Blood folate status and expression of proteins involved in immune function, inflammation, and coagulation: biochemical and proteomic changes in the plasma of humans in response to long-term synthetic folic acid supplementation

Progressive reduction in circulating levels of carotenoids and other micronutrients in patients with chronic pancreatitis

BACKGROUND

Although micronutrients modulate immunity and inflammation, it remains elusive whether they are implicated in the development and progression of chronic pancreatitis (CP). This study aimed to investigate differences in the circulating levels of selected carotenoids and vitamins between CP and controls and trends in the levels of these micronutrients across controls, early CP, and definite CP.

METHODS

Demographic and lifestyle data were extracted from medical records for 53 patients with CP (13 early and 38 definite) and obtained using a questionnaire for 52 controls. Plasma β-carotene, lycopene, cryptoxanthin, zeaxanthin, and α-tocopherol and serum 25(OH)D, folate, IL-6, TNF-α, and MCP-1 were measured with state-of-the-art methods.

RESULTS

The levels of all micronutrients (except folate) were significantly lower in CP than in controls. There was a progressive decrease in the levels of these micronutrients across controls, early CP, and definite CP (all p values for trend: ≤0.0012); e.g., plasma lycopene was 36.6, 21.5, and 14.5 μg/dL for controls, early CP, and definite CP, respectively. After adjustment for confounders, there were strong, inverse associations between the levels of all micronutrients (except folate) and CP (e.g., OR (95% CI) for ≥ median vs. <median: 0.10 (0.04, 0.27) for lycopene, 0.15 (0.05, 0.38) for α-tocopherol, and 0.24 (0.09, 0.64) for 25(OH)D). These associations became weaker after additional adjustment for inflammation markers (IL-6, TNF-α, and MCP-1).

CONCLUSIONS

The circulating levels of some carotenoids, α-tocopherol, and vitamin D were reduced in CP patients compared with controls and this reduction was more pronounced in definite CP than in early CP.

Genetically Predicted Circulating Concentrations of Micronutrients and COVID-19 Susceptibility and Severity: A Mendelian Randomization Study

Background

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which since 2019 has caused over 5 million deaths to date. The pathogenicity of the virus is highly variable ranging from asymptomatic to fatal. Evidence from experimental and observational studies suggests that circulating micronutrients may affect COVID-19 outcomes.

Objectives

To complement and inform observational studies, we investigated the associations of genetically predicted concentrations of 12 micronutrients (β-carotene, calcium, copper, folate, iron, magnesium, phosphorus, selenium, vitamin B-6, vitamin B-12, vitamin D, and zinc) with SARS-CoV-2 infection risk and COVID-19 severity using Mendelian randomization (MR).

Methods

Two-sample MR was conducted using 87,870 individuals of European descent with a COVID-19 diagnosis and 2,210,804 controls from the COVID-19 host genetics initiative. Inverse variance-weighted MR analyses were performed with sensitivity analyses to assess the impact of potential violations of MR assumptions.

Results

Compared to the general population, nominally significant associations were noted for higher genetically predicted vitamin B-6 (Odds ratio per standard deviation [OR_SD]: 1.06; 95% confidence interval [CI]: 1.00, 1.13; p-value = 0.036) and lower magnesium concentrations (OR_SD: 0.33; 95%CI: 0.11, 0.96; P = 0.042) with COVID-19 infection risk. However, the association for magnesium was not consistent in some sensitivity analyses, and sensitivity analyses could not be performed for vitamin B-6 as only two genetic instruments were available. Genetically predicted levels of calcium, folate, β-carotene, copper, iron, vitamin B-12, vitamin D, selenium, phosphorus, or zinc were not associated with the outcomes from COVID-19 disease.

Conclusion

These results, though based only on genetically predicated circulating micronutrient concentrations, provide scant evidence for possible associations of micronutrients with COVID-19 outcomes.

Folate Intake and Risk of Urothelial Carcinoma: A Systematic Review and Meta-Analysis of Epidemiological Studies

We aimed to investigate the association between folate intake and the risk of urothelial carcinoma (UC). A systematic literature search using Pubmed and EMBASE databases was performed to find prospective cohort studies, population-based case-control study or hospital-based case-control study investigating the association of folate intake and the risk of UC. A total of 19 studies involving 11,175 cases and 656,161 individuals were included. High intake of folate was associated with a decreased risk of UC, with a pooled OR of 0.78 (95% CI: 0.66-0.93, P = 0.006) for the highest category of intake vs. the lowest. The data suggested that folate may contribute to the prevention of urothelial cancer. However, the association was observed only in case-control studies (OR = 0.56, 95% CI: 0.39-0.79, P = 0.001), but not in cohort studies (RR = 0.97, 95% CI: 0.87-1.09, P = 0.638). Dose-response meta-analysis showed that an increment of folate intake (100 μg/day) corresponded to an 8% deceased risk of invasive UC (RR = 0.92, 95% CI: 0.87-0.98, P = 0.004). High folate intake might be inversely associated with risk of UC particularly invasive UC, which needs to be confirmed.

Effects of Citrus Fruit Juices and Their Bioactive Components on Inflammation and Immunity: A Narrative Review

The immune system provides defence to the host against pathogenic organisms. A weak immune system increases susceptibility to infections and allows infections to become more severe. One component of the immune response is inflammation. Where inflammation is excessive or uncontrolled it can damage host tissues and cause pathology. Limitation of oxidative stress is one means of controlling inflammation. Citrus fruit juices are a particularly good source of vitamin C and folate, which both have roles in sustaining the integrity of immunological barriers and in supporting the function of many types of immune cell including phagocytes, natural killer cells, T-cells and B-cells. Vitamin C is an antioxidant and reduces aspects of the inflammatory response. Important bioactive polyphenols in citrus fruit juices include hesperidin, narirutin and naringin. Hesperidin is a glycoside of hesperetin while narirutin and naringin are glycosides of naringenin. Hesperidin, hesperetin, naringenin, naringin and narirutin have all been found to have anti-inflammatory effects in model systems, and human trials of hesperidin report reductions in inflammatory markers. In humans, orange juice was shown to limit the post-prandial inflammation induced by a high fat-high carbohydrate meal. Consuming orange juice daily for a period of weeks has been reported to reduce markers of inflammation, including C-reactive protein, as confirmed through a recent meta-analysis. A newly emerging topic is whether polyphenols from orange juice have direct anti-viral effects. In summary, micronutrients and other bioactives present in citrus fruit juices have established roles in controlling oxidative stress and inflammation and in supporting innate and acquired immune responses. Trials in humans demonstrate that orange juice reduces inflammation; its effects on innate and acquired immunity require further exploration in well-designed trials in appropriate population sub-groups such as older people.

