The Effects of Dietary Supplements on Asthma and Lung Cancer Risk in Smokers and Non-Smokers: A Review of the Literature.

Naser A Alsharairi

doi:10.3390/nu11040725

Abstract

Smoking is one of the major global causes of death. Cigarette smoke and secondhand (passive) smoke have been causally related to asthma and lung cancer. Asthma is a potential risk factor for developing lung cancer in both smokers and non-smokers. Prospective studies and randomized control trials (RCTs) of dietary supplements and lung cancer risk in adult smokers and non-smokers have yielded inconsistent results. A few prospective studies have shown that long-term use of high doses of some supplements, such as retinol, β-carotene, B vitamins, and vitamin E, increase lung cancer risk in current and former smokers. Limited evidence from RCTs suggests that vitamin D supplementation is effective in improving lung function and reducing asthma risk in current/former smokers. The relationship between dietary supplements and lung cancer risk has never before been examined in asthmatic smokers and non-smokers. This short review aims to examine the evidence from existing studies for the effects of dietary supplements on asthma/lung cancer risk and mortality in smokers and non-smokers.

Highlights

Smoking harms several organ systems of the body and is considered a major risk factor for many diseases that are the largest causes of death among adults worldwide [1,2,3]
A significant improvement in lung function was observed among ever-smokers with asthma/chronic obstructive pulmonary disease (COPD) over non-smokers (P = 0.0005)
This review found contradictory results across studies examining the effects of dietary supplements on lung cancer risk and mortality in adult smokers/non-smokers

Summary

Introduction

Smoking harms several organ systems of the body and is considered a major risk factor for many diseases (e.g., lung and other cancers, coronary heart diseases and stroke, chronic obstructive pulmonary diseases) that are the largest causes of death among adults worldwide [1,2,3]. Tobacco smoke contains thousands of toxic chemicals, of which 60 are identified carcinogens [4]. It is well known that exposure to second-hand smoke (SHS) is associated with deaths from serious diseases (e.g., ischemic heart disease, chronic obstructive pulmonary disease, stroke, lung cancer) in adults [5,6]. More than 600,000 premature deaths were estimated to have been caused by SHS exposure in 2004. The rate of female non-smokers (47%) was higher than that of children (28%) and men (26%) [7]

Methods

Results

Conclusion