Fact Check: Can onion juice mixed with sugar dissolve and pass kidney stones?

Claim: An Instagram post claims that drinking onion juice mixed with sugar can help dissolve and pass the kidney stone. The post has over 31k likes and can be accessed here.

Fact Check: The claim is FALSE.

What are Kidney stones?

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Kidney stones, or renal calculi, are solid masses made of crystals. Kidney stones originate in your kidneys but can develop anywhere along your urinary tract. Kidney stones cause severe pain, particularly when passing through the urinary tract. (1)

How are Kidney stones formed?

Kidney stones form when there is a decrease in urine volume and/or an excess of stone-forming substances in the urine. Here is a detailed explanation of the process:

Supersaturation of Urine: When the urine becomes highly concentrated with minerals and salts, such as calcium, oxalate, and uric acid, it can become supersaturated. This means there is more of these substances in the urine than can be dissolved.

Crystallization: The supersaturated urine allows for the formation of crystals from these substances. These crystals can start to stick together, forming a small mass or "seed."

Aggregation: Over time, more minerals attach to the seed, causing it to grow into a larger stone. Factors like urine pH, the presence of certain inhibitors or promoters of crystallization, and the lack of sufficient water can influence the growth and aggregation of these crystals.

Stone Growth and Movement: As the stone grows, it can move through the urinary tract. If it remains small, it might pass unnoticed. However, larger stones can cause blockages and intense pain as they move from the kidney to the bladder and out through the urethra.

Factors Contributing to Kidney Stone Formation:

Dehydration: Low fluid intake reduces urine volume, increasing the concentration of stone-forming minerals.

Diet: High intake of protein, sodium, and sugar can increase the risk of some types of kidney stones.

Medical Conditions: Conditions such as hyperparathyroidism, certain urinary tract infections, and metabolic disorders can predispose individuals to kidney stones.

Genetics: A family history of kidney stones can increase the risk.

Medications: Some medications, such as diuretics and calcium-based antacids, can contribute to stone formation.

Types of Kidney stones: 

Dr Vinant Bhargava, Senior Consultant Nephrologist at Sir Gangaram Hospital, explains, “A kidney stone is a hard object that is made from chemicals in the urine. There are certain types of kidney stones: calcium oxalate, uric acid, calcium phosphate struvite, and cystine. The cause of stone formation should be evaluated to prevent its reoccurrence. It can cause severe abdominal pain and blood in urine and can lead to urine infections. The treatment depends on the site and size of the stone. If the stone is small and lower down the urinary tract, it may get expelled on its own."

Can onion juice mixed with sugar help dissolve and pass kidney stones?

Some cultures use onion juice as a remedy for the expulsion of kidney stones. However, there is limited scientific evidence to support its efficacy.

In a study conducted by Wahid et al., it was found that the administration of Allium cepa extract (onion extract) demonstrated significant protective effects against kidney stone formation and improved kidney function in albino rats. These effects are attributed to the onion extract's ability to reduce oxidative stress, inflammation, and cellular damage in the kidneys. (6)

Onions are known to have several health benefits, including strong antioxidant properties due to their richness in flavonoids and sulfur-containing compounds (1). Another study published in the International Journal of Molecular Sciences found that onions contain quercetin, a flavonoid with significant anti-inflammatory properties, which can be beneficial in reducing inflammation in conditions like arthritis (2). Additionally, onions have antibacterial properties that can help fight various bacterial infections, as noted in a study published in the Journal of Ethnopharmacology (3).

Despite these benefits, onions are a source of oxalates, a compound that can contribute to the formation of kidney stones. A medium onion (around 100g) can contain anywhere between 7 and 25 milligrams of oxalate (4). High oxalate intake may exacerbate the formation of certain types of kidney stones (5).

No significant, peer-reviewed clinical evidence supports the use of onion juice to treat or prevent kidney stones. While onion juice may offer various health benefits, the high oxalate content in onions could potentially increase the risk of stone formation rather than prevent it. Therefore, relying on evidence-based treatments and consulting with healthcare providers to manage kidney stones is important.

What do the experts say?

The Health Dialogues Fact Check Team spoke with Dr Anurag Gupta, Senior Consultant Nephrology, Sir Ganga Ram Hospital, and he said, “So far, there is no medical literature supporting this. If you search the literature, there has been a study conducted in animal studies (rats) where the stones were reduced. However, if you look at the oxalate content of onions, it remains high, so it is difficult to say that if you take this combination, the patient will not develop stones. There is currently no scientific evidence to support this claim.”

Responding to the claim, Dr Bhargava added, “While there are certain rumours about onion juice leading to expulsion of kidney stone, there is currently no scientific evidence in humans. It has been reported that onion possesses a diuretic effect. Administration of allium cepa (onion) prevented excessive kidney stone formation while enhancing kidney function in rats exposed to crystal formation. This effect was mediated through the extract's anti-inflammatory, antioxidant, and immunomodulatory properties. But, there are no studies and scientific data to support this in humans. Further, 80% of renal stones are made of calcium oxalate, and a single raw onion contains approximately 50mg of oxalate. So to summarise the above, raw onion juice should be avoided, and it is advised to get yourself checked at the hospital with your physician.”

Health Dialogues Final Take:

While onions have some health benefits, no scientific evidence or medical consensus supports the claim that drinking onion juice with sugar can dissolve and pass kidney stones.

Hence, this claim is FALSE.

References:

1. National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Kidney stones. U.S. Department of Health and Human Services. Retrieved June 19, 2024, from https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones

2. Rodrigues, Ana & Almeida, Domingos & Simal-Gandara, Jesus & Perez, Rosa. (2017). Onions: A Source of Flavonoids. 10.5772/intechopen.69896.

3. Yang, D., Wang, T., Long, M., & Li, P. (2020). Quercetin: Its Main Pharmacological Activity and Potential Application in Clinical Medicine. Oxidative medicine and cellular longevity, 2020, 8825387. https://doi.org/10.1155/2020/8825387

4. Nicastro, H. L., Ross, S. A., & Milner, J. A. (2015). Garlic and onions: their cancer prevention properties. Cancer prevention research (Philadelphia, Pa.), 8(3), 181–189. https://doi.org/10.1158/1940-6207.CAPR-14-0172

5. University of California San Diego. (2019). Oxalate Content of Foods. Retrieved from https://basicneeds.ucsd.edu/_files/NutritionToolKit-Edited-5-9-2019.pdf

6. Wahid, R. M., Hassan, N. H., Samy, W., Faragallah, E. M., El-Malkey, N. F., Talaat, A., Ghoneum, A., Aldisi, D., & Malek, M. M. (2023). The protective effect of allium cepa against ethylene glycol-induced kidney stones in rats. Heliyon, 9(11), e21221. https://doi.org/10.1016/j.heliyon.2023.e21221