Effects of multivitamins and low-dose folic acid supplements on flow-mediated vasodilation and plasma homocysteine levels in older adults

Background Hyperhomocysteinemia is associated with aging, endothelial dysfunction, and increased risk of coronary heart disease in older adults; however, the effects of homocysteine-lowering therapy on vascular reactivity in older persons are unknown. The objective of this study was to determine the effects of multivitamins (MV) and folic acid (FA) supplements on flow-mediated vasodilation (FMD) in older adults. Methods Individuals ≥70 years old with homocysteine levels ≥10 μmol/L were recruited for this 40-week, prospective, single-blinded study. All subjects were treated sequentially, with each of the following daily therapies for 10 weeks: (1) placebo, (2) MV (400 μg FA, 6 mg vitamin B6, 25 μg vitamin B12), (3) placebo, then (4) MV + FA (total FA, 1400 μg). FMD, folate intake, and laboratory values were measured at each visit. Investigators were blinded to subject treatment phase when measuring vessel diameters and calculating FMD. Results Twenty subjects (mean ± SEM age, 78.0 ± 1.2 [range, 70 to 88] years, 9 women) completed the MV and 17 completed the MV + FA interventions. FMD was impaired at baseline (2.0% ± 1.2%). During the 40-week study, homocysteine levels decreased by 1.4 ± 0.9 μmol/L (ptrend = 0.034) from a baseline of 12.8 ± 0.6 μmol/L; however, FMD did not change significantly (ptrend = 0.874). FMD did not improve after therapy with MV alone (3.0% ± 0.9% [week 10] vs 2.4% ± 1.1% [week 20], P = .716) or with MV + FA (2.6% ± 0.9% [week 30] vs 1.9% ± 0.7% [week 40], P = .484). Conclusions At doses commonly prescribed in clinical practice, MV and FA supplements did not improve FMD in older adults with hyperhomocysteinemia.