Kidney stones are hard, crystalline mineral deposits formed within the kidney or urinary tract. Nephrolithiasis is the medical term for kidney stones.
Decrease in urine volume or increase in stone forming substances leads to formation of kidney stones. Most common kidney stones contain calcium with oxalate or phosphate. Certain urinary infections can also cause kidney stones.
The different types of kidney stones include:
- Calcium stones- These are made up of calcium oxalate, maleate or phosphate. Eating foods rich in oxalate increases your tendency to develop calcium stones.
- Uric Acid- This occurs when the urine is very acidic or individuals suffer from gout. Purines present in animal protein if taken in excess cause uric acid stones.
- Struvite- These stones are caused by urinary infection.
- Cystine: These stones are rare and caused in individuals with cystinuria.
Kidney stones cause severe pain and this pain is known as renal colic pain. The pain may be on one side of the back or abdomen. Other symptoms of kidney stone include:
- Blood in urine
- Foul smelling or discoloured urine
- Urgency to urinate or passing less urine
Kidney stones pass from the kidney to ureter and then bladder for excretion. However this can cause spasm and irritation leading to pain and bleeding. At times stones may block the passage of urine and lead to kidney damage and kidney infection.
Medications generally involve painkillers, diuretics and medications for treating different stones. In some cases surgery may also be required.
Lithotripsy is a method in which sound waves are used to break large stones such that they are small enough to pass out of the body.
What are the risk factors for developing kidney stones?
Anyone can develop kidney stones, however certain individuals are at a slightly higher risk of developing kidney stones.
- Urinary tract stones are more common in men than in women.
- A family history of developing kidney stones increases the risk for it.
- Certain pregnancy related changes can increase risk of developing kidney stones.
- Dehydration or low fluid intake can cause kidney stones.
- High dietary intake of animal protein, sodium, oxalate, refined sugars etc. may increase risk of kidney stones.
- Kidney stones are common in people with Crohn’s disease.
- Obesity is another risk factor for kidney stones.
- Metabolic conditions like distal renal tubular acidosis, Dent’s disease, primary hyperoxaluria increase tendency to develop kidney stones.
- Gout, a type of arthritis, increases tendency to develop kidney stones.
What is oxalate?
Oxalates are naturally occurring substances present in various foods. They are essential for certain metabolism related reactions. Apart from eating oxalate containing foods, we also make oxalates in our body.
20-40% of oxalates in our blood come from oxalate containing foods. Rhubarb has high concentration of oxalates- 450-600 mg for every 3.5 ounces.
Chocolate is also high in oxalates. Other foods rich in oxalates include spinach, almonds, beet greens, cashews ,peanuts etc.
The problem with oxalate arises when it overaccumulates in the body. Some individuals tend to absorb more oxalates via the intestine than others.
More oxalates absorbed mean more oxalates to be excreted. This in combination with high urinary calcium content in body increases risk of calcium oxalate kidney stones.
However this is not the case for everyone, some factors need to be considered regarding oxalate absorption:
- Only soluble oxalates get absorbed in the body.
- Our intestine contains healthy bacteria that break down oxalates.
- The combination of foods we eat determine the soluble oxalate content we consume.
The American Dietetic Association recommends that those who are prone to developing kidney stones should consume no more than 50mg of oxalate per day.
Some experts suggest that turmeric supplementation can cause kidney stones due to the oxalate content of turmeric. This is because turmeric contains high levels of oxalate and may increase urinary oxalate excretion.
However turmeric possesses certain properties that could even benefit in kidney stones. So what exactly is the role of turmeric in kidney stones?
What is the role of turmeric in kidney stones?
Turmeric powder is said to be high in oxalates which could increase risk of kidney stones. But standardized curcumin extracts are low in oxalates. Here is the real picture.
