Voluntary fortification with folic acid in Spain: An updated food composition database

Folic acid (FA) is a key vitamin in the prevention of many diseases including neural tube defects. In Spain, only voluntary FA food fortification is allowed and there is a lack of compositional data to assess the contribution of these products to population's dietary folate intakes. Since 2007, our group has been compiling and updating a FA fortified food composition database. FA levels were obtained from retailers in Madrid and information provided by manufacturers. FA was also quantified by an affinity chromatography-HPLC method. In the present study we recorded 375 products. Our results show a high variability in the declared FA levels amongst different products, and food groups, which is also dependant on the commercial brand. FA overages are commonly added by manufacturers to some fortified products. FA content label claims are missing in 64% of products. This database is a useful tool to manage FA fortified foods data but it is necessary to continuously update it for the sound evaluation and monitoring of population's FA dietary intakes.

[Folic acid fortified foods available in Spain: types of products, level of fortification and target population groups]

INTRODUCTION

Folic acid is a potentially relevant factor in the prevention of a number of pathologies (congenital abnormalities, cardiovascular disease, colorectal cancer and neurocognitive decline). This has led to the introduction of different strategies in order to increase folate intake: nutritional education, pharmacological supplementation and mandatory or voluntary fortification of staple foods with folic acid. In Spain there is a growing number of folic acid fortified products on a voluntary basis, but there is also a lack of reliable data to assess their impact on the population's dietary folate intakes.

OBJECTIVE

To gather a better knowledge of folic acid food fortification practices in Spain.

METHODS

A Food Composition Database was developed using data from a market study. Also, previously published data of unfortified staple foods from Food Composition Tables was reviewed.

RESULTS AND DISCUSSION

The Database included 260 folic acid fortified food items and it was periodically updated. Food groups included were primarily "Cereals and derivatives" (52%) followed by "Dairy products". Most of these foodstuffs lacked a target population for their consumption (37%) or were aimed at "Weight control" (28%) and "Children" (23%), but only 2% targeted women at a reproductive age. Number of unfortified foods included was 690. Fortification levels declared by manufacturers ranged between 15 and 430% of the Recommended Dietary Allowances (RDA) for folic acid per 100 g/ml, and simultaneous addition of B6 and B12 vitamins was observed in 75% of the products. Currently, Spain market offers a significant number of folic acid fortified products on a voluntary basis and at a level > or = 15% of the RDA per 100 g/ml or serving declared by manufacturers.

Supranormal dietary folic acid supplementation: effects on methionine metabolism in weanling rats

There are nationwide folic acid (FA) fortification programmes of staple foods established or under consideration in order to prevent neural tube defects. Universal FA fortification still remains controversial because of the concern that additional FA in the diets of population groups (e.g. children and elderly) not initially targeted for fortification may suffer adverse effects. However, dietary surveys regarding folate generally deal with adults and little is known about the consumption and long-term effects of fortified food and supplements in growing individuals. Recent reports from our laboratory show several effects of high-dose folate supplementation in rats. In the present work, we studied the effect of FA on the methionine cycle in weanling (3-week-old) male rats after 4 weeks of supplementation with 40 mg FA/kg dietv.control (1 mg FA/kg diet). FA supplementation resulted in a reduction of homocysteine and creatinine concentrationsv.control group. FA supplementation did not alterS-adenosylmethionine/S-adenosylhomocysteine ratio, DNA methylation, enzymatic activities or concentrations of vitamins involved in the nutritional regulation of the methionine cycle, except for folate. FA supplementation of 40 mg/kg did not lead to hepatic or renal damage. In conclusion, there were no apparent adverse effects on one-carbon metabolism after FA supplementation in the studied conditions.

