Kidney stones

If the urinary volume is low, and/or if the urine is more concentrated than is desirable, minerals and other substances in the urine may crystallise in the kidneys, and in time aggregate to form a stone.    

The vast majority of kidney stones are comprised of calcium oxalate or calcium phosphate. Uric acid, struvite and cystine stones are less common.  

Factors that contribute to the formation of kidney stones may include:

• Low fluid consumption, causing the urine to become more concentrated and increasing the likelihood of crystals forming   
• High levels of calcium, phosphate, oxalate or uric acid in the urine 
• Low levels of chemicals called stone inhibitors in the urine  
• Parathyroid gland overactivity 
• A personal or family history of kidney stones   
• Chronic or recurrent urinary infections   
• The use of certain medications 
• Obesity 
• Structural or metabolic abnormalities in the kidneys or elsewhere in the urinary tract

Consuming a diet that is low in fibre, or contains excessive quantities of refined carbohydrates, animal protein, alcohol, or fats may increase the risk of developing calcium-containing kidney stones. 

Other dietary factors may include consuming excessive amounts of oxalates, soft drinks (especially cola), alcohol (especially beer), caffeine, salt, or vitamin D. Low levels of magnesium (especially in relation to calcium), potassium or vitamin B6 may also be a factor. Either excessive and inadequate consumption of calcium may contribute to the formation of kidney stones.

Eating large quantities of fruit and vegetables appears to convey a degree of protection, as does being vegetarian.

Kidney stones require medical treatment. The following advice is intended as supportive therapy, and should only be followed on the instructions of your healthcare professional:

• The combination of too little magnesium and too much calcium in the body may be a risk factor for stone formation, and rectifying the balance by taking a magnesium supplement may help to reduce the recurrence of kidney stones. Ideally, magnesium should be taken as magnesium citrate, and combined with vitamin B6 (which reduces the body’s production and excretion of oxalates) and glutamic acid. 
• Natural therapists recommend drinking marshmallow and corn silk teas to relieve the pain of kidney stones.  

• Kidney stones require medical treatment, and in many cases can be resolved without surgery. Always consult your healthcare professional before changing your diet or lifestyle.
• Increase your consumption of water in order to keep your urine dilute and help prevent concentrations of the minerals and salts that form stones. You may need to drink up to three litres of water throughout the day and evening. Citrus or cranberry juice may also be beneficial.   
• Avoid sugar, soft drinks, alcohol (especially beer), caffeine, and salt.
• Some sufferers may benefit from becoming vegetarian. 
• Eat a diet high in fibre and complex carbohydrates that includes large quantities of fresh fruit and vegetables. However, avoid foods high in oxalic acid, which include beetroot and beet leaves, spinach and silver beet, celery, eggplant, green beans, green capsicum, figs, kiwifruit, rhubarb, wheat products (including whole grain varieties), oatmeal, chickpeas, lentils, soy products, nuts, seeds, beer, chocolate and tea. 
• Uric acid stone formers may benefit from avoiding foods high in purines, which contribute to the body's production of uric acid. These include: organ meats (e.g. liver, kidneys, brains, heart, pate, lambs fry), sardines and anchovies.

• Seek immediate medical attention if you are suffering from symptoms of kidney stones or infection.