Best Low Ash Cat Food

best low ash cat food

We normally associate the term “ash” with charred organic matter or combustion remnants. However, if you closely inspect some of the pet food nutritional information, you’ll realize that it’s a widespread ingredient. Ash content in cat food is not a priori bad, however, many see it as sign of low quality and look for low ash cat food products. Some cat’s require low ash diet for health reasons. We bring you the best products with low ash content along with some general information about this ingredient.

Best Cat Food For Urinary Crystals


What is Ash in Cat Food?

The term ash describes the mineral content present in cat food. Ash is a form that some materials take after the organic matter is burnt under high temperatures, approx. 550-600 degrees. However, ash is not added to the cat food in such form. It is actually a mineral-rich ingredient that is safe to add to pet food as a dietary supplement. It is called ash for the simple reason that after the cat food is burned in process of discovering ingredients and their energy value, ash remains from a certain subset of ingredients. We describe it in more details in the sections below.

Minerals that are part of “ash” are vital for your cat’s diet. However, some health conditions make it necessary to feed your pet a low-ash cat food. Best cat food for kidney issues will definitely have low ash content.

How is Ash Content Measured?

low magnesium low ash cat food bomb calorimeter
A bomb calorimeter

Pet food scientists test the diets to work out the amount of protein, minerals, fiber, fat, and carbohydrate present in the pet food. This test is performed using a bomb calorimeter, which measured how much energy and what type of nutrients it released when burnt. The energy density Kcal/100g, and total amount of protein/crude protein, fiber/crude fiber, and fats/crude oils and fats, present in the diet are calculated. After the burning process is complete, anything that doesn’t burn is the food’s mineral content, which is an inorganic matter called ash. Again, it must be noted that pet food doesn’t contain burnt ingredients. This method is only used to calculate the levels of different nutrients and energy the food offers.

What is Ash in Cat Food Composed Of?

Ash is composed of non-caloric minerals found in organic materials, including 

  • iron, 
  • magnesium, 
  • phosphorus, 
  • zinc, 
  • sodium, 
  • calcium, 
  • and other materials. 

What is Considered Low Ash Cat Food?

Some cat food products are already rich in certain nutrients, and some aren’t. Manufacturers use ash to boost the overall nutritional value of the food. That’s why you find some ash content in most of the commercially prepared cat foods, especially in nutritionally boosted formulas for young cats. Best cat foods already pack enough nutrition and won’t contain as much ash. Such foods are called low ash cat foods. On the flip side, low ash cat food is already rich in minerals and nutrients and doesn’t require any add-on like ash to boost its nutritional value. 

Is Ash in Cat Food Dangerous?

Cat food ash isn’t really dangerous for a young and growing cat. That’s because a healthy cat doesn’t face any difficulty in dealing with excess minerals. But, as cats grow older, their kidneys’ ability to remove extra minerals decreases substantially. If the food has a high ash content, it will increase the concentration of minerals in the blood and impact the cat’s blood’s pH balance. This change will adversely affect the cat’s kidneys, urinary tract and overall health and wellbeing. That’s why as your feline advances in age, it is important to feed it a special diet with a low minerals concentration to lower its kidneys’ workload. Cats experiencing renal infections like a chronic renal failure will benefit the most from low ash cat food.

Why PH Matters?

Research reveals that the ash content in food doesn’t impact young cats unless they are experiencing urinary tract problems. That’s when urine pH starts to matter. A high pH is usually associated with high magnesium levels, and it can lead to the development of struvite crystals. When the pH is low or acidic, it causes the formation of calcium oxalate crystals.

In comparison to struvite crystals, more cats are reportedly experiencing calcium oxalate crystals primarily because of consuming foods that have low magnesium levels. According to Cornell University research, struvite crystals develop in fewer cats because commercial pet foods are usually prepared according to the latest research and offer more balanced formulas.

Ash and Magnesium in Cat Food

Ash comprises of minerals that are derived from the food’s meat and bone content, or vegetable sources. More minerals are added during preparation of the pet food. Red meats like lamb or beef have a higher ash content whereas white meats’ like fish and chicken’s ash content is relatively low. High quality meat, particularly fresh meat, has low levels of ash as it contains less bone compared to poor quality meat sources and dry meat meals.

Usually, the food’s ash content is derived from tendons, bone, and cartilage, which is ground into the meat meal. This, however, doesn’t include muscle because of its low ash levels. Since muscle is considered the most nutritious part of an animal, having high proportions of ash can indicate that animal parts of lesser quality were used to create cat food.

