How nutrition can support bladder stones and urinary crystals in cats

What are bladder stones and urinary crystals in cats?

Urine is produced in the kidneys, stored in the bladder and runs out of the body through the “urethra tube”.  Urine carries away water, dissolved protein waste and excess minerals. 

Crystals can form when there are more waste materials than can be dissolved in the urine. Often, if the cat has a perfectly healthy urinary tract, then these crystals can be passed out before they become big enough to cause a problem.

When crystals become stones

If not passed out then these microscopic crystals can join together to form small sand like grains. Further materials are then deposited onto these grains building them into larger stones – at which point they can cause problems. 

These stones can restrict the outflow of urine, causing a build-up of urine and waste elements in the bladder. The tension in the bladder can cause pain and retained waste elements can seriously harm the body. In the worst case, if the obstruction is in the urethra, then there is a risk of a complete blockage that, without immediate veterinary care, may prove fatal

Stones can form anywhere in the urinary tract.  Those forming in the bladder being referred to bladder stones and those in the kidney as kidney stones.

Signs of bladder or kidney stones in cats:

Sometimes cats will show no symptoms but things to look out for are

  • Blood in the urine
  • Are they showing signs of difficulty when urinating
  • Are they urinating more often
  • Are they excessively licking their genitals.
  • Are they suffering from repeated urinary tract infections
  • Are they urinating in unusual places

How are stones diagnosed in cats?

If the stones are big enough your vet may be able to feel them, however X-ray or ultrasound is also used to detect some stones.  Analysis of the urine will also provide important information.

Recommended food for bladder and urinary problems

Treatment of stones in cats:

This will depend on the type of stone and its location and size but the options include

  • Diet – in some cases a specially formulated diet will be enough to dissolve the stones – this depends on the type of stone involved
  • Filling the bladder to create heavier urination to flush out the stone
  • Surgical removal of stones
  • Sometimes cats can simply pass out the stone when urinating, particularly females with wider urinary tracts.
  • Breaking down the stone with shock waves – a process called Lithotripsy

Types of Stones:

Struvite Stones:
The most common urinary stones. These form if there is too much magnesium and phosphorous in the urine and the urine is not acidic enough. The good news is the right diet can dissolve these stones.

Calcium-oxalate stones: 
These cannot be dissolved and must be removed surgically but once removed the right diet can help prevent re-formation.  These form when there is too much urinary calcium and oxalate.

Urate stones:
Stones within the urinary tract composed of ammonium urate.

Cystine stones:
Caused by an excess of the amino acid (a building block of protein) cysteine

How nutrition can help:

Nutrition can help in 3 ways

  • By reducing the mineral and protein waste for the urine to excrete – giving less material for crystals to form
  • By changing the acidity of the urine helping to dissolve struvite stones and preventing other stones from re-forming
  • By encouraging drinking so increasing urination and helping flush out waste.

Different types of stone require a different type of diet – below are the SPECIFIC diets for each type of stone

Recommended food for bladder and urinary problems


Struvite Stones:

  • Make the urine more acidic helping to dissolve the stones;
  • Encourages drinking to increase urination and so flush out the stones.
  • Reduced mineral content, particularly magnesium and phosphorus, to help prevent crystals reforming.

SPECIFIC™  FCD/FCW/FCD-L Crystal prevention and FSW Struvite Dissolution: A choice of wet and dry foods designed to help dissolve and prevent the recurrence of Struvite stones in cats. For cats with a tendency to gain weight there is a light version SPECIFIC™ FCD-L


Calcium-oxalate stones:

  • Has lower protein – reducing the concentration of oxalate in the urine.
  • Makes the urine more alkaline, discouraging crystals from forming.
  • Added potassium citrate keeps the calcium oxalate in solution rather than forming into solid crystals

SPECIFIC™ FKD & FKW Kidney Support: A choice of wet and dry foods to help prevent the recurrence of Calcium Oxalate and the less common Urate and Cystine stones.

Urate stones and Cystine stones:

  • Has a low purine concentration
  • Has lower protein
  • Creates more alkaline urine discouraging crystals from forming.
SPECIFIC™ FKD & FKW Kidney Support: A choice of wet and dry foods to help prevent the recurrence of Calcium Oxalate and the less common Urate and Cystine stones.



Recommended diets for bladder stones and urinary crystals

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