It is safe to take turmeric in diet even if one has kidney stones. However, high doses of turmeric in the form of supplements should be avoided by individuals who have stones or who are at risk of developing kidney stones.
This is because turmeric contains oxalates and some minerals which could further deteriorate kidney function in susceptible individuals.
Instead, curcumin supplements could be taken.
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Is it safe to take Turmeric when I have Kidney Stones?
Let us know what scientists have to say about this.
Does Turmeric cause Kidney Stone Formation?
Normally, it does not.
In fact, studies have shown that curcumin, the phenolic component of turmeric, can prevent the formation of both calcium oxalate and struvite stones in kidneys.
It lowers the concentrations of stone-forming components in urine.   
However, in individuals having family history or risk of stone formation, high doses of turmeric could contribute to the formation of calcium oxalate stones.
How can Turmeric Contribute to Stone Formation?
Turmeric usually contains 2-3% oxalates.
Out of this, 91% is soluble oxalates which get absorbed by the body readily. 
High amounts of oxalates can bind with metals like calcium and cause the formation of calcium oxalate stones. These are the most common types of kidney stones, and it has been found that almost 80% of kidney stones are composed of calcium oxalate. 
In a study published in the American Journal of Clinical Nutrition, turmeric was found to increase urinary oxalate secretion, thereby enhancing the risk of stone formation, particularly in high-risk individuals. 
While some researchers state that dietary oxalate consumption does not directly influence the stone formation, it is also a fact that susceptible individuals tend to absorb and synthesize more oxalates.   
So, if one has kidney stones, it might be a good idea to limit turmeric intake to dietary levels, to control more oxalate absorption by the body.
How else could Turmeric Affect Individuals with Kidney Stones?
Apart from oxalates, some minerals found in turmeric might also be a concern for individuals with kidney stones. This includes sodium, potassium and phosphorous.
People having kidney stones are advised to control the intake of these minerals.
This is because, in persons with kidney stones, high levels of sodium cause hypertension, of potassium, leads to abnormal heart rhythms, and that of phosphorous could decrease calcium levels and deteriorate bone health.  
Turmeric contains about 0.038% sodium, 2.5% potassium and 0.27% potassium. 
If one is taking supplemental doses of turmeric, it could increase the plasma concentrations of these minerals and affect kidney health adversely, another reason to lower turmeric intake.
Should Turmeric be Avoided Altogether?
No, turmeric can still be included in the diet in various foods. In diet, turmeric is usually present in low amounts, which provides very low concentrations of oxalates and minerals.
This is unlikely to have any significant effects on kidney health.
However, if you have kidney stones, avoid high or supplemental doses of turmeric.
Then how to benefit from turmeric?
Most of the health benefits of turmeric are attributed to the presence of curcumin.
If one wishes to avail these benefits to maintain good health, prevent diseases or treat other health problems, curcumin supplements can be taken, which contain mostly curcumin and negligible amounts of oxalates.
A study conducted by Sabinsa Corporation to examine the composition of its curcumin supplement Curcumin C3 revealed that the supplement contained just 0.025% oxalates as compared 9% oxalates in turmeric powder.
Also, this supplement did not raise urinary oxalate concentration or increase the risk of stone formation, even in susceptible individuals. 
Thus, it opting for curcumin supplements instead of turmeric supplements might be better if one has kidney stones.
There are several types of turmeric / curcumin supplements available in the market today. Some are just simple curcumin while others are patented formulations.
Check our detailed article on the types of supplements and how to find the best one for your purpose>