Nutritional management of diabetes mellitus during the pandemic of COVID-19: a comprehensive narrative review

Objectives

According to the recent epidemiological studies, patients with diabetes mellitus (DM) may be at higher risk of hospitalization due to COVID-19. Regarding the important role of nutrition on the immunity, the present review article aimed to outline nutritional support of DM during the outbreak of COVID-19 with a mechanistic insight.

Methods

Searches were performed in PubMed/MEDLINE, ScienceDirect, Scopus, and Google Scholar databases from 2000 until December 2020 using the following keywords. All relevant clinical and experimental studies published in English were included.

Results

Evidences revealed that hyperglycemia is a significant predictor of some viral infections including COVID-19 which can exacerbate the complications of DM. According to the literature review, adequate intake of dietary protein, fiber, essential fatty acids and some micronutrients especially vitamins D, C, B12, folate, zinc and selenium has beneficial effects on the prevention and treatment of COVID-19 in diabetic patients through modulation of innate and adaptive immune responses or direct effects on virus enzymes or the rate of cell entrance.

Conclusions

It is well understood that malnutrition may increase susceptibility to viral infections and disease progression. Therefore, considering nutritional status of diabetic patients and reasonable supplementation of the above mentioned nutrients can ameliorate the symptoms of COVID-19 in DM. However, further well-designed clinical trials are needed to determine their therapeutic dose.

Nutritional approach for increasing public health during pandemic of COVID-19: A comprehensive review of antiviral nutrients and nutraceuticals

Background: The novel coronavirus (COVID-19) is considered as the most life-threatening pandemic disease during the last decade. The individual nutritional status, though usually ignored in the management of COVID-19, plays a critical role in the immune function and pathogenesis of infection. Accordingly, the present review article aimed to report the effects of nutrients and nutraceuticals on respiratory viral infections including COVID-19, with a focus on their mechanisms of action. Methods: Studies were identified via systematic searches of the databases including PubMed/ MEDLINE, ScienceDirect, Scopus, and Google Scholar from 2000 until April 2020, using keywords. All relevant clinical and experimental studies published in English were included. Results: Protein-energy malnutrition (PEM) is common in severe respiratory infections and should be considered in the management of COVID-19 patients. On the other hand, obesity can be accompanied by decreasing the host immunity. Therefore, increasing physical activity at home and a slight caloric restriction with adequate intake of micronutrients and nutraceuticals are simple aids to boost host immunity and decrease the clinical manifestations of COVID-19. Conclusion: The most important nutrients which can be considered for COVID-19 management are vitamin D, vitamin C, vitamin A, folate, zinc, and probiotics. Their adequacy should be provided through dietary intake or appropriate supplementation. Moreover, adequate intake of some other dietary agents including vitamin E, magnesium, selenium, alpha linolenic acid and phytochemicals are required to maintain the host immunity.

Maternal periconceptional folate status and infant atopic dermatitis: A prospective cohort study

BACKGROUND

Maternal folate status is linked with the risk of allergic disorders including atopic dermatitis (AD) in children, but findings remain inconclusive. We aim to assess the relationship between maternal folate status in early gestation and early-onset infant AD, based on a prospective mother-child cohort study.

METHODS

Pregnant women were recruited at 12-14 weeks of gestation. Red blood cell folate (RBC folate) and serum folate concentrations were examined at enrollment. Periconceptional folic acid supplementation was investigated through a self-administered questionnaire. The primary outcome was AD incidence before 6 months of age, diagnosed according to Williams' criteria. Multivariate logistic regression was used to evaluate associations of maternal folate status with infant AD by adjusting parental and child covariates.

RESULTS

In total, 107 (23.4%) of 458 infants developed AD before 6 months, with more male infants affected (P = .002). Higher maternal RBC folate levels (per 100 ng/mL) were associated with an increased risk of AD (adjusted odds ratio [aOR] 1.16, 95% confidence interval [CI] 1.04-1.31). An RBC folate level ≥620 ng/mL was associated with increased infant AD by 91% (aOR 1.91, 95% CI 1.09-3.36). However, associations were not observed for maternal serum folate at early gestation or periconceptional folic acid supplement intakes.

CONCLUSIONS

We provide the first evidence that higher maternal RBC folate concentrations during early gestation are associated with increased early-onset infant AD. Our findings support the importance of maintaining appropriate folate levels during the periconceptional period to reduce the risk of AD in infants.

Investigation of the natural supplement IQP-AS-119 for the prevention of upper respiratory tract infections in marathon race participants: A randomized, double-blind, placebo-controlled pilot study

Intense and prolonged exercise leads to immune suppression, causing upper respiratory tract infections (URTI). A proprietary standardized dietary supplement, IQP-AS-119 has been previously developed to aid immune responses under such conditions. The current randomized, double-blind, placebo-controlled pilot study aimed to investigate the effects of IQP-AS-119 on marathon runners. A total of 80 participants were randomized equally into groups receiving either placebo (P group) or IQP-AS-119 (V group) treatment, starting 3 weeks before and for 14 days after the marathon. Benefit assessment was performed using different questionnaires. Post-marathon, the V and P groups reported 1±2.38 and 2.11±3.25 days with upper respiratory tract symptoms (URTS), respectively (P=0.038). During the 14 days post-marathon, 20.0% of the participants in the V group compared with 44.4% in the P group reported URTS (P=0.042). The V group reported significantly milder URTS compared with the P group on Days 9, 12, 13 and 14 post-marathon (P<0.05). The total Perceived Stress Questionnaire-20 score on days 2-14 were significantly lower for the V group compared with the P group (P=0.035). In the Short Form 12 Health Survey, the V group exhibited significant improvement in mental composite score on days -5 to 14 compared with the P group (P=0.038). In the overall treatment effect assessment, there were no statistically significant differences between the groups. The IQP-AS-119 was rated ‘very good’ or ‘good’ by investigators and participants, respectively, for 71 and 65% of the participants. The tolerability of IQP-AS-119 was rated as ‘very good’ or ‘good’ by both investigators and 95% of participants. No clinically relevant differences were observed between groups regarding adverse events or other safety parameters. Therefore, IQP-AS-119 was demonstrated to reduce the incidence and severity of URTI in marathon runners. Given its good tolerability profile, IQP-AS-119 may be a good nutritional supplement for the reduction of URTS in susceptible individuals.

