On Facebook I shared a recent article from IFLScience about antioxidant supplementation increasing skin cancer spread in mice, along with my usual advice to eat real food and mostly plants. However I thought I would share a little more on the subject here in my blog.

IFLScience link here http://www.iflscience.com/health-and-medicine/antioxidant-supplements-may-drive-skin-cancer-spread

So what’s the deal here? “Aren’t antioxidants good for us?” you may be asking as you reach for some blueberries! Well that depends on where you’re getting your antioxidants.

Antioxidants and Reactive Oxygen Species

Antioxidants do an important job in dealing with reactive oxygen species (ROS), which are produced in the body as part of your normal metabolism. In fact you’re your body makes it’s own antioxidants to deal with these. The problem arises when there are excess ROS. This can cause damage to our cells and potentially cancer.

The Plot Thickens

So shouldn’t that mean having more antioxidants is protective? And absolutely when those antioxidants are gotten from a diet rich in fruits and vegetables you are right. In fact this was what led researchers back in the late 1980’s to design trials to see if supplementation with beta-carotene and vitamin A would reduce lung cancer risk in high risk populations (smokers and those occupationally exposed to asbestos). However both the ATBC and the CARET studies were stopped early because of an increase in risk not a decrease. In the CARET study there was a 28% increase in lung cancer in those taking the antioxidants compared to those in the placebo group. And even a 17% increase in all cause mortality.

Take Away Message

So forget the antioxidant supplements but continue to reach for those blueberries and enjoy a wide range of colourful fruits and veggies, safe in the knowledge you are giving your body a superfriend not foe.

Unless you have food chemical intolerances but that’s a story for another day!


ATBC Study

The Effect of Vitamin E and Beta Carotene on the Incidence of Lung Cancer and Other Cancers in Male Smokers [ONLINE] Available at: http://www.nejm.org/doi/full/10.1056/NEJM199404143301501. [Accessed 12 October 2015].


Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. [ONLINE] Available at: http://escholarship.org/uc/item/0mr2057n. [Accessed 12 October 2015].