Side Effects and Nutritional Values of Star Fruit November 2008
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We need to be cautious on Star Fruit. Its side effects can be fatal, depending
on how much you eat and your physical conditions. The star fruit or carambola
is a tropical fruit that is gaining popularity in the United States. This fruit
acquired its name from the five pointed star shape when cut across the
middle of the fruit. It has a waxy, golden yellow to green color skin with a
complicated flavor combination that includes plums, pineapples, and lemons.
What are the nutritional values of start fruit? One serving of star fruit is 1/2 cup
(54 g). One serving contains 20 calories, no fat nor sodium, 3 g of sugar and 1
g of dietary fiber. It has 20% DV of vitamin C. [6]
Originally from Sri Lanka and the Moluccas, and cultivated in Southeast Asia
and Malaysia for several hundred years, this fruit also goes by many other
names including: bilimbi, belimbing, Chinese star fruit, five-angled fruit and
the star apple. Today, star fruit flourishes in south Florida and Hawaii
because the fruit thrives on growing in a warm environment. Two types of star
fruit are grown, tart and sweet. Tart varieties typically have narrowly spaced
ribs, while sweet varieties tend to have thick, fleshy ribs. The tastes between
the two are hardly distinguishable, as the tart variety still has some
sweetness. This tropical fruit is readily available July through February.
Star fruits are an excellent source of vitamin C, is low fat, and naturally sodium
and cholesterol free. A small whole star fruit will provide approximately 2/3 cup
sliced. [6]
Acute oxalate nephropathy associated with ingestion of star fruit (carambola)
has been reported. Doctors from Kaohsiung Veterans General Hospital,
Taiwan, reported the first two cases. These patients developed nausea,
vomiting, abdominal pain, and backache within hours of ingesting large
quantities of sour carambola juice; then acute renal failure followed. [3]
Carambola contains a large quantity of oxalate, which can induce depression
of cerebral function and seizures. Carambola can also cause rats die after
seizure. [4]
Commercial carambola juice usually is prepared by pickling and dilution
processes that reduce oxalate content markedly, whereas pure fresh juice or
mild diluted postpickled juice for traditional remedies, as used in our cases,
contain high quantities of oxalate. An empty stomach and dehydrated state
may pose an additional risk for development of renal injury. To avoid acute
oxalate nephropathy, pure sour carambola juice or mild diluted postpickled
juice should not be consumed in large amounts, especially on an empty
stomach or in a dehydrated state. [3]
Patients with renal failure should avoid star fruit (Averrhoa carrambola). In
1998, six cases of patients in a dialysis program who were apparently
intoxicated by ingestion of star fruit were reported. After ingestion of 2-3 fruits
or 150-200 ml of the fruit juice, the six patients, who had previously been
stable in a regular dialysis programme, developed a variety of symptoms
ranging from insomnia and hiccups to agitation, mental confusion and (in one
case) death. [1] In 2000, death after ingestion of star fruit in uremic patients
was also reported in Taiwan. Their initial presentations included
sudden-onset limb numbness, muscle weakness, intractable hiccups,
consciousness disturbance of various degrees, and seizure. Death occurred
within 5 days despite emergent hemodialysis and intensive medical care. [2]
In 2003, researchers from Brazil reported that patients who were promptly
treated with haemodialysis, including those with severe intoxication,
recovered without serious consequence. However, patients with severe
intoxication who were not treated or treated with peritoneal dialysis did not
survive. [5] Similar reports were found in Hong Kong, Thailand and France.
[8-9]
Though some researchers suggested the seizures in patients ingested large
amounts of star fruits were due to oxalate, researchers from Faculdade de
Medicina de Ribeirão Preto, SP, Brazil isolated a neurotoxic fraction (AcTx)
from star fruit. They found this faction specifically inhibited GABA binding in a
concentration-dependent manner (IC(50)=0.89muM) and induced behavioral
changes, including tonic-clonic seizures in animals. Chemical
characterization of AcTx showed that this compound is a nonproteic molecule
with a molecular weight less than 500, differing from oxalic acid. [7]
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[1] Neto MM, Robl F, Netto JC. Intoxication by star fruit (Averrhoa carambola) in six
dialysis patients? (Preliminary report) Nephrol Dial Transplant. 1998 Mar;13(3):570-2. [2]
Chang JM, Hwang SJ, Kuo HT, Tsai JC, Guh JY, Chen HC, Tsai JH, Lai YH. Fatal
outcome after ingestion of star fruit (Averrhoa carambola) in uremic patients. Am J Kidney
Dis. 2000 Feb;35(2):189-93. [3] Chen CL, Fang HC, Chou KJ, Wang JS, Chung HM. Acute
oxalate nephropathy after ingestion of star fruit. Am J Kidney Dis. 2001 Feb;37(2):418-22.
[4] Chen CL, Chou KJ, Wang JS, Yeh JH, Fang HC, Chung HM. Neurotoxic effects of
carambola in rats: the role of oxalate. J Formos Med Assoc. 2002 May;101(5):337-41. [5]
Neto MM, da Costa JA, Garcia-Cairasco N, Netto JC, Nakagawa B, Dantas M. Intoxication
by star fruit (Averrhoa carambola) in 32 uraemic patients: treatment and outcome. Nephrol
Dial Transplant. 2003 Jan;18(1):120-5. [6] Fruit of the Month: Star Fruit, Fruit of the
Month: Star Fruit, fruitsandveggiesmatter.gov [7] Carolino RO, Beleboni RO, Pizzo AB,
Vecchio FD, Garcia-Cairasco N, Moyses-Neto M, Santos WF, Coutinho-Netto J. Convulsant
activity and neurochemical alterations induced by a fraction obtained from fruit Averrhoa
carambola (Oxalidaceae: Geraniales). Neurochem Int. 2005 Jun;46(7):523-31. [8]
Niticharoenpong K, Chalermsanyakorn P, Panvichian R, Kitiyakara C. Acute deterioration
of renal function induced by star fruit ingestion in a patient with chronic kidney disease. J
Nephrol. 2006 Sep-Oct;19(5):682-6. [9] Signaté A, Olindo S, Chausson N, Cassinoto C,
Edimo Nana M, Saint Vil M, Cabre P, Smadja D. Star fruit (Averrhoa carambola) toxic
encephalopathy. Rev Neurol (Paris). 2008 Aug 26.
