Epigenetic effects of folate and related B vitamins on brain health throughout life: Scientific substantiation and translation of the evidence for health improvement strategies

Impact of varying maternal dietary folate intake on cerebellar cortex histomorphology and cell density in offspring rats

The cerebellum has a long, protracted developmental period that spans from the embryonic to postnatal periods; as a result, it is more sensitive to intrauterine and postnatal insults like nutritional deficiencies. Folate is crucial for foetal and early postnatal brain development; however, its effects on cerebellar growth and development are unknown. The aim of this study was to examine the effects of maternal folate intake on the histomorphology and cell density of the developing cerebellum. Twelve adult female rats (rattus norvegicus) were randomly assigned to one of four premixed diet groups: standard (2 mg/kg), folate-deficient (0 mg/kg), folate-supplemented (8 mg/kg) or folate supra-supplemented (40 mg/kg). The rats started their diets 14 days before mating and consumed them throughout pregnancy and lactation. On postnatal days 1, 7, 21 and 35, five pups from each group were sacrificed, and their brains were processed for light microscopic analysis. Histomorphology and cell density of the external granule, molecular, Purkinje and internal granule layers were obtained. The folate-deficient diet group had smaller, dysmorphic cells and significantly lower densities of external granule, molecular, Purkinje and internal granule cells. Although the folate-enriched groups had greater cell densities than the controls, the folate-supplemented group had considerably higher cell densities than the supra-supplemented group. The folate supra-supplemented group had ectopic Purkinje cells in the internal granule cell layer. These findings imply that a folate-deficient diet impairs cellular growth and reduces cell density in the cerebellar cortex. On the other hand, folate supplementation increases cell densities, but there appears to be an optimal dose of supplementation since excessive folate levels may be detrimental.

Maternal usage of varying levels of dietary folate affects the postnatal development of cerebellar folia and cortical layer volumes

OBJECTIVE

The cerebellum has a long, protracted developmental period; therefore, it is more sensitive to intrauterine and postnatal insults like nutritional deficiencies. Folate is an essential nutrient in fetal and postnatal brain development, and its supplementation during pregnancy is widely recommended. This study aimed to describe the effects of maternal folate intake on postnatal cerebellum development.

METHODS

Twelve adult female Rattus norwegicus (6-8 weeks old) rats were randomly assigned to one of four groups and given one of four premixed diets: a standard diet (2 mg/kg), a folate-deficient (folate 0 mg/kg), folate-supplemented (8 mg/kg), or folate supra-supplemented (40 mg/kg). The rats began consuming their specific diets 14 days before mating and were maintained on them throughout pregnancy and lactation. Five pups from each group were sacrificed, and their brains processed for light microscopic examination on postnatal days 1, 7, 21, and 35. The data gathered included the morphology of the cerebellar folia and an estimate of the volume of the cerebellar cortical layer using the Cavalieri method.

RESULTS

Folia of the folate-supplemented and supra-supplemented groups were thicker and showed extensive branching with sub-lobule formation. The folate-deficient diet group's folia were smaller, had more inter-folial spaces, or fused. When compared to the folate-deficient group, the volumes of the cerebellum and individual cerebellar cortical layers were significantly larger in the folate-supplemented and supra-supplemented groups (p<0.05).

CONCLUSION

Folate supplementation during pregnancy and lactation improves the degree and complexity of the cerebellar folia and the volumes of individual cerebellar cortical layers.

Dietary intake, nutritional adequacy and food sources of vitamins involved in the methionine-methylation cycle from Spanish children aged one to <10 years: results from the EsNuPI study

Background

Methionine-methylation cycle and the derived critical functions during infancy are key regulated by folates, vitamins B12, and B6. At present in Spain, there is an absence of studies that assess the intakes and dietary sources of total folates and B12 by children consuming all types of milks and those regularly consuming adapted milk formulas. Thus, our aim was to evaluate folates intakes alongside with vitamins B6 and B12 while describing their major dietary contributors in Spanish children aged one to <10 years.

Methods

A total of 1,448 children aged between 1 and 10 years (49.7% girls and 50.3% boys) from the EsNuPI, a prospective cross-sectional study, were allocated into two cohorts: one Spanish Reference Cohort (SRS) of the general population (n = 707), and another including children consuming adapted milks called Adapted Milk Consumers Cohort (AMS) (n = 741) completed two 24 h dietary recalls used to estimate their nutrient intakes and to compare them to the European Food Safety Authority (EFSA) Population Reference Intakes.

Results

The median intake of vitamin B6 was 1.35 (1.06-1.70) mg/day in the SRS and 1.45 (1.17-1.79) mg/day in the AMS, being significantly higher in the AMS for all age-groups. Prevalence of adequacy for vitamin B6 in the SRS and AMS was 97.7 and 98.7%, respectively. Total folates intakes in the AMS were significantly higher (p ≤ 0.001) in all age groups than in the SRS, independently of age. In addition, the prevalence of adequacy for folates intakes in all groups was more than 60%. Vitamin B12 intake increased with age independently of the type of milk consumed. The prevalence of adequacy for vitamin B12 was highly compliant by all population groups. The major contributors to vitamin B6 were milk and dairy products being significantly higher in AMS than SRS (p ≤ 0.001). The highest contributors to folates intakes were milk and dairy products, cereals, vegetables, and fruits in both groups whereas for vitamin B12 in the SRS sample were milk and dairy products followed by meat and meats products and for adapted milks, were milk and dairy products, followed by eggs, then meat and meats products.

Conclusion

A satisfactory prevalence of adequacy for vitamins B6, and B12 amongst the Spanish children population was observed, which was not the case for folates, regardless of the dietary group evaluated. Nevertheless, a possible strategy to increase folate intake among the youngest children is to increase the consumption of milk and dairy products within a healthier dietary pattern, as these may contribute significantly to the vitamin needs of the infant population.