Validity of brief food frequency questionnaire for estimation of dietary intakes of folate, vitamins B6and B12, and their associations with plasma homocysteine concentrations

Depression and Vegetarians: Association between Dietary Vitamin B6, B12 and Folate Intake and Global and Subcortical Brain Volumes

Deficiency of vitamin B6 and vitamin B12, mostly in vegetarians, is found to be associated with depression and adverse neurological function. We investigated whether vitamin B6, B12, and folate have an effect on brain structure, especially among depressed people who follow a specific diet. The study sample comprised 9426 participants from the UK Biobank cohort with a mean age of 62.4 years. A generalized linear model controlling for age, sex, body mass index, ethnicity, town send deprivation index, educational qualification, smoking, and alcohol intake was used to test the association between study groups and structural brain volumes. Depression was more prevalent, and intake of vitamin B6 and B12 was lower among vegetarians, while non-vegetarians had a lower intake of folate. Overall, no significant association was observed between vitamin B6, B12, and folate intakes and both global and subcortical brain volumes among participants with depression. However, vitamin B12 intake was positively associated with right pallidum among non-depressed participants, and a significant interaction between vitamin B12 intake and depression status on the right pallidum was observed. Also, a significant interaction between folate intake and depression status on grey matter (GM) volume and left thalamus was observed. Upon diet stratification, folate intake is associated with total brain volume and GM volume among vegetarians with depression. Furthermore, no significant associations were observed for subcortical regions. Our findings suggest that dietary intake of vitamin B6 and B12 might have an effect on brain structure. Vegetarians, particularly those who suffer from depression may benefit from supplementing their diets with vitamins B6, B12, and folate to ensure brain health. Further studies, especially with a larger sample size and longitudinal design, are needed to confirm these findings.

The genomics of micronutrient requirements

Healthy nutrition is accepted as a cornerstone of public health strategies for reducing the risk of noncommunicable conditions such as obesity, cardiovascular disease, and related morbidities. However, many research studies continue to focus on single or at most a few factors that may elicit a metabolic effect. These reductionist approaches resulted in: (1) exaggerated claims for nutrition as a cure or prevention of disease; (2) the wide use of empirically based dietary regimens, as if one fits all; and (3) frequent disappointment of consumers, patients, and healthcare providers about the real impact nutrition can make on medicine and health. Multiple factors including environment, host and microbiome genetics, social context, the chemical form of the nutrient, its (bio)availability, and chemical and metabolic interactions among nutrients all interact to result in nutrient requirement and in health outcomes. Advances in laboratory methodologies, especially in analytical and separation techniques, are making the chemical dissection of foods and their availability in physiological tissues possible in an unprecedented manner. These omics technologies have opened opportunities for extending knowledge of micronutrients and of their metabolic and endocrine roles. While these technologies are crucial, more holistic approaches to the analysis of physiology and environment, novel experimental designs, and more sophisticated computational methods are needed to advance our understanding of how nutrition influences health of individuals.

Homocysteine levels in schizophrenia and affective disorders-focus on cognition

Although homocysteine (Hcy) has been widely implicated in the etiology of various physical health impairments, especially cardiovascular diseases, overwhelming evidence indicates that Hcy is also involved in the pathophysiology of schizophrenia and affective disorders. There are several mechanisms linking Hcy to biological underpinnings of psychiatric disorders. It has been found that Hcy interacts with NMDA receptors, initiates oxidative stress, induces apoptosis, triggers mitochondrial dysfunction and leads to vascular damage. Elevated Hcy levels might also contribute to cognitive impairment that is widely observed among patients with affective disorders and schizophrenia. Supplementation of vitamins B and folic acid has been proved to be effective in lowering Hcy levels. There are also studies showing that this supplementation strategy might be beneficial for schizophrenia patients with respect to alleviating negative symptoms. However, there are no studies addressing the influence of add-on therapies with folate and vitamins B on cognitive performance of patients with schizophrenia and affective disorders. In this article, we provide an overview of Hcy metabolism in psychiatric disorders focusing on cognitive correlates and indicating future directions and perspectives.

Relative validity and reproducibility of a quantitative FFQ for assessing nutrient intakes of vegetarians in Taiwan

OBJECTIVE

To assess the relative validity and reproducibility of the quantitative FFQ used in the Tzu Chi Health Study (TCHS).

DESIGN

The reproducibility was evaluated by comparing the baseline FFQ with the 2-year follow-up FFQ. The validity was evaluated by comparing the baseline FFQ with 3 d dietary records and biomarkers (serum folate and vitamin B12). Median comparison, cross-classification and Spearman correlation with and without energy adjustment and deattenuation for day-to-day variation were assessed.

SETTING

TCHS is a prospective cohort containing a high proportion of true vegetarians and part-time vegetarians (regularly consuming a vegetarian diet without completely avoiding meat).

SUBJECT

Subsets of 103, seventy-eight and 1528 TCHS participants were included in the reproducibility, dietary record-validity and biomarker-validity studies, respectively.

RESULTS

Correlations assessing the reproducibility for repeat administrations of the FFQ were in the range of 0·46-0·65 for macronutrients and 0·35-0·67 for micronutrients; the average same quartile agreement was 40%. The correlation between FFQ and biomarkers was 0·41 for both vitamin B12 and folate. Moderate to good correlations between the baseline FFQ and dietary records were found for energy, protein, carbohydrate, saturated and monounsaturated fat, fibre, vitamin C, vitamin A, K, Ca, Mg, P, Fe and Zn (average crude correlation: 0·47 (range: 0·37-0·66); average energy-adjusted correlation: 0·43 (range: 0·38-0·55); average energy-adjusted deattenuated correlation: 0·50 (range: 0·44-0·66)) with same quartile agreement rate of 39% (range: 35-45%), while misclassification to the extreme quartile was rare (average: 4% (range: 0-6%)).

