Lemon juice prevents recurrent kidney stones

Previous studies had shown that standard diet with normal calcium and reduced animal proteins and salt content reduces kidney stone recurrence in calcium oxalate nephrolithiasis. But recent studies have demonstrated how lemon juice supplementation further reduces recurrence rate. Calcium oxalate stones are the most common type of kidney stone.

The study published in the journal EClinicalMedicine is titled “Fresh lemon juice supplementation for the prevention of recurrent stones in calcium oxalate nephrolithiasis: A pragmatic, prospective, randomised, open, blinded endpoint (PROBE) trial.”

In this single-centre, prospective, randomised, open, blinded endpoint trial (Clinical Trials gov NCT01217372) the researchers evaluated the effects of fresh lemon juice supplementation (60 mL twice daily) versus no supplementation, on time to stone recurrence in 203 patients with recurrent idiopathic calcium oxalate nephrolithiasis who were all prescribed a standard diet. Patients were included between July 2009 and March 2017 at the Nephrology Unit of the Papa Giovanni XXIII hospital in Bergamo, Italy. Time to stone recurrence at two years of follow-up was the primary outcome. Analyses were by intention-to-treat.

During two years of follow-up 21 of 100 patients randomised to lemon juice supplementation and 32 of 103 controls randomised to no supplementation had stone recurrence. Patient adherence to lemon juice supplementation, however, progressively decreased from 68 per cent at one-year to 48 per cent at two-year follow-up. At explorative analyses restricted at one-year follow-up, 10 patients with supplementation versus 22 controls had stone recurrence. After adjustment by age, sex and normo or hypocitraturia, the HR (95 per cent) was still significant. At six months, 24 hour urinary sodium excretion decreased in patients receiving lemon juice supplementation and increased in controls. Changes significantly differed between groups. This difference was subsequently lost. Treatment was safe. In patients with lemon juice supplementation gastrointestinal disorders were more frequent. Renal and urinary tract disorders were similar between groups.

Explorative analyses suggest that fresh lemon juice supplementation to standard diet might prevent stone recurrence in patients with calcium-oxalate nephrolithiasis. However, treatment effect was likely reduced by progressively declining adherence to lemon juice supplementation.

In conclusion, in patients with calcium oxalate nephrolithiasis, fresh lemon juice supplemented to a standard diet with normal calcium content but reduced amounts of sodium and animal proteins appeared to exert some protective effect against stone recurrence as compared to the same standard diet but without lemon juice supplementation. Treatment effect, however, was largely mitigated by progressively decline patient adherence during the study period and emerged only at explorative, post-hoc analyses restricted to the first year of follow-up. “Thus, our findings are not robust enough to recommend oral juice supplementation in everyday clinical practice, but provide novel useful information to inspire more effective strategies to improve patient adherence in future trials aimed to further test the hypothesis that oral juice supplementation might decrease the risk of stone recurrence in patients with calcium oxalate nephrolithiasis,” the researchers wrote.

Calcium oxalate nephrolithiasis is the most common form of nephrolithiasis. It may affect two to 15 per cent of the general population, with an incidence rate ranging from 114 to 720 new cases reported every year per 100,000 individuals. Without specific pharmacological therapy, 27 to 50 per cent of patients may have stone recurrence over five years. Of note, in 15 per cent of cases recurrence of stones is associated with clinical symptoms and many symptomatic patients require surgical intervention yearly.

Kidney stone formation requires crystals to form, grow, aggregate and interact with a non-crystalline organic matrix. The pathogenesis is multifactorial and includes an increased excretion of urinary lithogenic solutes including calcium, oxalate, phosphate, uric acid, and sodium, along with a reduced urinary excretion of inhibitors of crystallisation such as citrate and magnesium. Moreover, a reduction or an increase in urinary pH may favour the precipitation of uric acid or calcium phosphate salts, respectively.

In addition to genetic and metabolic factors, also environmental factors including diet play an important role in the development of nephrolithiasis. Diet based on restricted intake of animal proteins and salt, combined with a normal calcium intake, may reduce the risk of stone formation. However, the efficacy in preventing stone recurrences is limited, in particular in chronic stone formers. Potassium citrate is effective in preventing stone recurrence in patients with calcium oxalate nephrolithiasis, but approximately one third of treated patients stop the medication because of gastrointestinal disorders such as eructation, bloating or gaseousness, and diarrhoea.

