Kidney Stones Diet

The best diet for kidney stones is a diet balanced in nutrients and minerals, affecting urine status. Essential nutrients in renal stone patients are proteins, calcium, sodium, and potassium. The amount of their kidney stone diet intake should be modified to prevent or help treat kidney stones patients before or after the surgery. Our dietitians organize the best diet and recommend the foods to eat or avoid that can help kidney stones patients.

Kidney stones

Kidney stones occur between 30-50 years old. It is more common between men than women.
There are 5 types of kidney stones:
♦ Calcium oxalate stones (the most common type of kidney stones)
♦ Calcium phosphate stones
♦ Uric acid stones
♦ Struvite (magnesium ammonium phosphate) stones
♦ Cysteine stones

It is a complex process that includes saturation, Supersaturation, Nuclearizing, crystals development, and accumulation. Increased incidence of obesity, diabetes, metabolic syndrome lead to increased incidence of kidney stones.
♦ Calcium stones are the most common kidney stones.
♦ 60 % of calcium kidney stones are oxalate
♦ 10% calcium oxalate and calcium phosphates
♦ 10% calcium phosphates
♦ 5-10% Uric acid stones
♦ 5-10% struvite kidney stones
♦ 1% of cystine kidney stones

The causes of kidney stones and their risk factors:

Some risk factors that can increase the risk of forming kidney stones include:
♦ Low urine volume
♦ Oxalate
♦ Uric acid
♦ Acidic urine
♦ Long term urine retention
♦ Calcium

General tips in kidney stones diet:

♦ Curing medical disorder
Nutrition counselling and diet therapy (kidney stone diet)
♦ High fluid intake
♦ Drink a glass of liquids during each meal and between them, bedtime, and in the middle of the night
♦ At least half of the liquids should be water
♦ Need to drink more fluids if you have diarrhea or excessive sweating
♦ Avoid grapefruit juice
♦ Avoid consuming beverages containing phosphoric acid
♦ Drink diluted tea with milk
♦ Reduction in consuming animal sources of protein



Obese people who have kidney stones secrete Larger amounts of sodium, calcium, citrate, uric acid, and their urine has a lower pH.

When the body weight increases, the secretion of calcium, oxalate, and uric acid will rise.
Men with higher BMI secrete less ammonium, and along with BMI increase, the creation possibility of uric acid overcomes the oxalic acid.

Uric acid kidney stones are strongly related to total body fat tests and upper-fat mass to total body weight ratio and total lean body mass. Uric acid kidney stones are common in type 2 diabetes. High levels of insulin in patients promotes the development of calcium stones. Weight management to control the BMI in the 18-25 range is recommended. In some malabsorption conditions such as the Gastric bypass surgery (RYGB) method, urinary stones' formation is more common in these patients because the increase in urinary excretion of oxalate and decrease in citrate happens.

10 Tips to Prevent Kidney Stones

Calcium kidney stones

33-50% of patients have calcium stones that occur due to the excessive calcium secretion in the urine (Hypercalciuric kidney stones).
The causes of this kind of kidney stones include:
♦ Primary hyperparathyroidism
♦ Sarcoidosis
♦ High intake of vitamin D
♦ Hyperthyroidism
♦ Using glucocorticoids

The increase in calcium absorption in intestinal tracts has been seen in all of the calcium kidney stones patients even despite following the restricted calcium, sodium, and animal source proteins diet. Bone loss is common in patients due to the bone calcium enters in the urine.
The phosphorus status is in a negative balance, and therefore, the vitamin D absorption will increase.


Food for calcium kidney stone

The restricted calcium diet is not useful for patients with calcium kidney stones because they may suffer from decreased bone density.
High protein intake from non-dairy sources can lead to the separation of minerals from bones.
Reduction in animal protein non-dairy sources intake is recommended.
Taking calcium supplements with meals can increase the urinary excretion of calcium, citrate and lower kidney stones' risk. Calcium carbonate is a good choice for supplementation. There is a risk of cardiovascular disease and kidney stones after taking calcium supplements. Therefore, the Calcium supplementation should be proper and based on DRI(Dietary reference intake).
The diet affects the acidity of urine. Using excessive dietary protein, phosphorus, chloride, and organic acids are major sources of an acidic diet. The kidney stones diet should be prepared to contain both acidic and foods producing alkali to set a balance and prevent the formation of stones. For example, meats and cheeses should be consumed with fruits and vegetables. This kidney stone diet can lower the risk of kidney stones, hypertension, insulin resistance, low immune system function, and osteoporosis.

