Kidney Stones: Nutritional Therapy and Prevention

Kidney stones (nephrolithiasis) are hard deposits made of minerals and salts that form inside your kidneys.

Kidney stones have many causes and can affect any part of your urinary tract — from your kidneys to your bladder. Often, stones form when the urine becomes concentrated, allowing minerals to crystallize and stick together.

Causes of Kidney Stones

Kidney stones often have no definite, single cause, although several factors may increase your risk.

Kidney stones form when your urine contains more crystal-forming substances — such as calcium, oxalate and uric acid — than the fluid in your urine can dilute. At the same time, your urine may lack substances that prevent crystals from sticking together, creating an ideal environment for kidney stones to form.

Types of Kidney Stones

Knowing the type of kidney stone helps determine the cause and may give clues on how to reduce your risk of getting more kidney stones. If possible, try to save your kidney stone if you pass one so that you can bring it to your doctor for analysis.

Types of kidney stones include:

  1. Calcium stones. Most kidney stones are calcium stones, usually in the form of calcium oxalate. Oxalate is a naturally occurring substance found in food and is also made daily by your liver. Some fruits and vegetables, as well as nuts and chocolate, have high oxalate content. Dietary factors, high doses of vitamin D, intestinal bypass surgery and several metabolic disorders can increase the concentration of calcium or oxalate in urine.Calcium stones may also occur in the form of calcium phosphate. This type of stone is more common in metabolic conditions, such as renal tubular acidosis. It may also be associated with certain migraine headaches or with taking certain seizure medications, such as topiramate (Topamax).
  2. Struvite stones. Struvite stones form in response to an infection, such as a urinary tract infection. These stones can grow quickly and become quite large, sometimes with few symptoms or little warning.
  3. Uric acid stones. Uric acid stones can form in people who don’t drink enough fluids or who lose too much fluid, those who eat a high-protein diet, and those who have gout. Certain genetic factors also may increase your risk of uric acid stones.
  4. Cystine stones. These stones form in people with a hereditary disorder that causes the kidneys to excrete too much of certain amino acids (cystinuria).

Risk Factors

Factors that increase your risk of developing kidney stones include:

  • Family or personal history. If someone in your family has kidney stones, you’re more likely to develop stones, too. And if you’ve already had one or more kidney stones, you’re at increased risk of developing another.
  • Dehydration. Not drinking enough water each day can increase your risk of kidney stones. People who live in warm climates and those who sweat a lot may be at higher risk than others.
  • Certain diets. Eating a diet that’s high in protein, sodium (salt) and sugar may increase your risk of some types of kidney stones. This is especially true with a high-sodium diet. Too much salt in your diet increases the amount of calcium your kidneys must filter and significantly increases your risk of kidney stones.
  • Being obese. High body mass index (BMI), large waist size and weight gain have been linked to an increased risk of kidney stones.
  • Digestive diseases and surgery. Gastric bypass surgery, inflammatory bowel disease or chronic diarrhea can cause changes in the digestive process that affect your absorption of calcium and water, increasing the levels of stone-forming substances in your urine.
  • Other medical conditions. Diseases and conditions that may increase your risk of kidney stones include renal tubular acidosis, cystinuria, hyperparathyroidism, certain medications and some urinary tract infections.

Signs and Symptoms

A kidney stone may not cause symptoms until it moves around within your kidney or passes into your ureter — the tube connecting the kidney and bladder. At that point, you may experience these signs and symptoms:

  • Severe pain in the side and back, below the ribs
  • Pain that radiates to the lower abdomen and groin
  • Pain that comes in waves and fluctuates in intensity
  • Pain on urination
  • Pink, red or brown urine
  • Cloudy or foul-smelling urine
  • Nausea and vomiting
  • Persistent need to urinate
  • Urinating more often than usual
  • Fever and chills if an infection is present
  • Urinating small amounts

Pain caused by a kidney stone may change — for instance, shifting to a different location or increasing in intensity — as the stone moves through your urinary tract.

Nutritional Therapy

If you have already had kidney stones, ask your health care professional which type of kidney stone you had. Based on the type of kidney stone you had, you may be able to prevent kidney stones by making changes in how much sodium, animal protein, calcium or oxalate is in the food you eat.

You may need to change what you eat and drink for these types of kidney stones:

  • Calcium Oxalate Stones
  • Calcium Phosphate Stones
  • Struvite Stones
  • Uric Acid Stones
  • Cystine Stones

Calcium Oxalate Stones

Reduce oxalate

If you’ve had calcium oxalate stones, you may want to avoid these foods to help reduce the amount of oxalate in your urine:

  • nuts and nut products
  • peanuts—which are legumes, not nuts, and are high in oxalate
  • rhubarb
  • spinach
  • wheat bran

Talk with a health care professional about other food sources of oxalate and how much oxalate should be in what you eat.