Systemic vitamin intake impacting tissue proteomes

The kinetics and localization of the reactions of metabolism are coordinated by the enzymes that catalyze them. These enzymes are controlled via a myriad of mechanisms including inhibition/activation by metabolites, compartmentalization, thermodynamics, and nutrient sensing-based transcriptional or post-translational regulation; all of which are influenced as a network by the activities of metabolic enzymes and have downstream potential to exert direct or indirect control over protein abundances. Considering many of these enzymes are active only when one or more vitamin cofactors are present; the availability of vitamin cofactors likely yields a systems-influence over tissue proteomes. Furthermore, vitamins may influence protein abundances as nuclear receptor agonists, antioxidants, substrates for post-translational modifications, molecular signal transducers, and regulators of electrolyte homeostasis. Herein, studies of vitamin intake are explored for their contribution to unraveling vitamin influence over protein expression. As a body of work, these studies establish vitamin intake as a regulator of protein abundance; with the most powerful demonstrations reporting regulation of proteins directly related to the vitamin of interest. However, as a whole, the field has not kept pace with advances in proteomic platforms and analytical methodologies, and has not moved to validate mechanisms of regulation or potential for clinical application.

Role of nutrition in immune response: Case of Covid-19

The relationships between nutrition and immunity have been the subject of several studies. The main fact lies in the deep entanglement between immunity, and nutritional state: all deficiencies in proteins, essential fatty acids, metallo-enzymes, vitamin factors, and antioxidant elements lead to a dysfunction of the immune system. On the other hand, some excess food (total lipid intake, type of fatty acids, simple sugars, etc.) can, also, have deleterious effects. The emergence of new infectious diseases with new pathogenic properties is a serious global health problem. Covid-19 infection (Coronavirus Disease-2019) caused by the coronavirus SARS-CoV2 (Severe Acute Respiratory Syndrome Coronavirus-2), is recognized as pandemic by the World Health Organization (WHO).This implies strict prevention measures, and a strategy to be developed throughout good hygiene, healthy and balanced diet, and compliance with the con-finement rules.

Association Between One-carbon Metabolism-related Vitamins and Risk of Breast Cancer: A Systematic Review and Meta-analysis of Prospective Studies

Epidemiologic studies focusing on the association between 1-carbon metabolism-related vitamins (ie, folate, vitamin B₆, vitamin B₂, vitamin B₁₂) and breast cancer risk have reported inconsistent findings. We conducted a systematic search of the reported data and performed a meta-analysis of prospective case-control and cohort studies to derive a more precise evaluation. The PubMed and EMBASE databases were searched to identify eligible studies. A total of 27 studies involving 49,707 cases and 1,274,060 individuals were included in the meta-analysis. The results indicated that a high intake of folate, vitamin B₆, and vitamin B₂ might decrease the risk of breast cancer. The corresponding pooled relative risks (RRs) for the highest intake compared with the lowest were 0.93 (95% confidence interval [CI], 0.88-0.99; P = .018), 0.94 (95% CI, 0.89-1.00; P = .037) and 0.90 (95% CI, 0.82-0.99; P = .026). No significant association between vitamin B₁₂ and breast cancer risk was found (RR, 0.99; 95% CI, 0.94-1.04; P = .604). Further study showed that folate and vitamin B₆ might decrease the risk of estrogen receptor-negative (ER^-)/progesterone receptor-negative (PR^-) breast cancer but not ER⁺/PR⁺ breast cancer. The dose-response meta-analysis indicated a significant linearity relationship between folate intake and a reduced risk of ER^-/PR^- breast cancer. An increment of folate intake (100 μg/d) corresponded to a 7% deceased risk of ER^-/PR^- breast cancer (RR, 0.93; 95% CI, 0.89-0.98; P = .007). In conclusion, a high intake of 1-carbon metabolism-related vitamins might contribute to the prevention of breast cancer, especially ER^-/PR^- breast cancer.

Effect of Dietary Folic Acid Supplementation during Pregnancy on Blood Characteristics and Milk Composition of Ewes

The objective of the present study was to investigate the dynamic change of serum parameters and milk composition by dietary FA supplementation with ewes with different litter size from mating to lambing. The ewes were divided into six treatments (TW-CON, TW-F16, TW-F32, TR-CON, TR-F16, TR-F32) according to dietary FA levels (control, CON; 16 or 32 mg·kg^-1 rumen-protect-FA supplementation, F16 and F32) and litter size (twin born, TW; and triplet born, TR). In serum, the concentration of folate increased linearly with dietary FA supplementation (P < 0.05), regardless of the litter size, they showed a quadratic response to gestation progression (P < 0.05). With dietary FA addition, IGFI-I levels significant increased from late gestation to after lambing (P < 0.05), and linearly increased immunoglobulin during the perinatal period (P < 0.05). In colostrum and milk at d 15, the content of folate, lactoferrin, and IgG were affected positively by FA supplementation (P < 0.05). IgG was higher in the TW group than TR in colostrum (P < 0.05), and lactoferrin in TW was lower than TR in milk of d 15 (P < 0.05). FA supplementation increased protein content in colostrum (P < 0.05), while it had no effect on the fat, lactose, and BUN of colostrum and milk of d 15 (P > 0.05). These results suggest that FA supplementation during gestation could regulate maternal blood metabolism and contribute to milk immune composition.

Skin fairness is a better predictor for impaired physical and mental health than hair redness

About 1-2% of people of European origin have red hair. Especially female redheads are known to suffer higher pain sensitivity and higher incidence of some disorders, including skin cancer, Parkinson's disease and endometriosis. Recently, an explorative study performed on 7,000 subjects showed that both male and female redheads score worse on many health-related variables and express a higher incidence of cancer. Here, we ran the preregistered study on a population of 4,117 subjects who took part in an anonymous electronic survey. We confirmed that the intensity of hair redness negatively correlated with physical health, mental health, fecundity and sexual desire, and positively with the number of kinds of drugs prescribed by a doctor currently taken, and with reported symptoms of impaired mental health. It also positively correlated with certain neuropsychiatric disorders, most strongly with learning disabilities disorder and phobic disorder in men and general anxiety disorder in women. However, most of these associations disappeared when the darkness of skin was included in the models, suggesting that skin fairness, not hair redness, is responsible for the associations. We discussed two possible explanations for the observed pattern, the first based on vitamin D deficiency due to the avoidance of sunbathing by subjects with sensitive skin, including some redheads, and second based on folic acid depletion in fair skinned subjects, again including some (a different subpopulation of) redheads. It must be emphasized, however, that both of these explanations are only hypothetical as no data on the concentration of vitamin D or folic acid are available for our subjects. Our results, as well as the conclusions of current reviews, suggest that the new empirical studies on the concentration of vitamin D and folic acids in relation to skin and hair pigmentation are urgently needed.

