Folate bioavailability

An inadequate folate status is associated with increased risk of anaemia and neural tube defects. In many countries a folate intake below recommendations has been reported for women in childbearing age. However, data on folate intake and status are not always associated, since factors other than intake, e.g. bioavailability, affect folate status. This thesis studied the bioavailability of folate using in vivo and in vitro models. The effect of two pieces of Swedish nutritional advice on folate status of healthy women was assessed in a 12-week randomised controlled intervention trial. By combining a human plasma area under the curve (AUC)/ileostomy model with a stable isotope technique, the bioavailability of wholemeal bread fortified with reduced folate (5-CH3-H4folate) or folic acid was determined. In vitro effects of the food matrix on bioaccessibility and uptake of reduced folates were studied using a dynamic gastrointestinal model (TIM) and Caco-2 cells. The intervention breakfast diet (contributing ~1/3 of recommended daily folate intake) significantly improved folate status of the women, indicating a high folate bioavailability. The bread intervention diet (contributing ~1/5 of recommended daily folate intake) maintained folate and decreased homocysteine concentrations. Based on folate content in stomal effluent, the bioavailability of both folate fortificants tested was similarly high (~90%) but plasma kinetics differed significantly depending on ingested folate form. Data from in vitro TIM and Caco-2 cell experiments showed an inhibitory effect (~25%) of the bread matrix on bioaccessibility and uptake of reduced folates, which was higher than in vivo findings. Overall, data from these in vivo and in vitro studies suggest that the bioavailability of reduced folate is high and comparable to that of synthetic folic acid. Food matrix effects, e.g. of bread or a typical breakfast meal, on folate bioavailability seem negligible at physiological folate intake doses

Improving food composition data by standardizing calculation methods

Food composition data is important in nutritional policy making. However, food analyses are expensive and to use analysed values only is not economically justifiable; hence recipe calculations are important for the quality of food composition databases. The aim with this project, financed by the Nordic Council of Ministers, was to improve and standardize the recipe calculation method. A general recipe calculation method was developed, implemented and validated by comparing analysed and calculated content. The method and the foods recalculated within the project will be used in national dietary surveys and are available to the public through the national food composition databases. This report may be used as a guide through recipe calculations. Furthermore, the importance of well-structured methods for recipe calculations and possible consequences otherwise are highlighted

Improving food composition data by standardizing calculation methods

Food composition data is important in nutritional policy making. However, food analyses are expensive and to use analysed values only is not economically justifiable; hence recipe calculations are important for the quality of food composition databases. The aim with this project, financed by the Nordic Council of Ministers, was to improve and standardize the recipe calculation method. A general recipe calculation method was developed, implemented and validated by comparing analysed and calculated content. The method and the foods recalculated within the project will be used in national dietary surveys and are available to the public through the national food composition databases. This report may be used as a guide through recipe calculations. Furthermore, the importance of well-structured methods for recipe calculations and possible consequences otherwise are highlighted

Dietary intake and biomarker status of folate in Swedish adults

PURPOSE: National data on folate status are missing in Sweden, and regional data indicate folate insufficiency in up to more than 25% of the study populations. The objectives were to determine folate intake and status in the adult Swedish population as well as identifying dietary patterns associated with beneficial folate status. METHODS: Folate intake was estimated using a web-based 4-d food record in adults aged 18-80 years (n = 1797). Folate status was measured as erythrocyte (n = 282) and plasma folate concentrations (n = 294). Factor analysis was used to derive a dietary pattern associated with a higher folate status. RESULTS: Median folate intake was 246 µg/day (Q 1 = 196, Q 3 = 304, n = 1797) and for women of reproductive age 227 µg/day (Q 1 = 181, Q 3 = 282, n = 450). As dietary folate equivalents (DFE), median intake was 257 µg/day (Q 1 = 201, Q 3 = 323) and for women of reproductive age 239 µg/day (Q 1 = 185, Q 3 = 300). Low blood folate concentrations were found in 2% (erythrocyte concentrations <317 nmol/L) and 4% (plasma concentrations <6.8 nmol/L) of the participants, respectively. None of the women of reproductive age had erythrocyte folate concentrations associated with the lowest risk of neural tube defects. Dietary patterns associated with higher folate status were rich in vegetables, pulses and roots as well as cheese and alcoholic beverages, and low in meat. CONCLUSIONS: Prevalence of low erythrocyte folate concentrations was low in this population, and estimated dietary intakes are well above average requirement. However, to obtain a folate status optimal for prevention of neural tube defects major dietary changes are required and folic acid supplements recommended prior to conception