Wheatgrass (Triticum aestivum): Uses, Evidence and Safety

Safety first: raw juice, nausea and what the evidence does not show

Memorial Sloan Kettering (MSK) says wheatgrass is not known to cause serious side effects, but it does not call it risk-free. [1] Two cautions come first. The juice is made from sprouts grown for about 7 to 10 days and is drunk raw, so contamination with germs is a concern. [1] The strong grass taste can also cause nausea and make the juice hard to swallow. [1] If you are having chemotherapy, are pregnant, or have a weak immune system, ask your care team before drinking raw juice; see what to tell your care team about natural remedies and raw sprouts and other raw-food risks. Wheatgrass is not a replacement for medicines for ulcerative colitis, cancer, anaemia or any other illness. MSK states that claims it treats or prevents cancer or AIDS, helps chronic fatigue, or "detoxifies" the body are not supported by clinical studies. [1]

Overview

Wheatgrass is the young leaf of common wheat, Triticum aestivum L. GBIF lists it as an accepted species in the grass family Poaceae. [2] MSK describes it as made by sprouting wheat seeds in water for 7 to 10 days and juicing the leaves; it is also sold as a powder. [1] This page covers the juice, powders and tablets made from the young leaves. Native range of the species: not found in the sources we read. Do not confuse it with "intermediate wheatgrass" (Thinopyrum intermedium), a different perennial grass that regulators have assessed as a grain and flour novel food, [3] or with couch grass. Powders and "greens" blends are discussed in greens powder ingredients.

Traditional use (not proof of benefit)

MSK lists many purported uses: AIDS, cancer, chronic fatigue, boosting the immune system, ulcerative colitis, tooth decay, high blood pressure, arthritis-type pain, colds and skin conditions. [1] It also reports a claim that the chlorophyll in the juice raises oxygen in the blood, and says current science does not support this. [1] We did not find a regulator's monograph (for example EMA or WHO) for wheatgrass in the sources we read, so there is no official recognised medicinal use to report.

What research shows

Human studies are few, small and mostly old. MSK describes the human evidence as preliminary and mixed and says larger studies are needed. [1] Animal and lab work suggests antioxidant and cholesterol-lowering effects, but that is not proof of benefit in people. [1]

Wheatgrass compared with standard colitis treatment, long-term safety, and effects in healthy people: Proper evidence not found in the sources we read.

Forms and why the form matters

Fresh juice, powders made from juice or leaf, and tablets have all been used, and trials used one form each, such as 100 mL of juice daily in the colitis trial. [4][7] Content depends on growing conditions and the product, so a result with one product should not be assumed for another. Gluten: lab tests with two standard gluten assays found gluten in wheatgrass leaf tissue below the detection limit, both in commercial and home-grown samples, and the authors concluded properly prepared wheatgrass contains no gluten. [12] Gluten is found in wheat, barley and rye, [13] so seeds, flour or grain mixed into a powder or blend could still carry it. For people with coeliac disease the label and the maker matter; see coeliac disease. We did not read a source on wheat allergy and wheatgrass, so we make no claim either way; people with a wheat allergy should ask their allergy doctor.

Safety in more detail

• Common side effects: nausea and difficulty swallowing the juice because of its grass-like taste. [1] In the breast cancer pilot, worsened nausea led six people to stop. [6]
• Contamination: raw juice from sprouts grown for 7 to 10 days may carry germs, according to MSK. [1] Sources we read give no numbers for wheatgrass juice; see herbal product contamination.
• Medicines: MSK does not discuss drug interactions and advises telling your healthcare providers about any supplement. [1] A 2022 review lists wheatgrass among complementary products used in ulcerative colitis, and said such products may interact with liver enzymes; the abstract gives nothing specific for wheatgrass. [14]
• Pregnancy and breastfeeding: the MSK page does not address them. [1] Proper evidence not found in the sources we read.
• Children: a randomised study gave wheatgrass to children with thalassaemia, and the paper called it promising with limited evidence. [8] This is not a safety recommendation for children in general.
• Liver and kidney: Proper evidence not found in the sources we read (we did not read LiverTox for wheatgrass).
• Surgery: no wheatgrass-specific advice found; see supplements before surgery.
• Gluten and allergy: see Forms above. [12][13]

Official statements

• MSK (US cancer centre), page last updated 17 March 2023: lists purported uses, says small studies suggest possible benefit for ulcerative colitis symptoms and for infection during chemotherapy but larger studies are needed, and says detox and haemoglobin claims are unsupported. [1]
• Regulators (EMA, WHO, FDA): no wheatgrass statement found in the sources we read.

Related pages

• Inflammatory bowel disease
• Spirulina
• Greens powder side effects and cautions
• Herbs and cancer treatment
• Detox foods and juice cleanse claims
• Coeliac disease