The video below tells us that there is evidence that supports that taking vitamin C actually protects us from radiation. On the other hand, there are many that believe the entire study mentioned in the following video is complete rubbish.
I am not an expert at any of these things, but in my opinion, whether it is as effective as the study shows or not, what damage could come over using the theory to potentially save yourself from the suffering that radiation can bring?
Seriously, if a vitamin might aid in protection, why not keep it stock piled? Lets say something catostrophic happens, and we have to survive radiation. Chances are that most people won't have any protective equiptment such as masks and the suits used to protect from radiation. That stuff is expensive and people with lower financial capabilities will surely suffer and parish. Vitamin C is better than nothing at all and is a cheap addition to any other means of protection.
Those that troll around and mock or discount this study and others like it are likely going to suffer if the things they argu actually happen and they are caught with their pants down!
Personally, I will be adding lots of vitamin C to our survival packages. Is it any different than adding bandages to your car just in case?
Sea salt and baking soda - http://www.naturalcuresnotmedicine.com/2013/11/sea-salt-and-baking-soda-best-all.html#z1sqYaqrv5lvTXcH.99