Editor’s note: Handy tips for kidney disease! Based on his research, please read what he has to say about “star fruit” and why it should be avoided.
Anyone with kidney disease, following the appropriate diet, must avoid the fruit known as “star fruit”, or carambola. This fruit comes from a tree native to Indonesia, 
Philippines, Malaysia, India, Sri Lanka and Bangladesh. This fruit is consumed heavily throughout South Pacific, South Asia and parts of East Asia.
The tree and its fruit are also cultivated throughout non-indigenous tropical counties and areas, such as in the Caribbean, Latin America and in the south of the United States. It is often consumed by hand and can be made into juices, relishes, and preserves.
Why Must Someone with Chronic Kidney Disease
Avoid This Fruit in Their Diet?
Research has shown that this fruit contains a neurotoxin called caramboxin that can be fatal if ingested by anyone with kidney disease. In a healthy person
with normal kidney function, this toxin can be easily filtered out without any harm to the body.
However, when kidney function is decreased, this toxin can cause such symptoms as persistent and intractable hiccups, vomiting, and variable degrees of
disturbed consciousness: mental confusion, nervous ticks, anxiety. Other symptoms include decreased muscle strength, numbness in legs and arms, paresis, insomnia, seizure, coma and even death. If you have kidney disease, this fruit must be avoided in your diet.
Commonly Asked Questions about Star Fruit:
- Q: How fast would you feel the symptoms of star fruit poisoning?
- A: Typical symptoms occur within one to five hours and include the symptoms previously listed.
- Q: Isn’t the star fruit’s high oxalic acid content responsible for the poisoning?
- A: This was speculated about in previous research, but follow-up studies discovered that caramboxin was the toxic agent.
- Q: How is starfruit poisoning treated in people with kidney disease?
- A: When someone with kidney disease ingests star fruit, the recommended treatment is dialysis for a short period of time, to filter out caramboxin.
- Q: How much starfruit does a person with kidney disease need to ingest to produce toxic effects?
- A: As little as one-half of a star fruit and less than eight ounces of star fruit juice have caused serious problems. Cases have been reported of people dying from eating just one starfruit.
- Q: Who is at risk?
- A: Anyone with decreased kidney function, high blood pressure, and diabetes should avoid star fruit in their diet. The reason to avoid it in diabetes and high blood pressure is the fact that these conditions are responsible for 50% of kidney failure cases, and kidney function may already be impaired to some extent in these conditions. Your doctor may not have warned you about this danger, or any impairment of kidney function may not have been detected yet.
References: Diet in kidney disease
Cassinotto C, El Zein I, Herbland A, Mehdaoui H,Meunier C,Rieux D,Valentino R. 2009. Starfruit poisoning is potentially life-threatening in patients
with moderate chronic renal failure. Intensive Care Medical, 35(8), 1459-63.
Da Costa JA, Dantas M, Garcia-Cairasco N, Neto MM, Netto JC, Nakagawa B. Intoxication by star fruit (Averrhoa carambola) in 32 uraemic patients: treatment
and outcome. Nephrology Dialysis Transplant, 18(1), 120-5.