Traditionally used for
- Digestion
- Bowel health
- Urinary & fluids
- Skin
☯ TCM Properties
Clears Heat and removes toxicity; Relaxes the bowels and induces diuresis
Traditional Chinese Uses
Xian Cai is edible amaranth, Amaranthus tricolor (Chinese spinach). Sweet and cool, entering the Large and Small Intestine channels, it clears Heat and relieves toxicity, and it moistens and relaxes the bowels while promoting urination. As a food-grade medicinal it is used for damp-heat patterns of the intestines — bacillary and amebic dysentery, enteritis and diarrhea — and for constipation, painful or bloody urination, childhood nutritional impairment, and Heat-toxin sores and swellings.
It is typically eaten as a cooked vegetable or decocted in larger amounts (about 30-60 g), and for dysentery the red-leaved form is often simmered and taken as a sweetened compote. Being cool and moistening, it is used cautiously in those with Spleen-Stomach cold or chronic loose stools.
Western Herbalism Properties
Relationships
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Botanical Description
Amaranthus tricolor L. (Amaranthaceae), edible amaranth or Chinese spinach, called Xian Cai, is a fast-growing annual herb 30-130 cm tall, cultivated throughout China and tropical Asia as a leaf vegetable. Stems are erect, stout, often grooved and tinged red or purple, glabrous to sparsely pubescent. Leaves are alternate, broadly ovate, rhombic, or lanceolate, 4-12 cm long, with entire or slightly undulate margins, an acute or obtuse tip, and long petioles; cultivars exhibit striking colour patterns of green, yellow, red, and purple, often variegated. The minute green to reddish flowers are unisexual or bisexual, densely clustered in axillary glomerules along the upper stems and in short terminal spikes, each subtended by small membranous bracts; the fruit is a small circumscissile utricle containing a single shiny black or brown lenticular seed. Used in TCM as a mild cooling food-herb to clear heat, resolve toxicity, support the intestines, and treat dysenteric disorders and red-and-white discharge; nutritionally rich in iron, calcium, and vitamins.
Active Constituents
Amaranthine
Betacyanin (betalain pigment)Concentration: the principal betacyanin of the species; betalain, betacyanin and betaxanthin are two- to five-fold higher in red leaf sectors than in green sectors of the same leaf
The red-violet pigment that gives the red cultivars of Xian Cai their colour. It is a strong radical scavenger in vitro and is the main contributor to the antioxidant capacity of the red morphs; it is water-soluble, heat- and pH-labile, so much of it is lost in prolonged cooking or decoction.
Isoamaranthine
Betacyanin (betalain pigment)Concentration: a minor stereoisomer accompanying amaranthine in pigmented leaves
The C15 epimer of amaranthine, formed alongside it in the betalain pathway. It shares amaranthine's radical-scavenging behaviour and is reported together with it in pigment profiling of A. tricolor leaf.
Oxalic acid (soluble oxalate)
Dicarboxylic organic acid (antinutrient)Concentration: the principal antinutrient of amaranth leaf; present at levels high enough that as little as 0.66 g amaranth leaf per 100 g of dry diet measurably reduced calcium absorption in a rat balance trial
Oxalate binds calcium in the gut lumen as insoluble calcium oxalate. This both blocks absorption of the calcium in the meal and, once absorbed, raises urinary oxalate — the reason amaranth leaf is restricted in calcium-oxalate stone formers despite its high calcium content on paper.
Nitrate
Inorganic anionConcentration: amaranth is a recognised dietary nitrate accumulator; a 2000 mg dose of A. tricolor extract raised plasma and salivary nitrate and nitrite significantly above placebo in healthy adults
Dietary nitrate is reduced by oral commensal bacteria to nitrite and then to nitric oxide, producing vasodilation and lower blood pressure. This is the basis of amaranth's cardiovascular claims and also of its main pharmacological hazard, since the same pathway is additive with nitrate drugs.
Calcium, iron and zinc
Essential mineralsConcentration: across 30 strains of A. tricolor, calcium 1.7 g/100 g, iron 1234 mg/kg and zinc 792 mg/kg of leaf
Xian Cai is genuinely mineral-dense, which is why it is promoted as a remedy for iron and calcium deficiency. The caveat is bioavailability: the same leaf carries the oxalate that impairs absorption of the calcium it contains, so the analytical figures overstate what the eater actually absorbs.
Cadmium and antimony (soil-derived)
Toxic trace element contaminantConcentration: not intrinsic to the plant; concentration tracks the growing soil, and A. tricolor is a documented accumulator that takes up antimony and cadmium readily from contaminated agricultural soils
Not a phytochemical but a real hazard of this species specifically. Amaranth's efficiency at taking up divalent and metalloid contaminants makes provenance a safety question for a herb eaten in quantity, particularly material grown on peri-urban or mine-affected land.
⚠ Drug Interactions
Oral calcium supplements and calcium-dependent regimens (including in osteoporosis)
In a randomised balance trial in growing rats, adding as little as 0.66 g of amaranth leaf per 100 g dry matter to a rice-based diet significantly reduced fractional calcium absorption and retention, and femur bone mass and calcium and phosphorus densities were lower in every diet containing amaranth. The authors attributed this to the leaf's oxalate content. The study used Amaranthus gangeticus, which is a synonym of Amaranthus tricolor, so it is the same species as this monograph, but it is a rodent balance trial and not a human study.
