**13. Effect of fruits and vegetable on urolithiasis**

The role of fruits and vegetables in kidney stone formation is always been a controversial as these have shown both beneficial effects as well as harmful effects in case of Kidney stone disease. As fruits and vegetables are one of the important dietary sources of oxalate and this absorbed oxalate will be excreted in urine. If urine gets saturated with oxalate content it may become a risk factor for urolithiasis but however this oxalate is not withstanding [80]. Whereas there are some studies which have shown beneficiary effects of fruits and vegetables on urolithiasis as they contain high amount of magnesium and potassium and less amount of animal protein and sodium chloride. In addition, some fruits and vegetables also give alkaline therapy to the urine composition with their high content of bicarbonate and citric acid [81]. So it's important to note that not all the vegetables and fruits are harmful for urolithiasis as very few will be rich in oxalate such as spinach, beets, nuts wheat bran etc. which significantly results in oxaluria [82]. Along with effect of dietary oxalate content, the absorption rate of oxalate may vary person to person, as a study conducted by 80 showed that around 9–12% of idiopathic urolithiasis patients have shown increased oxaluria because of their increased intestinal absorption rate by 15–30% [83]. Another study conducted by Lemann et al. [84] reported that intake of fruits and vegetables can enhance magnesium excretion which is one of the important inhibitors for calcium crystallisation. And also favours the dissolution of uric acid by changing pH of urine [84]. By considering all above-mentioned factors, we suggest physicians to recommend intake of fruits and vegetable in their day today life to all the type of stone formers with a note of restricting foods having increase oxaluric activity to avoid calcium oxalate stone formation. Elimination of fruit and vegetables from diet of normal subjects causes unfavourable changes in urinary composition and may become risk factor for stone formation as their deficiency may significantly increase in super saturation of urine for calcium oxalate and calcium phosphate [85]. Considering above mentioned facts, we encourage physicians to advise their patients to consume fruits and vegetables regularly with restriction of vegetables showing hyperoxaluric effect to avoid increment in urinary oxalate content.