Supplemental doses of turmeric spice increases oxalate excretion in healthy individuals without causing any health risks
Cinnamon and turmeric have high amounts of oxalate. But cinnamon has high calcium levels so it provides insoluble calcium oxalate which is not absorbed by the body. This is not the case with turmeric.
Tang et. al in their study ‘Effect of cinnamon and turmeric on urinary oxalate excretion, plasma lipids, and plasma glucose in healthy subjects’ have demonstrated that turmeric at supplemental doses may increase risk of kidney stones.
11 healthy individuals enrolled in this study and for 4 weeks they were given either 3g of cinnamon or 2.8g of turmeric powder in form of capsules. They provided an oxalate load of 55mg oxalate per day which is more than the recommended limit of 50mg.
However cinnamon provided only 6% of soluble oxalate due to its high calcium content whereas turmeric provided 91% soluble oxalate. Oxalate levels excreted via urine were monitored.
Within 6 hours the % absorption of oxalate was 8.2% with turmeric and 2.6% with cinnamon. Hyperoxaluria is when urinary oxalate excretion is 40mg in 24 hours.
The 24 hour oxalate excretion for turmeric was 24.9mg which was below the cut off.
However the researchers suggested that the 6 hour oxalate absorption rate for turmeric was significantly higher than cinnamon and hence it could increase the risk of developing kidney stones in susceptible individuals.
Two concerns about this study is that: it uses turmeric spice powder (not extracts) and the amounts used are way higher than what we would include in diet daily.
So healthy individuals who have good oxalate metabolism and use dietary amounts of turmeric (1 tsp) daily would not experience any risk of kidney stone.
Kidney stone formers have high rate of synthesizing oxalate in the body and may absorb higher amount of dietary oxalate. Also kidney stone formers are likely to have higher oxalate intake than those used in the study.
Therefore an additional load of supplemental turmeric may increase 24 hour urinary oxalate excretion levels close to or above 40mg cut off.
What does this mean?
In the study that mentions turmeric at supplemental doses (2.8g) increases risk of developing kidney stones in susceptible individuals, the turmeric absorption at 6 hours was 8.2% but the 24 hour urinary excretion was less than 40mg cut off.
The turmeric tested was turmeric powder in capsules. Daily dietary turmeric consumption is much less than the amount studied and hence it would not have any adverse effect in healthy individuals.
However researchers state that the oxalate load of turmeric could add to the already high oxalate load of susceptible individuals and thus supplemental doses of turmeric spice could increase risk of kidney stone development.
Sabinsa Corp. rejects the idea that supplemental turmeric could increase risk of kidney stones
In response to the above mentioned paper, Sabinsa Corp. investigated the oxalate content of the standardized curcumin extract. Curcumin C3 complex is standardized extract of curcumin that is manufactured by Sabinsa Corporation.
Curcumin C3 complex contains 70-80% of curcumin, 15-20% of demethoxycurcumin and 2.5-6.5% of bisdemethoxycurcumin. It was patented by Sabinsa in 1996. It is prepared from dried rhizomes of turmeric by strict and standardized procedures of manufacturing and purification.
The oxalic acid content of three samples were analysed:
- Dry turmeric powder
- Water extract concentrate of turmeric powder
- Standardized Curcumin C3 complex
Dry turmeric powder contained 0.27% oxalate, dry aqueous extract of turmeric powder had 9% oxalate while Curcumin C3 complex had only 0.025% oxalate.
Curcumin C3 complex recommended dose is 500mg which is equivalent to the curcumin supplied by 30gm of turmeric powder. It provides only 0.025mg of oxalate.
Curcumin C3 complex has oxalate content 160 times lower than that of turmeric powder used in study ‘Effect of cinnamon and turmeric on urinary oxalate excretion, plasma lipids, and plasma glucose in healthy subjects’.
Curcumin C3 complex has oxalate content way lower than that found in group 4 low oxalic acid group (5 to 10mg). The oxalic acid content of Curcumin C3 complex is 88 times lower than the lowest level required to classify the food as high oxalate food.
