Dietary supplements and asthma: another one bites the dust

Throughout history, clinical observation and clinical trials have identified links between nutritional deficiency and disease. For example, scurvy was described by Hippocrates over 2000 years ago, and native cultures have known its cause and cure for centuries. The first intervention study to demonstrate the successful treatment of scurvy with citrus fruits was published in 1753 by Captain James Lind in “A Treatise of the Scurvy”. Moving forward to the 20th century, one of the resounding achievements in this field has been identification of the importance of folic acid supplements in the prevention of spina bifida, leading to an overall reduction in incidence in the Western world. The possibility that nutritional factors may play a similarly important role in the aetiology of chronic respiratory disease is therefore intriguing and has recently attracted a great deal of interest.

The aetiology of asthma remains unclear, but it is widely accepted that environmental factors play a major role and, of these, diet is a potentially important contender. Evidence for this arises from the observations that the prevalence of asthma increases as societies move from a rural subsistence towards a more Western lifestyle; this is associated, among other factors, with a change in dietary pattern including adoption of a more processed and “convenience-orientated” diet. The result of this dietary change is an overall increase in the intake of refined sugars, fats and additives, and a relative reduction in the intake of complex carbohydrates and micronutrients. This change is a relatively modern phenomenon, occurring in the UK …