Overview
How to prevent kidney stones gains tremendous importance for those who are at risk or have developed one — for the simple reason that the pain of a kidney stone is probably the worst type you can ever experience.
Faced with a stone in your urinary tract, you adopt measures to pass it out through the urine as quickly as possible. But again, the pain of passing a kidney stone out through urine can also be extremely painful.
Unfortunately, both these pains may not be a one-time event. It is an established fact through studies that people who develop stones often have a recurrence. Those who have developed stone once are at a 50% risk of developing another stone within the next 5 to 7 years.
However, you can prevent kidney stones from developing again. The natural preventive measures involve avoiding foods that encourage stone formation, following certain lifestyle changes, and avoiding long-term use of certain medicines.
There is no surety in this especially if you have a family history. Nevertheless, certain measures you adopt can drastically reduce your risk. It isn’t difficult; all you need is some determination.
Kidney stones form when certain minerals that are filtered from the blood get concentrated in the kidneys. This happens when there is less fluid in the kidneys to dilute these minerals. The crystals of these minerals thus formed, grow larger by clumping together and forming stones.
Types of kidney stones
There are different types of kidney stones and they are classified according to their composition. Calcium oxalate stones are the most common.
Type of kidney stones in order of prevalence:
- Calcium oxalate stones – 64.2%
- Calcium phosphate stones – 18.8%
- Calcium oxalate and phosphate mixed stones – 6.2%
- Struvite stones – 4.2%
- Uric acid stones – 3.8%
- Others – 2.8%
As can be seen, calcium stones account for 89.2% of all types of stones. These details help to formulate a plan that, if implemented, can go a long way to help you prevent kidney stones from forming and recurring.
The stone prevention plan, besides advising you to stay properly hydrated, focuses on what foods you should eat and what you should avoid to prevent these minerals from getting concentrated in the urine.
Having a history of kidney stones increases the risk of developing another one. This also increases the risk of developing chronic kidney disease and kidney failure.
The prevention plan aims to prevent the formation of kidney stones. If you have had a stone and have undergone treatment, this plan aims at preventing a recurrence.
Tips to prevent kidney stones from forming
Having established the importance of preventing kidney stones, here are five ways you can do it. As mentioned above, this is easy-to-follow advice; all you need is determination.
1. Stay well hydrated
Drinking an adequate amount of water every day keeps your urine well diluted to dissolve the minerals filtered by the kidneys. Maintaining enough fluidity can also include drinking citrus drinks like lemonade and orange juice. These beverages contain citrate, which inhibits stone formation.
To prevent the formation of kidney stones, you should aim at maintaining a fluid intake of 3 to 4 liters. Drinks like tea, coffee, and fruit juice can be considered to be part of fluid intake, but water is the healthiest option and works best for preventing kidney stones.
If you drink any readymade packed beverage, make sure to check the salt (sodium) content and avoid high-sodium beverages.
2. Eat calcium-rich foods
As seen from the stats above, calcium oxalate stones are the most common and account for 64% of all kidney stones. Calcium oxalate stones are caused by too much oxalate in the urine.
To prevent these types of stones from forming, you have to reduce the concentration of oxalate in the urine. Calcium in your foods binds to oxalate in the intestines during the digestion process and prevents oxalate from being absorbed into the blood.
This decreases the concentration of oxalate in the blood that ultimately reaches the kidney. There is, therefore, less risk of calcium and oxalate binding together to form calcium oxalate stones.
Calcium in the diet should not be restricted below the recommended daily intake (1000-1200 mg/d) unless specifically indicated.
3. Reduce sodium (salt) intake
A high sodium diet increases the excretion of calcium in the urine, increases the pH of urine (making it alkaline), and reduces the excretion of citrate.
As a result, the saturation of calcium phosphate and monosodium urate increases in the urine, and the stone-inhibiting action against the crystallization of calcium oxalate decreases.
Therefore, because of a high sodium (high salt) diet, there is an increased tendency for the crystallization of calcium salts in urine.
According to the current guidelines, you should limit your daily sodium intake to 2,300 mg. However, if you have had kidney stones in the past due to a high-sodium diet, you should limit your daily sodium intake to 1,500 mg.
4. Limit animal protein intake
Just six weeks of eating a diet high in animal proteins and low in carbohydrates can increase your risk of kidney stones. This happens due to several reasons:
A high animal protein diet
- reduces the body’s ability to absorb calcium
- increases the acid load on the kidneys, which raises the risk of stone formation due to an acidic urine
- boosts urinary excretion of oxalate, which combines with calcium to form calcium oxalate kidney stones
- reduces levels of urinary citrate, the stone inhibitor chemical in urine that helps prevent stones from forming.
Foods that contain high animal proteins include red meat, pork, poultry, eggs, and seafood. If you are at risk of developing kidney stones, you should avoid these foods.
5. How to prevent uric acid stones?
Red meat, organ meats, and shellfish contain high amounts of purines. These are naturally occurring chemical compounds, which increase the production of uric acid in the body. This leads to more acidic urine. Acidic urine makes it easier for uric acid stones to form.
To prevent uric acid stones from forming, you should avoid high-purine foods such as red meat, organ meats, beer/alcoholic beverages, sardines, anchovies, and shellfish.
Incorporate in your diet vegetables and fruits, whole grains, and low-fat dairy products. Limit sugar-sweetened foods and drinks. Limit alcohol because it can increase uric acid levels in the blood and make the urine acidic, which can facilitate stone formation.
Kidney stone diet: Foods to eat and foods to avoid
The kidney stone diet incorporates foods that help prevent the buildup of stones in the urinary tract and cuts out foods that can promote stone formation.
Many nephrologists and urologists advocate the DASH diet for people with kidney stones and those with risk factors. This is the diet, which is advised to people with high blood pressure.
According to the American Family Physician, a balanced diet is ideal for preventing stone recurrence. The diet should have
- high fiber and vegetable content
- normal calcium content
- low sodium and animal protein
Foods to consume
1. Drink an adequate amount of water. To prevent stones, you should aim to drink up to 3 litres (5.2 pints) of fluid throughout the day, every day.
2. Eat enough calcium-rich foods
These include:
- low-fat or fat-free milk products
- calcium-fortified foods, such as cereals, bread, and juices
- beans
- berries
- dark green vegetables
- calcium-rich vegetables, such as broccoli
- seaweed, such as kelp
Foods to avoid
Some foods encourage kidney stone formation due to their mineral content. You should avoid them. They include:
- Beets
- Chocolate
- Spinach
- Rhubarb
- Tea
- Most nuts
- High doses of vitamin C in the form of supplements
- All the above foods are rich in oxalate, which can contribute to kidney stones. If you suffer from stones or harbor risk factors, you should avoid eating them or consuming them in small amounts.
Avoid long-term use of certain medicines
Certain medications taken over a prolonged period can predispose to stone formation. If you are on any of these drugs, you should talk to your doctor.
These medicines include:
- Decongestants used for the common cold
- Diuretics used for high blood pressure
- Protease inhibitors are antiviral drugs that are widely used to treat HIV/AIDS and hepatitis C.
- Anticonvulsants used in epilepsy
- Steroids
- Chemotherapy drugs used in the treatment of cancer
- Uricosuric drugs increase the excretion of uric acid in the urine. They can predispose you to uric acid stones.