[Homocysteine related vitamins and lifestyles in the elderly people: The SENECA study]

The SENECA study started in 1988 and consisted of a random age- and sex-stratified sample of inhabitants of 19 European towns. A total of 2.100 elderly people were finally able to be included in the study. The present study includes results for total plasma homocysteine (tHcy) and the related vitamins folate, B12 and B6. Other style factors as alcohol consumption or smoking have been also evaluated. The lowest values for tHcy corresponded to Mediterranean countries (Portugal, Spain, and Greece), compared to central or northern european countries (Netherland or Belgium (differences higher than 4 micromol/l). In addition, an interesting north-south gradient is observed, with the lowest values for tHcy corresponding to Betanzos (Spain), 12.38 micromol/l followed by both centers in Portugal, whereas the highest concentrations are found in Maki (Poland), 21.92 pmol/I and Culemborg (Netherlands), 20.41 mircromol/l. The mean tHcy concentration for all the European centers was 15.98 micromol/l. Effect of sex has been also evaluated: those countries with the lowest tHcy concentration (i.e. Spain or Portugal) show significant (p < 0.01) higher tHcy concentration in men vs women, whereas these differences by sex are not observed in countries with the highest tHcy values. The effect of "aging" within the same individuals after ten years of follow up was also evaluated: a significant difference was observed for the same individuals in the 10-years period. Plasma folic acid was compared to tHcy values, resulting also in marked differences between north and southern countries. Plasma vitamin B12 also shows a close pattern. Either plasma folate or vitamin B12 were shown as strong predictors of tHcy. This effect was not observed for plasma vitamin B6. Total alcohol intake was positively and significantly (p < 0.01) correlated with tHcy ("no" intake corresponded with the lowest tHcy, 14.3 micromol/l vs "high" intake-over 30 g/d-with the highest tHcy, 17 micromol/l). The type of alcoholic beverage was also evaluated: wine and spirits drinkers showed positively significant (p < 0.005) correlation whereas beer intake was not significantly associated. Smoking was also analysed: "never" smokers had the lowest tHcy concentration (13.82 +/- 0.20 micromol/1) vs "current" smokers (16.64 +/- 0.35 pmol/1), a significant difference (p < 0.05).

[Dietary food habits, nutritional status and lifestyle in menopausal women in Spain]

AIM

To analyse the diet and the dietary food habits in a sample of 1,218 Spanish women, aged 40 to 77 years, in the menopausal or perimenopausal condition. Women were recruited nationwide and the diet was assessed using a food frequency questionnaire.

RESULTS

Diet in our population group was close to the representative dietary habits of the Spanish population, except for dairy products. These were highly consumed (approximately 4 servings/day) by menopausal women. Energy, protein and cholesterol intakes, as well as most vitamins and mineral intakes, were very high, as compared to recommended dietary allowances. We only found marginal deficient intakes for folate and vitamin D. Women over 60 years consume less eggs, sweats, sugar and miscellany, and therefore less lipids and cholesterol, as well as vitamin D, than younger women. A high rate (61%) of overweight and obesity (BMI > 25) was present in our population group and was associated with a higher intake of meat, fish and eggs, as well as energy. A healthier diet (high intake of dairy products, fresh vegetables, fruits, legumes, cereals and fish) was associated with a healthier lifestyle (no smoking, physical exercise) and the use of fortified foods and vitamin/mineral supplements. A high percentage of women regularly consumed fortified food (52,7%) and micronutrient supplements (22,8%) although diets provided enough vitamins and minerals.

CONCLUSION

Diet in our study group is in accordance to healthy dietary habits and physical activity recommendations. This is probably due to a greater concern for health in women close to the menopause condition.

Folate status and S-adenosylmethionine/S-adenosylhomocysteine ratio in colorectal adenocarcinoma in humans

OBJECTIVES

This study reports the influence of colorectal neoplasia on methylation intermediates and folate concentrations in human colonic mucosa, as well as systemic measures of folate status, to examine biomarkers and possible mechanisms of folate-related carcinogenesis.

SUBJECTS

A total of 47 patients were selected from those previously diagnosed with adenocarcinoma of the colorectum undergoing surgery. For each individual, we obtained a biopsy of the adenocarcinoma and a biopsy of normal appearing mucosa, to perform an intra-individual comparison.