Review of cobalamin status and disorders of cobalamin metabolism in dogs

Disorders of cobalamin (vitamin B₁₂) metabolism are increasingly recognized in small animal medicine and have a variety of causes ranging from chronic gastrointestinal disease to hereditary defects in cobalamin metabolism. Measurement of serum cobalamin concentration, often in combination with serum folate concentration, is routinely performed as a diagnostic test in clinical practice. While the detection of hypocobalaminemia has therapeutic implications, interpretation of cobalamin status in dogs can be challenging. The aim of this review is to define hypocobalaminemia and cobalamin deficiency, normocobalaminemia, and hypercobalaminemia in dogs, describe known cobalamin deficiency states, breed predispositions in dogs, discuss the different biomarkers of importance for evaluating cobalamin status in dogs, and discuss the management of dogs with hypocobalaminemia.

Targeted proteomic response to coffee consumption

PURPOSE

Coffee is widely consumed and implicated in numerous health outcomes but the mechanisms by which coffee contributes to health is unclear. The purpose of this study was to test the effect of coffee drinking on candidate proteins involved in cardiovascular, immuno-oncological and neurological pathways.

METHODS

We examined fasting serum samples collected from a previously reported single blinded, three-stage clinical trial. Forty-seven habitual coffee consumers refrained from drinking coffee for 1 month, consumed 4 cups of coffee/day in the second month and 8 cups/day in the third month. Samples collected after each coffee stage were analyzed using three multiplex proximity extension assays that, after quality control, measured a total of 247 proteins implicated in cardiovascular, immuno-oncological and neurological pathways and of which 59 were previously linked to coffee exposure. Repeated measures ANOVA was used to test the relationship between coffee treatment and each protein.

RESULTS

Two neurology-related proteins including carboxypeptidase M (CPM) and neutral ceramidase (N-CDase or ASAH2), significantly increased after coffee intake (P < 0.05 and Q < 0.05). An additional 46 proteins were nominally associated with coffee intake (P < 0.05 and Q > 0.05); 9, 8 and 29 of these proteins related to cardiovascular, immuno-oncological and neurological pathways, respectively, and the levels of 41 increased with coffee intake.

CONCLUSIONS

CPM and N-CDase levels increased in response to coffee intake. These proteins have not previously been linked to coffee and are thus novel markers of coffee response worthy of further study. CLINICAL TRIAL REGISTRY: http://www.isrctn.com/ISRCTN12547806.

Biological Activities, Health Benefits, and Therapeutic Properties of Avenanthramides: From Skin Protection to Prevention and Treatment of Cerebrovascular Diseases

Oat (Avena sativa) is a cereal known since antiquity as a useful grain with abundant nutritional and health benefits. It contains distinct molecular components with high antioxidant activity, such as tocopherols, tocotrienols, and flavanoids. In addition, it is a unique source of avenanthramides, phenolic amides containing anthranilic acid and hydroxycinnamic acid moieties, and endowed with major beneficial health properties because of their antioxidant, anti-inflammatory, and antiproliferative effects. In this review, we report on the biological activities of avenanthramides and their derivatives, including analogs produced in recombinant yeast, with a major focus on the therapeutic potential of these secondary metabolites in the treatment of aging-related human diseases. Moreover, we also present recent advances pointing to avenanthramides as interesting therapeutic candidates for the treatment of cerebral cavernous malformation (CCM) disease, a major cerebrovascular disorder affecting up to 0.5% of the human population. Finally, we highlight the potential of foodomics and redox proteomics approaches in outlining distinctive molecular pathways and redox protein modifications associated with avenanthramide bioactivities in promoting human health and contrasting the onset and progression of various pathologies. The paper is dedicated to the memory of Adelia Frison.

Effect of increasing fruit and vegetable intake by dietary intervention on nutritional biomarkers and attitudes to dietary change: a randomised trial

PURPOSE

Low fruit and vegetable consumption is linked with an increased risk of death from vascular disease and cancer. The benefit of eating fruits and vegetables is attributed in part to antioxidants, vitamins and phytochemicals. Whether increasing intake impacts on markers of disease remains to be established. This study investigates whether increasing daily intake of fruits, vegetables and juices from low (approx. 3 portions), to high intakes (approx. 8 portions) impacts on nutritional and clinical biomarkers. Barriers to achieving the recommended fruit and vegetable intakes are also investigated.

METHOD

In a randomised clinical trial, the participants [19 men and 26 women (39-58 years)] with low reported fruit, juice and vegetable intake (<3 portions/day) were randomised to consume either their usual diet or a diet supplemented with an additional 480 g of fruit and vegetables and fruit juice (300 ml) daily for 12 weeks. Nutritional biomarkers (vitamin C, carotenoids, B vitamins), antioxidant capacity and genomic stability were measured pre-intervention, at 4-, 8- and 12 weeks throughout the intervention. Samples were also taken post-intervention after a 6-week washout period. Glucose, homocysteine, lipids, blood pressure, weight and arterial stiffness were also measured. Intake of fruit, fruit juice and vegetables was reassessed 12 months after conducting the study and a questionnaire was developed to identify barriers to healthy eating.

RESULTS

Intake increased significantly in the intervention group compared to controls, achieving 8.4 portions/day after 12 weeks. Plasma vitamin C (35%), folate (15%) and certain carotenoids [α-carotene (50%) and β-carotene (70%) and lutein/zeaxanthin (70%)] were significantly increased (P < 0.05) in the intervention group. There were no significant changes in antioxidant capacity, DNA damage and markers of vascular health. Barriers to achieving recommended intakes of fruits and vegetables measured 12 months after the intervention period were amount, inconvenience and cost.

CONCLUSION

While increasing fruit, juice and vegetable consumption increases circulating level of beneficial nutrients in healthy subjects, a 12-week intervention was not associated with effects on antioxidant status or lymphocyte DNA damage.

TRIAL REGISTRATION

This trial was registered at Controlled-Trials.com; registration ISRCTN71368072.

