Acute absorption of folic acid from a fortified low-fat spread

Expanding Fortification with Folic Acid: Thinking Outside the Cereal-Grain Box

(1) Background: Fortifying maize and wheat flours with folic acid has effectively reduced neural tube defect-affected births. However, maize and wheat flours may not be widely consumed in all countries; further reduction in neural tube defect-affected births could benefit from the identification of alternative food vehicles. We aimed to use dietary intake or apparent consumption data to determine alternative food vehicles for large-scale fortification with folic acid in low-income and lower-middle-income countries (LILMICs) and identify current research related to examining the technological feasibility of fortifying alternative foods with folic acid. (2) Methods: We identified 81 LILMICs, defined by the World Bank's (WB) 2018 income classifications. To identify dietary intake or apparent consumption, we reviewed WB's Microdata Library and Global Health Data Exchange for national surveys from 1997-2018. We reviewed survey reports for dietary intake or apparent consumption data and analyzed survey datasets for population coverage of foods. We defined alternative food vehicles as those that may cover/be consumed by ≥30% of the population or households; cereal grains (maize and wheat flours and rice) were included as an alternative food vehicle if a country did not have existing mandatory fortification legislation. To identify current research on fortification with folic acid in foods other than cereal grains, we conducted a systematic review of published literature and unpublished theses, and screened for foods or food products. (3) Results: We extracted or analyzed data from 18 national surveys and countries. The alternative foods most represented in the surveys were oil (n = 16), sugar (n = 16), and salt (n = 14). The coverage of oil ranged from 33.2 to 95.7%, sugar from 32.2 to 98.4%, and salt from 49.8 to 99.9%. We found 34 eligible studies describing research on alternative foods. The most studied alternative foods for fortification with folic acid were dairy products (n = 10), salt (n = 6), and various fruit juices (n = 5). (4) Conclusions: Because of their high coverage, oil, sugar, and salt emerge as potential alternative foods for large-scale fortification with folic acid. However, except for salt, there are limited or no studies examining the technological feasibility of fortifying these foods with folic acid.

Random serial sampling to evaluate efficacy of iron fortification: a randomized controlled trial of margarine fortification with ferric pyrophosphate or sodium iron edetate

BACKGROUND

Random serial sampling is widely used in population pharmacokinetic studies and may have advantages compared with conventional fixed time-point evaluation of iron fortification.

OBJECTIVE

Our objective was to validate random serial sampling to judge the efficacy of iron fortification of a low-fat margarine.

DESIGN

We conducted a 32-wk placebo-controlled, double-blind, iron-intervention trial in 18-40-y-old Swiss women (n = 142) with serum ferritin (SF) concentrations <25 μg/L. Women were randomly assigned to 3 groups to receive 20 g margarine, with 14 mg added iron as either micronized ground ferric pyrophosphate (MGFePP) or sodium iron edetate (NaFeEDTA), or placebo daily. We measured hemoglobin and iron status of subjects at 2 fixed time points (at baseline and the endpoint) plus 3 randomly assigned time points between 4 and 28 wk. With the use of bootstrapping, the number of observations per individual was reduced to 3 and then compared with the 5-time-point data. Mixed-effects models were used to estimate iron repletion over time for random sampling, and analysis of covariance was used for fixed time-point sampling.

RESULTS

Body iron stores increased in women who received MGFePP or NaFeEDTA compared with women who received placebo (P < 0.05). The increase in body iron stores with NaFeEDTA fortification was 2-3 times the increase with MGFePP fortification (P < 0.05); the difference was more marked in women with baseline SF concentrations <15 μg/L (P < 0.05). Random serial sampling reduced the required sample size per group to one-tenth of that for 2 fixed time points. Compared with the 5-time-point analysis, the 3-time-point sparse sampling generated comparable estimates of efficacy.

CONCLUSIONS

When used to evaluate the efficacy of iron fortificants, random serial sampling can reduce the sample size, invasiveness, and costs while increasing sensitivity. Random serial sampling more clearly describes the pattern of iron repletion and may prove useful in evaluating other micronutrient interventions.

Plasma folate concentrations after a single dose ingestion of whole and skimmed folic acid fortified milks in healthy subjects

BACKGROUND

Since mandatory folic acid fortification of grains and cereals was introduced in order to prevent neural tube defects, the number of products that are being fortified with folic acid is growing, especially milk and dairy products. However, the effectiveness of this action remains controversial.

