Star fruit: Properties and Benefits

Star fruit

The carambola (Star fruit) is a fruit with some useful medicinal properties for health, but the fruit is dangerous for those with kidney problems

Star fruit plant, scientific name Averrhoa carambola, is an evergreen belonging to the Oxalidaceae family. The plant can reach 10 meters in height and it’s native to tropical Asia. The fruit is yellow and has a section in the shape of a five-point star. Hence the star fruit name.

Star fruit: properties and benefits
Star fruit: properties and benefits

Star fruit has a thin skin that does not need to be removed in order to be consumed. The taste has a particular aroma with nuances reminiscent of pineapple and lemon.

There are two main varieties of this fruit , similar in appearance but with different organoleptic properties. One sweet and the other sour. In Italy it is now possible to find it on the market even in supermarkets and hypermarkets. The variety that is imported into our country is the sweet one.


These tropical fruits are commonly used in Ayurvedic and traditional Chinese medicine, in India, China and Brazil. It is used to relieve disorders such as chronic headaches, fever, cough, gastroenteritis, diarrhea and skin inflammation.

The carambola is known to have a high antioxidant property that effectively eliminates free radicals and helps in hypoglycemic treatments and hypocholesterolemia. ( 1 , 2 )

Star fruits are also commonly used in the preparation of juices, pickles and salads. The fruit can be eaten raw and is also used for cleaning tools. This is because it helps remove rust caused by iron oxidation. The fruits are well known for their oxalic acid content which has a negative effect when consumed by uremic patients. ( 3 , 4 )

Star Fruit Chemical Composition

Chemical composition for 100 grams of star fruit
Water g 91,38
Protein g 1,04
Carbohydrates g 6.73
Fat g 0,33
Sugars g 3,98
Fibers g 2,8
Ashes g 0,52
Calcium mg 3
Copper mg 0,137
Iron mg 0,08
Magnesium mg 10
Manganese mg 0,037
Phosphorus mg 12
Potassium mg 133
Selenium mg 0.6
Sodium mg 2
Zinc mg 0.12
Vitamin A IU 61
Vitamin A, RAE mcg 3
B1 mg 0,014
B2 mg 0,016
B3 mg 0,367
B5 mg 0,391
B6 mg 0,017
C vitamin mg 34.4
Vitamin E mg 0,15
Vitamin J mg 7,6
Vitamin K mcg
Beta Carotene mcg 25
Lutein Zeaxanthin mcg 66
Folate mcg 12

Source: Nutritionvalue

Amino acids: aspartic acid and glutamic acid, alanine, arginine, cystine, glycine, phenylalanine, histidine, isoleucine, leucine, lysine, proline, methionine, serine, tyrosine, tryptophan and valine.


It is a low-calorie fruit , in fact 100 grams of pulp provide a caloric intake of 31 kcal .

Star Fruit: Properties and Benefits

Free Radicals

Studies have reported that these fruits contain proanthocyanins which, like vitamin C and gallic acid, have antioxidant properties. ( 5 ) The main purpose of antioxidants is to eliminate free radicals. ( 6 )

Star fruit consumption is useful for removing toxins from the body and helps the immune system protect itself against tumors and free radical damage. ( 7 )

Insoluble Fibers

The star fruit contains about 60% of cellulose, 27% of hemicellulose and 13% of pectin. ( 8 ) This indicates that the fruit is really rich in fractions of insoluble fibers .

The insoluble fibers have the ability to retain water more than the cellulose. Insoluble fibers have the ability to retain water. They therefore help the regular movement in the intestine and have the ability to reduce blood sugar by slowing the absorption of carbohydrates in our body. ( 9 , 10 )

Furthermore, the fibers also facilitate the lowering of the total cholesterol level in the body by promoting the hypoglycemic effect.

Star Fruit and Inflammation

Studies indicate that its anti-inflammatory properties help reduce inflammatory skin conditions. ( 11 , 12 ) In a study on mice, the ethanolic extract of leaves applied to the skin attenuated inflammation and gradually reduced eczema in mice. ( 13 )


Scientific research suggests that this fruit extract inhibits the growth of Staphylococcus aureus   and Klebsiella. The extracts are also effective against Escherichia coliPseudomonas aeruginosa  and Bacillus cereus. ( 14 )


Traditionally these fruits are used to relieve stomach pain or any ulcer-like disorders. Studies have shown that leaf extracts of the Averrhoa carambola plant have anti-ulcer properties.

The mucilage provides a coating to the gastrointestinal mucosa, thus helping to avoid damage due to gastritis. ( 15 )

Saliva Production

In traditional Chinese medicine this fruit is used to calm thirst and to treat dry mouth. This property of the carambola is due to the presence of malic acid which is also a good bactericide.


The presence of oxalic acid on the other hand gives this fruit the ability to counteract bleeding and to treat bleeding hemorrhoids.

Star Fruit Contraindications

The carambola, as we have seen, has many therapeutic properties. However, this fruit also poses a health threat as it has toxic effects in patients with high uremia or patients with chronic kidney disease. This is due to its high oxalate content . ( 16 , 17 )

Patients with kidney problems are not able to effectively secrete toxic substances from their bodies. As a result they are negatively affected by oxalates. ( 18 ) Reports also suggest that uremic patients experienced nephrotoxic and neurotoxic effects when they consumed this fruit. ( 19 )

Most patients were able to recover after immediate hemodialysis. Some though they showed kidney failure that caused death. Although these fruits have many nutritional benefits and documented medicines, due to the oxalate and caramboxine content, they are toxic to patients with kidney problems.

Star Fruit Main Varieties

It is cultivated in various states such as Brazil, Israel, Colombia and Hawaii but the largest country  carambola producer is Malaysia.

The main varieties  are DwarfArkinMaher and Thayer.


In regions with tropical climate such as Malaysia, which has an ideal climate for this type of fruit, the star fruit flowers and bears fruit continuously and is therefore available all year round.

Thanks to this characteristic, it is not unlikely to find flowers, ripe and unripe fruits on the tree at the same time.

The length of the fruit varies from 5 to 15 centimeters.

Thanks to its properties it  is used in Chinese medicine for the treatment of diabetes.

It grows gathered in bunches and its color varies from green when unripe to yellow when ripe.

Due to its five-pointed star shape it is also called star fruit.

Always thanks to its star-shaped form, it is often used as a decorative element in the preparation of exotic cocktails and confectionery.

It is also used for the preparation of ice creams and jams. When still unripe , having the same taste as lemon, it is used to garnish desserts or is squeezed on foods just like lemon.

When fully mature it falls to the ground. Despite this the harvest is carried out when the fruit is still green tending to yellow.

Maybe not everyone knows that

Maturation takes place later in environments with a temperature between 15 ° and 20 °.

The star fruit propagation techniques are three: by seed, by cuttings and by grafting.

The plant does not tolerate low temperatures close to zero.

With its juice, distilled liquors are prepared while excellent pulp is obtained from the pulp.

Star fruit: properties and benefits

Italian language version


This is not a medical newspaper, the information provided by this site is for informational purposes only and is of a general nature, it cannot in any way replace the prescriptions of a doctor or other health professionals authorized by law. The notions of dosage, medical procedures and product descriptions on this site have an illustrative purpose and do not allow to acquire the necessary experience and manual skills for their practice or their use. If you have been prescribed medical care I urge you not to interrupt or modify them, because all the suggestions you find on  must always and in any case be compared with the opinion of your doctor.

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