The Antimicrobial Activity of Combination of Vitamin D3 and Omega-3 against Pathogenic Microorganisms

Food supplements such as vitamin D₃ and omega-3 have a significant role in activating the immune system and impacting the diversity of gut microbiota; thus, controlling the growth of invading pathogens indirectly.

This study aims to evaluate the direct antimicrobial activity of vitamin D3 and omega- 3 individually, combined together, and combined with low concentrations of gentamicin or amphotericin B against selected pathogenic microorganisms. In addition, this study hypothesizes the potential antimicrobial mechanism and recommends suitable studies to be conducted.

Minimum inhibitory concentration of different serial dilutions of vitamin D₃ (0.7 μg/mL-83.3 μg/mL) or omega-3 (0.7 mg/mL-100 mg/mL) or combined (vitamin D3:1.3 μg/mL-83.3 μg/mL and omega-3:1.56 mg/mL-100 mg/mL) with/without antibiotic have been investigated on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans using check board technique.

The highest concentration of vitamin D₃ (83.3 μg/mL) demonstrated a complete eradication of the tested microorganisms. Conversely, omega-3 had a lower effect on them. The highest concentration of combining vitamin D3 and omega-3 with/without gentamicin resulted in a complete eradication of the S. aureus, E. coli and P. aeruginosa with a 6.8 to 7 log reduction. On the other hand, C. albicans was inhibited when using vitamin D3 (83.3 μg/mL) or when this concentration is combined with 100 mg/mL of omega-3. However, when these two concentrations were added to amphotericin B the log reduction dropped to 0.45 suggesting antagonistic effect.

These findings suggested that, unlike omega 3, vitamin D₃ possesses good antimicrobial effects against pathogenic microorganisms. The combination of the studied food supplement showed enhanced microbial inhibition at high concentration, while they had antagonistic effect when combined with amphotericin B and applied on C. albicans combined. Further studies on the exact antimicrobial mechanism are still required to understand the measured data here.