Factors related to plasma folate and vitamin B12. The SENECA study

Relationship between intake and plasma concentrations of vitamin B12 and folate in 873 adults with a physically active lifestyle: a cross-sectional study

BACKGROUND

Vitamin B12 and folate function as co-factors in pathways used during physical activity. Physical activity may therefore increase vitamin requirements, leading to a risk of deficient plasma concentrations. We aimed to investigate the relationship between intake and plasma concentrations of vitamin B12 and folate in physically active adults, as well as identify other determinants of vitamin B12 and folate plasma concentrations.

METHODS

The study population consisted of 873 adults (528 men and 345 women), aged 19-78 years, who participated in a 4-day walking event. The relationship between intake and plasma concentrations of vitamin B12 and folate was assessed using correlation and linear regression analyses. In addition, potential other determinants (sex, age, body mass index, energy intake and physical activity) of vitamin plasma concentrations were investigated.

RESULTS

Significant positive correlations were observed between intake and plasma concentrations of vitamin B12 [Pearson's correlation coefficient = 0.15; 95% confidence interval (CI) = 0.08-0.21] and folate (Pearson's correlation coefficient = 0.18; 95% CI = 0.12-0.25). In addition to vitamin intake, sex, age and energy intake were also determinants of both vitamin B12 and folate plasma concentrations in multivariable regression models.

CONCLUSIONS

The results suggest a positive association between intake and plasma concentrations for both vitamin B12 and folate in physically active people. By contrast to our hypothesis, physical activity was not a determinant of vitamin B12 and folate plasma concentrations. However, sex, age and energy intake were found to be determinants. Thus, when studying the relationship between intake and plasma concentrations of vitamin B12 or folate, these factors should be taken into account.

Phenytoin, folic acid and gingival enlargement: Breaking myths

Background:

Epilepsy is described as a chronic neurological disorder characterized by recurrent seizures of cerebral origin, presenting with episodes of sensory, motor or autonomic phenomenon with or, without loss of consciousness. A recent meta-analysis of published and unpublished studies puts an overall prevalence rate of epilepsy in India at 5.59 per 1,000 populations. There have been studies that report clinical benefits of the use of folic acid as an adjuvant to the anti-epileptic therapy in the prevention of anti-epileptic drug induced gingival enlargement. However, studies conducted in the past have also reported precipitation of epileptic attacks in patients on folic acid adjuvant therapy due to fall in sera levels of phenytoin due to drug interactions. The study was planned to investigate the association of phenytoin induced gingival enlargement and sera levels of folic acid in epileptic patients on phenytoin therapy so as to justify the use of folic acid as a routine adjuvant to the usual anti-epileptic therapy to prevent this inevitable adverse effect without destabilizing the ongoing regimen leading to the precipitation of seizures in an otherwise stable patient (breakthrough seizures).

Materials and Methods:

A total of 100 patients between the ages 18 and 50 years were clinically diagnosed with epilepsy prior to the start of phenytoin therapy were included based on selection criteria and written informed consents were obtained. Assessment of serum folic acid levels and gingival enlargement was performed prior to the start of and after 1 year of phenytoin therapy.

Statistical Analysis Used:

The statistical analysis was carried out using t-test and the baseline serum folate levels and the serum folate levels obtained after 1 year of phenytoin therapy were correlated with the respective grades of gingival enlargement using Pearson's coefficient formula.

Results:

The results of the study confirmed a significant association between low serum folate levels with increasing severity as well as an early onset of phenytoin induced gingival enlargement.

Conclusions:

The results of the study suggest a higher incidence of gingival enlargement with an early onset and increased severity in phenytoin treated epileptic patients with a positive correlation with falling serum folic acid levels as the duration of the therapy increases.

A study on gingival enlargement and folic acid levels in phenytoin-treated epileptic patients: Testing hypotheses

Background:

There have been studies that report clinical benefits of the use of folic acid as an adjuvant to the antiepileptic therapy in the prevention of antiepileptic drug-induced gingival enlargement. However, studies in the past have also reported precipitation of epileptic attacks in patients on folic acid adjuvant therapy due to fall in sera levels of phenytoin due to drug interactions. The study was planned to investigate the association of phenytoin-induced gingival enlargement and sera levels of folic acid in epileptic patients on phenytoin therapy. The statistical analysis was done using t-test and the baseline serum folate levels and the serum folate levels obtained after 6 months of phenytoin therapy were correlated with the respective grades of gingival enlargement using Pearson's coefficient formula.

Methods:

A total of 25 patients aged between 18 and 50 years, clinically diagnosed with epilepsy prior to the start of phenytoin therapy were included based on selection criteria and written informed consents were obtained. Assessment of serum folic acid levels and gingival enlargement was done prior to the start of and after 6 months of phenytoin therapy.

Results:

The results of the study confirmed a significant association between low serum folate levels with increasing severity as well as an early onset of phenytoin-induced gingival enlargement.

Conclusions:

The results of the study suggest a higher incidence of gingival enlargement in phenytoin treated epileptic patients with a positive correlation with falling serum folic acid levels as the duration of the therapy increases.

Serum vitamin B12 and folate levels in patients with non-alcoholic fatty liver disease

The aim of the study was the evaluation of serum vitamin B12 and folate levels in patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD) and their association with the disease severity. Thirty patients with biopsy-proven NAFLD and 24 healthy controls matched for gender, age, body mass index and waist circumference were recruited. Blood samples for vitamin B12, folate, insulin and standard biochemical tests were obtained after overnight fasting. Homeostatic model of assessment-insulin resistance was calculated. There was no difference in serum vitamin B12 and folate levels between groups. Neither vitamin B12 nor folate levels were significantly different within any histological category, including steatosis grade, fibrosis stage, lobular inflammation, portal inflammation and ballooning. In conclusion, similar vitamin B12 and folate levels were observed in non-alcoholic steatohepatitis and non-alcoholic fatty liver patients, and controls. Furthermore, vitamin B12 and folate levels were not associated with either insulin resistance or the severity of liver disease.

