scholarly journals Folate bioavailability

2004 ◽  
Vol 63 (4) ◽  
pp. 529-536 ◽  
Author(s):  
Helene McNulty ◽  
Kristina Pentieva
Keyword(s):  
Folic Acid ◽  
Methodological Approach ◽  
Relative Bioavailability ◽  
Food Sources ◽  
Future Research ◽  
Natural Food ◽  
Limiting Factor ◽  
Folic Acid Fortification ◽  
Folate Status ◽  
Folate Bioavailability

The achievement of optimal folate status to prevent neural-tube defects, and possibly other diseases, is hindered by the well-recognised incomplete bioavailability of the natural folates found in foods compared with the synthetic vitamin, folic acid. Folate bioavailability from different foods is considered to be dependent on a number of factors, including the food matrix, the intestinal deconjugation of polyglutamyl folates, the instability of certain labile folates during digestion and the presence of certain dietary constituents that may enhance folate stability during digestion. There is conflicting evidence as to whether the extent of conjugation of polyglutamyl folate (in the absence of specific inhibitors of deconjugation in certain foods) is a limiting factor in folate bioavailability. Estimates of the extent of lower bioavailability of food folates compared with folic acid (relative bioavailability) show great variation, ranging anywhere between 10 and 98%, depending on the methodological approach used. The lack of accurate data on folate bioavailability from natural food sources is of particular concern in those countries in which there is no mandatory folic acid fortification, and therefore a greater reliance on natural food folates as a means to optimise status. Apart from the incomplete bioavailability of food folates, the poor stability of folates in foods (particularly green vegetables) under typical conditions of cooking can substantially reduce the amount of vitamin ingested and thereby be an additional factor limiting the ability of food folates to enhance folate status. A recent workshop convened by the Food Standards Agency concluded that gaining a better understanding of folate bioavailability in representative human diets is a high priority for future research.

Folate bioavailability: UK Food Standards Agency workshop report

2003 ◽  
Vol 90 (2) ◽  
pp. 473-479 ◽  
Author(s):  
Peter Sanderson ◽  
Helene McNulty ◽  
Pierpaolo Mastroiacovo ◽  
Ian F. W. McDowell ◽  
Alida Melse-Boonstra ◽  
...  
Keyword(s):  
Folic Acid ◽  
Weighted Average ◽  
Relative Bioavailability ◽  
Evidence Base ◽  
Future Research ◽  
Workshop Report ◽  
Food Standards ◽  
Folate Bioavailability ◽  
The Uk ◽  
Review Current

The UK Food Standards Agency convened a group of expert scientists to review current research investigating folate bioavailability. The workshop aimed to overview current research and establish priorities for future research. Discrepancies were observed in the evidence base for folate bioavailability, especially with regard to the relative bioavailability of natural folates compared with folic acid. A substantial body of evidence shows folic acid to have superior bioavailability relative to food folates; however, the exact relative bioavailability still needs to be determined, and in particular with regard to mixed diets. The bioavailability of folate in a mixed diet is probably not a weighted average of that in the various foods consumed; thus the workshop considered that assessment of folate bioavailability of whole diets should be a high priority for future research.

scholarly journals Comparison of (6S)-5-methyltetrahydrofolic acidv.folic acid as the reference folate in longer-term human dietary intervention studies assessing the relative bioavailability of natural food folates: comparative changes in folate status following a 16-week placebo-controlled study in healthy adults

2009 ◽  
Vol 103 (5) ◽  
pp. 724-729 ◽  
Author(s):  
Anthony J. A. Wright ◽  
Maria J. King ◽  
Caroline A. Wolfe ◽  
Hilary J. Powers ◽  
Paul M. Finglas
Keyword(s):  
Folic Acid ◽  
Intervention Studies ◽  
Relative Bioavailability ◽  
Food Group ◽  
Relative Increase ◽  
Natural Food ◽  
Folate Concentration ◽  
Folate Status ◽  
Erythrocyte Folate ◽  
Food Folate

Folic acid (pteroylmonoglutamic acid) has historically been used as the reference folate in human intervention studies assessing the relative bioavailability of dietary folate. Recent studies using labelled folates indicated different plasma response kinetics to folic acid than to natural (food) folates, thus obviously precluding its use in single-dose experiments. Since differences in tissue distribution and site of biotransformation were hypothesised, the question is whether folic acid remains suitable as a reference folate for longer-term intervention studies, where the relative bioavailability of natural (food) folate is assessed based on changes in folate status. Healthy adults aged 18–65 years (n163) completed a 16-week placebo-controlled intervention study in which the relative bioavailability of increased folate intake (453 nmol/d) from folate-rich foods was assessed by comparing changes in plasma and erythrocyte folate concentration with changes induced by an equal reference dose of supplemental (6S)-5-methyltetrahydrofolic acid or folic acid. The relative increase in plasma folate concentration in the food group was 31 % when compared with that induced by folic acid, but 39 % when compared with (6S)-5-methyltetrahydrofolic acid. The relative increase in erythrocyte folate concentration in the food group when compared with that induced by folic acid was 43 %, and 40 % when compared with (6S)-5-methyltetrahydrofolic acid. When recent published observations were additionally taken into account it was concluded that, in principle, folic acid should not be used as the reference folate when attempting to estimate relative natural (food) folate bioavailability in longer-term human intervention studies. Using (6S)-5-methyltetrahydrofolic acid as the reference folate would avoid future results' validity being questioned.

