Title: The Medical Use of Wheatgrass: Review of the Gap Between Basic and Clinical Application
Authors: Gil Bar-Sela¹ ⁴, Miri Cohen², Eran Ben-Arye³ ⁴ and Ron Epelbaum¹ ⁴
A wide range of health benefits have been attributed to wheatgrass, the young grass of the common wheat plant Triticum aestivum. Its components include chlorophyll, flavonoids, and vitamins C and E. Forms of wheatgrass include fresh juice, frozen juice, tablets, and powders, with compositions varying according to their production processes, as well as to the growing conditions of the wheatgrass. Laboratory in vitro studies, mostly using the fermented wheat germ extract, have demonstrated anticancer potential and have identified apoptosis as a possible mechanism. In animal experiments, wheatgrass demonstrated benefits in cancer prevention and as an adjunct to cancer treatment, as well as benefits to immunological activity and oxidative stress. Clinical trials show that wheatgrass may induce synergistic benefits to chemotherapy and may attenuate chemotherapy-related side effects, as well as benefit rheumatoid arthritis, ulcerative colitis, hematological diseases, diabetes, obesity, and oxidative stress. However, all the trials were small and a number of methodological problems arose. No adverse events of wheatgrass have been reported, although some forms pose problems of tolerability. The popularity of wheatgrass continues to grow. Nevertheless, the advantages seen in the clinical trials need to be proved in larger studies before clinical recommendations for the public can be given.
Wheatgrass is young grass, most often of the common wheat plant Triticum aestivum. In the 1930s, Dr. Charles Schnabel, who has been called the "father of wheatgrass", began documenting a wide range of its health benefits, based on his observations in animals and humans. Schnabel patented a dietary supplement derived from the dehydration of young wheatgrass shoots, which was marketed until the 1950s. In the 1970s, Ann Wigmore renewed the popularity of wheatgrass. Based on her personal health experience, Wigmore wrote books and lectured on the benefits of wheatgrass, as part of a raw/living food diet. Only some of the many claimed health benefits of wheatgrass have been scientifically investigated. While a number of components of wheatgrass have demonstrated positive effects, the added value encompassed by the substance as an entity is not clear. We start this review with an examination of the qualities of the components of wheatgrass, followed by a discussion of the forms of wheatgrass and their characteristics. Next, we review the evidence for the health benefits of wheatgrass, from in vitro experiments, experiments in animals, and clinical trials. While healing qualities have also been attributed to the topical application of wheatgrass extract , the scope of this review is limited to oral administration. At the end, we raise issues to be considered in the clinical realm and in future research.
COMPONENTS OF WHEATGRASS AND THEIR HEALTH BENEFITS
Chlorophyll, which has been referred to as "living food" and as "green blood", is the primary nutrient in fresh wheatgrass. In addition, flavonoids, a large variety of vitamins including vitamins C and E, choline, minerals, enzymes, indoles, and a number of amino acids are considered to be responsible for the health benefits claimed. The alkaline pH of 7.4 is also considered an asset.
Among the qualities attributed to chlorophyll are the promotion of cancer prevention, protection against side effects of cancer treatment, and contribution to a positive hematological status. Extracts from wheat sprout roots and leaves were shown to inhibit metabolic activity of carcinogens, and chlorophyll was identified as the active substance. Chorophyllin, a derivative of chlorophyll, was shown to protect mitochondria against oxidative damage and to induce the activity of mammalian phase 2 proteins that protect cells against oxidants and electrophiles. This anti-oxidant activity has implications in cancer prevention. The capability of chlorophyll to protect mitochondrial membranes against gamma-radiation may be beneficial during cancer treatment. The structural similarity between chlorophyll and hemoglobin, which differs by the inclusion of magnesium and iron, respectively, may explain observed hematological benefits of chlorophyll-rich substances, although a mechanism of such has not been elucidated.
Wheatgrass is also rich in flavonoids, particularly apigenin, which is known for its functions in anti-oxidation; in anti-inflammation by inhibiting cytokine-induced leukocyte adhesion; in anti-carcinogenesis by antiproliferative and proapoptotic activities through regulation of signaling pathways such as PI3K/Akt/mTOR and MAPK; and in cardiovascular protection by inducing endothelial derived hyperpolarizing factor (EDHF)- mediated vascular dilatation.
Vitamin C (ascorbic acid), a component of fresh wheatgrass, has been associated with the prevention and treatment of cancer through a number of mechanisms that relate to antioxidant and pro-oxidant properties, stimulation of the immune system, altering carcinogen metabolism, enhancement of collagen synthesis, and interference with cancer cell signaling . The possibility that antioxidant agents may interfere with chemotherapy necessitates the specific investigation of each agent and the timing of its administration. When received simultaneously with chemotherapy, vitamins C and E were found to restore antioxidant status that had decreased due to breast cancer and its treatment, and to reduce DNA damage.
Choline and indoles are other components of wheatgrass that have had anti-cancer activity attributed to them. Phytochemical screening and gas chromatography-mass spectrometry analysis has verified, in the aqueous extract of wheatgrass: flavonoids, triterpenoids, anthraquinol, alkaloids, tannins, saponins, sterols, squalene, caryophyllene and amyrins, many of which have demonstrated anti-oxidant activity.
Oligosaccharides isolated from wheatgrass were found to stimulate the expression of inflammatory cytokines in human peripheral blood mononuclear cells. The oligosaccharide, maltoheptaose, is the first immunostimulatory component of wheatgrass to be identified. Maltoheptaose was shown to activate monocytes via Toll-like receptor 2 (TLR-2) signaling.
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