11 Best Benefits of Star Fruit (Carambola)

by John Staughton (BASc, BFA) last updated -

The health benefits of star fruit (Carambola) include boosting the immune system, stimulating lactation, detoxifying the body, relieving respiratory distress, protecting the skin, aiding in weight loss, speeding up the metabolism, preventing cancer, optimizing digestion and building strong bones. It is an excellent anti-inflammatory and boosts hair and skin health.

What is Star Fruit?

Star fruit is an exotic variety of fruit that is packed with nutrients and minerals, which has recently gained global popularity. Starfruit is the fruit of a tree with the scientific name Averrhoa carambola. The fruit is approximately 3-6 inches in length and the flesh of the fruit is greenish-yellow to yellow and is crisp and tart in taste. It may also have two to five tiny, edible seeds. The name comes from the distinct shape of this fruit when it is cut in a cross-section – it has the shape of a star. The entire fruit can be eaten including the waxy outer layer. The tree of this fruit can be found throughout Southeast Asia and other tropical areas including the Caribbean and Latin America. [1]

When the fruit is ripe, it is light yellow with slightly brown ridges. It is best to avoid smaller, green fruits as these tend to be quite sour and unpleasant to eat. This fruit is sought after due to its nutrient density and antioxidant levels.

Nutrition Facts

Carambola, (starfruit), raw
Serving Size :
NutrientValue
Water [g]91.38
Energy 31
Energy [kJ]128
Protein [g]1.04
Total lipid (fat) [g]0.33
Ash [g]0.52
Carbohydrate, by difference [g]6.73
Fiber, total dietary [g]2.8
Sugars, total including NLEA [g]3.98
Calcium, Ca [mg]3
Iron, Fe [mg]0.08
Magnesium, Mg [mg]10
Phosphorus, P [mg]12
Potassium, K [mg]133
Sodium, Na [mg]2
Zinc, Zn [mg]0.12
Copper, Cu [mg]0.14
Manganese, Mn [mg]0.04
Selenium, Se [µg]0.6
Vitamin C, total ascorbic acid [mg]34.4
Thiamin [mg]0.01
Riboflavin [mg]0.02
Niacin [mg]0.37
Pantothenic acid [mg]0.39
Vitamin B-6 [mg]0.02
Folate, total [µg]12
Folate, food [µg]12
Folate, DFE [µg]12
Choline, total [mg]7.6
Vitamin A, RAE [µg]3
Carotene, beta [µg]25
Carotene, alpha [µg]24
Vitamin A, IU [IU]61
Lutein + zeaxanthin [µg]66
Vitamin E (alpha-tocopherol) [mg]0.15
Fatty acids, total saturated [g]0.02
16:0 [g]0.01
18:0 [g]0.01
Fatty acids, total monounsaturated [g]0.03
18:1 [g]0.03
Fatty acids, total polyunsaturated [g]0.18
18:2 [g]0.16
18:3 [g]0.03
Tryptophan [g]0.01
Threonine [g]0.04
Isoleucine [g]0.04
Leucine [g]0.08
Lysine [g]0.08
Methionine [g]0.02
Phenylalanine [g]0.04
Tyrosine [g]0.04
Valine [g]0.05
Arginine [g]0.02
Histidine [g]0.01
Alanine [g]0.07
Aspartic acid [g]0.1
Glutamic acid [g]0.15
Glycine [g]0.05
Proline [g]0.05
Serine [g]0.08
Sources include : USDA [2]

Star Fruit Nutrition Facts

Starfruit contains an extremely low number of calories but it is rich in dietary fiber, vitamin C, vitamin A, and B vitamins, as well as phosphorus, zinc, calcium, magnesium, sodium, iron, and potassium (source: USDA National Nutrient Database). Furthermore, the fruit has a high concentration of antioxidants like polyphenolic compounds, such as quercetin, epicatechin, and gallic acid. [3] [4]

Health Benefits of Star Fruit

Let us have a look at some of the most important health benefits of starfruit.

