British Journal of Nutrition

  • British Journal of Nutrition / Volume 105 / Issue 01 / January 2011, pp 118-122
  • Copyright © The Authors 2010. The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution-NonCommercial-ShareAlike licence <>. The written permission of Cambridge University Press must be obtained for commercial re-use.
  • DOI: (About DOI), Published online: 23 August 2010

Full Papers

Human and Clinical Nutrition

Reduction of common cold symptoms by encapsulated juice powder concentrate of fruits and vegetables: a randomised, double-blind, placebo-controlled trial

Stephanie Rolla1 c1, Marc Nocona1 and Stefan N. Willicha1

a1 Institute for Social Medicine, Epidemiology and Health Economics, Charité University Medical Centre, Luisenstrasse 57, 10098 Berlin, Germany


Dietary supplements have been suggested in the prevention of the common cold, but previous investigations have been inconsistent. The present study was designed to determine the preventive effect of a dietary supplement from fruits and vegetables on common cold symptoms. In a randomised, double-blind, placebo-controlled trial, healthcare professionals (mainly nursing staff aged 18–65 years) from a university hospital in Berlin, Germany, were randomised to four capsules of dietary supplement (Juice Plus+®) or matching placebo daily for 8 months, including a 2-month run-in period. The number of days with moderate or severe common cold symptoms within 6 months (primary outcome) was assessed by diary self-reports. We determined means and 95 % CI, and differences between the two groups were analysed by ANOVA. A total of 529 subjects were included into the primary analysis (Juice Plus+®: 263, placebo: 266). The mean age of the participants was 39·9 (sd 10·3) years, and 80 % of the participants were female. The mean number of days with moderate or severe common cold symptoms was 7·6 (95 % CI 6·5, 8·8) in the Juice Plus+® group and 9·5 (8·4, 10·6) in the placebo group (P = 0·023). The mean number of total days with any common cold symptoms was similar in the Juice Plus+® and in the placebo groups (29·4 (25·8, 33·0) v. 30·7 (27·1, 34·3), P = 0·616). Intake of a dietary supplement from fruits and vegetables was associated with a 20 % reduction of moderate or severe common cold symptom days in healthcare professionals particularly exposed to patient contact.

(Received March 16 2010)

(Revised June 23 2010)

(Accepted July 19 2010)

(Online publication August 23 2010)


c1 Corresponding author: S. Roll, fax +49 30 450 529902, email