February 06, 2009
Starfruit, aka Carambola.
I've seen a few of these things at the open market. I was never brave enough to try one, but they are described as "sweet without being overwhelming and extremely juicy. The taste is difficult to compare, but it has been likened to a mix of papaya, orange and grapefruit all at once" by someone on wikipedia.
Grapefruit is a good way to phrase it, since it has similar health effects. Grapefruit and starfruit juice inhibits liver enzymes involved in the breakdown of certain drugs through the Cytochrome P450 system. (Namely, CYP3A4,5,7: the most important metabolizing enzyme of the bunch.)
The blue slice of the pie is BLOCKED by starfruits and grapefruits!
Not only that, but it can create a lethal buildup of oxalate crystals in the kidney in patients with kidney disease. Oxalate crystals are the same byproduct from ethylene glycol poisoning, the treatment for which is hemodialysis and fomepizole (or ironically, ethanol.)
How can you spot someone with starfruit toxicity? Typically, they will present with persistent hiccups, vomiting, neurologic problems, and occasionally convulsions.
Treatment for starfruit poisoning consists of prompt hemodialysis. Surprisingly, even though starfruits have a lot of potassium, intoxicated patients were not shown to have hyperkalemia.
I'm certainly not trying to fearmonger with this post, merely inform. I'm going to give starfruits a try the next time I see them as a part of my pledge for better health. They sound tangy and delicious!
 Intoxication by star fruit (Averrhoa carambola) in 32 uraemic patients: treatment and outcome
Photo by AZAdam