Antioxidant use associated with increased cancer risk.

[schrute]

Just thought this was interesting, though it's based off a questionnaire.
Courtesy of Dr. Barrett.

Researchers who analyzed data from 77,126 people who answered detailed questions about their supplement use over a ten-year period have found that longer duration of use of individual beta-carotene, retinol, and lutein supplements was associated with significantly higher risk of lung cancer. The authors concluded: "Long-term use of individual beta carotene, retinol, and lutein supplements should not be recommended for lung cancer prevention, particularly among smokers." [Satia JA and others. Long-term Use of (beta)-carotene, retinol, lycopene, and lutein supplements and lung cancer risk: Results from the VITamins And Lifestyle (VITAL) Study. American Journal of Epidemiology, Feb 10, 2009]
http://www.ncbi.nlm.nih.gov/pubmed/19208726

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[SaltySqueegee]

Last year at AACR, the consensus among investigators was that while antioxidants mitigate reactive oxygen species in, in vitro models, it may not bare true in, in vivo contexts. Studies from the lab I work in corroborate with many other labs indicating that the level of oxidant stress an individual is exposed to and their relative odds of developing cancer are in a fixed relationship. Relationships include: peripheral blood lymphocytes from patients diagnosed with lung cancer tend to have 1) reduced DNA repair capacity and 2) reduced or altered expression (from the norm) of genes (transcript and protein levels) involved in DNA repair, phase 1/2 metabolism and cell-cycle control, compared to controls. Currently, there is not significant statistical power in genome wide association studies to link specific loci with a clinically relevant odds ratio to lung cancer risk. Work from Qie and Spitz out of MD Anderson suggests that antioxidant supplements do not alter DNA repair capacity or antioxidant pathways significantly in peripheral blood lymphocyte models. This indicates that an individuals level of robustness against developing lung cancer is primarily intrinsic, to some degree.

In other case-control studies, if you do not smoke and are at a young age, antioxidant supplements may actually decrease your risk of lung cancer diagnosis slightly. And in other studies, if you are older, have smoked for a significant time period, antioxidant supplements may provide your abnormally dividing lung epithelium with a selective advantage! Antioxidants are a double-edged sword.

Prescribe em' when your young and healthy for long term prevention. Back off of them when you are older is the consensus.