Reduce sodium

Your chance of developing kidney stones increases when you eat more sodium. Sodium is a part of salt. Sodium is in many canned, packaged, and fast foods. It is also in many condiments, seasonings, and meats.

Talk with a health care professional about how much sodium should be in what you eat. See tips to reduce your sodium intake.

Limit animal protein

Eating animal protein may increase your chances of developing kidney stones.

A health care professional may tell you to limit eating animal protein, including

  • beef, chicken, and pork, especially organ meats
  • eggs
  • fish and shellfish
  • milk, cheese, and other dairy products

Although you may need to limit how much animal protein you eat each day, you still need to make sure you get enough protein. Consider replacing some of the meat and animal protein you would typically eat with beans, dried peas, and lentils, which are plant-based foods that are high in protein and low in oxalate.

Talk with a health care professional about how much total protein you should eat and how much should come from animal or plant-based foods.

Get enough calcium from foods

Even though calcium sounds like it would be the cause of calcium stones, it’s not. In the right amounts, calcium can block other substances in the digestive tract that may cause stones. Talk with a health care professional about how much calcium you should eat to help prevent getting more calcium oxalate stones and to support strong bones. It may be best to get calcium from low-oxalate, plant-based foods such as calcium-fortified juices, cereals, breads, some kinds of vegetables, and some types of beans. Ask a dietitian or other health care professional which foods are the best sources of calcium for you.

Calcium Phosphate Stones

Reduce sodium

Your chance of developing kidney stones increases when you eat more sodium. Sodium is a part of salt. Sodium is in many canned, packaged, and fast foods. It is also in many condiments, seasonings, and meats.

Talk with a health care professional about how much sodium should be in what you eat. See tips to reduce your sodium intake.

Limit animal protein

Eating animal protein may increase your chances of developing kidney stones.

A health care professional may tell you to limit eating animal protein, including

  • beef, chicken, and pork, especially organ meats
  • eggs
  • fish and shellfish
  • milk, cheese, and other dairy products

Although you may need to limit how much animal protein you have each day, you still need to make sure you get enough protein. Consider replacing some of the meat and animal protein you would typically eat with some of these plant-based foods that are high in protein:

  • legumes such as beans, dried peas, lentils, and peanuts
  • soy foods, such as soy milk, soy nut butter, and tofu
  • nuts and nut products, such as almonds and almond butter, cashews and cashew butter, walnuts, and pistachios
  • sunflower seeds

Talk with a health care professional about how much total protein you should eat and how much should come from animal or plant-based foods.

Get enough calcium from foods

Even though calcium sounds like it would be the cause of calcium stones, it’s not. In the right amounts, calcium can block other substances in the digestive tract that may lead to stones. Talk with a health care professional about how much calcium you should eat to help prevent getting more calcium phosphate stones and to support strong bones. It may be best to get calcium from plant-based foods such as calcium-fortified juices, cereals, breads, some kinds of vegetables, and some types of beans. Ask a dietitian or other health care professional which foods are the best sources of calcium for you.

Struvite Stones

Increase fluid intake

Drink lots of water, fruit juice, vegetable juice and other drinks. At least 50% total fluid intake should be water. Drink about 3-5 liters of water as water dilutes urine and there by hinders the stone formation.

Never let yourself to become dehydrated. Drink more water if you are doing strenuous work or are working in hot humid climate.  Drink lots of orange juice or other citrus fruit juices like – grapefruit, cranberry and grape juice. Citrus fruits especially orange juice is rich in potassium and citrate, potassium citrate is commonly used to prevent kidney stones.

Reduce sodium intake.

High sodium intake increases the risk of kidney stone by increasing urinary saturation of calcium phosphate and monosodium rate and decreases the inhibitory activity against calcium oxalate crystallization.

Increase intake of fiber

Foods rich in fiber are the following: bran, whole grains, oat, green leafy vegetables, peas, beans, potatoes, raw vegetables, salads, dried fruits and fresh fruits.

Consume good amount of B-complex vitamin daily

Pyridoxine (Vitamin B-6) and B-1 (thiamine) as their deficiency is associated with formation of stones.

Reduce intake of sugar

Several studies say reducing sugar intake is associated with kidney stones.

