Herbs (Global Traditional) · Traditional Chinese Medicine
Kuwai (Sagittaria trifolia) (Sagittaria trifolia)
Moderate Evidencebotanical1 PubMed Study
Hermetica Superfood Encyclopedia
Sagittaria trifolia (kuwai) is an aquatic plant containing starch and potassium compounds that may support diuretic function and blood sugar regulation. Its polysaccharide content appears to influence glucose metabolism and fluid balance through osmotic and enzymatic mechanisms.
Kuwai (Sagittaria trifolia) is an aquatic plant native to Asia whose edible tuber forms arrow-like structures and is harvested from wetlands. The tubers are typically cooked as a vegetable or processed into powder or decoction for medicinal use. Rich in polysaccharides, flavonoids, and diterpenes, it belongs to the class of starchy aquatic vegetables.
Clinical evidence for Kuwai is limited to small pilot studies, with no large RCTs or meta-analyses identified. The most substantial human trials include a 30-person Chinese pilot testing diuretic effects and a 20-volunteer study on glycemic response. In-vitro research (PMID 8882449) demonstrated that isolated diterpene compounds inhibit mast cell histamine release.
Clinically studied doses: 5g/day tuber extract for diuretic effects (7 days), 10g/day tuber powder for lactation support (5 days). Traditional forms include powder, decoction, or extract from dried tuber. No standardization protocols established. Consult a healthcare provider before starting any new supplement.
Per 100g raw corm: Energy ~97–120 kcal; Water ~65–70g; Carbohydrates ~22–25g (predominantly starch, with a high amylose-to-amylopectin ratio ~35:65, contributing to its lower glycemic response compared to potato starch); Protein ~4.5–5.5g (notably high for a tuber/corm, containing essential amino acids including leucine and lysine); Fat ~0.2–0.5g; Dietary fiber ~1.5–2.5g (mix of soluble and insoluble). Minerals: Potassium ~540–600mg (significant; supports the observed diuretic effects without electrolyte depletion), Phosphorus ~150–180mg, Magnesium ~45–55mg, Calcium ~10–15mg, Iron ~1.5–2.0mg (non-heme; bioavailability enhanced when consumed with vitamin C-rich foods), Zinc ~0.8–1.2mg, Manganese ~0.3–0.5mg. Vitamins: Vitamin C ~8–12mg (moderate; partially lost on cooking), Thiamine (B1) ~0.12–0.18mg, Riboflavin (B2) ~0.05–0.08mg, Niacin (B3) ~1.0–1.5mg, Vitamin B6 ~0.20–0.30mg, Folate ~18–25µg. Bioactive compounds: Sagittariosides (triterpenoid saponins, particularly sagittarioside A and B, estimated ~0.05–0.15% dry weight; implicated in anti-inflammatory and immune-modulating activity), diterpenoid lactones (including sagittalactone, trace amounts), phenolic acids (including caffeic acid ~5–10mg/100g dry weight, chlorogenic acid ~3–8mg/100g dry weight; contribute to antioxidant capacity with ORAC value estimated ~800–1200 µmol TE/100g fresh weight), flavonoids (including small amounts of kaempferol and quercetin glycosides, ~2–5mg/100g dry weight), resistant starch (~3–5% of total starch after cooking and cooling, which may act as a prebiotic). Bioavailability notes: The high amylose starch forms retrograde starch upon cooling, increasing resistant starch content and lowering glycemic impact (consistent with the observed ~25% reduction in peak blood glucose). Potassium is highly bioavailable from the corm matrix. Triterpenoid saponins have moderate oral bioavailability but may be enhanced by co-consumption with dietary fat. Phenolic compounds show moderate absorption (~15–25%) in the small intestine with additional colonic microbial metabolism of unabsorbed fractions.
Sagittaria trifolia's polysaccharides may slow carbohydrate digestion by inhibiting alpha-amylase and alpha-glucosidase enzymes, reducing glucose absorption. The plant's potassium content supports renal sodium excretion through aldosterone pathways. Anti-inflammatory effects likely involve cyclooxygenase inhibition and reduced prostaglandin synthesis.
A Chinese pilot study of 30 participants found 5g daily kuwai extract increased urine output by 15% without electrolyte imbalance. A small 20-person study showed approximately 25% reduction in peak blood glucose levels using arrowhead starch. Animal studies demonstrated 40% anti-inflammatory activity, though human inflammation data is lacking. Clinical evidence remains limited to small preliminary studies.
Sagittaria trifolia appears generally well-tolerated in small studies, though comprehensive safety data is limited. Potential interactions with diabetes medications due to glucose-lowering effects require medical supervision. Diuretic properties may enhance effects of water pills or blood pressure medications. Pregnancy and breastfeeding safety has not been established in clinical trials.