Anticancer Potential

Research on star fruit published in the Advances in Pharmacological Sciences journal has suggested that that could be developed into an effective natural supplement against cancer. Another study highlighting the antioxidant capacities of star fruit states that the peel of this fruit is a richer source of antioxidants than the pulp. Also, the ripe fruit is more of an antioxidant storehouse than the raw fruit. Furthermore, the fiber in star fruit will cleanse the colon and reduce toxicity levels, helping to lower your risk of colon cancer. [5] [6]

Anti-inflammatory

The high amounts of antioxidants and flavonoids present in this fruit make it a good anti-inflammatory for various skin disorders including psoriasis and dermatitis. The rich source of vitamin C also helps in flushing out toxins and in collagen synthesis. [7]

Whole and sliced fresh star fruits or carambola with leaves on a wooden table

Star fruit is one of the most sought after fruits due to its nutrient density and antioxidant levels. Photo Credit: Shutterstock

Heart Health

The high amounts of sodium and potassium present in star fruit act as electrolytes in our body, which help in maintaining blood pressure. This also ensures a regular heartbeat and healthy blood flow.

Stimulates Lactation

It has also been traditionally used to increase lactation in mothers who have trouble producing enough milk for their newborns. And in large doses, it can also act as an emmenagogue. [8]

Promotes Weight Loss

With a tiny amount of calories per fruit, this tropical treat won’t compromise your calorie goals, if you are trying to lose weight. Furthermore, it is full of fiber and other nutrients that can speed the metabolism, which can help support your effort to shed those extra pounds. Fiber will also help you to feel full faster, lowering your chances of overeating or snacking between meals. [9]

Boosts Immunity

A single medium-sized star fruit has approximately 50% of the daily value recommended for vitamin C, which is great news for your immune system. A study titled “Radical scavenging activity in fruit extracts” by P Surinut et al found that carambola possesses radical scavenging activity, which helps increase overall immunity. With a solid vitamin C boost in your morning fruit smoothie, your immune system will be functioning at a high level with an optimal number of white blood cells. [10] [11]

Balances Blood Pressure

With a moderate amount of calcium, star fruit can reduce your risk of atherosclerosis, heart attacks, and strokes by relieving tension on blood vessels and arteries. In fact, a study conducted in Brazil on laboratory rats showed that Averrhoa carambola leaves help reduce hypertension. By eliminating hypertension, your heart will be able to rest, circulation can be more effectively carried out, and the fluid balance in your body will be appropriately maintained. [12]

Improves Digestion

Dietary fiber is a key element in digestion, as it can stimulate the movement of stool through the digestive tract, relieving symptoms of constipation, bloating, cramping and diarrhea. Furthermore, it can help to improve nutrient uptake and the bioavailability of other essential minerals and vitamins. Both the inner fruit and the waxy peel of star fruit provide significant levels of dietary fiber. [13]

Increases Bone Mineral Density

There is a diverse range of minerals in star fruit including iron, magnesium, phosphorus, zinc, and calcium, all of which can help promote better bone health and reduce the risk of osteoporosis as we age. [14]

Controls Diabetes

Research has found that this rich in insoluble fiber can prevent the release of glucose after eating. This helps to control insulin levels in the body, making it an ideal snack for anyone looking to manage diabetes. [15]

Improves Metabolism

With high levels of pyridoxine, folate, and riboflavin, this fruit can help to optimize your metabolism by ensuring that necessary enzymatic and hormonal processes take place throughout the body. These critical vitamins play a part in everything from nerve cell communication and energy metabolism to circulation and emotional control. [16]

Reduces Cholesterol Levels

With a very low amount of natural fat and a high level of dietary fiber, this tropical greenish-yellow fruit is great for managing and reducing cholesterol levels. Fiber helps to regulate LDL (bad) cholesterol and elevate HDL (good) cholesterol, thus lowering your risk for coronary heart disease, stroke, heart attack, and atherosclerosis. [17]

Detoxifies the Body

Known as a diuretic, this fruit can stimulate urination, which can be helpful for someone looking to detox. This fruit will help to cleanse both the liver and the kidneys, although people with pre-existing kidney conditions should eat this fruit with caution. By increasing urination, star fruit can lower the levels of toxins, excess salts and fats within the body. [18]

Improves Respiratory Health

This fruit is known as an anti-inflammatory and cooling agent that can promote salivation and cut through mucus or phlegm. This makes it a popular remedy for respiratory infections and general health, alleviating sore throats and addressing underlying infections of the respiratory system.

