Vitamins and Chronic Wounds: How Altered Pharmacokinetics and Comorbidities Contribute to Vitamin Deficiencies

Wound healing is complex and requires adequate amounts of macro- and micronutrients. When wound healing is delayed, a wound is considered chronic. Increasing evidence shows that vitamin deficiencies are prevalent in patients with chronic wounds, yet intervention studies with vitamin supplementation yielded inconsistent effects. These inconsistencies may be explained by suboptimal study designs and vitamin doses. To substantiate optimal dosing, it is important to understand how vitamin pharmacokinetics and requirements are altered in patients with chronic wounds. However, a comprehensive overview of factors that influence vitamin kinetics during wound repair is lacking. This review aims to address this. A multitude of interfering factors may co-exist in individuals with chronic wounds, including medication, malabsorption, inflammation, as well as overweight, obesity and renal insufficiency. Several of these factors are linked to diabetes and advancing age as overarching factors. Limited evidence suggests that vitamin requirements may be higher in individuals with diabetes. More work is needed to understand vitamin pharmacokinetics and vitamin requirements in patients with chronic wounds. Data on the effects of the treatment of combinations of deficiencies, and for B-vitamins, are entirely lacking. Healthcare professionals should be aware of the prevalence and risk factors for vitamin deficiencies in populations with chronic wounds, and monitoring of blood concentrations may be warranted. Provisional recommendations are made on how to treat and prevent vitamin deficiencies.