Research Database -
International Updates

Respiratory Infections / Colds

Issue 22

HEMILA, Department of Public Health, University of Helsinki Finland writes that in 1971, Linus Pauling carried out a meta-analysis of 4 placebo-controlled trials. His conclusions were that it was highly unlikely that the decrease in the "integrated morbidity of the common cold in vitamin C groups was caused by chance alone. Research conducted since then have consistently found that vitamin C of dose greater than or equal to 1 g per day alleviates common cold symptoms, demonstrating that vitamin C does indeed exert physiological effects upon colds. However, widespread conviction still abounds that vitamin C has no proven effects upon the common cold. METHODS and RESULTS: The author reviews three of the most influential reviews which conclude that vitamin C has no effect and which are cited in the current edition of the RDA nutritional recommendations as evidence that vitamin C is ineffective against colds. These three reviews are shown to contain serious inaccuracies and shortcomings, making them unreliable sources for this subject. In addition, possible conceptual reasons are suggested for the persistent resistance to the idea that vitamin C may have effects on colds. CONCLUSIONS: Despite the fact that placebo-controlled trials have shown that vitamin C does alleviate common cold symptoms, important questions still remain.
Hemila H. Vitamin C supplementation and common cold symptoms: problems with inaccurate reviews. Nutrition 12(11-12): 804-9. Nov-Dec. 1996.

COMMENTS: Why is it that even after 25 years, serious inaccuracies and shortcomings in reporting of the vitamin C - cold research have not been corrected? It is scandalous that the general perception is that vitamin C does not help with colds, despite the considerable evidence to the contrary.

WESTERVELD and colleagues, Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital Vrije Universiteit, Amsterdam, the Netherlands write that imbalances between oxidant formation and antioxidative defense are association with several chronic respiratory tract inflammatory disorders, suggesting that oxidative stress plays a role in chronic upper airway tract infections. METHODS: Samples of inflamed mucosal biopsy specimens were obtained from 9 patients with chronic sinusitis; normal samples were collected from 10 healthy controls. Levels of reduced glutathione, oxidised glutathione, uric acid and vitamin E were determined biochemically. RESULTS: Compared with the controls, there was a significant reduction of reduced glutathione and uric acid levels in patients with chronic sinusitis. There were no difference in oxidised glutathione or vitamin E levels between the groups. CONCLUSIONS: Decreased levels of glutathione and uric acid in patients with chronic sinusitis lead to diminished antioxidant defense, which may be associated with the pathogenesis of upper respiratory tract disorders.
Westerveld GJ et al. Antioxidant levels in the nasal mucosa of patients with chronic sinusitis and healthy controls. Arch Otolaryngol Head Neck Surg 123(2): 201-4. Feb 1997.