What does this mean?
Sabinsa Corp. has conducted a study and proven that supplements that contain high purified standardized curcumin extract Curcumin C3 complex does not increase risk of kidney stones in susceptible individuals.
In fact it provides only 0.025mg of oxalate in 500mg dose and has oxalate content way lower than that found in group 4 low oxalic acid group foods.
Curcumin can benefit in prevention of kidney stones
Two of the most important pharmacological properties of curcumin that benefit in kidney stones are its anti-inflammatory and antioxidant properties. These properties make curcumin a kidney protective agent.
In an animal model of kidney stones the effect of plant antioxidants, rutin and curcumin was studied. Rutin and curcumin supplementation restored the elevated levels of calcium and oxalate in urine and kidneys to normal levels.
Additionally reduced tissue damage and reduced number of kidney stones was observed in curcumin and rutin treated animals.
Lithotripsy is a treatment used in removal of kidney stones where sound waves are used to breakdown large stones to smaller sizes such that they can be excreted.
However this treatment causes oxidative damage to kidney tissue. Research shows that curcumin can be used as a protective agent against kidney injury during lithotripsy.
What does this mean?
Curcumin can protect kidney from damage and injury due to kidney stones and can also reduce kidney stones deposits. It can also serve as a protective agent in lithotripsy. To use turmeric for kidney stones one can opt for standardized curcumin extract supplements.
Dosage of Turmeric For Kidney Stones
We generally recommend taking turmeric as The Golden Paste. It is a good blend of turmeric, black pepper and healthy fats which ensure better absorption of turmeric.
The dosage is 1-2 teaspoons once or twice a day which would be around 1-2 g of turmeric powder.
Turmeric as a spice has high oxalate content as much as 26-99 mg per serving. Hence turmeric spice should be avoided or limited (to less than 1 tsp daily) by those who are at a high risk of developing kidney stones.
This is not applicable to healthy individuals who have healthy oxalate metabolism. They can safely consume supplemental doses of turmeric spice as Golden Paste.
The oxalate content of turmeric powder may be of concern if you are prone to developing kidney stones. In this case, with doctor’s consult, it is advisable to take good quality turmeric supplements with standardized curcumin extract.
The recommended dose of turmeric supplements is 400-600mg 2-3 times a day. It is best to consult a doctor before taking turmeric supplements.
If you need help deciding good brand of turmeric please check this link.
Turmeric in diet is safe but if you are prone to kidney stones you have to watch the amount you consume. Turmeric in excess could cause gastric discomfort.
Turmeric supplements should be avoided in pregnancy and lactation. Turmeric may mildly increase bleeding risk, hence should be discontinued 2 weeks prior to surgery.
If suffering from gallstones problem avoid turmeric supplements.
Turmeric supplements could have drug interactions with blood thinning medications, diabetes medications, stomach acid reducing drugs and certain antidepressants.
Turmeric powder due to its high oxalate content could pose some risk to individuals susceptible to kidney stones if they already have a high dietary oxalate load.
In healthy individuals, the oxalate content of turmeric is not an issue. There has been one study shows that high doses of turmeric spice increases oxalate excretion in healthy individuals but this is below the cut-off level that would otherwise be considered as a risk factor for kidney stones.
Those who are at risk of developing kidney stones are asked to limit their dietary oxalate intake. In such a case it is advisable to limit daily turmeric intake to less than 1 tsp or avoid turmeric powder completely.
Turmeric supplements made from standardized curcumin extracts such as Curcumin C3 complex contain very low levels of oxalate.
This could be beneficial for high risk individuals. For example gout increase risk of developing kidney stones.
If someone would like to treat their gout with turmeric they would have to opt for turmeric supplements as the amount of turmeric powder they would require to consume would increase their oxalate load.
Turmeric, especially curcumin, holds benefits for kidney stones. Its best to consult a doctor and take turmeric supplements when advised.