Nutritional status in pregnant adolescents: a systematic review of biochemical markers

Adolescent pregnancy is a major public health challenge for many industrialized countries and is associated with significant medical, nutritional, social and economic risk for mothers and their infants. Despite this, relatively little is known about the nutritional status of this population. The aim of this paper was to conduct a systematic review of the current evidence relating to the biochemical markers of nutritional status of pregnant adolescents living in industrialized countries. Six papers were identified that fulfilled the inclusion criteria, the majority of which were conducted in the United States. The studies were of variable quality and most failed to control for potential confounders which may have strongly influenced the findings. Due to limited research, conclusions cannot be drawn about the zinc and calcium status of pregnant adolescents, and data on folate and vitamin B(12) status appeared conflicting. There was some consensus among studies, however, to suggest that indicators of anaemia and iron status were compromised in pregnant adolescents, particularly during the third trimester of pregnancy. Chronological age did not appear to influence nutritional status, although there was some evidence to suggest that increasing gynaecologic age may positively influence plasma ferritin levels. Current research is limited by sampling and measurement bias, and research is urgently required to address these limitations. Further consideration should also be made of the influence of the role of socio-economic support on pregnant adolescents' nutritional status. The achievement of improved nutrition in pregnancy among adolescents requires multidisciplinary collaborations of adolescent healthcare providers, academics, professional organizations, policymakers, industry and service users. Only once this is achieved can adolescent nutrition, and adolescent nutrition in pregnancy, be significantly and sustainably optimized.

Homocysteine and coronary heart disease risk in the PRIME study

INTRODUCTION

Despite recent meta-analyses suggesting that homocysteine is an independent predictor of coronary heart disease (CHD), there is debate regarding whether elevated homocysteine may be deleterious only in the presence of other risk factors, with which it acts synergistically to exert a multiplicative effect on CHD risk, emerging only as a CHD predictor in patients with pre-existing risk factors. The Prospective Epidemiological Study of Myocardial Infarction (PRIME) Study is a multicentre prospective study of 10593 men from France and Northern Ireland, investigating cardiovascular risk factors. We investigated: (1) whether higher homocysteine is associated with increased CHD risk in the PRIME case-control cohort; (2) whether homocysteine interacts synergistically with pre-existing CHD risk factors.

METHODS

Homocysteine was measured in 323 participants who had developed CHD at 5-year follow-up and in 638 matched controls.

RESULTS

There was no significant difference in homocysteine between cases and controls (p=0.18). Homocysteine was significantly higher in current smokers (geometric mean mumol/l (interquartile range mumol/l) 9.45 (7.43, 11.75)) compared with non-smokers (8.90 (7.32, 10.70); p=0.007). There was a significant interaction between homocysteine, smoking and CHD risk (chi2=10.29, d.f.=2, p=0.006).

CONCLUSIONS

These findings suggest that elevated homocysteine is significantly associated with CHD risk in current smokers.

Predictors of micronutrient status in men and women over 75 years old living in the community

Serum ferritin, serum vitamin B12, erythrocyte folate, plasma vitamin C and plasma 25-hydroxycholecalciferol levels were measured in 208 men and 197 women, >75 years old and living in the community, in order to assess micronutrient status. Anthropometric measurements (height, weight, demispan and mid-upper arm circumference) were made and a 114-item questionnaire covering a wide range of health and diet-related topics was administered by an interviewer. Only 4 % of subjects had a BMI <20, but the prevalence of marginal deficiency of the micronutrients ranged from 7 % for Fe to 47 % for vitamin D. There was no association between low micronutrient status (defined as being in the lowest third of the distribution of micronutrient status) and having BMI or mid-upper arm circumference in the lowest third of the distribution for any of the nutrients. Leaving food on the plate was strongly associated with both low Fe status and low vitamin D status. Having breakfast cereal less than once per week was strongly associated with low folate status, while having fresh fruit juice less than once per week, having had less than two portions of fruits and vegetables the previous day and believing that food is not important for health were strongly associated with low vitamin C status. Low vitamin D status was strongly associated with a wide range of general health and disability measures. Having a weekly household income of less than pound 150 was associated with low status of Fe, folate, vitamin C and vitamin D.

Reference values for serum levels of vitamin B12 and folic acid in a population-based sample of adults between 35 and 80 years of age

OBJECTIVES

To examine folic acid and vitamin B12 status in a group of 1000 persons sampled from the community of Umeå, Sweden, and aged 35, 40, 45, 50, 55, 60, 65, 70, 75 or 80 years. Reference data for folate and age-stratified reference data for vitamin B12 are presented, together with an examination of potential confounders.

MEASUREMENTS

All subjects participated in extensive health examinations and interviews, and laboratory blood testing was performed.

RESULTS

A series of exclusion criteria were applied, and data from 961 subjects were analysed. Vitamin B12 levels were found to decrease with increasing age, whereas folate levels remained constant across the age span studied. None of the vitamins was found to vary with sex, education, smoking or alcohol consumption, body mass index, prescription-free vitamin supplements, level of haemoglobin, or mean cell volume of erythrocytes. Further, none of these factors was associated with the age-related decrease of vitamin B12 level.

CONCLUSIONS

The offered reference ranges should be used only in order to rule out deficiency. For B12 levels, the age of the subject should be considered such that, for elderly people in particular, values above the medians should be considered as indicative of normal vitamin status.