I found the following article particularly interesting because they have reports on studies conducted which validate their claims.
One of the most important factors to consider when choosing what to eat, is the fiber content.
"Sulfur-containing antioxidants found in cruciferous vegetables, such as broccoli, kale, and cabbage, have been found to provide protection against radiation exposure through their detoxifying properties. Pectin in fruits has also been shown to reduce levels of the radioactive substance Cs-137. Plant based foods provide protection against free radical damage and they can reduce the absorption of radioactive substances."
Learn more: http://www.naturalnews.com/031878_radiation_protection.html#ixzz1I4fMRXP2Simple foods provide protection against radiation exposure