Star Fruit
Scientific Name(s): Averrhoa carambola L.
Common Name(s): Belimbing, Blimbing, Carambolo, Chinese gooseberry, Kamaranga, Kamrakh, Kamranga, Star fruit, Starfruit, Tamarindo, Thambaratham
Medically reviewed by Drugs.com. Last updated on Sep 21, 2023.
Clinical Overview
Use
Star fruit has been studied for its anti-inflammatory, antioxidant, and lipid-lowering properties, and for improvement in exercise capacity. However, clinical trial data are lacking to recommend use for any indication.
Dosing
200 g/day of fresh star fruit juice (in 2 divided doses) for 4 weeks has been used in clinical trials.
Contraindications
Use is contraindicated in patients with chronic kidney disease (CKD).
Pregnancy/Lactation
Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
Star fruit consumption should be avoided in individuals taking bosutinib, panobinostat, and venetoclax.
Adverse Reactions
Cases of oral allergy syndrome and anaphylactic shock have been reported with consumption of star fruit.
Toxicology
Symptoms of star fruit poisoning are thought to be a result of excessive stimulation of the gamma-aminobutyric acid (GABA)–ergic system. Nephrotoxicity and neurotoxicity have been described in several studies and have been attributed mostly to the start fruit components caramboxin and oxalic acid.
Scientific Family
- Oxalidaceae (wood sorrel)
Botany
A. carambola is a bushy, round plant growing up to 9 m in height and believed to have originated in Sri Lanka. It is a slow-growing, woody plant with a short trunk that can be 15 cm in diameter. The leaflets are sensitive to nightfall and shock and will fold up in these scenarios. The 5-petaled flowers form in clusters and are usually red, lilac, or purple. The small, dark-green fruits turn yellow when fully ripe and have 5 longitudinal ridges that produce a star shape when sliced horizontally. The plant is cultivated extensively in tropical regions (ie, Southeast Asia, Malaysia) but is widely distributed around the world.(Muthu 2016) A. carambola should not be confused with Averrhoa bilimbi, which is not suitable for consumption.(Lakmal 2021, Vasant 2014)
History
Star fruit is a commonly consumed fruit, has been used as a cleanser for its rust removal properties, and has been used medicinally. The fruits are crunchy and have a slightly tart, sweet, and acidic taste. Star fruits can be eaten raw or cooked and are commonly used in preparation of juices, pickles, jams, and salads, or fermented into alcoholic beverages. Medicinally, various plant parts are used as herbal treatments in many parts of the world and in Ayurvedic and traditional Chinese medicine preparations for treatment of fever, sore throat, cough, asthma, chronic headache, diarrhea, fungal skin infections, skin inflammation, and bleeding hemorrhoids.(Lakmal 2021, Muthu 2016)
Chemistry
Star fruits are a rich source of insoluble fiber (approximately 60% cellulose, 27% hemicelluloses, and 13% pectin). The plant is also a good source of antioxidants and contains numerous vitamins and minerals. The 3 most prevalent minerals are potassium, phosphorous, and magnesium, with up to 168 mg, 17.88 mg, and 12.05 mg, respectively, found in 100 g of the fruit. Other detectable minerals include calcium, sodium, manganese, zinc, iron, and copper. Vitamin C (25.8 mg per 100 g) and oxalic acid (9.6 mg per 100 g) are the 2 most common acids, followed by tartaric acid, ketoglutaric acid, citric acid, vitamins B1 and B2, gallic acid, and carotene. Extracts of the leaves, fruits, and roots contain saponins, flavonoids (ie, proanthocyanins), alkaloids, tannins, phytosterols, and pyrogallic steroids, as well as phenols (ie, anthocyanins, anthocyanidins), chalcones, aurones, leucoanthocyanidins, catechins, and triterpenoids (ie, saponins). The composition of nutrients varies with maturity of the plant and fruits.(Lakmal 2021, Muthu 2016, Vasant 2014)
Uses and Pharmacology
Analgesic effects
Animal data
In a mouse pain model, intraperitoneally administered star fruit extract inhibited both neurogenic pain and inflammatory responses. Antinociceptive effects appeared to be secondary to anti-inflammatory effects; reductions in paw edema observed with polysaccharides extracted from star fruit were similar to those with the positive controls meloxicam and indomethacin.(Leivas 2016)
Anti-inflammatory effects
Clinical data
In 29 healthy subjects (mean age, 72.4 years; range, 54 to 87 years) who consumed fresh star fruit juice 100 g twice daily for 4 weeks, significant reductions in some proinflammatory cytokines (ie, tumor necrosis factor alpha [TNF-alpha], interleukin 23) and nitric oxide (NO) were observed (P<0.001 for each vs weeks 0 and 2 of the control period).(Leelarungrayub 2016a)
Antioxidant effects
Clinical data
A preliminary study conducted in 27 Thai subjects (mean age, 69.5 years; range, 56 to 85 years) receiving fresh star fruit juice 100 g twice daily for 4 weeks demonstrated significant improvements in 3 of 4 oxidative stress parameters (ie, total antioxidant capacity, malondialdehyde, protein hydroperoxide; P<0.05 for each). Additionally, star fruit juice consumption led to significant increases in serum levels of vitamins C and A, but not E (P<0.05 each).(Leelarungrayube 2016b)
Exercise capacity
Clinical data
