A variety of factors play a role in the development of urinary kidney stones. To a high degree, individual eating habits and the intake of certain food components influence the development of pathological urinary values. These can be improved by a purposeful nourishing therapy.
A detailed nourishing anamnesis (nourishing minutes over several days) and a stone-specific nourishing therapy co-ordinated on it, can work against the emergence of urinary stones and prevent relapses. The most common types of stone are calcium oxalate and uric acid stones. They make up about 80% of all types of stones and their formation can be influenced by nutritional therapy.
A prerequisite for the formation of urinary calculus/kidney stones is the increased concentration of a certain substance (for example calcium and oxalate) and the insufficient dilution of urine. Increasing the fluid intake and thus also the urine volume is considered a priority measure to prevent the formation of stones. A too low drinking volume or heavy sweat loss due to intensive sports, sauna, sunbathing etc.
can cause a risky low and concentrated urine volume. Regular and excessive consumption of alcohol carries an increased risk of the formation of urinary stones. Initially alcohol has a diuretic effect, followed by a phase in which only little urine is produced and the risk of accumulation of certain substances increases.
In addition, alcohol consumption causes the body to produce more lactate, which is responsible for the increased excretion of acids via the kidneys and increases the urinary pH value. Due to these effects, alcohol (including beer) is not suitable for preventing the formation of urinary calculus. An increased intake of animal protein (meat, sausage, fish, eggs) increases the risk of developing urinary calculus kidney stones.
The reason for this is the low pH value of the urine that develops during this diet. Increased calcium and citrate in the urine is observed. Citrate favors the formation of calcium-containing stones.
An excessive consumption of easily digestible carbohydrates, such as sugar and white flour, leads to increased calcium excretion in the urine and can promote the formation of urinary stones. As a risk factor for the emergence of calcium oxalate stones, oxalic acid is more important than calcium. Already small changes of the Oxalsäurekonzentration can lead to stone formation.
The consumption of oxalsäurehaltigen food (for example rhubarb, spinach, beet) is to be limited therefore strongly. The supply of the mineral calcium (primarily from dairy products, mineral water) is also necessary for the stone patient at a level of 800 – 1000 mg daily. However, the supply should not exceed the need because otherwise the risk of stone formation increases.
By a sufficient ballast material supply the calcium excretion with the urine can be decreased. This dietary fiber intake should correspond to the usual recommendations for intake. An excessive intake, for example in the form of bran, is not indicated.
It can lead to an increased formation of oxalic acid and increased oxalic acid concentrations in the urine. After increased intake of sodium in the form of common salt, increased calcium excretion in the urine has been observed. This mineral increases the readiness to form calcium oxalate stones.
By the supply of ballast materials from vegetable and fruit the usability of magnesium can be obviously reduced. An excessive supply of magnesium is not indicated. An excessive intake of purine-rich foods leads to an increased excretion of uric acid.
This increases the risk of stone formation. The primary goal of preventing the formation of urinary calculus kidney stones is to ensure a sufficient amount of urine. This dilutes the urine and prevents critical concentrations of certain substances.
To achieve the desired urine volume of 2.5 l in 24 hours, the daily drinking quantity must be 2.5 to 3 l. Preference should be given to low-energy and urine-alkalizing (pH value increasing) drinks. Bicarbonate-rich mineral waters contain more than 1500mg bicarbonate and increase the pH value of the urine. In addition, diluted citrus juices are very suitable for the therapy of uric acid stones and calcium oxalic acid stones.
Neutral drinks are mineral water low in minerals (little calcium), tap water, fruit, herbal, kidney and bladder teas. Less suitable drinks are coffee, black tea and peppermint tea.They should only be drunk in small quantities. It should also be mentioned that milk cannot be included in the daily fluid balance.
Milk is not a drink but a foodstuff and counts as a dairy product in the daily diet. Alcoholic drinks and sugary lemonades and cola drinks are unsuitable. Basically, the guidelines for a balanced mixed diet of the German Society for Nutrition (Nutrition Pyramid) apply to the stone patient as they are also recommended for the healthy person.
Some points must be considered however by patients with uric acid – or calcium oxalate stones additionally:
- The protein intake should not exceed 0.8 g per kg body weight. The intake of animal protein from meat and sausages must be limited. A maximum of 150 g of meat or sausage products per day is permitted.
- The calcium intake should be 800 – 1000 mg per day.
About 500 mg comes from the rest of the diet and 500 mg should be taken in the form of milk and dairy products. 500 mg of calcium are for example contained in: 125 g yoghurt, 150 ml milk and 30 g brie cheese.
- Purine-rich foods should be avoided or restricted. These are mainly offal, sardines, herrings, mackerel, mussels, and the skin of fish and poultry.
- Common salt should be used very sparingly.
Avoid adding salt in the kitchen. Prepared dishes, smoked and cured products, snacks (chips and co.) contain high amounts of table salt and should be avoided as far as possible.
- Fiber-rich food such as whole grain products, vegetables and fruit should be eaten preferably.
- Foods rich in oxalic acid should be avoided and under no circumstances consumed in large quantities. These are these: Beet, rhubarb, spinach, chard, nuts, cocoa powder, peppermint leaves, black tea leaves and soluble coffee powder
- Drink 2, 5 to 3 liters per day.
Preferably bicarbonate-rich and low-calcium mineral waters and diluted citrus juices. Avoid alcoholic beverages.
- Keep protein intake rather low. 0.8 g protein per kg body weight is sufficient. Limit the intake of meat and sausage.
- Calcium intake should not exceed 800 to 1000 mg daily. 500 mg of this comes from milk and milk products and 500 mg from the rest of the diet
- Remove oxalic acid-rich foods from the menu.
- Do not salt when cooking and avoid extremely salty foods.
- Prefer foods rich in fiber.
