Starfruit implicated in yet another neurotoxin
Found this interesting article:
This fruit can end your life!
This is not an April Fool Joke. But a stern reminder to all my readers. We were advised to have a few servings of fruits a day in order to reap the benefits of fruits right? But obviously this is one big no-no fruit to be excluded from your fruity feast!
In Shenzen, more than 10 people who consumes the star fruit had died. And now a 66-year-old, Malaysian who has been suffering from kidney ailment fell into coma after eating the start fruits. Yes, all it takes is one fruit or 100ml of its juice and the ordinarily harmless star fruit transforms poison in a matter of hours for kidney patients. So does this mean, people without kidney problems should be fine with star fruit! My take: Not at all! Prevention is better right?
Universiti Malaya Medical Centre consultant nephrologist said that star fruits contain a neurotoxin which is not present in other fruits. It affects the brain and nerves. In healthy persons, the kidneys filter it out. But for those with kidney problems, this potent toxin cannot be removed and will worsen the consumers’ conditions.
And yet another article:
Abstract
Star fruit has been reported as containing neurotoxins that often cause severe neurological complications in patients with chronic renal disease. We report two patients with chronic renal failure at a pre-dialyzed stage who developed refractory status epilepticus after ingestion of star fruit. In addition, we review 51 cases in the literature. Among 53 patients, 16 patients presented with epileptic seizures (30%). The mortality rate was as high as 75% in patients with seizures. On the other hand, in patients without seizures, the mortality rate was only 0.03%. There is a poor correlation with the degree of underling renal function and mortality due to intoxication. We propose that epileptic seizure is significantly associated with poor prognosis, and that status epilepticus is an unpredictable and potentially fatal complication in star fruit intoxication. We advise consultant neurologists that star fruit intoxication must be considered when patients with chronic renal disease present with seizures or other unexplained neurological or psychiatric symptoms. Since no effective treatment has been established, star fruit consumption should be avoided in patients with chronic renal disease, especially in the elderly.
The following thread was started by Axel on July 26, 2009 at 9:36 pm PST
Oh well, they don't taste like much anyway.
Oxalic acid I guess is the problem here.
I can't help but take these sort of reports with a huge grain of salt. Millions of starfruit have been consumed by millions of people over thousands of years. I'd be more worried about cholesterol from a hamburger than toxic starfruit.
The above followup was added by Virgil on July 26, 2009 at 9:42 pm PST.
The reports are prety explicit and suggest the neurotoxin is normally filtered out by the kidneys, but for patients with kidney problems, the kidney can't filter out the toxins.
I'd be careful with the statement about people ingesting millions of star fruit. In general, if you read history books, you will find that fruits have only had as "renaissance" in the 19th century. Before that, people's diets were primarily focused on meat, and people only ate fruit occasionally.
The problem is that not all fruits are created equal, there are fruit that are in fact harmful when eaten frequently. So far, the list I am aware of includes all annonas, star fruit, and monstera deliciosa. The latter two will give you chronic kidney problems because of the high doses of oxalic acid, never mind that there is any neurotoxins in them.
Personally, I like to stick with those fruits that are proven to be very healthy for you, where more is better. Starfruit is no loss, I've only eaten good starfruit once in my life, in Hawaii, the fruit was very sweet, so apparently exceptionally low in oxalic acid.
I believe most of these problems can be overcome through proper breeding. After all, there are bitter almonds that can kill in large enough quantities, yet there are plenty of almond varieties with a low enough amygdalin content making them safe for consumption.
The pawpaw institute did a study on some of the varieties, looking for those varieties that have the lowest levels of annonacins. I forget which ones they are, the point is that it is possible to breed out the neurotoxins.
The above followup was added by Axel on July 27, 2009 at 8:45 am PST.
Interesting to know if rhubarb causes problems for people with weak kidneys. Its very high in oxalic acid too and is very popular as a dessert 'fruit' here in NZ and the UK. Sorrel is again very similar re oxalic acid content and is very popular in France.
I would question how many poor medieval inhabitants of SE Asia were eating meat regularly, but they may not have paid much attention to star fruit- its so boring!
The above followup was added by Virgil on July 27, 2009 at 1:05 pm PST.
