Impact of Almond Milk Fortified with Vitamin D3-Loaded Soy Protein Nanoparticles on Serum 25(OH)D3 Concentrations in Adults with CKD: A Pilot Double-Blind Randomized Controlled Trial

Abstract

Background: Chronic kidney disease (CKD) impairs the activation of vitamin D, leading to deficiencies that exacerbate disease progression and metabolic complications. This pilot study investigated the effects of consuming almond milk fortified with vitamin D<inf>3</inf> nanoparticles on 25(OH)D<inf>3</inf> among adults with advanced stages of CKD. Methods: A 21-day, double-blind randomized controlled pilot study was conducted. Participants (n = 18) were randomly assigned to consume 4 oz (118 ml) of almond milk daily with 4000 IU of vitamin D<inf>3</inf> dispersed in soy protein nanoparticles (intervention group), or almond milk without vitamin D (control group). The primary outcome was the change in serum 25(OH)D<inf>3</inf> levels, while secondary outcomes included changes in serum calcium and parathyroid hormone (PTH). Results: From baseline to end of intervention, there was a significant decrease in serum 25(OH)D3 in the control group (49.2 ± 23.3 nmol/L to 44.5 ± 25.6 nmol/L; p < 0.05). In the intervention group, there was a significant increase in 25(OH)D3 (33.0 ± 15.8 nmol/L to 36.4 ± 15.8 nmol/L; p < 0.05). A significant time × treatment interaction (p < 0.01) was observed, with the intervention group showing a marked increase in serum 25(OH)D<inf>3</inf>. No differences between groups were observed in serum calcium and PTH. Conclusion: The consumption of almond milk fortified with vitamin D<inf>3</inf> dispersed in soy protein nanoparticles increased 25(OH)D<inf>3</inf> in adults with advanced stages of CKD over 21-days. Future research should explore the metabolism and long-term efficacy of nanoparticle-based delivery of vitamin D<inf>3</inf> in larger, more diverse populations. © 2025 Elsevier B.V., All rights reserved.