Is Eating Starfruit Dangerous?

A few blog posts claimed that starfruit could be dangerous for people with kidney problems. Rumor or fact? I finally got an expert's answer, Dr Andrew Weil, MD. These are excerpts from an article published 7/21/2009 written by him.

If you have no kidney problems, you can eat all the star fruit you want - it has no effect on healthy kidneys.

But if your kidney function is impaired, eating star fruit can be very dangerous, even deadly. Symptoms of "star fruit intoxication" include persistent hiccups, nausea, vomiting, agitation, insomnia, mental confusion and convulsions that occur within one to five hours of eating the fruit.

The problem seems to be the high levels of oxalic acid (or oxalate) in this fruit that can accumulate in weakened kidneys. But since kidney patients don't seem to have problems eating other oxalate-rich foods (such as spinach), Brazilian researchers who have been studying the reaction suggest that another, unidentified substance toxic to nerves is the real culprit. Whatever this toxin may be, people with healthy kidneys have no problem excreting it while those with impaired kidney function run into trouble with the combination of the unknown toxin and oxalate.