Kidney stones Q&As
Published by Bupa's health information team, June 2009.
Answers to questions about kidney stones
This section contains answers to common questions about this topic. Questions have been suggested by health professionals, website feedback and requests via email.
- I have been told that kidney stones are caused by drinking too much milk and eating too many foods that contain calcium. Is that true?
- I've heard that the pain can be severe. What painkillers should I take?
- Will a kidney stone harm my health?
- Does having a kidney stone make me more likely to have another one?
I have been told that kidney stones are caused by drinking too much milk and eating too many foods that contain calcium. Is that true?
No, it isn't true. In fact, not eating enough calcium can make you more likely to develop a kidney stone. It's important to eat a healthy diet that contains calcium-rich foods.
Explanation
Four out of five kidney stones are made from calcium, either calcium oxalate or calcium phosphate. Because the stones are made from calcium many people in the past thought that eating too much calcium, such as drinking a lot of milk, made developing a stone more likely. However, research shows that the opposite seems to be the case. Not eating enough calcium makes developing a stone more likely.
To stay healthy, it's important that you eat a healthy, balanced diet that contains calcium. Foods rich in calcium include milk, cheese and other dairy products, leafy green vegetables and bony fish like sardines and pilchards. Don't take calcium supplements unless your doctor advises you to. Calcium supplements affect your body in a different way to the calcium found naturally in foods and can increase your chances of developing a kidney stone. A few people develop kidney stones made from calcium oxalate. If you have this type of kidney stone, you may be advised to cut down or eat fewer foods that contain high amounts of calcium oxalate. These include chocolate, spinach, nuts and rhubarb.
If you are making any major changes to the foods you eat, you should speak to your doctor or dietitian for advice and information.
Further information
- Kidney Research UK
www.kidneyresearchuk.org
Sources
- Kidney Stones. Kidney Research UK. www.kidneyresearchuk.org, accessed 11 February 2009
- Calcium. Food Standards Agency. www.eatwell.gov.uk, accessed 11 February 2009
- Parmar M. Kidney stones. BMJ 2004;328:1420-1424
I've heard that the pain can be severe. What painkillers should I take?
Kidney stones can be very painful. Depending on how severe your pain is, there are a number of different painkillers that you can either buy from your pharmacist, or which your doctor can prescribe for you. If your kidney stone becomes very painful, and you start to feel sick and have a fever, you should see your doctor as soon as possible.
Explanation
The pain you get with a kidney stone can be severe. The pain usually becomes severe when the stone moves from your kidney down towards your bladder through a tube called the ureter.
The pain that you get from a kidney stone is called renal colic. It often starts suddenly and is usually felt in your lower back, sometimes spreading down to your groin. Not everyone with a kidney stone has this type of severe pain.
Pain affects everyone differently - what one person describes as mild pain may be very painful to someone else. So it's important to make sure that you take the right painkiller for you, for the level of pain you are experiencing.
If your pain is mild, you can take paracetamol and/or codeine. A group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to be effective for the more severe kind of pain that some people get when they have kidney stones. Some examples are ibuprofen and diclofenac. You can buy ibuprofen from your pharmacist and take it as a tablet.
Always read the patient information that comes with your medicine and if you have any questions, ask your pharmacist for advice.
Don't take NSAIDs if you have ever had a stomach ulcer or if you have asthma, as NSAIDs can make these conditions worse. The most common side-effects of taking NSAIDs are an upset stomach and indigestion. You can reduce the risk of this if you take this kind of medicine with food or a glass of milk.
Always ask your doctor or pharmacist for advice and read the patient information leaflet that comes with your medicine.
Further information
- British National Formulary
www.bnf.org
Sources
- Miller N, Lingeman J. Management of kidney stones. BMJ 2007; 334:468-472
- Renal colic. GP Notebook. www.gpnotebook.co.uk, accessed 6 February 2009
- Parmar M. Kidney stones. BMJ 2004;328:1420-1424
- Kidney stones. BMJ Clinical Evidence. www.clinicalevidence.bmj.com, accessed 12 February 2008
- Renal colic - acute. Management issues. Clinical Knowledge Summaries. http://cks.library.nhs.uk, accessed 11 February 2009
- Joint Formulary Committee, British National Formulary. 55th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008: 534-540
Will a kidney stone harm my health?
Most kidney stones pass easily and don't cause serious problems. Others may be painful but can be effectively treated and either broken up or removed. However, if a kidney stone blocks your ureter (the tube which joins the kidney to your bladder) and it's not treated quickly, your kidney can become damaged or you may develop an infection. This can be life-threatening, which is why it's vital to get treatment quickly.
Explanation
Most kidney stones are small enough to be passed in your urine without needing any treatment and, apart from pain and discomfort, they don't cause any serious problems. However, if the stone is large or gets stuck inside your ureter, it can cause more serious problems and will need to be treated.
If the stone blocks your ureter, urine can't flow down to the bladder and it collects in your kidney. This can cause your kidney to swell and, if this isn't treated, it can cause permanent damage. If they aren't treated, kidney stones can also cause an infection which can spread and may become life-threatening.
Further information
- Kidney Research UK
www.kidneyresearchuk.org
Sources
- Kidney stones. BMJ Clinical Evidence. www.clinicalevidence.bmj.com, accessed 12 March 2008
Does having a kidney stone make me more likely to have another one?
Once you have had a kidney stone you're more likely to get another, compared to someone who has never had one. You can reduce your risk of having another kidney stone by drinking enough fluids every day and eating the right foods.
Explanation
Once you have had a kidney stone your chances of developing another do increase. Around one in seven people who have a kidney stone go on to develop another one within a year. One in three people develop another kidney stone within five years of the previous one. However, there are some things that you can do that will help to reduce your risk of developing another stone.
By drinking enough fluids you can help to keep your urine watered down, which helps to prevent a build up of some of the chemicals that can cause kidney stones. You are aiming for your urine to be clear, rather than a yellow colour.
Eat a healthy balanced diet, without too much salt or animal protein such as meat and fish. However, if your previous kidney stone was caused by certain chemicals, your doctor might ask you to change the foods you eat. This can help to cut down the amount of these chemicals in your body and reduce your risk of having another kidney stone. Don't change your diet without advice from your doctor or a dietitian.
Depending on the kind of stone you have had, and what caused it, your doctor might ask you to take medicines that help to prevent another stone forming.
Further information
- Kidney Research UK
www.kidneyresearchuk.org
Sources
- Kidney Stones. Kidney Research UK. www.kidneyresearchuk.org, accessed 11 February 2009
- Renal colic - acute. Management issues. Clinical Knowledge Summaries. http://cks.library.nhs.uk, accessed 11 February 2009
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This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: June 2009
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