Fruit and vegetable concentrates may reduce common cold symptoms

Intake of a dietary supplement derived from fruits and vegetables may be associated with a reduction of moderate or severe common cold symptoms, a new German study suggests.

In the randomized controlled trial, 543 healthcare professionals, aged between 18 and 65 years, received either two capsules of a supplement derived from fruits (150 mg vitamin C, 20 mg vitamin E, 3.2 mg beta-carotene and 100 mcg vitamin B9 per capsule) plus two capsules of a supplement from vegetables (50 mg vitamin C, 26 mg vitamin E, 4.3 mg beta-carotene and 300 mcg vitamin B9 per capsule) per day or a matching placebo for eight months (1). The subjects self-reported the number of days with moderate or severe cold symptoms in six months over the winter. While the mean number of total days with cold symptoms was seen to be the same in the supplement and the placebo group, the former reported fewer days with moderate to severe symptoms (a mean of 7.6 days vs. 9.5 days).

The study included physically fit healthcare professionals, mainly nursing staff, who have an increased risk of infection as they regularly come into contact with patients suffering from a cold. The researchers concluded that the supplement may reduce the number of days with moderate to severe cold symptoms. However, more research would be needed to establish whether longer term use could further reduce frequency or severity of colds, and the underlying mechanism.

Consumers in many Western countries are advised to consume between five and nine portions of fruit and vegetables a day, to support vital functions, such as the immune system, with micronutrients. Many people do not achieve this intake recommendation. Dietary supplements have been suggested as preventive strategies for common cold, but previous results were inconsistent.

1. Roll S. et al. Attenuation of common cold symptoms by encapsulated juice powder concentrate. The FASEB Journal. 2010.