The Vitamin D⁻Folate Hypothesis as an Evolutionary Model for Skin Pigmentation: An Update and Integration of Current Ideas

Vitamin D is unique in being generated in our skin following ultraviolet radiation (UVR) exposure. Ongoing research into vitamin D must therefore always consider the influence of UVR on vitamin D processes. The close relationship between vitamin D and UVR forms the basis of the “vitamin D–folate hypothesis”, a popular theory for why human skin colour has evolved as an apparent adaption to UVR environments. Vitamin D and folate have disparate sensitivities to UVR; whilst vitamin D may be synthesised following UVR exposure, folate may be degraded. The vitamin D–folate hypothesis proposes that skin pigmentation has evolved as a balancing mechanism, maintaining levels of these vitamins. There are several alternative theories that counter the vitamin D–folate hypothesis. However, there is significant overlap between these theories and the now known actions of vitamin D and folate in the skin. The focus of this review is to present an update on the vitamin D–folate hypothesis by integrating these current theories and discussing new evidence that supports associations between vitamin D and folate genetics, UVR, and skin pigmentation. In light of recent human migrations and seasonality in disease, the need for ongoing research into potential UVR-responsive processes within the body is also discussed.

Folic acid modulates cancer-associated micro RNAs and inflammatory mediators in neoplastic and non-neoplastic colonic cells in a different way

SCOPE

Scientific evidence suggests that folic acid (FA) supplementation protects the healthy colonic mucosa from neoplastic transformation but may promote the progression of precancerous lesions. The underlying molecular mechanisms are not fully understood. Therefore, we explored, if high physiological FA doses provoke changes in (i) promoter-specific DNA methylation (ii) expression of cancer-associated micro RNAs (miRNAs) and (iii) inflammatory mediators in human neoplastic and non-neoplastic colonic cell lines.

METHODS AND RESULTS

The malignant and the non-malignant colonic cell lines HT29 and HCEC were adapted to different near-physiological FA concentrations. Using DNA methylation and pathway specific PCR arrays, high-physiological FA concentrations revealed no relevant impact on promoter methylation but a number of differences between the cell lines in the expression of miRNAs and inflammatory mediators. In the HCEC cell line pro-inflammatory genes were repressed and the miRNA expression remained nearly unaffected. In contrast, in the HT29 cell line tumour-suppressive miRNAs were predominantly down-regulated and the expression of genes involved in chemotaxis and immunity were modulated.

CONCLUSION

The different effects of high-physiological FA concentrations in malignant and non-malignant colonic cell lines regarding cancer-associated miRNAs and inflammatory mediators may contribute to the different effects of FA supplementation on colonic carcinogenesis.

Maternal Folic Acid Supplementation during Pregnancy and Childhood Allergic Disease Outcomes: A Question of Timing?

Since the early 1990s, maternal folic acid supplementation has been recommended prior to and during the first trimester of pregnancy, to reduce the risk of infant neural tube defects. In addition, many countries have also implemented the folic acid fortification of staple foods, in order to promote sufficient intakes amongst women of a childbearing age, based on concerns surrounding variable dietary and supplementation practices. As many women continue to take folic acid supplements beyond the recommended first trimester, there has been an overall increase in folate intakes, particularly in countries with mandatory fortification. This has raised questions on the consequences for the developing fetus, given that folic acid, a methyl donor, has the potential to epigenetically modify gene expression. In animal studies, folic acid has been shown to promote an allergic phenotype in the offspring, through changes in DNA methylation. Human population studies have also described associations between folate status in pregnancy and the risk of subsequent childhood allergic disease. In this review, we address the question of whether ongoing maternal folic acid supplementation after neural tube closure, could be contributing to the rise in early life allergic diseases.

Hyperhomocysteinemia in Greyhounds and its Association with Hypofolatemia and Other Clinicopathologic Variables

Background

Folate and cobalamin are essential cofactors for homocysteine (HCY) metabolism. Hyperhomocysteinemia, a multifactorial condition, may reflect B vitamin deficiency and is associated with increased risk of cardiovascular disease, thrombosis, and neurodegenerative and chronic gastrointestinal diseases in humans. Hyperhomocysteinemia has been reported in Greyhounds with suspected chronic enteropathy.

Objectives

To evaluate the frequencies of and the association between hypofolatemia and hyperhomocysteinemia in Greyhounds.

Animals

Data and serum samples from 559 Greyhounds.

Methods

Nested case‐control study. The frequency of hypofolatemia in Greyhounds was determined by a laboratory database search. The relationship between hyperhomocysteinemia (measured by gas chromatography‐mass spectrometry) and hypocobalaminemia and hypofolatemia was evaluated, and its frequency compared between healthy Greyhounds and Greyhounds with thrombosis or chronic diarrhea.

Results

Hypofolatemia was identified in 172 of 423 (41%) Greyhounds and was more common in hypo‐ than in normocobalaminemic dogs (49% vs. 35%; P = .0064). Hyperhomocysteinemia was detected in 53 of 78 (68%) of Greyhounds, being more common in hypo‐ than in normofolatemic dogs (88% vs. 59%; P = .0175). All healthy Greyhounds, 21 of 30 (70%) of dogs with chronic diarrhea and 6 of 8 (75%) of those with thrombosis, were hyperhomocysteinemic. Serum HCY concentrations were inversely correlated with serum folate concentration (ρ = −0.28; P = .0386) and were positively associated with serum albumin concentration (ρ = 0.66; P = .0022).

Conclusions and Clinical Relevance

Hyperhomocysteinemia occurs frequently in the Greyhound population. Its association with hypofolatemia suggests decreased intracellular availability of B vitamins, but the functional implications warrant further investigation. Hyperhomocysteinemia in Greyhounds potentially may serve as a spontaneous canine model to further investigate hyperhomocysteinemia in humans.

Effect of in ovo feeding of folic acid on the folate metabolism, immune function and epigenetic modification of immune effector molecules of broiler

This study was conducted to investigate the effect of in ovo feeding (IOF) of folic acid on the folate metabolism, immune function and the involved epigenetic modification of broilers. A total of 400 (Cobb) hatching eggs were randomly divided into four groups (0, 50, 100 and 150 µg injection of folic acid at embryonic age 11 d), and chicks hatched from each treatment were randomly divided into six replicates with 12 broilers/replicate after incubation. The results indicated that, in ovo, 100- and 150-µg folic acid injections improved the hatchability. The average daily gain and feed conversion ratio increased in the 150-µg group during the late growth stage. Simultaneously, in the 100- and 150-µg groups, an increase was observed in hepatic folate content and the expression of methylenetetrahydrofolate reductase (d1 and 42) and methionine synthase reductase (d21). IgG and IgM concentrations, as well as plasma lysozyme activity of broilers, showed a marked increase along with increasing folic acid levels. The splenic expression levels of IL-2 and IL-4 were up-regulated, whereas that of IL-6 was down-regulated, in the 100- and 150-µg folic acid treatment groups. In addition, histone methylation in IL-2 and IL-4 promoters exhibited an enrichment of H3K4m2 but a loss of H3K9me2 with the increased amount of folic acid additive. In contrast, a decrease in H3K4m2 and an increase in H3K9me2 were observed in the IL-6 promoter in folic acid treatments. Furthermore, in ovo, the 150-µg folic acid injection improved the chromatin tightness of the IL-2 and IL-4 promoter regions. Our findings suggest that IOF of 150 µg of folic acid can improve the growth performance and folate metabolism of broilers, and enhance the relationship between immune function and epigenetic regulation of immune genes, which are involved with the alterations in chromatin conformation and histone methylation in their promoters.