Citrus fruits are a natural rich source of citrate and diet supplementation with fresh juice of citrus fruits may represent a valuable alternative option to citrate supply. Amongst the most commonly consumed citrus fruits, lemons contain the greatest concentrations of citric acid. Indeed, citric acid concentration in lemon juice (49·2 g/Kg) exceeds by approximately five-folds the concentration in orange juice. The citrate supplied with the juice that escapes metabolic degradation in vivo is excreted unchanged in the urine where it may prevent the tendency of calcium oxalate salts to precipitate. Moreover, urinary oxalate excretion is not affected by lemon juice, but is increased by orange juice supplementation. This difference probably reflects the greater ascorbic acid concentration in orange compared to lemon juice.

Thus, fresh lemon juice has been suggested as a possible alternative to potassium citrate for the treatment of patients with calcium oxalate nephrolithiasis, in particular those with hypocitraturia.

Hypocitraturia, generally defined as urinary citrate excretion less than 320 mg (1.67 mmol) per day for adults, is a common metabolic abnormality in stone formers, occurring in 20 per cent to 60 per cent. Citrate is a known inhibitor of stone formation, working through a variety of mechanisms.

Results of the present study show that a standard recommended diet with normal calcium content but reduced amounts of salt and animal proteins integrated with 60 mL twice daily of fresh lemon juice and a standard diet without lemon juice supplementation are similarly effective in reducing the risk of recurrent stones in patients with calcium oxalate nephrolithiasis.

Lemon juice supplementation was safe, but was not well tolerated. Indeed, it was associated with an excess incidence of gastrointestinal disturbances, in particular gastric pyrosis. Conceivably, in addition to treatment costs, also gastrointestinal disturbances contributed to the progressively decreasing patient adherence to lemon juice supplementation observed during the study period. Notably, poor adherence could be a major limitation to the use of lemon juice as a protective intervention against stone recurrence also in everyday clinical practice.

MEANWHILE, there have been claims and counter claims on the use of lemon (Citrus limon) to effectively treat degenerative diseases such as cancer and Human Immuno-deficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS).
Other natural remedies for kidney stones

According to a report published by Medical News Today, besides lemon juice supplementation, other reported natural remedies include: apple cider vinegar, manage weight, avoid caffeine, calcium, wheatgrass juice, dandelion root juice, and celery root juice.

Before trying any home remedies for kidney stones, it is essential to consult with a doctor, especially when someone has an underlying medical condition or takes medications regularly.

Although many of these remedies may help relieve the symptoms or reduce the risk of future recurrences, kidney stones can cause intense pain. Therefore, it might be best to use home remedies alongside more traditional treatments.

Some people may even need surgery to extract or break up the stones and intravenous pain medication. Drinking water is one of the easiest ways to treat and prevent kidney stones, as dehydration is one of the leading causes. Most health authorities recommend drinking six–eight glasses of water per day to prevent dehydration.

Lemons contain citrate, which helps break down calcium deposits and slow the growth of kidney stones. A 2019 cross-sectional study found that sugar-free lemon juice was an effective remedy for kidney stones. In addition, lemon juice contains citrate, which reduces the amount of calcium in the urine leading to a lower risk of kidney stones.

It is essential to read labels carefully when purchasing juice products. For example, many lemon juice products contain small amounts of pure lemon extract and high amounts of sweeteners, increasing the risk of kidney stones.

Buying pure extract or purchasing fresh lemons and squeezing them at home are the easiest ways to get undiluted lemon juice. Good alternatives include watermelon and orange juice, which contain high levels of citric acid.

Apple cider vinegar also has citric acid content that may help dissolve calcium deposits. A 2019 study of over 9,000 people found that those who consumed dietary vinegar had a significantly lower risk of kidney stones.

However, more research will be necessary to confirm the benefits of consuming apple cider vinegar as a natural remedy for kidney stones. A 2019 study showed that out of 146 people with recurring kidney stones, 43.8 per cent had obesity or overweight.

Although this does not suggest causality, the research indicates there may be a link between weight and kidney stones. In addition, the study authors believe that metabolic conditions such as high cholesterol and high blood pressure may contribute to kidney stone formation.

