There's really not a good natural iron chelator that can handle the volume needed to chelate those getting transfusions. Your body hangs on to iron very well. Small amounts are lost through sweating and all antioxidant have some level of chelation ability but not very effective in iron overload cases.
Some have had success with wheat grass but IMO, it's not very promising as first line therapy for chelation. John tried it for about a year but had no benefit from it.
Marlene, wife to John DX w/SAA April 2002, Stable partial remission; Treated with High Dose Cytoxan, Johns Hopkins, June 2002. Final phlebotomy 11/2016. As of January 2017, FE is 233, HGB 11.7, WBC 5.1/ANC 4.0, Plts 146K.