Chronic Kidney Disease and the Dangers of Star Fruit

Renal Dietitians specialize in the dietary needs of people with chronic kidney disease (CKD).  Although I am not a renal dietitian, there have been a few times when I’ve had to counsel people with various stages of CKD who had no access to a renal dietitian. 

Low protein diets have been recommended for decades for pre-dialysis CKD patients and more recent research points to the specific damaging effects of animal protein as compared to plant protein.  This entails the promotion of a whole food plant-based diet as ideal for CKD patients.  However, there is one whole plant food that is a major problem for people with CKD.

Beware The Star Fruit

 A few years back, thanks to the Nutrition Guide for Clinicians, I discovered that Star Fruit is a fruit that should ABSOLUTELY be avoided by anyone with CKD at any stage.  The explanation the guide provides is as follows:

“Several reports have noted the toxic effects of Averrhoa carambola in patients with both CKD and end-stage renal failure on dialysis. The primary symptoms are neurological and include hiccoughing, vomiting, asthenia, paresis, muscle twitching, insomnia, mental confusion, convulsion, and coma. The outcome is fatal in some cases despite hemodialysis. The cause is thought to be tubular obstruction by calcium oxalate crystals as well as apoptosis of renal tubular epithelial cells.”

Armed with this information, I made sure I provided this warning to each CKD patient I counseled.  I’m aware that Star Fruit is not a popular fruit in the US and the likelihood that the patient would encounter star fruit would be low.  But I was recommending a diet very high in plant foods.  I felt it was very important to let patients know of a particular plant food that they should avoid.

If you have CKD and you encounter a fruit that you can’t identify, I recommend that you don’t eat it.

Maybe We All Should Be Careful with Star Fruit

One reason everyone might want to treat Star Fruit with caution is that according to The National Kidney Foundation, 90% of people with CKD don’t even know they have it.

A recent video by Dr. Michael Greger compares the toxicity of Star Fruit for people with normal functioning kidneys with people with impaired kidney function.  It’s very clear that Star Fruit poses a much greater danger to people with CKD.  However there is some research that shows that those with normal kidneys could develop dangerous neurotoxicity by consuming 15 or more star fruit. Eating as little as 4 star fruit may not cause neurotoxicity, but it may cause some kidney damage. I suggest watching the video so you can make a more informed choice about whether or not you should avoid reaching for the star fruit.

Stay Healthy and Strong!