Vitamin D ₃ fortified food may improve serum vitamin D level, suggesting that the prevention of adverse consequences of hypovitaminosis D is possible with food fortification. The aim of this randomized controlled trial (RCT) was to examine the effects of vitamin D and calcium fortified yogurt on spatiotemporal gait parameters, cognitive performance, handgrip strength, and serum 25OHD levels in healthy older females.
Forty older community-dwelling females were recruited in a single-blind, randomized, controlled, superiority clinical trial in two parallel groups (20 participants in the intervention group and 20 in the control group) with intent-to-treat. The intervention group took fortified yogurts daily (i.e., 400 UI of vitamin D ₃ and 800 mg calcium) for 3 months. The non-fortified yogurts contained similar proteins, carbohydrates and lipids, as well as a lower dose of calcium (300 mg) and no vitamin D ₃ supplementation. Spatiotemporal gait parameters (mean value and coefficient of variation) were assessed using a computerized walkway. Handgrip strength was measured with hydraulic dynamometers. Cognitive performances, including global cognitive functioning assessed with the Mini Mental Status Examination (MMSE) were recorded. All the outcomes were assessed at baseline and at the end of follow-up. The primary outcome was the coefficient of variation of stride time.
The intervention group maintained its global cognitive performance and serum 25OHD concentrations, whereas these outcomes decreased (i.e., worst performance) in the control group. The changes in the MMSE score (p = 0.022) and serum 25OHD concentrations were different (p ≤ 0.001) with better values reported in the intervention group compared to the control group. There was no significant change in gait parameters (p ≥ 0.518) and handgrip strength (p ≥ 0.600).
Fortified yogurts with vitamin D (i.e., 200 IU) and calcium (i.e., 400 mg) twice a day maintained global cognitive performance and vitamin D status in older females, but not gait performances, signifying that they mainly prevent hypovitaminosis D-related extra-skeletal disorders.