakes and concentrations.

DESIGN

Cross-sectional study.

SETTING

Population-based representative sample of 557 participants, aged 18-65 years, from the Canary Islands Nutrition Survey (ENCA).

SUBJECTS

All participants completed two 24-h dietary recalls and a general questionnaire collecting socio-demographic and health-related lifestyle information.

INTERVENTIONS

Plasma homocysteine and serum vitamin B12 levels were measured by immunoassay, whereas folate levels through an automated ionic capturing method.

RESULTS

Median plasma homocysteine was 11.9 micromol/l, higher in men (13.1 micromol/l) than in women (10.9 micromol/l) (P<0.001) and positively associated with age in both sexes (P<0.001). The prevalence of hyperhomocysteinaemia (> or = 15 micromol/l), 21.4%, was also greater in men (32.2%) than in women (13.4%). There were significant negative correlations between plasma homocysteine and serum (r=-0.32, P<0.001) and erythrocyte (r=-0.26, P<0.001) folate, as well as serum vitamin B12 (r=-0.28, P<0.001) concentrations. When divided in quartiles of vitamin intakes or concentrations, men with the lowest vitamin B12 and folate serum values had significantly higher plasma homocysteine concentrations than those in the other three quartiles. In women, hyperhomocysteinaemia was higher in the lowest quartiles of folate intake and serum and erythrocyte folate concentrations.

CONCLUSIONS

These data provide further evidence that hyperhomocysteinaemia is a sensitive marker of inadequate folate and vitamin B12 status, allowing for the identification of those with greatest need for nutritional interventions.

Intake of vitamin D by Finnish children aged 3 months to 3 years in relation to sociodemographic factors

OBJECTIVE

To study the total daily intake of vitamin D from food and supplements among Finnish children aged 3 months to 3 years, the dietary sources of vitamin D and the association between vitamin D intake and sociodemographic factors.

SUBJECTS AND METHODS

The subjects are participants in the Finnish Type I Diabetes Prediction and Prevention Nutrition Study born between October 1997 and October 1998. At the age of 3 and 6 months, 1, 2 and 3 years, 342 (72% of the invited families), 298 (63%), 267 (56%), 233 (49%) and 209 (44%) families, respectively, participated in the present study. Food consumption was assessed by a 3-day food record. A structured questionnaire was used to record the parents' socioeconomic status.

RESULTS

The mean dietary vitamin D intake exceeded the recommendation (10 microg/day) at the age of 3 (11.0 microg) and 6 months (12.0 microg), but decreased thereafter being 9.8, 5.0 and 4.1 microg at 1, 2 and 3 years of age, respectively. Among the children 91, 91, 81, 42 and 26% used vitamin D supplements at the age of 3 and 6 months, and 1, 2 and 3 years, respectively. In children not using vitamin D supplements, vitamin D intake was less than 10 microg/day at all ages. Vitamin D intake from food did not differ in children who used and did not use vitamin D supplements. Vitamin D supplements were the main source of vitamin D intake in all age groups studied, followed by vitamin D-fortified infant formula in 3-month-olds and infant formula and baby foods in 6-month-olds. After the age of 1 year, the most important food sources of vitamin D were margarine, fish, baby foods, low-fat milk and eggs. Sociodemographic factors, especially the number of children in the family and maternal age, were associated with the total vitamin D intake and vitamin D supplement use.

CONCLUSION

Vitamin D supplements are not used according to the dietary recommendations in a substantial proportion of Finnish children.

Dietary and other lifestyle correlates of serum folate concentrations in a healthy adult population in Crete, Greece: a cross-sectional study

Background

Folate has emerged as a key nutrient for optimising health. Impaired folate status has been identified as a risk factor for cardiovascular disease, various types of cancers, and neurocognitive disorders. The study aimed at examining the distribution and determinants of serum folate concentrations in a healthy adult population in Crete, Greece.

Methods

A cross-sectional sample of 486 healthy adults (250 men, 236 women) aged 39 ± 14 years, personnel of the Medical School and the University Hospital of Crete in Greece, was examined. Serum folate and vitamin B₁₂ concentrations were measured by microbiological assay, and total homocysteine was determined fluorometrically and by high-pressure liquid chromatography. Lifestyle questionnaires were completed, and nutrient intakes and food consumption were assessed by 24-h dietary recalls. Multivariate analyses were performed using SPSS v10.1.

Results

The geometric mean (95% confidence interval) concentrations of serum folate were 15.6 μmol/l (14.6–16.8) in men and 19.2 μmol/l (17.9–20.7) in women (p < 0.001). Inadequate folate levels (≤7 nmol/l) were present in 6.8% of men and 2.1% of women (p < 0.001). Approximately 76% of men and 87% of women did not meet the reference dietary intake for folate (400 μg/day). Serum folate was inversely related to total homocysteine levels (p < 0.001). Increased tobacco and coffee consumption were associated with lower folate concentrations (p < 0.05 for both) but these associations disappeared after controlling for nutrient intakes. In multivariate analysis, intakes of MUFA, fibre, calcium, magnesium, folate, and vitamins A, E, C, B₁, and B₆ were positively associated with serum folate. Consumption of potatoes, legumes, fruits, and vegetables were favourably related to the serum folate status.

Conclusion

Serum folate concentrations were associated with various demographic, lifestyle and dietary factors in healthy Cretan adults. Large-scale epidemiological studies should be conducted within the general Greek adult population to assess the prevalence of impaired folate status and further examine associations with dietary patterns and chronic disease risk. Considering the importance of folate in health maintenance, it is important to increase the public's awareness of modifiable lifestyle patterns and diet and tobacco use in particular, which may be associated with improved folate status.

The effect of MTHFR(C677T) genotype on plasma homocysteine concentrations in healthy children is influenced by gender

OBJECTIVE

To explore the influence of gender, together with folate status, on the relation between the common methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and plasma total homocysteine (tHcy) concentrations in healthy children.

DESIGN

Cross-sectional study by face-to-face interview.

SETTING AND SUBJECTS

A total of 186 sixth-grade students participated from twelve randomly selected primary schools in Volos, Greece.

METHODS

Fasting tHcy, folate, and vitamin B(12) were measured in plasma. The MTHFR genotypes were determined. Anthropometric and dietary intake data by 24-h recall were collected.

RESULTS

Geometric means for plasma tHcy, plasma folate and energy-adjusted dietary folate did not differ between females and males. The homozygous mutant TT genotype was associated with higher tHcy only in children with lower plasma folate concentrations (<19.9 nmol/l, P = 0.012). As a significant gender interaction was observed (P = 0.050), we stratified the lower plasma folate group by gender and found that the association between the genotype and tHcy was restricted to males (P = 0.026). Similar results were obtained when folate status was based on estimated dietary folate. Specifically, only TT males that reported lower dietary folate consumption (<37 microg/MJ/day) had tHcy that was significantly higher than tHcy levels of C-allele carriers (P = 0.001).

CONCLUSIONS

Under conditions of lower folate status (as estimated by either plasma concentration or reported dietary consumption), gender modifies the association of the MTHFR(C677T) polymorphism with tHcy concentrations in healthy children.

SPONSORSHIP

Kellog Europe.

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.