Oxalate kidney stones

Excessive exertion of oxalate in urine has an important role in the formation of kidney stones. Genetic defects in liver enzymes lead to excessive production of oxalate and an increase in urinary oxalate concentration. Concentration and accumulation of oxalate in urine bring out oxalate kidney stones. The oxalate status of urine is defined by diet and food intakes, the gastrointestinal system's proper function, destructive oxalate bacteria, and genetic disorders.
In IBD and after Bypass surgery, oxalate kidney stones' formation will result because of fat malabsorption and increased absorption of food oxalate. The amount of oxalate in the body depends on the lean body mass. In kidney failure patients, a high intake of vitamin c leads to kidney stones.
The formation of oxalate doesn't grow by a high protein diet because vitamin B6 transforms oxalate to glycine.
The cooking methods, composition of meals, food processes, and some bacteria can affect the body's oxalate content.


Food to eat and food to avoid in oxalate kidney stone

♦ Use more probiotic bacteria in your kidney stone diet
♦ Lessen the dietary oxalate intake
♦ Using high calcium foods and supplements in kidney stones diet
♦ Avoiding short term and severe weight loss diets
♦ Avoiding plant-based diets with high oxalate


High oxalate foods

Rhubarb, spinach, strawberry, chocolate, wheat bran, products based on whole wheat, nuts, peanuts, walnuts, beet, green/black/ice/instant tea, high dosage of curcumin

Uric acid kidney stone

Half of the purine, which is the substance that turns into uric acid, is originated from foods, and it has an important role in defining the amount of uric acid in urine.
The volume of urine, amount of excreted uric acid and pH affects the status of urine. The possibility of formation of uric acid kidney stones is higher in pH under 5.5.
In IBD, due to diarrhea and dehydration, there is a risk formation of uric acid kidney stones.
Diabetes, obesity, and hypertension are related to kidney stones. Diabetes and insulin resistance are important factors in the incidence of uric acid kidney stones.
Controlling diabetes, Purine restriction in kidney stones diet, reducing and avoiding animal protein sources such as red meat, chicken, fish, haggis, sardine, and broth.
Uric acid kidney stones patients should use less acidic foods.

Cysteine kidney stones

The first approach for this type of patient is lowering the exertion of cysteine in the urine. The urine pH should be in the alkaline range. Drinking more than 4 litres of fluids in the day is recommended to prevent the crystallization of cysteine. Reducing sodium intake can lower the amount of cysteine in the urine.
Methionine is an amino acid that can turn into cysteine in the body. Patients with cysteine kidney stones should avoid foods high in methionine in their kidney stone diet, such as animal protein sources like milk, meat, and egg. Consuming vegetables and fruits like lemon, orange, fresh tomato juice, and melon can help the balance of urine acidity.

Struvite kidney stones

These stones are well known as infectious stones. And they will be formed in the presence of particular bacteria such as Klebsiella, Pseudomonas, Proteus mirabilis, and Urealyticum. The prevalence in women is twice as high as in men. The urine should not be alkaline; therefore, the kidney stone diet has to become modified. The Calcium, Oxalate, animal protein, salt, purines, plant-based products, and fluid intakes should be assessed.
The urine volume should increase 2-2.5 litres per day, so the fluid intake should be all day long between meals, before bed, and beside meals. Warm weather conditions, excessive sweating, and severe exercises are the reasons to increase the fluid intake to 3 litres per day. Therefore, it is possible to prevent the formation of struvite stones.
Drinking tea is recommended to be beside milk to reduce the absorption of high oxalate in tea. Herbal tea has less oxalate rather than tea.
Cranberry juice makes the urine acidic, and it can help treat urinary tract infections and struvite stones.
Blackberry juice increases the urine citrate and oxalate and prevents the formation of uric acid stones by alkalizing urine.
Decaffeinated coffee, orange juice, tea, coffee, wine, and beer are correlated with lowering kidney stones' risk formation.
Non-cola drinks and sugar-sweetened drinks increase the risk of kidney stones formation to 33%, and cola has a 23% increase in kidney stones' formation risk.

