Hi 
Please check this article
http://en.wikipedia.org/wiki/WheatgrassThis article states that:
Proponents of wheatgrass claim regular ingestion of the plant can
improve the digestive system 
prevent diabetes and heart disease 
cure constipation 
detoxify heavy metals from the bloodstream   help make menopause more manageable 
promote general well-being. 
It says detoxify heavy metals from teh blood stream. Doest that mean iron as well. 
Table 1. Nutrient comparison of 1 oz (28.35 g) of wheatgrass juice, broccoli and spinach. 
Nutrient Wheatgrass Juice Broccoli Spinach 
Protein 860 mg 800 mg 810 mg 
Beta carotene 120 IU 177 IU 2658 IU 
Vitamin E 880 mcg 220 mcg 580 mcg 
Vitamin C 1 mg 25.3 mg 8 mg 
Vitamin B12 0.30 mcg 0 mcg 0 mcg 
Phosphorus 21 mg 19 mg 14 mg 
Magnesium 8 mg 6 mg 22 mg 
Calcium 7.2 mg 13 mg 28 mg 
Iron 0.66 mg 0.21 mg 0.77 mg 
Potassium 42 mg 90 mg 158 mg 
Data on broccoli and spinach from USDA database.[3] Data on Wheatgrass juice from indoor grown wheatgrass.[2]