Wheat grass is prepared by sprouting wheat seeds in water for 7–10 days before harvesting the leaves. Because the leaves are fibrous and difficult to digest, the juice from the leaves is extracted and consumed raw. Proponents believe the enzymes responsible for detoxifying the body are deactivated by the cooking process. Wheat grass is also marketed as a nutritional supplement in powder form.
Wheat grass juice has been claimed to neutralize toxins and carcinogens in the body, prevent tooth decay, reduce high blood pressure, and aid in the treatment and prevention of cancer and AIDS. It is also used to improve digestion, prevent hair from graying, for common colds, cough, rheumatic pain, chronic fatigue syndrome, ulcers, and skin conditions. However, none of these claims are supported by clinical studies.
Wheat grass proponents also equate its major constituent chlorophyll to hemoglobin, and believe that wheat grass consumption can increase oxygenation in the body. However, these concepts are not supported by current scientific understanding.
Animal models suggest that wheat grass may have hypolipidemic (1) and antioxidant (2) effects. Wheat grass supplementation reduced plasma lipid peroxidation levels in healthy volunteers engaged in regular exercise (3). A small study and systematic review indicate that wheat grass juice may be helpful for ulcerative colitis (4) (5). Other studies are mixed on whether it can reduce the need for transfusions in patients with thalassemia major (6) (7) (8). Wheat grass juice may decrease myelotoxicity in breast cancer patients undergoing chemotherapy (9). There is also a report that wheat grass juice can reduce serum ferritin in patients with myelodysplastic syndrome (13). Larger studies are needed to evaluate these findings.
Nausea has been reported following consumption of wheat grass juice. Because it is consumed raw, microbial contamination is also a concern.