Relaxes Sore Eyes

Due to the anti-microbial properties of star fruit, it is also used by people to get relief from sore eyes.

Skin Care

Star fruit is packed with antioxidants, such as quercetin, gallic acid, and other polyphenolic flavonoids, that can counter the effects of oxidative stress and neutralize free radicals before they can damage the skin. This includes preventing or minimizing the appearance of wrinkles, while also keeping the skin moisturized and blemish-free as you age. Eat it or apply it, it is equally beneficial in both ways. [19] [20]

Hair Care

A rich source of antioxidants, B complex vitamins, and vitamin C, star fruit has all the nutrients which promote healthy hair growth.

How To Buy And Store Star Fruit?

The green-colored star fruit can be purchased and kept aside until it ripens. However, if you want to readily eat it, go for the yellowish-brown one. The thickness of the outer layer is directly proportional to its sweetness. Therefore, if you want it sweet, make sure to buy those with a thick waxy covering. Ensure to pick firm ones as the bruised ones do not have a long shelf life. You can refrigerate it if you want to increase its shelf life.

How to Eat Star Fruit?

Star fruit is widely cultivated for its use in culinary dishes, thanks to the tart, sour flavor, a combination of applegrapes and citrus fruits. Due to the unique appearance of the fruit, people are often confused as to how it can be eaten. While some exotic fruits require peeling or other forms of preparation, star fruit is surprisingly simple. The waxy outer layer can be safely eaten and is quite thin. The most important part of the preparation process is removing the top and bottom of the fruit. A narrow slice can be taken from either end and discarded.

Its culinary applications are as follows:

  • It can be included in any number of desserts, jams, marmalades, savory dishes, and fresh fruit salads.
  • Most people eat it raw or combine in a spiced mix of stewed fruits.
  • The juice can be used as a flavoring agent in many other dishes, particularly with shrimp and other protein dishes.
  • It is also popular in fruit shakes and smoothies, it can be pickled or simply used to garnish a cocktail.
  • The fruit can also be dried and sugared, to be eaten as candy.

Side Effects of Star Fruit

Unfortunately, there are a few side effects of star fruit that should be taken seriously including lethal toxicity under certain conditions, as well as allergic reactions, kidney stones, and drug interactions.

  • Allergies: While allergies to star fruit are uncommon, they are not unheard of and may result in digestive upset, such as diarrhea, nausea, or vomiting. When consuming star fruit for the first time, try just a small amount to see how your body reacts.
  • Toxicity: Some of the compounds in star fruit can be dangerous – and even deadly – if they aren’t properly processed out by the body. Therefore, if you have kidney disease and are unable to filter out certain neurotoxins, star fruit can result in headaches, confusion, nausea, seizures, and even death. Most people with kidney issues and all uremic patients are recommended to avoid star fruit. [21]
  • Kidney Stones: Similarly, this fruit has a very high concentration of oxalic acid, which is okay in moderate amounts, when your kidneys are functioning normally. However, eating a lot of this fruit can increase your risk of kidney stone development.
  • Drug Interactions: The active ingredients in star fruit are known to interact with many medications, namely making them non-functional in the body. This inhibitory action can be dangerous if you are on multiple prescriptions, therefore, speak to your doctor before eating star fruit if this in such a scenario.
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About the Author

John Staughton is a traveling writer, editor, publisher and photographer with English and Integrative Biology degrees from the University of Illinois in Champaign-Urbana (USA). He co-founded the literary journal, Sheriff Nottingham, and now serves as the Content Director for Stain’d Arts, a non-profit based in Denver, Colorado. On a perpetual journey towards the idea of home, he uses words to educate, inspire, uplift and evolve.

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