If possible stick to vegetarian diet. Studies have shown that plant sources of oxalates and calcium are not the cause for stone formation. Diet high in animal protein affects certain minerals in the urine which aids in the formation of kidney stones.

Consume Vitamin C

Struvite stones are dissolved in acidic urine. Hence consume foods high in citrates. Consume lots of vitamin C especially orange juice should be consumed in large quantities. Vitamin C makes urine acidic and there by aids in eliminating infection and dissolves the stone.

Urinary infection and stones can be prevented by daily consumption of much greater amounts of ascorbic acid (vitamin C).

Uric Acid Stones

Limit animal protein

Eating animal protein may increase your chances of developing kidney stones.

A health care professional may tell you to limit eating animal protein, including

  • beef, chicken, and pork, especially organ meats
  • eggs
  • fish and shellfish
  • milk, cheese, and other dairy products

Although you may need to limit how much animal protein you have each day, you still need to make sure you get enough protein. Consider replacing some of the meat and animal protein you would typically eat with some of these plant-based foods that are high in protein:

  • legumes such as beans, dried peas, lentils, and peanuts
  • soy foods, such as soy milk, soy nut butter, and tofu
  • nuts and nut products, such as almonds and almond butter, cashews and cashew butter, walnuts, and pistachios
  • sunflower seeds

Talk with a health care professional about how much total protein you should eat and how much should come from animal or plant-based foods.

Losing weight if you are overweight is especially important for people who have had uric acid stones.

Cystine Stones

Drinking enough liquid, mainly water, is the most important lifestyle change you can make to prevent cystine stones. Talk with a health care professional about how much liquid you should drink.

How to Prevent Kidney Stones Naturally?

Making small adjustments to your current diet and nutrition plan may go a long way toward preventing kidney stones.

Stay hydrated

Drinking more water is the best way to prevent kidney stones. If you don’t drink enough, your urine output will be low. Low urine output means your urine is more concentrated and less likely to dissolve urine salts that cause stones.Lemonade and orange juice are also good options. They both contain citrate, which may prevent stones from forming.Try to drink around eight glasses of fluids daily, or enough to pass two liters of urine. If you exercise or sweat a lot, or if you have a history of cystine stones, you’ll need additional fluids.You can tell whether you’re hydrated by looking at the color of your urine — it should be clear or pale yellow. If it’s dark, you need to drink more.

Eat more calcium-rich foods

The most common type of kidney stone is the calcium oxalate stone, leading many people to believe they should avoid eating calcium. The opposite is true. Low-calcium diets may increase your kidney stone risk and your risk of osteoporosis.Calcium supplements, however, may increase your risk of stones. Taking calcium supplements with a meal may help reduce that risk.Low-fat milk, low-fat cheese, and low-fat yogurt are all good calcium-rich food options.

Eat less sodium

A high-salt diet increases your risk of calcium kidney stones. According to the Urology Care Foundation, too much salt in the urine prevents calcium from being reabsorbed from the urine to the blood. This causes high urine calcium, which may lead to kidney stones.Eating less salt helps keep urine calcium levels lower. The lower the urine calcium, the lower the risk of developing kidney stones.To reduce your sodium intake, read food labels carefully.Foods notorious for being high in sodium include:

  • processed foods, such as chips and crackers
  • canned soups
  • canned vegetables
  • lunch meat
  • condiments
  • foods that contain monosodium glutamate
  • foods that contain sodium nitrate
  • foods that contain sodium bicarbonate (baking soda)

To flavor foods without using salt, try fresh herbs or a salt-free, herbal seasoning blend.

Eat fewer oxalate-rich foods

Some kidney stones are made of oxalate, a natural compound found in foods that binds with calcium in the urine to form kidney stones. Limiting oxalate-rich foods may help prevent the stones from forming.Foods high in oxalates are:

  • spinach
  • chocolate
  • sweet potatoes
  • coffee
  • beets
  • peanuts
  • rhubarb
  • soy products
  • wheat bran

Oxalate and calcium bind together in the digestive tract before reaching the kidneys, so it’s harder for stones to form if you eat high-oxalate foods and calcium-rich foods at the same time.

Eat less animal protein

Foods high in animal protein are acidic and may increase urine acid. High urine acid may cause both uric acid and calcium oxalate kidney stones.You should try to limit or avoid:

  • beef
  • poultry
  • fish
  • pork

Avoid vitamin C supplements

Vitamin C (ascorbic acid) supplementation may cause kidney stones, especially in men.According to one @013 study, men who took high doses of vitamin C supplements doubled their risk of forming a kidney stone. Researchers don’t believe vitamin C from food carries the same risk.

 

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