Star fruit can be beneficial as a source of antioxidants in the diet. It is also a source of dietary fiber. However, people with certain health issues may need to avoid it.

Having a diet rich in fruits and vegetables is essential for good health.

In this article, we focus on star fruit, exploring its nutritional profile and health benefits, as well as the possible downsides of eating this tropical fruit. We also look at how to prepare it.

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A star fruit usually has five segments, giving it a star shape. It is a crunchy, juicy fruit with a light flavor. The skin is waxy, yellow or green, and edible, and the fruit has tiny dark seeds in its center.

Although star fruit is not a member of the citrus family, its sweetly sour taste may seem citrusy.

The fruit’s native home is Southeast Asia, where it sometimes goes by the name “carambola,” or “cane apple” in the Malay language.

A medium-sized star fruit weighing 91 grams (g) contains:

  • 28 calories
  • 6.1 g of carbohydrates
  • 1 g of protein
  • 2.5 g of fiber

Star fruit is rich in fiber, containing around 60% cellulose, 27% hemicellulose, and 13% pectin.

Star fruit contains an impressive range of vitamins and minerals, including natural antioxidants such as vitamin C and gallic acid, which help prevent cellular damage.

According to the fruit’s mineral and vitamin profile, a medium-sized star fruit weighing 91 g contains:

  • 121 milligrams (mg) of potassium
  • 31.3 mg of vitamin C
  • 10.9 mg of phosphorous
  • 9.1 mg of magnesium
  • 2.73 mg of calcium
  • 1.8 mg of sodium

Star fruit is a source of antioxidants, including beta carotene and vitamin C.

A person can take in around 31 mg of vitamin C from a medium-sized fruit. The recommended dietary allowance of vitamin C is 90 mg per day for adult males and 75 mg per day for adult females, though this increases to 85 mg per day during pregnancy and 120 mg per day during lactation.

The body cannot make vitamin C, so the diet must provide adequate amounts. In addition to combatting oxidative stress, vitamin C is essential for the production of collagen, which the body needs to heal.

Meanwhile, the high amount of fiber in star fruit can help the blood absorb glucose slowly and balance blood sugar levels.

Star fruit contains soluble and insoluble dietary fiber. Soluble fiber dissolves in water to form a gel-like substance. Insoluble fiber does not dissolve but creates bulk to help food and waste pass easily through the digestive tract.

The soluble fiber in star fruit has cholesterol-lowering effects. And because soluble fiber can help remove fat molecules from the blood, incorporating a source of this fiber, such as star fruit, into the diet could reduce the risk of cardiovascular disease.

Soluble fiber also helps reduce blood glucose levels by slowing the rate at which the body absorbs carbohydrates.

In many Asian countries and Brazil, star fruit is a popular alternative to conventional medication.

Practitioners of Ayurvedic and traditional Chinese medicine, for example, use it to treat a fever, a sore throat, a cough, asthma, headaches, and skin problems.

In addition, the leaves, fruit, and roots of the star fruit contain compounds called saponins, flavonoids, alkaloids, and tannins, which have antioxidant and healing properties.

There may be downsides to eating too many star fruits or eating any that are unripe. These can include:

Kidney stones

Star fruit is rich in a compound called oxalate or oxalic acid. This naturally occurs in various plants, such as rhubarb, beetroot, and dark leafy vegetables such as spinach and chard.

The body also produces oxalate as a waste product and naturally excretes it through the urine. If some people consume high levels of oxalate, it could cause kidney stones and damage.

An upset stomach

The entire star fruit is edible, and people should be sure that their fruit is ripe. Oxalate levels are higher in unripe star fruit, and eating this may cause an upset stomach or vomiting.

Complications of kidney conditions

Anyone with a kidney problem should avoid or limit their consumption of star fruit. In some people with these health issues, the fruit can cause neurological complications, including confusion and seizures.

If a person with no history of kidney issues consumes too many, star fruit can damage the kidneys over time.

For some people with chronic kidney disease, eating star fruit could be extremely dangerous and possibly fatal. Anyone with a kidney problem should consult their doctor before eating star fruit.

Interactions with medication

Star fruit can change the way that the body breaks down and uses medications. Like grapefruit, star fruit can slow down the rate at which the body clears drugs, possibly leading to higher levels of these drugs in the body than intended.

Anyone with concerns about possible interactions should contact a healthcare professional.

First, rinse a star fruit under running water to remove any contaminants, then cut it into thin slices, discard the seeds at the center, and enjoy.

A ripe fruit is mostly bright yellow, with minimal green areas. If any fruit has brown patches, cut these away before eating it.

A person can add star fruit to salads, juices, and smoothies. The slices can also make an attractive garnish because of their unusual shape. Some people also make star fruit syrup for desserts.

Star fruit is a nutritious tropical fruit that is low in calories and sugar but packed with fiber and antioxidants such as vitamin C.

Eating star fruit may help regulate blood sugar, protect the cardiovascular system, and support the immune system.

However, anyone with kidney problems and anyone taking prescription medication should speak with a healthcare professional before trying star fruit due to potential toxicity and drug interactions.