Clinical note: Separate calcium supplements from large amaranth-containing meals by two hours. Do not count Xian Cai as a calcium source for an osteoporotic or growing patient, and blanch and discard the cooking water to lower the soluble oxalate load.
Nitrate vasodilators (glyceryl trinitrate, isosorbide mono- and dinitrate) and PDE5 inhibitors
A randomised, double-blind, placebo-controlled four-way crossover study in 16 healthy adults showed that a single 2000 mg dose of Amaranthus extract — including A. tricolor — significantly raised plasma and salivary nitrate and nitrite over 24 hours compared with placebo, with Cmax and AUC bioequivalent across the three species tested. Enterosalivary reduction converts that nitrate to nitrite and then nitric oxide, the same final pathway as organic nitrate drugs and the pathway that PDE5 inhibitors amplify downstream.
Clinical note: Concentrated amaranth extracts are the concern rather than a plate of the cooked vegetable. Ask about amaranth or beetroot supplements before assuming an unexplained hypotensive episode on a nitrate or a PDE5 inhibitor is drug-related.
Antihypertensive drugs
The same demonstrated rise in circulating nitrate and nitrite after amaranth extract is the mechanism by which dietary nitrate lowers blood pressure. The bioavailability study measured nitrate and nitrite pharmacokinetics rather than blood pressure, so the downstream haemodynamic effect in treated hypertensive patients is inferred, not measured.
Clinical note: Generally benign and often desirable. Check postural blood pressure at the next review if a treated hypertensive patient starts taking a concentrated amaranth product.
Potassium citrate and other calcium-oxalate stone prophylaxis
Amaranth leaf is among the higher-oxalate leafy vegetables, and its oxalate is demonstrably bioactive in the gut — it measurably impaired calcium absorption at low inclusion rates in the rat balance study. Oxalate that is not bound in the lumen is absorbed and excreted in urine, which is precisely the parameter that oxalate-restricted diets and citrate therapy are trying to control. Urinary oxalate after amaranth has not been measured directly in stone formers.
Clinical note: Treat Xian Cai as a high-oxalate vegetable in anyone with recurrent calcium-oxalate stones: restrict it, keep dietary calcium with the meal so oxalate is bound in the gut, and maintain fluid intake.
Oral tetracyclines, fluoroquinolones, bisphosphonates and levothyroxine
These drugs are all chelated by divalent cations, and amaranth leaf is unusually rich in calcium, iron and zinc. No study has measured the absorption of any of them alongside amaranth, so this is an extrapolation from the well-established dairy and mineral-supplement interactions rather than a documented one.
Clinical note: Apply the ordinary rule: take these drugs on an empty stomach, at least two hours away from a mineral-rich meal.
Evidence Tier
Moderate evidence · 2 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
1
0 verified · 1 unverified
Other clinical trial
0
Observational / case report
0
In vitro / animal
1
1 verified · 0 unverified
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Comparison of Bioavailability of Nitrates and Nitrites in 3 Species of Amaranthus: A Randomized, Double-Blind, Placebo-Controlled, 4-Way Crossover Study in Healthy Subjects Under Fasting Conditions
Sixteen healthy fasted adults each received, in randomised crossover order, a single 2000 mg dose of extract from Amaranthus hybridus, A. hypochondriacus or A. tricolor, or placebo, with plasma and saliva sampled over 24 hours and nitrate and nitrite measured by validated LC-MS/MS. All three extracts produced significantly higher plasma and salivary nitrate and nitrite than placebo (P < 0.05) and were bioequivalent to one another for Cmax and AUC. This is direct human evidence that A. tricolor delivers an absorbable nitrate load, and it is the basis for treating concentrated amaranth preparations as pharmacologically active on the nitric oxide pathway.
The leafy vegetable amaranth (Amaranthus gangeticus) is a potent inhibitor of calcium availability and retention in rice-based diets
A randomised balance trial in growing rats, five rice-based diets and eight animals per diet over two one-week balance periods. Amaranth leaf, small fish and lentils together improved nitrogen retention and growth over plain rice, but a minor addition of amaranth (0.66 g per 100 g dry matter) significantly reduced fractional calcium absorption and retention, and femur mass and calcium and phosphorus densities were lower in all amaranth-containing diets; the authors attribute the effect to oxalate. The species used, Amaranthus gangeticus, is a synonym of Amaranthus tricolor, so the finding applies directly to Xian Cai — but it is a rodent study and the magnitude in humans is unmeasured.
References
- Sarker U, Oba S. Leaf pigmentation, its profiles and radical scavenging activity in selected Amaranthus tricolor leafy vegetables . Scientific Reports (2020) [DOI]
- Shukla S, Bhargava A, Chatterjee A, Srivastava J, Singh N, Singh SP. Mineral Profile and Variability in Vegetable Amaranth (Amaranthus tricolor) . Plant Foods for Human Nutrition (2006) [DOI]
- Liu S, Zheng X, Pan J, Peng L, Cheng C, Wang X, Zhao C, Zhang Z, Lin Y, XuHan X, Lai Z. RNA-sequencing analysis reveals betalains metabolism in the leaf of Amaranthus tricolor L. . PLOS ONE (2019) [DOI]
- Zhong Q, Ma C, Chu J, Wang X, Liu X, Ouyang W, Lin C, He M. Toxicity and bioavailability of antimony in edible amaranth (Amaranthus tricolor Linn.) cultivated in two agricultural soil types . Environmental Pollution (2020) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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