RESULTS

The 'methylation' ratio (S-adenosylmethionine/S-adenosylhomocysteine (SAH)) was lower in pathological tissue vs normal mucosa (P=0.08), mainly due to a much higher SAH concentration (P<0.005). Colonic folate concentration was significantly diminished in malignant tissue (P<0.0001). Plasma homocysteine concentration was within the normal to high range, and folate and vitamin B12 plasma concentrations were within the low to normal range as compared with normative values.

CONCLUSION

Our results contribute to the hypothesis that altered DNA methylation and methyl metabolism is associated with colorectal neoplasia.

Drugs-nutrient interactions: a potential problem during adolescence

The concept of drug-nutrient interactions is not new, but it has only recently gained currency in medicine. Although the elderly are normally considered to be at particular risk, other groups may also be at risk: infants, adolescents, pregnant women, alcohol and tobacco users, etc. In infants and adolescents there are several factors that may influence the possible interactions: firstly, nutrient needs are usually higher, mainly micronutrients; systems for detoxification of anutrients are not complete; the tendency to restricted diets (especially girls) that are unable to cover the actual recommended intakes for a number of micronutrients (i.e. vitamins); and the dangerous increase in alcohol consumption either in males or females. Administration of drugs in population with adequate vitamin intake is usually not a problem, but administration of drugs in those with borderline intake of vitamins or in patients with low nutritional status can result in symptomatic vitamin deficiency states. The groups at risk of poor vitamin status are smokers (a high proportion of adolescents are active smokers); dieters (skipping meals and dieting to lose weight frequently compromise micronutrient intake, and it should be considered that it is extremely difficult to meet all the requirements at intakes of less than 1,200 calories per day), oral contraceptive users, and pregnant and lactating women, excessive alcohol users, etc. The chapter also focuses on the case of folate: rapidly dividing tissues during the adolescent growth spurt increase requirements for folate. Because of this increased need, folate status appears to be of concern during the age of this rapid growth. A variety of drugs are known to interfere with vitamin utilization by blocking or altering transformation of the vitamin to its metabolically active form. Serum folate levels are known to be low in a high percentage of patients with rheumatoid arthritis, suggesting that aspirin alters the transport of folate by competition for binding sites on serum proteins. Methotrexate, a drug commonly used at low doses for the treatment of psoriasis, rheumatoid arthritis and certain liver disorders, limits the availability of methyl groups derived from one-carbon metabolism by inhibiting competitively a key enzyme in the intracellular folate metabolism. In humans, the antiepileptic drug valproic acid (VPA) is associated with two major adverse effects: teratogenicity and folate deficiency. The mechanisms by which VPA exerts the teratogenic or antifolate effect remain unclear, but an alteration in the methionine cycle is the strongest hypothesis proposed.

High-dose folic acid supplementation in rats: effects on gestation and the methionine cycle

There is new evidence that a good folate status may play a critical role in the prevention of neural-tube defects and in lowering elevated homocysteine concentrations. This adequate folate status may be achieved through folic acid dietary supplementation. Folate is a water-soluble vitamin with a low potential toxicity. However, the possible consequences of long-term high-dose folic acid supplementation are unknown, especially those related to the methionine cycle, where folate participates as a substrate. With the aim of evaluating such possible effects, four groups of Wistar rats were classified on the basis of physiological status (virgin v. pregnant) and the experimental diet administered (folic-acid-supplemented, 40 mg/kg diet v. control, 2 mg folic acid/kg diet). Animals were fed on the diets for 3 weeks. Results showed that gestation outcome was adequate in both groups regardless of the dietary supplementation. However, there were reductions (P < 0.001) in body weight and vertex-coccyx length in fetuses from supplemented dams v. control animals. Folic acid administration also induced a higher (P < 0.01) S-adenosylmethionine: S-adenosylhomocysteine value due to increased S-adenosylmethionine synthesis (P < 0.01). However, hepatic DNA methylation and serum methionine concentrations remained unchanged. Serum homocysteine levels were reduced in supplemented dams (P < 0.05). Finally, pregnancy caused lower serum folate, vitamin B6 and vitamin B12 levels (P < 0.05). Folic acid administration prevented the effect of pregnancy and raised folate levels in dams, but did not change levels of vitamins B12 and B6. These new findings are discussed on the basis of potential benefits and risks of dietary folic acid supplementation.

