Table 2.
Dietary folate intervention trials resulting in significant effects (presented as change (%) compared with baseline) on folate status.
| Intervention diet | Folate intake (µg/day) | W | N2 | Age | Erythrocyte folate | p/s-folate | tHcy | Ref. | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dose (Q) 1 | Total | Baseline (nmol/L) | End (%) | Baseline (nmol/L) | End (%) | Baseline (µmol/L) | End (%) | |||||
| Control | 0 | 236 | 16 | 43 | - | 26 ± 8 3 | −4 | 9 ± 3 3 | 0 | [69] | ||
| 5-a-day fruit/vegetables | 63 (C) | 306 | 16 | 41 | - | 26 ± 7 3 | +7 ♦ | 10 ± 4 3 | −11 | |||
| Low folate diet | 0 (L) | 131 | 4 | 23 | 50 ± 4 3 | 13 ± 6 3 | −8 | 14 ± 6 3 | −8 | [67] | ||
| 500 g fruit and vegetables | 97 (L) | 228 | 4 | 24 | 49 ± 6 3 | 16 ± 10 3 | 0 ♦ | 12 ± 4 3 | −9 ♦ | |||
| Control | 0 | 239 | 12 | 17, F | 48 (38, 57) 7 | 900 (647, 1079) 7 | −22 7 | 12 (11, 15) | 0 7 | 9 (7, 11) | +10 7 | [59] |
| 5 slices bread | 70 (T) | 379 | 12 | 17, F | 47 (40, 55) 7 | 855 (635, 992) 7 | −18 | 12 (9-16) | 0 | 9 (8, 11) | −21 * | |
| Breakfast (SNO [71]) | 125 (T) | 437 | 12 | 17, F | 49 (35, 53) 7 | 805 (742, 909) 7 | +12 ♦ | 12 (10, 16) | +8 | 7 (7, 9) | −23 *,♦ | |
| Folic acid-fortified bread | 188 (T) | 461 | 4 | 31 | 36 ± 13 3 | 606 ± 224 3 | +13 * | 12 ± 5 3 | +25 * | [60] | ||
| Rye and orange juice | 184 (T) | 461 | 4 | 33 | 36 ± 13 3 | 561 ± 190 3 | +15 * | 10 ± 3 3 | +23 * | |||
| Folic acid | 150 (T) | 221 4 | 4 | 15 | 19-48 5 | 12 ± 4 3 | +20 | 10 ± 2 3 | −11 | [61] | ||
| Vegetables, fruits, liver pate | 331 (T) | 427 4 | 4 | 29 | 19-41 5 | 12 ± 4 3 | +33 ♦ | 10 ± 3 3 | −11 | |||
| Placebo | 0 | ~360 9 | 16 | 43 | 46 ± 2 | 895 ±6 0 | +3 | 26 ±2 | −1 | 9 ± 0.4 | 0 | [19] |
| Food group | 200 (C) | ~305 9 | 16 | 38 | 45 ± 2 | 872 ± 61 | +14 ♦ | 25 ± 2 | +19 ♦ | 10 ± 1 | −6 ♦ | |
| 5-methyltetrahydrofolate caps | 200 (P) | ~295 9 | 16 | 42 | 45 ± 2 | 793 ± 42 | +30 ♦ | 22 ± 2 | +41 ♦ | 10 ± 1 | −14 ♦ | |
| Folic acid caps | 200 (P) | ~325 9 | 16 | 40 | 48 ± 2 | 833 ± 56 | +28 ♦ | 24 ± 2 | +44 ♦ | 9 ± 0.4 | −15 ♦ | |
| Control | 0 | 210 4 | 4 | 22 | 23 ± 8 3 | 347 ± 793 | −1 | 13 ± 3 3 | 0 | 10 ± 33 | +9 | [14] |
| Fruit and vegetables | 350 (T) | 560 4 | 4 | 23 | 23 ± 8 3 | 338 ± 813 | +16 ♦ | 14 ± 3 3 | +30 ♦ | 11 ± 53 | −10 ♦ | |
| Control | 0 (T) | 242 | 4 | 14 | 60 ± 15 3 | 18 (15-22) 6 | 0 6 | 14 (12-16) 6 | 0 6 | [62] | ||
| High folate diet | 355 (T) | 618 | 4 | 20 | 58 ± 18 3 | 18 (16-19) 6 | 28 6,♦ | 12 (11-13) 6 | −9 6,♦ | |||
| Control | 0 (T) | 227 | 12 | 15 | 36-71 8 | 539 ± 166 3 | 0 | 15 (12-18) 6 | −7 6 | 12 (11-14) 6 | 0 6 | [58] |
| High folate diet | ~350 (T) | 707 | 12 | 15 | 36-71 8 | 571 ± 162 3 | +11 | 15 (13-17) 6 | +32 6,♦ | 11 (9-12) 6 | −10 6 | |
| Pericarp flour bread | 223 (T) | 436 | 16 | 25 | 48-56 5 | 497 (414-581) 6 | +14 6 | 13 (11-15) 6 | +7 6 | 10 (8-11) 6 | −25 6 | [63] |
| Aleurone flour bread | 615 (T) | 836 | 16 | 25 | 46-54 5 | 509 (434-584) 6 | +34 6,♦ | 13 (10-16) 6 | +52 6,♦ | 9 (8-10) 6 | −29 6,♦ | |
W: week; caps: capsules; N: number of subjects; F: females; p/s-folate: plasma/serum folate concentration; tHcy: total homocysteine concentration in plasma/serum. End (%): relative increase (+) or decrease (−) in status parameter at end of intervention compared with baseline. 1 Q: Quantification of folate content in intervention doses by (C: calculation, T: using trienzyme extraction, L: lacking information); P: as provided by manufacturer; 2 Females and males; 3 Mean ± SD; 4 Folate dose analyzed and not estimated by dietary recall; 5 Range; 6 Geometric means (95% CI); 7 Median (quartile 1, quartile 3); 8 Age reported as inclusion criteria; 9 Folate intake given in nmol, calculated to µg (0.460−1 nmol/µg). * Significant effect within the group compared with baseline (P < 0.05); ♦ Significant effect compared with control (P < 0.05).