A comparison of the effect of advice to eat either ‘5-a-day’ fruit and vegetables or folic acid-fortified foods on plasma folate and homocysteine

Abstract

Objective: To assess and compare the effects of natural folate (100 mg) with those of folic acid from fortified sources (100 mg=day) on plasma folate and homocysteine. Design: Randomized controlled trial (parallel groups). Setting: Men and women living in South Wales, UK. Subjects: A total of 135 healthy individuals recruited from the local workforce and blood donor sessions. All subjects possessed the 'wild-type' CC genotype for C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR). Interventions: Subjects underwent one of the following dietary interventions for 4 months: (1) fortified diet -usual diet plus 100 mg=day folic acid from fortified foods; (2) natural folate diet -usual diet plus 100 mg=day folate from natural sources; (3) control -usual diet. Results: The fortified group increased reported intake of folic acid from fortified foods compared to other groups (P < 0.001) achieving an extra 98 mg=day (95% CI 88 -108). The natural folate group increased reported intake of natural source folates compared with the other two groups (P < 0.001), but achieved a mean increase of only 50 mg=day (95% CI 34 -66). Plasma folate increased (P < 0.01) by a similar amount in both intervention groups compared to controls (fortified group 2.97, 95% CI 0.8 -5.1; natural group 2.76, 95% CI 0.6 -4.9. Plasma homocysteine, vitamins B 6 and B 12 were not significantly changed. Conclusions: Subjects achieved increases in folate intake using fortified foods more easily than by folate-rich foods, however both sources increased plasma folate by a similar amount. These levels of intake were insufficient to reduce homocysteine concentrations in MTHFR CC homozygotes, but may be more effective in other genotypes. Sponsorship: This study was supported by the UK Ministry of Agriculture, Fisheries and Foods (latterly UK, Food Standards Agency, Project Reference N05002). The Kellogg Company of Great Britain provided funding for reimbursement of subjects for the cost of fortified foods.

Effect of fortified spread on homocysteine concentration in apparently healthy volunteers

“…Compared to other studies that tested the effect of folic acid fortified foods, the increase in serum folate appeared to be somewhat lower in our study, whereas on the other hand, the increase in erythrocyte folate and the decrease in tHcy was larger (Riddell et al, 2000;Johansson et al, 2002;Vahteristo et al, 2002;Ashfield-Watt et al, 2003;Carrero et al, 2004;Tapola et al, 2004;Tucker et al, 2004). Apart from the dose used, these differences can be explained by variations in study protocols, duration of the intervention and by the carrier of the vitamins (e.g.…”

Prevalences of hyperhomocysteinemia, unfavorable cholesterol profile and hypertension in European populations

“…Under wellcontrolled conditions, dietary interventions have been succesful in treating HHCY (Brouwer et al, 1999;Riddell et al, 2000;Ashfield-Watt et al, 2003), UNFAVCHOL (Hu et al, 2001) and HTEN (Appel et al, 1997). However, some of the intervention diets required extreme adaptations in the dietary habits of the subjects (eg consuming 45 servings of fruit/day; Appel et al, 1997) and may not be suitable in a 'free-living' situation.…”

Effect of Riboflavin Status on the Homocysteine-lowering Effect of Folate in Relation to the MTHFR (C677T) Genotype

“…The between-batch CVs for these measurements were 5.3%, 9.3%, and 4.0%, respectively. Plasma pyridoxal phosphate (vitamin B 6 ) was measured by HPLC with fluorescence detection as described previously (between-batch CV, 5.1%) (18 ).…”