High dietary folate supplementation affects gestational development and dietary protein utilization in rats

There is new evidence that good folate status may play a critical role in the prevention of neural tube defects and in the maintenance of adequate homocysteine levels, an amino acid recently identified as a risk factor for cardiovascular disease. This has led to different folate recommendations, all of them much higher than the present dietary recommendations. Folic acid is a water-soluble vitamin with a low potential toxicity. However, the possible consequences of long-term, high folate intakes are unknown. Therefore, the present study was undertaken to determine the effects of long-term, high dietary folate supplementation on gestational and nutritional markers in pregnant and virgin rats. Four groups of Wistar rats were classified on the basis of physiological status (virgin or pregnant) and the experimental diets administered (folic acid supplemented, 40 mg/kg diet; or control diet, 2 mg folic acid/kg diet). Rats were fed their respective diets for 3 wk. Two critical periods were used for metabolic balance studies (experimental d 1-5 and 17-21), which involved the determination of fat and protein digestibilities as well as metabolic protein utilization (MPU) and net protein utilization (NPU). Gestational development (number of live fetuses) was adequate in both diet groups regardless of folate supplementation. However, body weight and vertex-coccyx length in fetuses from supplemented dams were less than (P < 0.0001) in fetuses of control dams. Fat and nitrogen digestibilities were not affected by supplementation, but MPU and NPU coefficients were significantly lower (P < 0.05) in the folic acid-supplemented groups, irrespective of physiological status, compared to control rats. These new findings of macro-micronutrient interactions caused by high folate supplementation are discussed on the basis that the vitamin may act as a xenobiotic more than as a nutrient.

Impaired methionine synthesis and hypomethylation in rats exposed to valproate during gestation

BACKGROUND

The antiepileptic drug valproic acid (VPA) may be teratogenic. The mechanism of teratogenicity remains unclear, but it has been hypothesized that VPA interferes with folate metabolism.

OBJECTIVE

To study the effect of VPA on the methionine cycle and transmethylation reactions in pregnant rats.

METHODS

Wistar rats were treated with VPA (300 mg/kg/day) on gestation days 8, 9, and 10, alone or in combination with folinic acid (FOL, 4 mg/kg/day) on gestation days 8, 9, and 10 or S-adenosylmethionine (SAM, 10 mg/kg/day) throughout gestation days 1 to 10.

RESULTS

VPA induced a reduction in maternal methionine serum concentration (p < 0.05) caused by a 24% reduction of methionine synthase activity in liver. This provoked hepatic DNA hypomethylation, although the methylation ratio (S-adenosylmethionine/S-adenosylhomocysteine) was not altered. Homocysteine, folate, and vitamin B12 serum concentrations, as well as methionine adenosyltransferase and betaine homocysteine methyltransferase hepatic activities, did not change. In fetuses exposed to VPA, no effect was observed in hepatic methionine content, but the methylation ratio was reduced (p < 0.01), leading again to hepatic DNA hypomethylation. Coadministration of FOL prevented VPA-induced alterations in methionine synthesis and corrected fetal DNA hypomethylation. By contrast, SAM did not exert a protective effect on fetal DNA methylation.

CONCLUSION

Impaired methionine synthesis and DNA hypomethylation may be involved in VPA-induced teratogenesis.

