IN SHORT: Cancer can be debilitating and expensive to treat, which is why claims on social media that the cure lies in a widely available fruit could easily gain traction. But they are not backed up by science.
A post circulating on Facebook in Tanzania claims that pineapple peel juice can cure bladder cancer.
Written in Kiswahili, the language widely spoken in East Africa, the post is headlined: "JINSI YA KUTIBU KANSA YA KIBOFU (TEZI DUME) KWA KUTUMIA JUISI YA MAGANDA YA NANASI."
This translates to: "How to treat bladder cancer using juice from the pineapple peel."
However, the words "tezi dume" mix up bladder and prostate cancer.
The poorly written post goes on to provide instructions: "Menya maganda ya nanasi kwenye nanasi moja osha maganda vizuri saga kwenye blenda kwa kutumia maji nusu lita. (Kama huna blenda twanga kwenye kinu, loweka kwenye maji ndipo uchuje). Kunywa juisi hii asubuhi na jioni kwa siku 90 mfululizo. Kumbuka kuweka asali kwenye juisi hii usiweke sukari."
This translates to: "Wash the pineapple peel and blend it in half a litre of water. If you do not have a blender, use a mortar and pestle. Drink this juice morning and evening for 90 consecutive days. Remember to add honey to the juice, but not sugar."
The claim has been posted repeatedly on different dates by a Facebook page with over 7,000 followers, here, here and here. It also appears on another Facebook page with 1,200 followers.
But can this home remedy cure bladder cancer? We checked.
Anti-cancer properties of pineapple residues
A pineapple is a perennial plant that has an edible fruit.
According to the National Cancer Institute, the US government's main agency for cancer research, bladder cancer occurs when cells in the bladder grow out of control. The bladder is a hollow, balloon-like organ in the lower part of the abdomen that stores urine.
The potential anti-cancer properties of pineapple residues have been investigated by a number of researchers.
A 2023 review, published in the Frontiers in Oncology journal, looked at the data that has been published on the subject. It found research suggesting that bromelain, a group of enzymes found in pineapple, may be beneficial in treating cancer.
Bromelain can be extracted from the stem and, to a lesser extent, other parts of the pineapple. It has shown potential to have health benefits beyond its possible role in cancer treatment, but researchers say these need to be studied further.
The review described numerous studies that found bromelain to have anti-cancer properties. This is because it can help kill cancer cells directly and could stop them from spreading in the body.
However, most of this research was done in vitro, meaning in a test tube or looking at individual cells outside the body.
In order to properly investigate whether a potential new treatment could be effective, scientists carry out special studies known as clinical trials. The researchers in this review warned that although the studies on bromelain were promising, "the number of clinical trials is low and limited to early research".
It is too early to say whether bromelain could play a role in treating cancer.
Pineapples might support 'general health', but won't cure cancer
Asked by AFP Fact Check in August 2021 if the fruit could treat cancer, Dr Aru Wisaksono Sudoyo, chair of the Indonesian Cancer Foundation, said: "Like other fruits, including apples and avocados, pineapples are healthy. They are fruits that can support general health and immunity. No more than that."
Prof Edzard Ernst is an academic physician and researcher specialising in complementary and alternative medicine and emeritus professor at the University of Exeter in the UK. In his book Alternative Medicine, published in 2019, he warns that scientific evidence is needed for any medical treatment.
Africa Check asked Ernst if pineapple peel, or any fruit for that matter, could be a cure for cancer.
"To the best of my knowledge, there is no sound evidence for the claim. It is firstly biologically implausible, and secondly, not supported by clinical evidence," he said.
Claims about honey also unsubstantiated
The claim also suggests that honey should be added to the resulting mixture. We looked at studies investigating whether honey was a potential remedy for cancer.
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An article published in 2021 in the National Library of Medicine reviewed the role of natural honey in the prevention and treatment of a range of cancers. It noted that honey "has been suggested as a promising agent for the prevention and treatment of cancer" but added that "the exact and full mechanisms of these effects have not been well elucidated yet".
"Further studies should be conducted to confirm the anticancer function of honey before recommending its usage in clinical interventions for patients with cancer," the review said.
Africa Check has previously debunked a similar claim that hot pineapple water can cure cancer. Bogus health advice like this can be dangerous. Even if it's not strictly harmful, it could discourage sick people from seeking real medical help.
The claim that pineapple peel juice can treat bladder cancer is unproven and not supported by any available scientific evidence.
This report was written by Najma Juma Matengo, a fact-checking consultant with the Tanzania Media Foundation, during the 2023 Africa Check Fellowship in Nairobi, Kenya. The fellowship was sponsored by the US State Department.
