Tuesday, April 12, 2011

Kidney stones? How to eat and drink if you have kidney stones

How to eat and drink if you have kidney stones
Kidney stones are considerably more common in times of prosperity, whereas in times of shortage (e.g. world wars) substantially fewer stone disorders are recorded.
Eating the right foods in the right amounts will help to prevent kidney stones. What are the foods to avoid witey stones? What can you eat if you have kidney stones? How to eat and drink with kidney stones? Is there a diet for Kidney Stones? These are some questions we will try to address here. 
In this article:

Causes of Kidney Stones

Kidney stones are considerably more common in times of prosperity, whereas in times of shortage (e.g. world wars) substantially fewer stone disorders are recorded. Men are more frequently affected than women. Most kidney stones are 95% crystalline, while the rest is organic material. The following distinctions are drawn between different kinds of stone based on their crystalline composition: 80-85% are calcium stones (usually calcium oxalate, less commonly a mixture of calcium oxalate/calcium phosphate or pure calcium phosphate), 5-10% are uric acid stones, 5-10% are "infection stones" (struvite and carbonate apatite), and 1% are rare varieties, e.g. cystine stones.
No kidney stone disorder can be explained by nutrition alone. However, diet does play a crucial role in calcium and uric acid stones, triggering the formation of stones in people with a predisposition. Major studies have shown that excessive consumption of meat protein leads to a marked increase in kidney stones. The main risk factors for calcium stones are a low volume of urine, increased excretion of oxalic acid and calcium (less critical), and a deficiency of citrate, which inhibits crystallization in the urine. Overly acidic urine is the main risk factor for the formation of uric acid stones.
Fluids - the most important element for kidney stone patients 
One should drink enough fluid to produce a urinary volume of at least 2 litres a day. On days of profuse sweating or major physical exercise (heavy work, sport) a daily fluid intake of 3 or more litres (over 12 glasses or cups) is recommended. It is important that the fluid intake is distributed as equally as possible over the course of 24 hours, i.e. one should also drink before going to bed (an over-concentrated nocturnal urine encourages crystallization and stone formation). Almost all beverages are suitable, but bicarbonate and calcium-rich mineral water as well as fruit juices are particularly beneficial. On the other hand, the formation of stones is promoted by large quantities of black tea or iced tea (high oxalate content), cola (very acidic) and beer ("liquid binges" lead to an increase in oxalic acid and uric acid excretion).

Vegetables, fruits and nuts 
Vegetables and fruits increase the urinary excretion of the stone-inhibiting citrate. The consumption of foods with a high oxalate content (spinach, rhubarb, beetroot, chard and nuts) should always be kept to a minimum or combined at the same time with foods providing a plentiful supply of calcium (e.g. spinach with a cheese gratin), which prevents the absorption of large quantities of oxalate from the intestine which would lead to an increase in it's excretion in the urine.

Meat, poultry, fish 
An excessive intake of protein from meat and fish increases the risk of stone, because the urine is over-acidified and the excretion of oxalate, calcium and uric acid increases, whereas the excretion of citrate - which provides protection against stone formation - is decreased. The intake of these foods must therefore be reduced in cases of calcium and uric acid stone.

Milk and dairy products 
Contrary to earlier views, a restriction of calcium is no longer recommended. Large-scale studies in tens of thousands of cases have clearly shown that, with an increase in calcium intake up to about 1,200 mg/day, the risk of stone formation significantly falls - and does not rise, as was once wrongly assumed. A total calcium intake of 1,200 mg/day, of which 800 mg should come from dairy products, is thus recommended.

The sodium contained in common salt can increase the risk of stone formation, probably by increasing the urinary excretion of calcium. On the other hand, a drastic reduction of salt leads to a decrease in urinary volume. A slightly reduced salt intake (to about 8 g per day) is therefore recommended.

Excessive consumption of foods rich in sugar increases the urinary excretion of calcium and thus possibly also the risk of kidney stone. Probably more important, however, is the fact that chocolate, pralines and products containing cocoa have high oxalate content.

