Wheat Grass Juice
En Español (Spanish Version)
- What Is Wheat Grass Used for Today?
- Safety Issues
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 1960's by Ann Wigmore. She claimed that use of wheat grass juice had cured her of the disease 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 wheat grass, a succession of "green drinks" have become popular for "cleansing" the body and improving overall health. "Barley magma" and
both fall within this tradition.
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 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
defense system. Superoxide dismutase 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
has been cast in doubt by the failure of such supplements as
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
, 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 24 people with
and examined the effects of wheat grass juice taken at a dose of 100 cc 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 Ann 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; to learn why, see
Why Does This Database Depend on Double-Blind Studies
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, diabetes, etc. However, there is no meaningful scientific evidence to support these uses.
A typical dosage of wheat grass juice is 100 - 300 ml daily.
Wheat grass juice is believed to be safe. However, comprehensive safety studies have not been performed. Maximum safe doses in pregnant or nursing women, young children, or people with severe liver or kidney disease have not been reported.
Ben-Arye E, Goldin E, Wengrower D et al. Wheat grass juice in the treatment of active distal ulcerative colitis: a randomized double-blind placebo-controlled trial.
Scand J Gastroenterol
Young MA, Cook JL, Webster KE. The effect of topical wheat grass cream on chronic plantar fasciitis: a randomized, double-blind, placebo-controlled trial.
Complement Ther Med.
Last Reviewed September 2014