Managing body weight and adopting a nutritious balanced diet are essential steps for preventing and treating kidney stones. Carbonated, caffeinated, and alcoholic drinks can increase a person’s risk of developing kidney stones.

Research from 2020 suggests that drinking caffeine can increase the risk of stones. In addition, drinks and sodas that contain natural or artificial sugars can also lead to kidney stones.

Also, foods high in sugar, salt, and fat increase the risk of kidney deposits and intensify the symptoms. According to the National Kidney Foundation, for people with calcium oxalate stones, which are the most common kind, eating foods that contain calcium can help them meet their daily calcium requirement and manage their risk of kidney stones.

The National Institutes of Health noted that taking calcium supplements could increase the risk of kidney stones, as they may provide more than the recommended daily intake. Obtaining calcium from food sources, however, can help reduce the risk.

People can get calcium from: dairy products, kale, broccoli, grains, Chinese cabbage (bok choy), fish with soft edible bones, calcium-enriched cereals and juices.

Wheatgrass is the younger grass of wheat used in juices or powders for humans and animals to eat. It contains nutrients and antioxidants that benefit health.

According to a 2017 study, wheatgrass extract inhibited crystal growth by 88 per cent during the initial formation. Their research results indicate that drinking wheatgrass juice can help prevent kidney stones.

The root of the dandelion plant assists the kidneys in increasing urine output, eliminating waste, and helping digestion. In addition, the herb consists of vitamins and minerals that may benefit the body.

A 2018 study showed that dandelion effectively prevents kidney stone formation. If a person is allergic to specific plants, they may also be allergic to dandelions and should proceed with caution before using them.

Celery is a vegetable that contains potassium and antioxidants that work to prevent the buildup of minerals in the kidney, lowering the risk for stone development. Furthermore, it holds a high water content to assist with waste and toxin removal via the kidneys.

To process into a juice, take three to four washed celery stalks and cut them into pieces. Next, put the pieces in the blender with some water and consume immediately after blended.

Risk factors
According to a 2016 review, 10 per cent of the United States population received a diagnosis of kidney stones in 2016. Additionally, males are more likely to develop kidney stones than females.

Some estimates suggest that African American and Hispanic American people are less likely to report kidney stones. A 2021 review of the health disparities associated with kidney stone disease found underreporting of kidney stones was due to disparities in diagnostic imaging and socioeconomic status.

Some medical conditions, including kidney disease and Crohn’s disease, can cause kidney stones or increase the likelihood of developing them. Particular medications can also increase the risk of kidney stone formation, including: diuretics, Human Immuno-deficiency Virus (HIV) treatments, anti-seizure medications, and calcium-based antacids.

Obesity and diet are also primary risk factors for kidney stones. Around 11.2 per cent of people with obesity develop kidney stones. Diets high in dehydrating foods and compounds, such as sugar, salt, and alcohol, may also contribute to the development of kidney stones.

Specific foods, though otherwise nutritious, are also naturally rich in oxalate. According to the National Kidney Foundation, people with a high risk of developing kidney stones may therefore wish to avoid the following foods: nuts, buckwheat flour, rhubarb, okra, beets, sesame seeds, chocolate soy milk, miso, Swiss chard, and tahini.

A person should seek immediate medical attention if they experience severe pain in the lower abdomen or genitals. It is possible to treat kidney stones using fluid therapy and pain medications.

However, stones can get stuck in the urinary tract or damage the urinary tissues. This obstruction usually requires immediate surgery or another medical procedure to break up the stone.

A doctor should assess the following symptoms: persistent lower abdominal or lower back pain lasting longer than four weeks, fever or chills, vomiting, nausea, bloody urine, loss of consciousness, painful urination, cloudy or foul-smelling urine.
People can use some home remedies for smaller kidney stones. However, it may be necessary to seek more conventional treatments and use these home remedies as supporting therapies for larger kidney stones.

The Medical News Today report noted: “Kidney stones are hard deposits that form in the kidneys and exit the body through the urinary tract. Home remedies are unlikely to cause a stone to pass more quickly or less painfully, but they can help prevent stones from developing.

“Most kidney stones are treatable with pain medications, fluid therapy, or other medical intervention. There are also steps people can take to reduce their risk of developing kidney stones.

“Not all of these remedies require a prescription or even medication. However, if kidney stones become too painful, it is best to seek medical attention.”