What are wheat grass juice's therapeutic uses?

Overview

Grains such as wheat and barley are ordinarily consumed in their mature state,
once their seeds have fully matured. However, use of the deep green, immature
forms of these plants has been advocated for health promotion. Wheat grass juice
is one of these “green foods.” It was popularized in the 1960s by Ann Wigmore, who
claimed that use of wheat grass juice had cured her of ulcerative colitis;
furthermore, when she gave it to her neighbors, their health improved too. She
went on to become a major figure in the natural health movement.

Since the introduction of wheat grass, a succession of “green drinks” have become
popular for cleansing the body and improving overall health. Barley magma and
blue-green
algae both fall within this tradition.

Therapeutic Uses

There is no question that wheat grass juice is a nutritive food containing numerous amino acids, vitamins, and minerals. However, besides known human nutrients, wheat grass also contains a number of other substances that proponents claim provide benefit.

For example, wheat grass, like all leafy plant products, contains chlorophyll,
the substance used by plants to create glucose from carbon dioxide and light
energy. Chemically purified chlorophyll became a popular health food supplement in
the 1960s, when it was promoted as a cure for many diseases. Chlorophyll’s central
role in the metabolism of plants was somehow supposed to suggest benefit for
people. However, animals no more have an obvious use for chlorophyll than plants
have use for hemoglobin (the vital substance in red blood cells). It is certainly
possible that chlorophyll could, by chemical accident, offer benefit for animals,
but there is no meaningful evidence to indicate that it actually does.

Wheat grass also contains superoxide dismutase (SOD), a substance
used by the body as part of its natural antioxidant defense system. SOD is very
poorly absorbed by mouth, and it is unlikely that people who consume wheat grass
juice receive a meaningful quantity of this substance. Furthermore, the benefit of
antioxidants per se has been cast in doubt by the failure of
such supplements as vitamin E and beta-carotene to prove effective when tested in
enormous double-blind studies.

Proponents of wheat grass also point to a constituent called P4D1 as another source of benefit. However, while P4D1 has shown interesting properties in test-tube studies, there is no real evidence that it offers any benefit.

The only scientifically reliable way to determine whether a medical treatment truly offers medical benefits is to test it in double-blind, placebo-controlled studies. Two such studies have been reported for wheat grass. One found benefit but was seriously flawed; the other failed to find benefit.

The first of these double-blind, placebo-controlled studies enrolled twenty-four people with ulcerative colitis and examined the effects of wheat grass juice taken at a dose of 100 cubic centimeters daily for one month. According to various measures of disease severity, participants given wheat grass juice improved to a greater extent than those given placebo.

This study is interesting, as it tests the initial use of wheat grass popularized by Wigmore. However, the study suffers from two major limitations. One is that it was quite small, limiting the statistical validity of the results. The other is that wheat grass juice is extremely bitter, and therefore it seems unlikely on the face of it that participants and doctors did not know who was getting the wheat grass juice and who was getting the placebo. Indeed, when researchers polled the participants, a majority of those given wheat grass juice were aware of it. Such “unblinding” substantially invalidates a study.

Another double-blind, placebo-controlled study evaluated the potential benefits of a topical wheat grass cream for treating plantar fasciitis, a chronic painful condition of the feet. However, no greater benefit was seen in the treatment group than in the placebo group.

In promotional literature, wheat grass juice is additionally advocated for numerous other conditions, including cancer, arthritis, allergies, fatigue, and diabetes. However, there is no meaningful scientific evidence to support these uses.

Ben-Arye, E., et al. “Wheat Grass Juice in the Treatment of Active Distal Ulcerative Colitis.” Scandinavian Journal of Gastroenterology 37 (2002): 444-449.

Young, M. A., J. L. Cook, and K. E. Webster. “The Effect of Topical Wheat Grass Cream on Chronic Plantar Fasciitis.” Complementary Therapies in Medicine 14 (2006): 3-9.