Beta-Carotene Linked to Lung Cancer in Smokers

Background:
The study was to determine whether vitamins, minerals, or the combination of both could reduce incidence and mortality from lung cancer in healthy individuals and smokers.

Method:
The study were randomised controlled clinic trials comparing different vitamin and mineral supplements to healthy people, including placebo supplements to healthy people. The aim was to prevent lung cancer. Two researchers independently selected trials to be included in the review of this study, assessed with the quality of each trial. The study included males and females, and participants considerted at high risk, such as smokers. Six studies analysed vitamin A, vitamin C, vitamin E, selenium supplements, and six studied combinations of two or more. All researchers were classified as being of low risk to bias.

Results:
For people not at high risk of lung cancer and compared to the placebo, none of the individual supplements alone or combination of produced s statistically significance difference in lung cancer incidence or mortality except in one case of 7627 females. This case found that women were at higher risk of lung cancer when taking vitamin C, but not for total cvancer incidence. The effect was not seen in males. However, for people considered at high risk of lung cancer, beta-carotene showed a small but statistically significant higher risk of lung cancer incidence and mortality.

Commentary:
Its hard for me to agree with the results of this case know what vitamin C does for your immune system. A possible explanation could be that these people were already considered at a high level of risk for lung cancer as smokers, so the vitamin C alone could not be directly related to lung cancer. Also, the previous study on healthy individuals taking vitamin C showed not effect on risk level. However, perhaps vitamin C intake while smoking speeds up the process of lung cancer.

Study Source:
U.S. National Library of Medicine. (2012). National Institute of Health. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/230