[Morphological changes induced by valproate and its administration concomitant with folinic acid or S-adenosylmethionine in pregnant rats]

Neural tube defects (NTD) are serious congenital abnormalities that have a multifactorial etiology, including both genetic and environmental effectors (for example, diet and/or drugs). Valproic acid (VPA) is a frequently used anti-epileptic drug that has a potentially teratogenic character, as well as the capacity for inducing NTD and other less serious malformations. However, the mechanism of action of VPA has not been clearly established, and it has been suggested that it interferes in the folate cycle and therefore, with the methionine/methylation, possibly through a metabolic blocking of some biomarker that is a key of the cycle, such as for example S-adenosylmethionine (SAM) and folic acid (FA). The objective of the present study is to analyze the morphological and histological changes, which can occur in a high risk experimental model after the administration of VPA as well as for the induction of NTD and other malformations. In addition, the protective roles of the administration of folic acid, 5-formyltetrahydrofolate (FOL) and S-adenosylmethionine (SAM) are assessed. For this pregnant "Wistar" rats classified according to the following treatments: 1) VPA (300 mg/kg/day on days 8, 9, and 10 of the pregnancy); II) VPA (300 mg/kg/day on days 8, 9, and 10 of the pregnancy) and FOL (4 mg/kg/day i.p. on days 8, 9, and 10 of the pregnancy); III) VPA (300 mg/kg/day on days 8, 9, and 10 of the pregnancy) + SAM (10 mg/kg/day, on days 1-10 of the pregnancy); IV) CONTROL (no treatment). VPA decreases the fertility index by 25% compared to the control group, it increases the number of reabsorptions by mother (1.3 +/- 0.5 vs 1.0 +/- 0.5), and decreases the number of fetuses compared to the control (9.0 +/- 1.4 vs. 12.6 +/- 0.9). In the VPA + FOL group, the numbers for these parameters approach those of the control group and the VPA + SAM group is no different from the VPA group, showing no protective factors. With respect to the bone alterations observed, when these are grouped according to whether they affect the skull, trunk, and extremities, it is seen that there are no significant differences between the groups. The histological study and the immunohistochemical analysis show liver alterations in all groups treated, and a lower number of lymphocytes in the VPA group, and a greater number of Kupffer cells, The results are discussed in relation to, first, the effect of VPA per se in the interference of the methionine/methylation cycle, and secondly, with regard to how folic acid and/or S-adenosylmethionine can improve or not some of the harmful effects induced by VPA.

Carbon tetrachloride-induced hepatic injury is associated with global DNA hypomethylation and homocysteinemia: effect of S-adenosylmethionine treatment

Carbon tetrachloride (CCl4) administration to rats produces hepatic cirrhosis and supplementation with S-adenosylmethionine (SAM) can partially prevent CCl4-induced liver injury. These effects are thought to be caused by oxidative stress and the subsequent formation of free radicals, but the mechanism whereby this occurs and the accurate nature of the mechanisms by which SAM exerts its protective action are not well understood. The effect of short-term administration of CCl4 on hepatic DNA methylation and on SAM and S-adenosylhomocysteine (SAH) were assessed. CCl4 administration to rats for 3 weeks resulted in hypomethylation of liver DNA, determined by comparing the extent to which DNA from livers of control or treated animals could be methylated in vitro using [3H-methyl] SAM as methyl donor. This CCl4 effect on DNA methylation was corrected by the administration of SAM (10 mg/kg/d, intramuscularly), with values of methyl groups incorporation comparable with those observed in the control animals. hepatic SAM was decreased by CCl4 (65.3 +/- 5.27 vs. 102.2 +/- 4.89 nmol/g; P < .05) and SAH was increased (69.5 +/- 14.6 vs. 29.4 +/- 3.83 nmol/g; P < .05). This led to a marked reduction of the SAM/SAH ratio (the methylation ratio) from 3.47 in control rats to 0.94 in CCl4-treated animals (P < .05). SAM treatment partially prevented (P < .05) the reduction of the ratio SAM/SAH induced by CCl4. CCl4 also induced a marked elevation of serum homocysteine levels (more than 20-fold; P < .001), which was partially prevented by SAM administration.(ABSTRACT TRUNCATED AT 250 WORDS)