CONCLUSIONS

The FFQ is a reliable and valid tool to rank relative intake of major nutrients for TCHS participants.

The folate status of reproductive-aged women in a randomised trial of a folate-fortified oral contraceptive: dietary and blood assessments

OBJECTIVE

To assess the folate status of US women in a study of a folate-fortified oral contraceptive (OC) using the Short Folate Food Frequency Questionnaire and plasma and red blood cell (RBC) folate samples.

DESIGN

Sub-analysis from a multi-centre, randomised, double-blind, controlled contraceptive trial with assessments at baseline and 6 months. We calculated dietary folate equivalents (DFE) consumed and the proportion of participants meeting folate adequacy benchmarks.

SETTING

Eight centres in the USA.

SUBJECTS

Healthy women aged 18-40 years requesting contraception with no contraindications for OC use.

RESULTS

Overall, 385 participants were randomised to either a novel folate-fortified OC or a marketed OC. The 262 (68 %) participants compliant with the protocol were included in the analysis set. Baseline daily DFE consumption was 529·8 (sd 342·1) μg and similar in both groups. At follow-up, the fortified OC group had higher intake than the conventional OC group (1225·9 (sd 346·2) μg compared with 500·6 (sd 361·2) μg). Mean plasma folate level increased from 44·5 (sd 17·2) to 55·8 (sd 21·1) nmol/l. Mean RBC folate level increased from 996·7 (sd 369·8) to 1311·9 (sd 436·0) nmol/l. The proportion meeting selected folate adequacy benchmarks increased in the fortified OC group (P < 0·001).

CONCLUSIONS

Lack of adequate folate intake in reproductive-aged women from dietary sources or supplements alone suggests the need for novel approaches. Use of folate-fortified OC ensures adequate folate levels and meeting of folate benchmarks.

The biomarker-based validity of a food frequency questionnaire to assess the intake status of folate, pyridoxine and cobalamin among Iranian primary breast cancer patients

BACKGROUND/OBJECTIVES

Folate, pyridoxine and cobalamin are coenzymatically essential in one-carbon methyl metabolism, and their deficiencies could explain some alterations during breast carcinogenesis. We aimed to evaluate the validity of folate, pyridoxine and cobalamin estimates from a food frequency questionnaire (FFQ) on the basis of their corresponding fasting plasma biomarkers, in breast cancer (BC) patients.

SUBJECTS/METHODS

In a prospective, consecutive case series, 149 women with primary BC aged between 30 and 69 years as a representative sample of Iranian women with BC were recruited. The 136-item FFQ was used for the validity assay. Fasting plasma folate and cobalamin were tested by automated electrochemiluminescence. The high-pressure liquid chromatography with fluorescence detection was used to determine the plasma levels of pyridoxal-5'-phosphate (PLP) and total homocysteine (tHcy).

RESULTS

Area under the curve (AUC) for assessing the diagnostic accuracy of folate-related data through an FFQ was 0.74 (P<0.01) in the reference model (folate plasma level<5.9 ng/ml), with sensitivity and specificity of 68% and 63%, respectively. The positive and negative predictive values (PPV and NPV) were 96.9% and 96.8%, respectively. The AUC for cobalamin intake in the reference model (plasma cobalamin<260 pmol/l) was 0.64 (P<0.01), with 60% sensitivity and 61% specificity. Although tHcy ≥10.0 μmol/l was used as reference indicator, the folate intake (AUC=0.71, P<0.01) and cobalamin intake status (AUC=0.67, P<0.05) were also determined appropriately by FFQ.

CONCLUSIONS

Dietary folate and cobalamin estimates from FFQ were significantly correlated with their fasting plasma concentrations. Our data supported the validity of new FFQ to rank individuals by dietary intake status of folate and cobalamin.

Dietary folate intake and blood biomarkers reveal high-risk groups in a Mediterranean population of healthy women of childbearing potential

BACKGROUND/AIMS

An important public health issue is monitoring folate inadequacy in women of childbearing potential. The aim of the present study was to investigate associations between folate intake, red blood cell (RBC) folate, total homocysteine (tHcy) and the MTHFR 677T allele.

METHODS

A total of 204 women were enrolled in a cross-sectional study. Folate intake was assessed by a food frequency questionnaire, and RBC folate, tHcy and MTHFR C677T genotype were determined.

RESULTS

About half of the women had a decreased RBC folate level (<305 nmol/l) and all were <906 nmol/l, even though 51% of the subjects reported use of supplements. Overall 91.5% had a high Hcy concentration. Notably, younger women, and those with a low level of education, were shown to be at higher risk of inadequate RBC folate levels. Additionally, younger women were also at higher risk of carrying the TT genotype, particularly unfavorable in the setting of a low folate status.

CONCLUSIONS

Our study revealed significant folate deficiency in our Mediterranean population and higher than ideal Hcy concentrations, thus emphasizing that in these groups an improvement in the folate status is needed via a food-based approach or supplement. Consequently, public health policy strategies aiming at improved supplementation are required.