Feline Lower Urinary Tract Disease (FLUTD) is a generic name given to a group of challenging diseases of the lower urinary tract. Signs and causes are variable. But dietary approaches are very common, and often recommended by vets. So why is this?

Table of contents

When looking at urinary diets, we are looking at management of a few problems or SPECIFIC problems to help such as:

  • Stress management
  • Preventing the formation certain types of crystals that can cause urine stones
  • Boosting bladder wall health and integrity
  • Decreasing the retention of urinary crystals
  • Limiting inflammatory (via proinflammatory mediators) and increasing anti-inflammatory mediators 

What can cats get with FLUTD?

Feline lower urinary tract disease (FLUTD) is a term describing conditions that can affect the urinary bladder and/or urethra (the lower urinary tract) of cats. There are MANY diseases that can affect a cat’s urinary tract, therefore there are several different ‘prescription’ urinary diets. Remember that prescription diets don’t require an actual prescription, however they should only be started and advised upon by the veterinary surgeon looking after your pet initially – as you will see, there are a vast range of diets specifically formulated to help very specific issues. 

In a number of these cases, cats develop a disease without any obvious underlying cause therefore it is called ‘feline idiopathic cystitis’, and seems to be associated with stress, especially in younger cats.

There are several diseases that can result in clinical signs of FLUTD. In cats older than 10 years of age, the most likely differentials are:

  • Urinary tract infection (UTI)
  • Uroliths (urinary tract stones)
  • Uroliths and UTI
  • with neoplasia, trauma, idiopathic disease, and urinary incontinence occurring in the remaining cases.

Treatment

Considering multiple causes of FLUTD once the diagnosis is confirmed, your veterinary team will establish the treatment protocol including medical and nutritional recommendations tailored to your pet’s specific needs. 

According to the International Society of Feline Medicine, the idiopathic cystitis form of disease appears to bear many similarities to a disease in humans called ‘interstitial cystitis’. In both cats and humans, it can be difficult to manage, and many people must adopt a management plan that includes multiple interventions. This may include the use of:

  • Medication
  • Diet changes
  • Home adaptations
  • Supplements or therapeutically supplemented diets 

As these conditions can reoccur and can take up lots of time and money to manage, let’s investigate if the ingredients in some urinary foods are worth it.

Supplemented therapeutic diets

Looking into SOME of the common raw ingredients in some therapeutic diets we can see how they aim to work. 

Common ingredients seen include:

Milk Protein Hydrolysate 

One study showed a positive effect of urinary food supplemented with ingredients (milk protein hydrolysate and L-tryptophan) to control anxiety-related behaviours on signs of lower urinary tract disease and anxiety-related behaviours in cats with FIC. However, this study was heavily flawed in that it only had 10 participants with full clinical history – no strong conclusion can be drawn, and more robust methodology is required.

Quercetin

In theory, this is added to regulate inflammation and help to support stress coping mechanisms. There is some weak evidence that the Quercetin derivative has some anti-inflammatory activities. Therefore, it is plausible that there may be some benefits seen in administration.

L-Theanine

This is added as an amino acid, found in green tea, with claimed natural calming properties to reduce stress behaviours in cats. There is some weak evidence that this supplement helped to improve the undesirable manifestations of stress in cats. While the basic principle that L-theanine is biochemically active is plausible, there is still little compelling evidence it helps. Indeed, in this study using a small sample size the caregiver placebo effect among numerous other potential confounders and sources of error makes it impossible to draw reliable conclusions.

GAG

Cats with idiopathic cystitis demonstrate alterations within the glycosaminoglycan (GAG) layer. Although a generalised decrease in the GAG layer and a reduction in the GAG GP-51 have both been reported in cats, studies attempting to replenish the former have failed to demonstrate a benefit above that seen with placebo medications.

L-tryptophan

L-tryptophan is an essential amino acid that is a precursor for synthesis of serotonin, an inhibitory neurotransmitter. It may have an anxiolytic effect in cats. Results in one study suggest that L-tryptophan supplementation had an effect in changing the frequency of stress related behaviours, decreasing anxiety signals. Consequently, L-tryptophan supplementation can be an efficient tool to help treat some behavioural disorders in cats and dogs as part of behavioural therapy.

α-Casozepine 

α-Casozepine is available as a supplement and is an additive in some therapeutic urinary diets. It is derived from bovine milk and has anxiolytic properties. One study suggests that α-casozepine is beneficial in limiting anxiety and socially stressful conditions in cats.

Other Factors

What type of crystals or stones are forming in the urine will also be a factor.

Struvite uroliths

Sterile struvite uroliths occur most commonly in cats between one and 10 years of age. In at-risk cats (i.e. those with a lack of urolith inhibitors) fed a diet that leads to supersaturation of the urolith constituents, stone formation can occur.

Struvite uroliths can be dissolved by feeding a diet that is acidifying, and one restricted in magnesium, phosphorus, and protein. In cats with sterile struvite uroliths, such a diet has been shown to lead to dissolution in approximately 36 days (range 14 to 141 days). However, in infection-induced struvite urolithiasis, this was increased to approximately 79 days.

Calcium oxalate

Calcium oxalate uroliths cannot be dissolved by adjusting the patient’s diet; however things can be done to try to prevent them. Calcium oxalate uroliths form when urine is supersaturated with calcium and oxalate; consumption of diets supplemented with urinary acidifiers (e.g., ammonium chloride) is associated with increased urinary calcium excretion. 

There are medical and nutritional interventions that are recommended to decrease the recurrence of these uroliths in cats that are at risk.

The mainstay of treatment is to decrease urine concentration

In addition, diets have been formulated to promote:

  • High concentrations and activity of urolith inhibitors
  • Reduce urine acidity
  • Decrease calcium and oxalate concentration within the urine

What else is important?

Dilute the urine

Decreasing urine concentration (and therefore retention time) has been shown to markedly lower the risk of urolith formation.

More dilute urine is potentially less irritant to the cells lining the bladder. Encouraging more frequent urination and producing urine that is more dilute appears to be helpful in these cases.

We can achieve this by:

  • Modifying the diet by changing to a wet diet rather than a dry diet
  • Making sure a good supply of fresh water is always available – cats should be encouraged to drink by offering water from different bowls.
  • Using water fountains to encourage drinking
  • Adding flavours to water such as chicken
  • Adding a little more water to their wet food if they allow

Wet or dry?

Canned and dry diets vary considerably in their moisture content. Canned or pouch products generally contain more than 60%+ moisture and dry products generally less than 10%.

Theoretically, increasing the proportion of canned food and thereby increasing water intake may decrease the urine concentration.

Stress

Stress plays a very important role in triggering cystitis, see the 5 pillars to assess your cat’s needs. There are some diets that are specifically tailored to help reduce stress. 

Five pillars of a healthy feline environment include providing:

  1. A safe place
  2. Multiple and separated key environmental resources: food, water, toileting areas, scratching areas, play areas, and resting or sleeping areas
  3. An opportunity for play and predatory behaviour
  4. Positive, consistent and predictable human–cat social interaction
  5. An environment that respects the importance of the cat’s sense of smell

Conclusion

FLUTD is a term for a range of issues, it is sometimes as frustrating to treat for a veterinary professional as it is for the owner – it’s not always an ‘easy fix’ and requires lots of changes to different aspects of a cat’s life and environment to help. One of the factors that can play a role in this management, depending on the reason for the FLUTD, is diet. These are especially useful in certain types of bladder stones (uroliths).

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