Biomarkers of Nutrition for Development-Folate Review

The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-based advice to anyone with an interest in the role of nutrition in health. Specifically, the BOND program provides state-of-the-art information and service with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutrients in body tissues at the individual and population level. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, iron, zinc, folate, vitamin A, and vitamin B-12. This review represents the second in the series of reviews and covers all relevant aspects of folate biology and biomarkers. The article is organized to provide the reader with a full appreciation of folate's history as a public health issue, its biology, and an overview of available biomarkers (serum folate, RBC folate, and plasma homocysteine concentrations) and their interpretation across a range of clinical and population-based uses. The article also includes a list of priority research needs for advancing the area of folate biomarkers related to nutritional health status and development.

High serum level of haptoglobin is associated with the response of 12 weeks methotrexate therapy in recent-onset rheumatoid arthritis patients

BACKGROUND

We previously found, using microarray, haptoglobin (HP) expression signal was 5.1-fold increased in peripheral blood mononuclear cells (PBMCs) from methotrexate (MTX)-resistant rheumatoid arthritis (RA) patients.

OBJECTIVES

To investigate whether serum levels of HP are associated with the response of 12 weeks MTX therapy in recent-onset RA patients.

METHODS

Sixty-nine active RA patients with recent onset (< 24 months) were treated with MTX. Clinical variables, levels of HP messenger RNA (mRNA) in PBMCs and HP serum levels were tested at week 0 and week 12.

RESULTS

After 12 weeks of MTX treatment, 34.7% of RA patients were categorized as responders according to European League Against Rheumatism (EULAR) response criteria (Week 12 Disease Activity Score of 28 joints [DAS-28] ≤ 3.2 and decrease > 1.2) and all others (65.2%) were defined as non-responders. The baseline HP mRNA in PBMCs from non-responders is significantly higher than those in responders (P < 0.05). Similar to mRNA expression, non-responders showed significantly elevated serum HP levels at baseline (369.9 ± 159.8 mg/dL) compared to those in responders (255.3 ± 143.9 mg/dL) (P = 0.01). Serum HP levels were decreased significantly from 255.3 ± 143.9 mg/dL at baseline to 186.4 ± 108.5 mg/dL at week 12 (P = 0.04) in responders, but remained at high levels in non-responders.

CONCLUSIONS

High serum levels of HP at baseline are associated with inadequate response of 12 weeks MTX treatment in recent-onset RA patients. Further replication studies in larger samples are needed to validate HP as a potential predictive biomarker for response to MTX therapy in RA.

Neural tube defects, folate, and immune modulation

Periconceptional supplementation with folic acid has led to a significant worldwide reduction in the incidence of neural tube defects (NTDs). However, despite increasing awareness of the benefits of folic acid supplementation and the implementation of food fortification programs in many countries, NTDs continue to be a leading cause of perinatal morbidity and mortality worldwide. Furthermore, there exists a significant subgroup of women who appear to be resistant to the protective effects of folic acid supplementation. The following review addresses emerging clinical and experimental evidence for a role of the immune system in the etiopathogenesis of NTDs, with the aim of developing novel preventative strategies to further reduce the incidence of NTD-affected pregnancies. In particular, recent studies demonstrating novel roles and interactions between innate immune factors such as the complement cascade, neurulation, and folate metabolism are explored.

Biomarker responses to folic acid intervention in healthy adults: a meta-analysis of randomized controlled trials

BACKGROUND

The task of revising dietary folate recommendations for optimal health is complicated by a lack of data quantifying the biomarker response that reliably reflects a given folate intake.

OBJECTIVE

We conducted a dose-response meta-analysis in healthy adults to quantify the typical response of recognized folate biomarkers to a change in folic acid intake.

DESIGN

Electronic and bibliographic searches identified 19 randomized controlled trials that supplemented with folic acid and measured folate biomarkers before and after the intervention in apparently healthy adults aged ≥18 y. For each biomarker response, the regression coefficient (β) for individual studies and the overall pooled β were calculated by using random-effects meta-analysis.

RESULTS

Folate biomarkers (serum/plasma and red blood cell folate) increased in response to folic acid in a dose-response manner only up to an intake of 400 μg/d. Calculation of the overall pooled β for studies in the range of 50 to 400 μg/d indicated that a doubling of folic acid intake resulted in an increase in serum/plasma folate by 63% (71% for microbiological assay; 61% for nonmicrobiological assay) and red blood cell folate by 31% (irrespective of whether microbiological or other assay was used). Studies that used the microbiological assay indicated lower heterogeneity compared with studies using nonmicrobiological assays for determining serum/plasma (I(2) = 13.5% compared with I(2) = 77.2%) and red blood cell (I(2) = 45.9% compared with I(2) = 70.2%) folate.

CONCLUSIONS

Studies administering >400 μg folic acid/d show no dose-response relation and thus will not yield meaningful results for consideration when generating dietary folate recommendations. The calculated folate biomarker response to a given folic acid intake may be more robust with the use of a microbiological assay rather than alternative methods for blood folate measurement.

Systems Epidemiology: A New Direction in Nutrition and Metabolic Disease Research

Systems epidemiology applied to the field of nutrition has potential to provide new insight into underlying mechanisms and ways to study the health effects of specific foods more comprehensively. Human intervention and population-based studies have identified i) common genetic factors associated with several nutrition-related traits and ii) dietary factors altering the expression of genes and levels of proteins and metabolites related to inflammation, lipid metabolism and/or gut microbial metabolism, results of high relevance to metabolic disease. System-level tools applied type 2 diabetes and related conditions have revealed new pathways that are potentially modified by diet and thus offer additional opportunities for nutritional investigations. Moving forward, harnessing the resources of existing large prospective studies within which biological samples have been archived and diet and lifestyle have been measured repeatedly within individual will enable systems-level data to be integrated, the outcome of which will be improved personalized optimal nutrition for prevention and treatment of disease.

