Wheatgrass is a food prepared from the cotyledons of the common wheat plant, Triticum aestivum. It is sold either as a juice or powder concentrate. Wheatgrass differs from wheat malt in that it is served freeze-dried or fresh, while wheat malt is convectively dried. Wheatgrass is allowed to grow longer than malt. Like most plants, it contains chlorophyll, amino acids, minerals, vitamins, and enzymes. Claims about the health benefits of wheatgrass range from providing supplemental nutrition to having unique curative properties, though few, if any, have been scientifically proven. It is often available in juice bars, and some consumers grow and juice wheatgrass in their homes. It is available as fresh produce, tablets, frozen juice and powder. Wheatgrass contains no wheat gluten.
The consumption of wheatgrass in the Western world began in the 1930s as a result of experiments conducted by Charles F. Schnabel in his attempts to popularize the plant. By 1940, cans of Schnabel's powdered grass were on sale in major drug stores throughout the United States and Canada
Anne Wigmore was also a strong advocate for the consumption of wheatgrass as a part of a Raw Food Diet. Wigmore, founder of the Hippocrates Health Institute, believed that wheatgrass, as a part of a raw food diet, would cleanse the body of toxins while providing a proper balance of nutrients as a whole food. She also taught that wheatgrass could be used to treat those with serious disease. Wigmore's recommendations and reputation as a health practitioner have been heavily criticized, but many health institutes still endorse her teachings. 
Schnabel's research was conducted with wheatgrass grown outdoors in Kansas. His wheatgrass required 200 days of slow growth, through the winter and early spring, when it was harvested at the jointing stage. He claimed that at this stage the plant reached its peak nutritional value; after jointing, concentrations of chlorophyll, protein, and vitamins decline sharply. Harvested grass was dehydrated and made into powders and tablets for human and animal consumption. Wheatgrass grown indoors in trays for ten days contains similar nutritional content. Wheatgrass grown outdoors is harvested, dehydrated at a low temperature and sold in tablet and powdered concentrates. Wheat grass juice powder is also available either spray-dried or freeze-dried.
|Table 1. Nutrient comparison of 1 oz (28.35 g) of wheatgrass juice, broccoli and 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. Data on Wheatgrass juice from indoor grown wheatgrass.|
Proponents of wheatgrass make many claims for its health properties, ranging from promotion of general well-being to cancer prevention. However, according to the American Cancer Society, "available scientific evidence does not support the idea that wheatgrass or the wheatgrass diet can cure or prevent disease". There is some limited evidence of beneficial pharmacological effects from chlorophyll, though this does not necessarily apply to dietary chlorophyll.
There are a number of other small studies and pilots on the possible benefits of wheatgrass juice. According to Memorial Sloan Kettering Cancer Center, there may be a need for further study of wheatgrass therapy for ulcerative collitis; they cite a small pilot study which showed regular wheatgrass juice therapy significantly reduced rectal bleeding and overall disease activity.
Wheatgrass proponent Schnabel claimed in the 1940s that "fifteen pounds of wheatgrass is equal in overall nutritional value to 350 pounds of ordinary garden vegetables", a ratio of 1:23. Despite claims of vitamin and mineral content disproportional to other vegetables, the nutrient content of wheatgrass juice is roughly equivalent to that of common vegetables (see table 1).
Wheatgrass is also claimed to be superior to other vegetables in its content of vitamin B12, a vital nutrient. Contrary to popular belief, B12 is not contained within wheat grass or any vegetable; rather it is a byproduct of the microorganisms living on plants. Some analyses of B12 content in wheatgrass has confirmed that it contains negligible amounts of the compound even though the source of this analysis remains unclear. The USDA National Nutrient Database reports that wheatgrass contains no vitamin B12. 
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- Melina, Vesanto, MS, RD & Davis, Brenda, RD: "The New Becoming Vegetarian", page 186-187. Healthy Living Publications, 2003.
- "Nutrition Facts and Analysis for wheat grass". Nutritiondata.self.com. Retrieved 2013-04-19.