Best known in North America as “star fruit” due to its shape when sliced cross-wise, the carambola is actually native to Sri Lanka.
There are many varieties of this fruit grown in tropical regions around the world. Its flavors range from sour to sweet and are sometimes described as a combination of grape, apple, pear, and citrus.
Unique and novel in shape, it’s often seen as a garnish for other foods. But star fruit dietary benefits are even more impressive than its shape. Most notably, the leaves, flowers, roots and fruits are edible and have been used in Eastern and South American medicines for centuries.
Low in sugar and calories, the star fruit is high in vitamins, minerals, and antioxidants with protective benefits against hypertension, diabetes, and high cholesterol. It’s also widely used as an antibiotic, analgesic, and anti-inflammatory medicine.
Proceed with Caution
Please note: carambola is toxic to those suffering from kidney disease.
A Brazilian study found an amino acid in star fruit that easily binds to ether, alcohol, and acid groups, which researchers name “caramboxin”. In the phytochemical family of oxalates, this acid aids in plant and animal metabolism.
Healthy kidneys dispatch the amino acid as a matter of course but in the case of kidney malfunction, it can accumulate. It then enters the central nervous system, causing symptoms from uncontrollable hiccups and vomiting to seizures and coma—called “star fruit poisoning” (1). For people on dialysis, star fruit will almost always cause a severe adverse reaction and can lead to death if not treated quickly and properly (2).
Drug interactions: the juice of the star fruit significantly inhibits the activity of a particular enzyme that is critical to drug metabolism (CYP3A) (3, 4). If you are taking any pharmaceuticals, please consult your healthcare provider before eating even one star fruit.
If it’s safe to do so, proceed with glee.
9 Star Fruit Benefits
Here are 9 reasons to be a little adventurous and try this funky fruit.
1. Antimicrobial and Antioxidant
Chemicals in star fruit provide antibacterial and antifungal benefits against common pathogens such as Salmonella, E.coli, and Pseudomonas aeruginosa (causes blood infections and pneumonia) (5, 6). Its free-radical scavenging ability is impressive, with multiple compounds reducing inflammation and oxidative stress in the body.
2. Regulates Blood Sugar
4. Regulates Cholesterol
The shiny smooth skin of star fruit contains significant amounts of fiber. Getting enough fiber prevents the absorption of low-density lipoprotein (LDL) cholesterol. Plus, adequate amounts of dietary fiber contribute to the metabolism of fats. In one study, star fruit fiber prevented the development of fatty liver in laboratory animals (9). Epicatechin is a phytochemical in carambola that has been specifically found to inhibit the creation of fat cells (10).
5. Fetal Development
Folic acid is a B-complex vitamin (B9), a deficiency of which can cause birth defects—especially those of the central nervous system. Carambola is a good source of B2 and B6 as well—essential vitamins important for metabolism and liver and eye health (11,12). Vitamin B2 is necessary to facilitate the body’s use of folic acid and is itself an antioxidant.
6. Fluoride Toxicity
The leaves of carambola are used in traditional Brazilian medicine to moderate blood pressure. It works by inhibiting aortal contraction, allowing blood to move more freely (14). In addition, star fruit contains potassium and other electrolytes, which are known to control heart rate and blood pressure.
8. Immune System Support
9. Healthy Skin
Antioxidant flavonoids in star fruit are responsible for stimulating protective compounds in skin cells, reducing inflammation and inhibiting ultraviolet radiation (UV) damage (15).
The potency of this funky yellow fruit is undeniable.
Caution must be applied under certain conditions but if you can add star fruit to your diet, it’s a welcome choice.
A study in Bangladesh reviewed the chemistry of carambola and its use in that country:
“Fruits and its fruit juice are used as antioxidant, astringent, tonic also to treat diarrhoea, vomiting, dysentery, hepatic colic, bleeding piles, relieving thirst and febrile excitement. The leaves are antipruritic, antipyretic and anthelmintic and are also useful in scabies, fractured bones, and various types of poisoning, intermittent fevers and intestinal worms.” (16)
Carambola definitely gets a gold star in health.