Antioxidants in smokers

Abstract

Cigarette smoke (CS) is likely the most common preventable cause of human morbidity and mortality worldwide. Consequently, inexpensive interventional strategies for preventing CS-related diseases would positively impact health systems. Inhaled CS is a powerful inflammatory stimulus and produces a shift in the normal balance between antioxidants and oxidants inducing oxidative stress in both the respiratory system and throughout the body. This enduring and systemic pro-oxidative state within the body is reflected by increased levels of oxidative stress and inflammation biomarkers seen in smokers. Smokers might benefit from consuming antioxidant supplements, or a diet rich in fruit and vegetables, which can reduce the CS-related oxidative stress. This review provides an overview of the plasma profile of antioxidants observable in smokers and examines the heterogeneous literature to elucidate and discuss the effectiveness of interventional strategies based on antioxidant supplements or an antioxidant-rich diet to improve the health of smokers. An antioxidant-rich diet can provide an easy-to-implement and cost-effective preventative strategy to reduce the risk of CS-related diseases, thus being one of the simplest ways for smokers to stay in good health for as long as possible. The health benefits attributable to the intake of antioxidants have been observed predominantly when these have been consumed within their natural food matrices in an optimal antioxidant-rich diet, while these preventive effects are rarely achieved with the intake of individual antioxidants, even at high doses.

Role of Beta-Carotene in Lung Cancer Primary Chemoprevention: A Systematic Review with Meta-Analysis and Meta-Regression

“…Beta-carotene can readily form pro-oxidative oxidation products, especially at high concentrations in the oxidative environment of smokers’ lungs, characterized by increased cell oxidative stress and decreased antioxidant defence. Antioxidant supplements may alter the redox balance with deleterious effects on cellular functions, supporting cancerogenesis [ 24 ].…”

The Double-edged Sword of Antioxidant Supplements on Metabolic Diseases, A Necessity for Quantification of Oxidative Status

“…Whether antioxidant supplements could be beneficial for patients with liver diseases (18) or justify usefulness in critically ill patients (19) or reduce risks of pancreatic cancer incidence and mortality in a nonlinear dose-response pattern (20) or mitigate adverse health effects associated with traffic-related air pollution (21) are still uncertain. In comparison with an optimal antioxidant-rich diet in a healthy population (22), the intake of individual antioxidants scarcely achieves health benefits even at high doses in patients during cancer treatment despite the possible side effects induced by oversupplied antioxidants (23,24) and the association with risks of pancreatic cancer incidence and mortality in a nonlinear dose-response pattern (20). Vitamin E supplement has shown an inverse association with CVD in interventional trials (25).…”

Dietary Antioxidants and Lung Cancer Risk in Smokers and Non-Smokers

“…Levels of OS and LP were found to be higher, and antioxidant enzymes and vitamins/minerals were lower in current and former smokers than non-smokers. A recent review suggests that there are lower plasma levels of β-carotene, BCX, lycopene, vitamin E, vitamin C and selenium in current smokers than non-smokers [ 51 ]. In one cross-sectional study, female current, but not former smokers have higher levels of urinary 8-hydroxy-20-deoxyguanosine (8OHdG), a biomarker for CS-induced oxidative damage, than their male counterparts; although they had elevated serum levels of β-carotene and BCX.…”