In 29 healthy subjects (mean age, 72.4 years; range, 54 to 87 years) consuming fresh star fruit juice 100 g twice daily for 4 weeks, a significant increase in exercise capacity (6-minute walking distance) was observed at week 6 (P<0.0001 vs weeks 0 and 2). Levels of TNF-alpha were negatively correlated to exercise capacity, while a positive correlation was seen with NO levels (P=0.027 and P=0.004, respectively).(Leelarungrayub 2016a)
Fluoride toxicity
Animal data
Fluoride-induced carbohydrate, hepatic, lipid, and antioxidant alterations in rats were improved or ameliorated in a dose-dependent manner with oral administration of star fruit powder.(Vasant 2014)
Lipid effects
Clinical data
In 27 Thai subjects (mean age, 69.5 years; range, 56 to 85 years) who consumed fresh star fruit juice 100 g twice daily for 4 weeks, significant improvements in high-density lipoprotein and low-density lipoprotein cholesterol were observed (P=0.03 and P=0.02, respectively, vs weeks 0 and 2). Changes in triglycerides and total cholesterol were not significant.(Leelarungrayube 2016b)
Dosing
200 g/day of fresh star fruit juice (in 2 divided doses) for 4 weeks has been used in clinical trials.(Leelarungrayub 2016a, Leelarungrayub 2016b)
Pregnancy / Lactation
Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
Inhibition of CYP3A enzymes has been demonstrated in in vitro and in vivo studies.(Vasant 2014)
Bosutinib: Star fruit may increase the serum concentration of bosutinib. Avoid combination.(Bosulif November 2014, Bosulif July 2015, Hidaka 2004, Hidaka 2006, Zhang 2007)
Panobinostat: Star fruit may increase the serum concentration of panobinostat. Avoid combination.(Farydak February 2015, Hidaka 2004, Hidaka 2006, Zhang 2007)
Venetoclax: Star fruit may increase the serum concentration of venetoclax. Avoid combination.(Venclexta April 2016)
Adverse Reactions
A case of oral allergy syndrome (itching/burning sensation in lips, mouth, and ear canal) was reported in a Japanese female pastry chef within 15 minutes of consuming star fruit. Her medical history was positive for severe atopic dermatitis, pollinosis to cedar and cypress, and mild asthma. She had previously demonstrated a similar reaction after eating kiwi and papaya. Skin sensitization to star fruit via atopic skin was suspected. Immunoblotting testing revealed no cross-reactivity of star fruit to cedar, cypress, kiwi, or papaya.(Numata 2015)
A case of anaphylactic shock to star fruit was reported in a 58-year-old male within minutes of eating 4 pieces of star fruit for the first time. His medical history was negative for other food reactions and anaphylaxis. The subject cared for racing pigeons as a hobby; immunoblot assays revealed cross-reactivity of star fruit proteins to seed proteins in pigeon feed. Sensitization to star fruit via routine handling of birdseed was suspected.(Vazquez-Revuelta 2021)
A case series included adults with and without comorbidities who presented to the hospital with acute renal injury after consuming 3 to 6 starfruits. Symptoms most commonly reported following acute star fruit intoxication were nausea, vomiting, and abdominal/back pain, with a subsequent reduction in urine output and increased serum creatinine levels over hours to days. Nephrotoxicity was determined to be due to tubular obstruction by calcium oxalate crystals. Urinalysis for all 4 patients demonstrated oxalate crystals. Compared to "sweet" starfruit, the "sour" starfruit is known to contain more oxalate. All patients recovered within 1 month of discharge.(Herath 2021)
Toxicology
Symptoms of star fruit poisoning are thought to be a result of excessive stimulation of the GABAergic system and include hiccups, altered consciousness, confusion, incoherent speech, vomiting, psychomotor agitation, insomnia, paresthesias, muscle weakness, epileptic seizures, hypotension, shock, coma, and death.(Aranguren 2017) Neurological presentation may mimic, and be misinterpreted as, a stroke.(Alessio-Alves 2012)
Nephrotoxicity and neurotoxicity have been described in several studies and have been attributed mostly to the star fruit components caramboxin and oxalic acid. Caramboxin is a renally excreted neurotoxin that crosses the blood-brain barrier, whereas oxalate causes direct corrosive injury to the GI tract and subsequently obstructs renal tubules via formation of oxalate crystals.(Aranguren 2017, Stumpf 2020) A systematic review analyzed 123 cases of nephrotoxicity related to star fruit intoxication; 80% occurred in patients with CKD, of whom 27 died. In the remaining 20% of patients with previously normal renal function, consumption was associated with acute nephropathy; 1 patient died, 3 developed CKD, and 2 became dialysis dependent. Neurological symptoms were reported to be more severe in patients with preexisting CKD.(Aranguren 2017)
Treatment depends on clinical presentation, with hemodialysis the most reasonable approach, particularly when neurological symptoms are present. Little evidence supports the use of more conservative treatments (ie, prednisolone, urinary alkalization, diuretic therapy), and peritoneal dialysis does not appear to be effective in more severe intoxications.(Stumpf 2020) Animal studies suggest that administration of N-acetyl cysteine can attenuate star fruit–induced renal dysfunction, possibly via reduction of oxidative stress and normalization of redox status.(Shimizu 2017)
References
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This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.
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