Proteomic analysis of plasma after branched chain enriched mixture supplementation in mice

Background

Branched chain amino acid (BCAA) supplementation is a recently identified strategy to promote longevity in mice. A proteomic approach was used to identify proteins which are differentially expressed in the sera of mice following supplementation with selected branched chain amino acid enriched mixture (BCAAem).

Findings

12 male mice (C57Bl6, 9 months-old) were randomly assigned to unsupplemented (Control, n = 6) and supplemented (BCAA, n = 6, 0.1 mg/gr/day in drink water for 4 weeks). At the end of treatment total plasma samples from Control and BCAAem mice were separated by two-dimensional gel electrophoresis (2-DE). After staining, the gels were imaged and differential protein expression patterns were interrogated using image analysis software. Spots showing a different expression level were identified through a comparison with 2D maps found in databases officially recognized (ExPASy).

Master gels of Control and BCAA mice exhibited slightly different 2-DE patterns as only 10 spots out of 500 appeared differentially expressed: 8 were upregulated (corresponding to Apolipoprotein A-I (APOA1), Complement factor B, Complement C3, Immunoglobulin light chain) and 2 appeared downregulated (Alpha-1-antitrypsin and unknown).

Conclusions

Supplementation with BCAAem in mice results in a slight perturbation of the host serum proteome. Of particular interest is the increased Apolipoprotein A-I (APOAI) following treatment.

Associations between Intake of Folate, Methionine, and Vitamins B-12, B-6 and Prostate Cancer Risk in American Veterans

Prostate cancer (PC) is the second leading cause of cancer death in men. Recent reports suggest that excess of nutrients involved in the one-carbon metabolism pathway increases PC risk; however, empirical data are lacking. Veteran American men (272 controls and 144 PC cases) who attended the Durham Veteran American Medical Center between 2004–2009 were enrolled into a case-control study. Intake of folate, vitamin B12, B6, and methionine were measured using a food frequency questionnaire. Regression models were used to evaluate the association among one-carbon cycle nutrients, MTHFR genetic variants, and prostate cancer. Higher dietary methionine intake was associated with PC risk (OR = 2.1; 95%CI 1.1–3.9) The risk was most pronounced in men with Gleason sum <7 (OR = 2.75; 95%CI 1.32– 5.73). The association of higher methionine intake and PC risk was only apparent in men who carried at least one MTHFR A1298C allele (OR = 6.7; 95%CI = 1.6–27.8), compared to MTHFR A1298A noncarrier men (OR = 0.9; 95%CI = 0.24–3.92) (p-interaction = 0.045). There was no evidence for associations between B vitamins (folate, B12, and B6) and PC risk. Our results suggest that carrying the MTHFR A1298C variants modifies the association between high methionine intake and PC risk. Larger studies are required to validate these findings.

Gene set enrichment analysis identifies LIF as a negative regulator of human Th2 cell differentiation

In this study we show that IL-4 is crucial during reinforcement window of human Th2 differentiation for optimal Th2 development. We have also shown here that during this stage, IL-4 helps in cellular decision-making process of differentiation versus proliferation. We have combined computational and experimental methods to analyze Th2 transcription network to name novel players of the process of Th2 differentiation. Here we report that LIF through STAT3 negatively regulates Th2 differentiation. This approach can be generalized to analyze “omics” data to identify key regulatory modules.

Dietary methyl donor depletion protects against intestinal tumorigenesis in Apc(Min/+) mice

Despite recent population data, the influence of dietary folate supplementation on colon cancer risk remains controversial. This study examines the effects of folate deficiency, in combination with choline, methionine, and vitamin B12 depletion, on intestinal tumorigenesis in Apc(Min/+) mice. Methyl donor sufficient (MDS) and deficient (MDD) diets were started at five or 10 weeks of age and tumors evaluated at 16 weeks. MDD suppressed intestinal tumor formation in Apc(Min/+) mice (~80%) when started at five weeks of age. The protective effect was lost when MDD was initiated at 10 weeks of age, indicating an important time dependency on cancer suppression. Concomitant with cancer protection, MDD restricted body weight gain. Therefore, a second study was conducted in which MDS was given ad libitum or pair-fed with MDD. Although small intestinal tumors were reduced 54% in pair-fed MDS mice, MDD caused a further reduction (96%). In colon, although MDD did not affect tumor numbers, tumor size was reduced. Gene expression profiling of normal-appearing colonic mucosa after 11 weeks on MDD identified a total of 493 significantly downregulated genes relative to the MDS group. Pathway analysis placed many of these genes within general categories of inflammatory signaling and cell-cycle regulation, consistent with recently published human data obtained during folate depletion. Further studies are warranted to investigate the complex interplay of methyl donor status and cancer protection in high-risk populations.

Opportunities and challenges for nutritional proteomics in cancer prevention

Knowledge gaps persist about the efficacy of cancer prevention strategies based on dietary food components. Adaptations to nutrient supply are executed through tuning of multiple protein networks that include transcription factors, histones, modifying enzymes, translation factors, membrane and nuclear receptors, and secreted proteins. However, the simultaneous quantitative and qualitative measurement of all proteins that regulate cancer processes is not practical using traditional protein methodologies. Proteomics offers an attractive opportunity to fill this knowledge gap and unravel the effects of dietary components on protein networks that impinge on cancer. The articles presented in this supplement are from talks proffered in the "Nutrition Proteomics and Cancer Prevention" session at the American Institute for Cancer Research Annual Research Conference on Food, Nutrition, Physical Activity and Cancer held in Washington, DC on October 21 and 22, 2010. Recent advances in MS technologies suggest that studies in nutrition and cancer prevention may benefit from the adoption of proteomic tools to elucidate the impact on biological processes that govern the transition from normal to malignant phenotype; to identify protein changes that determine both positive and negative responses to food components; to assess how protein networks mediate dose-, time-, and tissue-dependent responses to food components; and, finally, for predicting responders and nonresponders. However, both the limited accessibility to proteomic technologies and research funding appear to be hampering the routine adoption of proteomic tools in nutrition and cancer prevention research.

On the epigenetics of vascular regulation and disease

Consolidated knowledge is accumulating as to the role of epigenetic regulatory mechanisms in the physiology of vascular development and vascular tone as well as in the pathogenesis of cardiovascular disease. The modulation of gene expression through modification of the epigenome by structural changes of the chromatin architecture without alterations of the associated genomic DNA sequence is part of the cellular response to environmental changes. Such environmental conditions, which are finally being translated into adaptations of the cardiovascular system, also comprise pathological conditions such as atherosclerosis or myocardial infarction. This review summarizes recent findings on the epigenetics of vascular regulation and disease and presents nutritional and pharmacological approaches as novel epigenetic strategies in the prevention and treatment of cardiovascular disease.

