Effects of vitamin D and zinc fortified biscuits on micronutrient status among healthcare workers in Indonesia: A randomised controlled trial

Abstract

Fortifying foods, such as biscuits, might help meet dietary requirements amid the widespread prevalence of vitamin D and zinc deficiencies. This study examined the effect of biscuit fortification with vitamin D and zinc on changes in serum vitamin D and zinc levels during the study. A double-blind, randomized pre-post-test trial was conducted among health workers in Tangerang Selatan, Indonesia, who were assigned to a non-fortified biscuit group, fortified biscuit group (7.5 mcg of vitamin D and 7.5 mg of zinc per serving), or supplementation group (10 mcg of vitamin D and 10 mg of zinc). The study collected baseline characteristics, food intake, and serum vitamin D and zinc levels, with biochemical measurements performed at baseline, four weeks, and eight weeks. The study revealed that 73.64% and 10.91% of respondents were deficient in vitamin D and zinc, respectively. Zinc intake was significantly higher in the supplementation group than in the other groups (P<0.05), whereas there were no significant differences among the groups in energy, fat, carbohydrate, or vitamin D intake (P>0.05). Compliance with the intervention treatments ranged from 47.8% to 54.6% (P>0.05). Following the eight-week intervention, serum vitamin D and zinc levels did not differ significantly among groups (P>0.05), and changes in serum vitamin D and zinc levels were also not significantly different (P>0.05). Low-dose vitamin D and zinc fortification through biscuits was insufficient to significantly improve serum vitamin D and zinc concentrations among health workers over eight weeks. Higher fortification doses and longer intervention periods warrant further investigation to address micronutrient deficiencies effectively.