Prevention of Kidney Stones - Dietary recommendations

Many factors affect our dietary behaviour: individual needs and desires, our day-to-day condition, the social environment, the food currently on offer, advertising etc. The following recommendations ensure a balanced and varied diet that provides an adequate intake of energy, nutrients and protective substances and thus a healthy approach to nutrition. The figures quoted are intended for the "average person", i.e. for adults who engage in normal physical activities and thus have an average energy and nutrient requirement. The figures would vary for other groups (such as children and adolescents, top athletes, pregnant women etc.). The quantities and portions given are likewise average values; they cannot be adhered to precisely every day. Those passages which appear in italics are particularly important for persons with a tendency towards kidney stones.

How to eat if you have kidney stones:

Fats and oils: 
Use 2 teaspoonfuls (10 g) of high-quality vegetable oil (e.g. sunflower oil, thistle oil, corn oil, olive oil, rapeseed oil) per day, unheated, e.g. for salad dressings. 
Use not more than 2 teaspoonfuls (10 g) of cooking fat or oil per day (e.g. peanut oil, olive oil) for the preparation of meals. 
Do not eat more than 2 teaspoonfuls (10 g) of spreading butter or margarine per day on bread. 
Do not eat more than one high-fat meal per day, such as deep-fried or breaded food, cheese dishes, fried potato, sausage, cream sauce, puff pastry, cakes, chocolate.

Eat sweets in moderation - exercise restraint especially with chocolate, pralines and chocolate cakes.

Meat, fish and eggs and pulses: 
Do not eat more than one portion (80 - 120 g) of meat a day 2 - 4 times a week; more is unnecessary, less is no problem. Do not substitute salted meat products, such as ham, sausage, or bacon, for meat more than once a week. Do not eat offal (liver, kidneys, tripe, sweetbreads) more than once a month (1 portion = 80 - 120 g). 
Plan to eat 1 - 2 portions of fish a week (1 portion = 100 - 120 g). 
Eat 1 - 3 eggs a week, including processed eggs e.g. in cakes and pastries, soufflees or creams. 
Pulses, pulse products: eat 1 - 2 portions of lentils, chickpeas, kidney beans (1 portion = 40 - 60 g, dry weight) and tofu (1 portion = 100 - 120 g) per week.

Milk and dairy products: 
Eat 3 - 4 portions of dairy products per day (1 portion = 2 dl milk or 1 cup of yogurt or 30 g hard cheese or 60 g soft cheese).

Cereal products and potatoes: 
Eat at least 3 portions of carbohydrate-rich foods per day, such as bread, potatoes, rice, cereal, or pasta, preferably wholemeal products. The size of the portion depends on the degree of physical activity the person engages in.

Eat 3 portions of fruit a day (1 portion = 1 apple, 1 banana, 3 plums or a dish of berries), ideally raw.

Eat 3 - 4 portions of vegetable per day, at least one of them raw, e.g. as a dip or a mixed salad (1 portion = 100 g raw or 150 - 200 g cooked vegetable). 
Exercise restraint, however, with spinach, chard and rhubarb (preferably eat these vegetables together with dairy products, e.g. spinach with cheese gratin).

How to drink if you have kidney stones:

Drink at least 3 litres of liquid per day, preferably unsweetened and alcohol-free beverages. Black tea or ice tea and cocoa beverages should only be drunk in small quantities.

Alkoholic drinks: 
Do not drink more than 2 glasses of wine or beer a day. Plan to have at least 1 day a week without alcohol! 

  • Drink at least 2 litres (8 glasses) of unsweetened beverages or water daily
  • Add less salt when preparing your meals, and eat salty food in moderation
  • Eat less meat (not more than 2-4 portions a week)
  • Exercise restraint with oxalate-rich foods
  • Preferably eat high-fibre foods 

If you are concerned about Kidney Stones, you might want to read these articles


How to eat and drink if you have kidney stones R. Griffith, Copyright: Swiss Association for Nutrition, Berne, 2000

No comments:

Post a Comment