It is often in my day that people tell me that they are taking natural remedies for any number of medical conditions – for aches and pains, diabetes, obesity, cancer prevention… the list goes on.  The thinking that often underlies the decision to take these remedies is that they are natural, so how could they possibly be harmful?

I worry about my patients taking natural or naturopathic products, because rigorous clinical trials are not done to show benefit, nor (most concerning) to understand potential harms.  So, when I came across two very serious case reports of kidney damage from the seemingly innocent star fruit, I wanted to share it to illustrate the potential dangers of natural remedies.

Star fruit comes from a tree native to India and southeast Asia.  In addition to eating them as a fruit (I’ve enjoyed them myself on occasion while traveling to these areas), they are also touted as a herbal remedy for various ailments (including diabetes) in these countries.

Recently, two cases of star fruit toxicity were published.  One case was that of a woman with type 2 diabetes who consumed 200 mL of star fruit juice (less than a cup) from six star fruits, which resulted in kidney failure due to an inflammatory reaction in the kidneys (acute interstitial nephritis) caused by the high oxalate content of star fruit.  Thankfully, with medical treatment, her kidneys recovered.

The second case was that of a man with a history of moderate kidney dysfunction, who developed kidney failure after eating four star fruits over four days.  Thankfully, he also recovered after about 2 weeks.

In addition, like the grapefruit, star fruit also inhibits a group of liver enzymes (cytochrome P450 isoforms) which are important for metabolism of medications such as statins (cholesterol medications).  This is why it is advised for patients on statins not to eat grapefruit – star fruit should be included in this counselling as well.

So, take these cases into consideration the next time you think about reaching for a herbal remedy – remember that we simply do not know enough about these remedies to know if they are safe.

As a patient, be sure to tell your doctor about any natural remedies you are taking.

As a health care professional – remember to ask.


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