If, indeed, these tropical fruits were so "deadly" to the masses I would not expect to see any of the trees growing anywhere near places where people live.
It's too easy to dismiss the intelligence of people who don't the wherewithall or temerity to abuse lab rats and suppose they can't draw a line from point A to point B. Local folklore and custom would have long since eliminated these fruits from the local diet and probably the trees/plants themselves would be pulled up wherever they encroached on settlements (children take time to learn).
Clearly at this point in time in the more developed world most people would already be aware if they had kidney problems, so it's not like they would blunder into the discovery by keeli\ng over after eating a slice of star fruit.
I think we really need to step back and cast a skeptical eye on reports like these. It can take a lot of dead rats to truly establish a causal link where ingested foods are concerned. So many potential cofactors.
Variety and moderation...........
The above followup was added by Steve in Los Osos on July 27, 2009 at 4:15 pm PST.
Steve, the report on the toxicity of starfruit is a result of recent "indigenous" folks with kidney problems blundering into the discovery of keeling over, in fact, dying, and others almost dying from eating starfruit. I would not so readily dismiss it. Go and Google the results yourself. You also cannot dismiss the reports from the Guadeloupe islands where the incidence of atypical parkinsons come from - another example of locals running into a problem with a local fruit.
Keep in mind one of the major differences in between tropical fruits and temperate fruits of northern latitudes is that the latter have been improved over centuries. As I mentioned before, almonds is an excellent example.
I don't particularly like starfruit, so it's not exactly hard to steer clear of it. however, I have had a bad experience with cherimoyas. Long before the reports of neurotoxins ever hit the news, I remember asking my doctor about the possibility that cherimoyas could be responsible for the migraines I was getting, which I had noticed were linked to my consumption of the fruit. Of course, at the time, the doctor dismissed it, but nowadays, he would have informed me that there might be a problem with consuming the fruit.
I still grow annonas because I've invested so much into them, and in the hopes that most of them will be off the hook once a bit more research reveals the exact mechanism of the Guadelupe parkinson's epidemy. I have an amazing collection of annonas that I have difficulty walking away from, with over 15 different hard to find varieties of cherimoyas, an equal collection of pawpaw trees, and several very hard to find annonas including the Brazilian Pindaiba and rollinia emarginata. I am not about to toss them out, but I now give away most of the fruit because I appear to have a a sensitivity to it.
So remember, the rat studies came AFTER indigenous populations "blundered into the discovery by keeling over after eating" one of the suspect tropical fruits. None of these fruits would have been called out as suspect if the natives didn't have any problems.
The above followup was added by Axel on July 27, 2009 at 6:13 pm PST.
I grew up in Europe, and I remember the big Rhubarb fields, and I also distinctly remember that we were told NOT to eat any other part of the plants besides the red part of the stem lest we wish to become gravely ill. That was enough for me not to want to try, but it didn't keep me from eating the red stems, they were delicious when dipped in sugar.
We were also tought in school about what mushrooms never to pick and eat. A lot of this knowledge was passed down through generations and generations. Fancy that! In the US, school kids nowadays don't even know that milk comes from a cow.
So there is a collective knowledge that grows as long as we don't become so disconnected from nature that we no longer have a clue, and then, big historical events like wars and colonization tend to disrupt such knowledge. Maybe a lot of knowledge within tropical populations has been lost through all the colonization that took place in tropical countries - the Europeans that dismissed all the native tropical plants and brought in the European crops. For example, a lot of the Andean crops were almost lost because the conquistadors considered the native crops to be inferior.
The above followup was added by Axel on July 27, 2009 at 6:22 pm PST.
Slightly off topic but I just ate a rhubarb and custard filled brioche from a local cafe. OMG that was some good eating!
The above followup was added by Virgil on July 28, 2009 at 4:48 pm PST.
Cooking / pasteurizing (even lightly) will destroy the oxalates. People with kidney disease cannot eat raw spinach or green amaranth either, for the same reason.
The above followup was added by abyssquick on July 28, 2009 at 4:52 pm PST.
It is important to cook the oxalate out of the greens you feed infants as well.
George
The above followup was added by George on August 04, 2009 at 7:59 am PST.