1.
Effect of β-Carotene Supplementation on the Risk of Pneumonia Is Heterogeneous in Males: Effect Modification by Cigarette Smoking.
Hemilä, H
Journal of nutritional science and vitaminology. 2018;(5):374-378
Abstract
Beta-carotene has been suggested to be a factor for improving the immune system, which implies that it might decrease the risk of infections. We therefore analyzed whether beta-carotene supplementation influenced pneumonia risk in 14,564 Finnish male smokers of the Alpha-Tocopherol Beta-Carotene (ATBC) Study. There were 231 pneumonia cases in the beta-carotene group and 217 cases in the placebo group. Thus, beta-carotene had no effect on the average incidence of pneumonia, RR=1.07 (95% CI: 0.89-1.29). However, cigarette smoking exposure significantly modified the effect. Beta-carotene increased pneumonia risk by RR=4.0 (95% CI: 1.63-10) among 990 participants who started to smoke at the age of ≥21 y and smoked ≥21 cigarettes per day at the study baseline. However, beta-carotene had no influence on pneumonia risk for the remaining participants. We also analyzed the effect of beta-carotene on participants who quit smoking during the ATBC Study. Among 4,290 participants who quit smoking, the 58 pneumonia cases were evenly distributed between the beta-carotene and placebo groups with RR=0.93 (95% CI: 0.55-1.55). Accordingly, no evidence was found that beta-carotene decreased pneumonia risk; instead, it significantly increased the incidence of pneumonia in a subgroup that covered 7% of the study population.
2.
β-Carotene and lutein inhibit hydrogen peroxide-induced activation of NF-κB and IL-8 expression in gastric epithelial AGS cells.
Kim, Y, Seo, JH, Kim, H
Journal of nutritional science and vitaminology. 2011;(3):216-23
Abstract
Reactive oxygen species (ROS) including hydrogen peroxide (H(2)O(2)) are involved in the pathogenesis of gastric inflammation. Interleukin-8 (IL-8) is a potent mediator of the inflammatory response by activating and recruiting neutrophils to the site of infection. Oxidant-sensitive transcription factor NF-κB regulates the expression of IL-8 in the immune and inflammatory events. Carotenoids (carotenes and oxygenated carotenoids) show antioxidant and anti-inflammatory activities. Low intake of β-carotene leads to high risk of gastric cancer. Oxygenated carotenoid lutein inhibited NF-κB activation in experimental uveitis. The present study aims to investigate whether β-carotene and lutein inhibit H(2)O(2)-induced activation of NF-κB and expression of IL-8 in gastric epithelial AGS cells. The cells were treated with carotenoids 2 h prior to the treatment of H(2)O(2). mRNA expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and real time RT-PCR analyses. IL-8 level in the medium was determined by enzyme-linked immunosorbent assay. NF-κB activation was assessed by electrophoretic mobility shift assay. ROS levels of the cells were detected by confocal microscopic analysis for fluorescent dichlorofluorescein. As a result, H(2)O(2 )induced the activation of NF-κB and expression of IL-8 in AGS cells time-dependently. β-Carotene and lutein showed inhibitory effects on H(2)O(2)-induced increase in intracellular ROS levels, activation of NF-κB, and IL-8 expression in AGS cells. In conclusion, supplementation of carotenoids such as β-carotene and lutein may be beneficial for the treatment of oxidative stress-mediated gastric inflammation.