[Dietary efficacy of a micronutrient combination in patients with recurrent upper respiratory tract infections. Results of a placebo-controlled doubleblind study.]

Background and Objectives: An optimal vitamin and mineral supply may contribute to the enhancement of immune defenses and thus favorably influence the course and intensity of recurrent upper respiratory tract infections (URIs). In the present study the dietary efficacy and benefits of a micronutrient combination in patients with recurrent URIs was evaluated.
Methods: 192 patients with recurrent URIs were enrolled in this randomized, placebo-controlled, double-blind multicenter trial for a study duration of 16 weeks. Efficacy variables were number, intensity and course of URIs (as assessed using a total common cold score [CCS]) and the alterations in micronutrient supply (vitamins C and D3, folic acid and selenium) during the study.
Results: In subjects who initially had at least two common cold symptoms (N = 107) the symptoms improved in the active group (AG) significantly more than in the placebo group (PG; ΔCCS: AG -6.9 ± 4.8; PG -5.4 ± 4.5; p = 0.034). In patients with initially severe common cold (CC) episodes the symptoms improved in the AG to a statistically significant extent (ΔCCS: AG -93.8%, PG -91.2%, p = 0.043). In the age group below 45 years significantly fewer AG than PG patients were absent from their job during the second or third CC episode (AG: 14.3%, PG: 47.8%, p = 0.038). Patients with vitamin-D deficiency and/or insufficient vitamin-C supply reported significantly fewer CC episodes in AG than in PG. In the course of the trial, in AG vs. PG the serum vitamin C, folic acid and selenium levels increased (p ? 0.001). The concentration of 25(OH)D3 decreased in both groups, but less so in the AG (AG -8.8%; PG -14%; p = 0.001).
Conclusion: Study results show the efficacy of a nutritional medical treatment with a special micronutrient combination in patients susceptible to infections and suffering from recurrent respiratory tract infections.