Genomic DNA methylation changes in response to folic acid supplementation in a population-based intervention study among women of reproductive age

Folate is a source of one-carbons necessary for DNA methylation, a critical epigenetic modification necessary for genomic structure and function. The use of supplemental folic acid is widespread however; the potential influence on DNA methylation is unclear. We measured global DNA methylation using DNA extracted from samples from a population-based, double-blind randomized trial of folic acid supplementation (100, 400, 4000 µg per day) taken for 6 months; including a 3 month post-supplementation sample. We observed no changes in global DNA methylation in response to up to 4,000 µg/day for 6 months supplementation in DNA extracted from uncoagulated blood (approximates circulating blood). However, when DNA methylation was determined in coagulated samples from the same individuals at the same time, significant time, dose, and MTHFR genotype-dependent changes were observed. The baseline level of DNA methylation was the same for uncoagulated and coagulated samples; marked differences between sample types were observed only after intervention. In DNA from coagulated blood, DNA methylation decreased (−14%; P<0.001) after 1 month of supplementation and 3 months after supplement withdrawal, methylation decreased an additional 23% (P<0.001) with significant variation among individuals (max+17%; min-94%). Decreases in methylation of ≥25% (vs. <25%) after discontinuation of supplementation were strongly associated with genotype: MTHFR CC vs. TT (adjusted odds ratio [aOR] 12.9, 95%CI 6.4, 26.0). The unexpected difference in DNA methylation between DNA extracted from coagulated and uncoagulated samples in response to folic acid supplementation is an important finding for evaluating use of folic acid and investigating the potential effects of folic acid supplementation on coagulation.

Proteomics and systems biology: current and future applications in the nutritional sciences

In the last decade, advances in genomics, proteomics, and metabolomics have yielded large-scale datasets that have driven an interest in global analyses, with the objective of understanding biological systems as a whole. Systems biology integrates computational modeling and experimental biology to predict and characterize the dynamic properties of biological systems, which are viewed as complex signaling networks. Whereas the systems analysis of disease-perturbed networks holds promise for identification of drug targets for therapy, equally the identified critical network nodes may be targeted through nutritional intervention in either a preventative or therapeutic fashion. As such, in the context of the nutritional sciences, it is envisioned that systems analysis of normal and nutrient-perturbed signaling networks in combination with knowledge of underlying genetic polymorphisms will lead to a future in which the health of individuals will be improved through predictive and preventative nutrition. Although high-throughput transcriptomic microarray data were initially most readily available and amenable to systems analysis, recent technological and methodological advances in MS have contributed to a linear increase in proteomic investigations. It is now commonplace for combined proteomic technologies to generate complex, multi-faceted datasets, and these will be the keystone of future systems biology research. This review will define systems biology, outline current proteomic methodologies, highlight successful applications of proteomics in nutrition research, and discuss the challenges for future applications of systems biology approaches in the nutritional sciences.

Altered folate availability modifies the molecular environment of the human colorectum: implications for colorectal carcinogenesis

Low folate status increases colorectal cancer risk. Paradoxically, overly abundant folate supplementation, which is not uncommon in the United States, may increase risk. The mechanisms of these effects are unknown. We conducted two translational studies to define molecular pathways in the human colon altered either by folate supplementation or by dietary folate depletion (followed by repletion). In the first study, 10 healthy, at-risk volunteers (with documented stable/normal folate intake) received supplemental folic acid (1 mg/d) for 8 weeks. In the second study, 10 similar subjects were admitted to a hospital as inpatients for 12 weeks to study folate depletion induced by a low folate diet. A repletion regimen of folic acid (1 mg/d) was provided for the last 4 of these weeks. Both studies included an 8-week run-in period to ensure stabilized folate levels prior to intervention. We obtained 12 rectosigmoid biopsies (from 4 quadrants of normal-appearing mucosa 10-15 cm from the anal verge) at baseline and at measured intervals in both studies for assessing the primary endpoints: genome-wide gene expression, genomic DNA methylation, promoter methylation (depletion/repletion study only), and p53 DNA strand breaks. Serum and rectosigmoid folate concentrations accurately tracked all changes in folate delivery (P < 0.05). In the first study, gene array analysis revealed that supplementation upregulated multiple inflammation- and immune-related pathways in addition to altering several 1-carbon-related enzymes (P < 0.001). In the second study, folate depletion downregulated genes involved in immune response, inflammation, the cell cycle, and mitochondrial/energy pathways; repletion reversed most of these changes. However, changes in gene expression after repletion in the second study (involving immune response and inflammation) did not reach the levels seen after supplementation in the first study. Neither genomic nor promoter-specific DNA methylation changed during the course of the depletion/repletion protocol, and genomic methylation did not change with supplementation in the first study. p53 DNA strand breaks increased with depletion after 12 weeks. In sum, depletion downregulates, whereas repletion or supplementation upregulates pathways related to inflammation and immune response. These findings provide novel support to the concept that excessive folate supplementation might promote colorectal carcinogenesis by enhancing proinflammatory and immune response pathways. These results indicate that modest changes in folate delivery create substantial changes in the molecular milieu of the human colon.

Associação da deficiência de ácido fólico com alterações patológicas e estratégias para sua prevenção: uma visão crítica

A deficiência de ácido fólico está associada às doenças crônicas não-transmissíveis, complicações na gestação e doenças neurodegenerativas. Objetivou-se discutir o papel do ácido fólico na prevenção de doenças, os aspectos epidemiológicos de sua deficiência, fortificação dos alimentos e suplementação medicamentosa. Realizou-se levantamento bibliográfico, consultando as bases de dados para a obtenção dos artigos completos: MedLine, SciELO, PubMed, Highwire Press e Science Direct. Foram selecionados estudos realizados com seres humanos publicados entre 2004 e 2010. O ácido fólico é importante para as reações de metilação do ácido desoxirribonucléico, prevenção da hiper-homocisteinemia e atua como antioxidante. A deficiência dessa vitamina é descrita em adolescentes, mulheres em idade fértil, gestantes e em idosos. Seu alcance pela dieta é difícil, sendo necessária a inclusão de alimentos fortificados ou suplementos. É importante avaliar o estado nutricional de ácido fólico dos indivíduos antes e após a adoção dessas estratégias, de modo a gerar subsídios para ela-boração de medidas governamentais mais adequadas e eficazes. Destacamos ainda a necessidade da reeducação nutricional para a população brasileira a fim de aumentar o consumo de alimentos fontes de ácido fólico.