AIM OF THE STUDY

To investigate the efficiency of skimmed milk as a vehicle for folic acid fortification by the determination of the acute absorption from low-fat fortified milk compared to fortified and unfortified whole milk in healthy subjects.

DESIGN

A single-dose bioavailability study was performed using three commercially available milks (whole and skimmed milk fortified with folic acid and unfortified whole milk). Healthy volunteers (3 women, 2 men) were administered a single dose of 430 ml of each milk, at 1-week intervals between test days. Plasma total folate concentrations, at baseline and hourly from 1.5 up to 6.5 h after ingestion, were measured.

RESULTS

Plasma folate concentration was significantly increased, when compared to baseline values, 1.5 h after ingestion of skimmed fortified milk, and 2.5 h after whole fortified milk, and remained significantly higher than baseline values for up to 6.5 h after both treatments. The highest plasma folate concentration (20.9 ± 3.1 nmol/l) was obtained 6.5 h postprandial in response to skimmed fortified milk. The acute absorption of folic acid, calculated on the basis of area under the plasma folate concentration curve, was significantly higher from skimmed fortified milk compared to fortified and unfortified whole milk.

CONCLUSIONS

The absorption of folic acid from fortified skimmed milk is faster than the absorption of folic acid from fortified whole milk, and it renders significantly higher plasma folate concentration when compared to whole milk. These findings indicate that skimmed milk could be considered an efficient food matrix for folic acid fortification.

Effect of fortified spread on homocysteine concentration in apparently healthy volunteers

OBJECTIVE

To determine the effect of folic acid, vitamin B(6) and B(12) fortified spreads on the blood concentrations of these vitamins and homocysteine.

DESIGN AND SETTING

A 6-week randomized, double-blinded, placebo-controlled, parallel trial carried out in a clinical research center.

SUBJECTS

One hundred and fifty healthy volunteers (50% males).

INTERVENTIONS

For 6 weeks, the subjects consumed the test spreads (20 g/day): containing per 20 g (1) 200 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6), or (2) 400 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6) or (3) no B-vitamins (control spread).

RESULTS

The B-vitamin status increased on using the test spreads, with the largest effect on the serum folate concentration: 48% in men and 58% in women on spread 1 and 92 and 146%, respectively, on spread 2 (P-values all <0.05). The plasma homocysteine decreased in the groups treated with the fortified spreads as compared to the control group. Average decreases were for males: 0.7+/-1.5 micromol/l (6.8%) on spread 1 and 1.7+/-1.7 micromol/l (17.6%) on spread 2 and for females: 1.4+/-1.2 micromol/l (14.2%) and 2.4+/-2.0 micromol/l (23.3%), respectively (P-values all <0.05).

CONCLUSIONS

Consumption of a spread fortified with folic acid, vitamin B(6) and vitamin B(12) for 6 weeks significantly increases the blood concentrations of these vitamins and significantly decreases the plasma concentration of homocysteine. Fortified staple foods like spreads can contribute to the lowering of homocysteine concentrations.

The rate of intestinal absorption of natural food folates is not related to the extent of folate conjugation

BACKGROUND

Evidence is conflicting as to whether the bioavailability of food folates is influenced by the extent of their conjugation.

OBJECTIVE

The objective was to compare the bioavailability of 3 representative food folate sources with various degrees of glutamylation-ie, egg yolk, spinach, and yeast, whose polyglutamyl folate content measured 0%, 50%, and 100%, respectively.

DESIGN

In a randomized crossover trial, 13 male subjects, after a prestudy folate saturation procedure, received in random order either placebo or 500 mug total folate, which was provided as concentrated freeze-dried extract removed from the normal food matrix of egg yolk, spinach, or yeast. Blood samples (n = 10) were collected before and up to 10 h after treatments, which were administered at weekly intervals.

RESULTS

A significant increase from baseline plasma folate concentrations was observed by 0.5 h after treatment with egg yolk folate or spinach folate and by 1 h after treatment with yeast folate, and the concentrations remained significantly elevated for 3-5 h; no plasma folate response was observed after placebo treatment. The overall responses, calculated as plasma folate area under the curve (AUC) for egg yolk, spinach, and yeast folate, were 122.6 +/- 23.6, 136.2 +/- 21.4, and 102.5 +/- 21.1 nmol . h/L, respectively. No significant differences in AUC were seen between monoglutamyl (egg yolk) folate and either of the polyglutamate-containing folates examined.

CONCLUSION

These results suggest that the ratio of monoglutamate to polyglutamate in natural folates is not a factor that limits the extent of intestinal absorption of food folate.