Kidney stones diet chart

Potentially acidic foods:

Meat, shellfish, egg, all kind of cheeses, peanut and peanut butter, walnut, sesame, sunflower seeds, salad souses, mac, white sugar, all bread with brans


Potentially based foods:

Vegetables, legumes, beet, cabbage, spinach, turnip, fruits, date, figs, raisins, banana, dried apricot, apple, all of the condiments and spices, basil, mint, parsley, coffee, sweets, corn syrup, brown sugar, cocoa


Neutral foods:

Butter, margarine, milk, corn, honey, water, tea


Animal source protein:

Excessive consumption of animal protein can increase the calcium, oxalate, uric acid in the urine. It can also decrease the citrate and urine pH, which can increase the risk of formation of kidney stones.
Balanced protein intake in patients with oxalate calcium stones and uric acid stones with a high uric acid level is recommended about 0.8-1.
Long-term usage of whey and albumin protein supplements for bulking muscles and improved sports function can increase urine calcium, urine sodium, and urine albumin and lower urine pH.


Calcium and Oxalate

Oxalate absorption depends on calcium content. The absorption percentage of oxalate is about 3-8% that is relied on dietary calcium. Every 5mg increase in urine oxalate is correlated to a 70-100% increase in kidney stones formation. Patients regularly consume 150mg calcium (which is available in half of a cup of milk, ice-cream, and 3/4oz cheese).
Calcium in kidney stones diet can decrease the absorption of oxalate. It seems that calcium has a huge influence on urine oxalate rather than dietary oxalate.
The development of kidney stones does not seem to be a permanent and constant process because it depends on the high concentration of oxalate in meals. Unusual usage of high oxalate foods and low calcium like spinach can fasten the development of kidney stones.
DASH diet is high in oxalate foods, so the modified DASH diet with less oxalate content is more effective.
Probiotics, especially Lactobacillus acidophilus, can prevent the intestinal absorption of oxalate and decrease the amount of oxalate in urine.


Potassium

Potassium intake has an inversion effect in the formation of kidney stones. A diet high in low oxalate fruits and vegetables for people who have kidney stone maker is effective. It is recommended to increase the potassium in their diet. The high potassium diet prevents kidney stones and stimulates the excretion of urine citrate.


Magnesium

Magnesium can make some soluble complex compounds with oxalate and diminish the formation of kidney stones. Magnesium, much like calcium, reduces the absorption of oxalate from the intestine and helps hyperoxaluric patients.


Phosphate

High urine phosphate increases the formation risk of phosphate calcium. Phosphate calcium stones occur in a pregnant woman in their second and third trimesters of pregnancy.


Sodium

Sodium affects the excretion of urine calcium that is one of the causes of kidney stones and hypertension. The risk of kidney stones is higher in people with high blood pressure than those with normal blood pressure. Therefore, sodium intake should be under 2300 mg per day. The DASH diet can decrease the risk of kidney stones. A low sodium diet with water therapy can reduce sodium, calcium, and urine oxalate.


Citrate

Citrate is an inhibitory factor in kidney stone formation that can bind to calcium and create complex and lower the possibility of oxalate calcium and phosphate calcium stones.
Using long-term lemonade, lemon, and lemon juice can increase urine citrate level and decrease the amount of kidney stone formation.
Mineral water includes magnesium and bicarbonate that can increase the urine pH and prevents kidney stone formation.
Melon juice has a high level of citrate and malate, and it is better than orange juice.
Tomato juice has got citrate and malate, but it also includes sodium and oxalate. It should be restricted and be consumed in balance.


Fructose

The increase in corn syrup consumption during the last 30 years had some effects on people's dietary approach. Fructose may increase the calcium and oxalate excretion in urine, and fructose is the only carbohydrate that can produce uric acid. Fructose can cause insulin resistance and lessen the urine pH. Eventually, it is associated with most types of kidney stones. An increase in fruits and vegetable intake is considered due to a high intake of potassium, but the amount of fructose in fruits may have some harmful effects. There is more emphasis on the recommendation to eat more vegetables than fruits.


Supplementation in kidney stones diet

Vitamin C supplementation (1000 mg/day) is associated with a double increase in men's kidney stones formation, increasing urine oxalate. These men induce calcium oxalate stones. They have to avoid getting vitamin c supplements and focus on dietary vitamin C intake.
Vitamin B6 should be in moderation because it can reduce the amount of oxalate in urine.
People with kidney stones have a high Vitamin D status. Still, there is no correlation between supplementation and the risk of kidney stones.

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