scholarly journals Intake and status of folate and related B-vitamins: considerations and challenges in achieving optimal status

2008 ◽  
Vol 99 (S3) ◽  
pp. S48-S54 ◽  
Author(s):  
Helene McNulty ◽  
John M. Scott
Keyword(s):  
Folic Acid ◽  
Folic Acid Supplementation ◽  
B Vitamins ◽  
Natural Food ◽  
Vitamin B ◽  
High Dose ◽  
Folic Acid Fortification ◽  
Younger Women ◽  
Folate Status ◽  
The Uk

Folate and the metabolically related B-vitamins, vitamin B12and riboflavin, have attracted much scientific and public health interest in recent years. Apart from a well established role in preventing neural tube defects (NTDs), evidence is emerging to support other potential roles for folate and/or related B-vitamins in protecting against cardiovascular disease (especially stroke), certain cancers, cognitive impairment and osteoporosis. However, typical folate intakes are sub-optimal, in that although adequate in preventing clinical folate deficiency (i.e. megaloblastic anaemia) in most people, they are generally insufficient to achieve a folate status associated with the lowest risk of NTDs. Natural food folates have a limited ability to enhance folate status as a result of their poor stability under typical cooking conditions and incomplete bioavailability when compared with the synthetic vitamin, folic acid (as found in supplements and fortified foods). Current folate recommendations to prevent NTDs (based primarily on folic acid supplementation) have been found to be ineffective in several European countries. In contrast, in North America and Chile, the policy of mandatory folic acid-fortification has proven itself in terms of lowering the prevalence of NTD, but remains controversial because of concerns regarding potential risks of chronic exposure to high-dose folic acid. In the case of vitamin B12, the achievement of an optimal status is particularly difficult for many older people because of the common problem of food-bound B12malabsorption. Finally, there is evidence that riboflavin status is generally low in the UK population, and particularly so in younger women; this warrants further investigation.

Folate Status of Young Canadian Women after Folic Acid Fortification of Grain Products

2008 ◽  
Vol 108 (12) ◽  
pp. 2090-2094 ◽  
Author(s):  
Aysheh M. Shuaibi ◽  
James D. House ◽  
Gustaaf P. Sevenhuysen
Keyword(s):  
Folic Acid ◽  
Folic Acid Fortification ◽  
Folate Status ◽  
Grain Products

scholarly journals Intestinal absorption of different types of folate in healthy subjects with an ileostomy

2002 ◽  
Vol 88 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Erik J. M. Konings ◽  
Freddy J. Troost ◽  
Jacqueline J. M. Castenmiller ◽  
Harry H. S. Roomans ◽  
Piet A. van den Brandt ◽  
...  
Keyword(s):  
Folic Acid ◽  
Folate Intake ◽  
Limiting Factor ◽  
Short Term ◽  
Relative Absorption ◽  
Different Types ◽  
The Difference ◽  
Folate Bioavailability ◽  
Serum Response ◽  
Food Folate

Our knowledge on the absorption of folate is incomplete. The deconjugation process as a possible limiting factor in the absorption of folates was investigated. The study also attempted to validate the use of the area under the serum response curve (AUC) from food compared with folic acid as a proxy variable for food folate bioavailability. Folate absorption was determined in healthy ileostomy volunteers (n11) using a single-dose short-term protocol. In a randomised crossover design, volunteers received spinach meals and a supplement. Based on analysis of test meals and ileostomy effluents, there was no difference in folate absorption between spinach with a mono-:polyglutamate ratio 40:60 and the same spinach with a 100:0 ratio. The absolute absorption of spinach folate (79 %) calculated from the difference between folate intake and folate content of ileostomy effluents was approximately equal to the relative absorption (81 %) calculated from the AUC after consumption of spinach meals in relation to the AUC after consumption of the folic acid supplement. We conclude that the deconjugation process is not a limiting factor in the absorption of spinach folates. Comparison of AUC of food folatev.folic acid in a short-term protocol may be suitable for assessing food folate bioavailability.

scholarly journals Is there more to folates than neural-tube defects?

2003 ◽  
Vol 62 (3) ◽  
pp. 591-598 ◽  
Author(s):  
Paul M. Finglas ◽  
Anthony J. A. Wright ◽  
Caroline A. Wolfe ◽  
David J. Hart ◽  
Dawn M. Wright ◽  
...  
Keyword(s):  
Folic Acid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Gene Polymorphisms ◽  
Common Gene ◽  
Folate Status ◽  
Health And Disease ◽  
Precision And Accuracy ◽  
Folate Bioavailability ◽  
B Vitamin

The purpose of the present paper is to review our current understanding of the chemistry and biochemistry of folic acid and related folates, and to discuss their impact on public health beyond that already established in relation to neural-tube defects. Our understanding of the fascinating world of folates and C1metabolism, and their role in health and disease, has come a long way since the discovery of the B-vitamin folic acid by Wills (1931), and its first isolation by Mitchellet al. (1941). However, there is still much to do in perfecting methods for the measurement of folate bioavailability, and status, with a high extent of precision and accuracy. Currently, examination of the relationships between common gene polymorphisms involved in C1metabolism and folate bioavailability and folate status, morbidity, mortality and longevity is evaluated as a series of individual associations. However, in the future, examination of the concurrent effects of such common gene polymorphisms may be more beneficial.

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