Low ash levels thus indicate the superior quality of food.

Magnesium is an essential mineral included in cat or dog foods for various reasons. It helps in energy production, boosts heart health, improves muscle function and bone and teeth health. 

High magnesium content in food is associated with feline lower urinary tract disease (FLUTD), but it is a minor contributor compared to the influence of imbalance in urine ph. Including magnesium chloride in cat food doesn’t cause urinary crystals to develop in the urine, as long as its acidity is maintained. If the urine’s pH is 7.5 or higher, it will cause struvite crystals to form despite consuming a low-magnesium diet.

If you want to feed your cat a diet low in magnesium to protect its urinary health, look for the ratio of several minerals in the low magnesium cat food, including calcium, magnesium, and phosphorus. Their levels should be this: calcium (Ca)- 1.3: Phosphors (P)- 1: Magnesium (Mg)- .06.

Low Ash Cat Food Percentages

It is important to note that ash isn’t a single ingredient but a group of nutrients, essentially minerals. Just like protein, fiber or fat is labeled on the packaging, similarly, ash content is also indicated. It is required in food as cats need roughly around 2% ash to meet their daily minerals requirements. When in the wild, the feline gnaws on vegetables or bones to receive the essential dietary minerals. But, above 2% of ash levels in commercial pet foods is not recommended because higher ash content won’t add any value to the pet’s diet and would be considered low-quality food. Low ash content cat food should have 2% or less.

Too much ash in your cat’s diet can impact its ability to absorb other vital nutrients. A higher level of phosphorus can decrease calcium absorption, and excessive calcium can impact healthy bone mineralization.

Best Low Ash Cat Food Reviews

What is the best food for cats with urinary tract issues? There are no specialized low ash cat food brands, however we have reviewed several products which are low ash and present our findings below. Unfortunately, in this review we didn’t include any low ash dry cat foods that we could recommend. If you are looking for such foods, do check our partner site and do an explicit search.

Tiki Cat Puka Puka Luau Succulent Chicken in Chicken Consomme Grain-Free Canned Cat Food

Tiki Cat Puka Puka Luau Succulent Chicken in Chicken Consomme Grain-Free Canned Cat Food

Tiki Cat Puka Puka Luau offers an incredibly delicious and nutritional meal for your cat. It’s packed with flavors of succulent shredded chicken breast simmered in real chicken broth. Since the food is prepared using real broth, it keeps your furry carnivore hydrated and supports urinary and digestive health. Moreover, this grain-free formula contains essential minerals, vitamins, omegas, and taurine, so it is a complete and balanced meal for cats of all ages. It doesn’t contain gluten, grains, starches, carbohydrates, and flours, so it’s a perfectly healthy option. This is probably best non prescription cat food for urinary crystals.


  • Aids digestion and light for the cat’s stomach.
  • Packed with nutritional value to boost the health and overall wellness of your cat.
  • Prepared with premium quality ingredients.
  • A certified grain-free meal, so it doesn’t irritate your cat’s digestive system or trigger an allergic reaction.


  • The packaging isn’t too practical from a consumer’s perspective.
  • There have been complaints that the food has a foul smell.

Hill’s Prescription Diet c/d Multicare Urinary Care with Chicken Canned Cat Food

Hill's Prescription Diet c/d Multicare Urinary Care with Chicken Canned Cat Food

This prescription cat food’s sole aim is to help with urinary tract infections and stones. It has proven to lower the recurrence of urinary issues caused by food by 89%. Has a direct impact on creation of struvite crystals which on average dissolve after 27 days. This low magnesium canned cat food has beneficial effects on pH levels.


  • A rich source of quality animal protein
  • Balanced levels of magnesium, phosphorus and calcium
  • Formulated by veterinarians


  • Not available in free sale

A great option if you want to keep things simple when it comes to cat food and avoid high ash concentrations is freeze dried raw cat food.

Low Ash Cat Food FAQs

What does low ash in cat food mean?

Low ash cat food indicates a higher-grade meal as it contains more higher value ingredients compared to bones and other minerals.

Which ingredient in cat food causes crystals in urine?

Struvite and calcium oxalate are two common types of crystals that form in the urine. However, their formation is never pinned to a single factor or cause. Many types of crystals can develop if your cat isn’t receiving a complete and balanced diet. Low ash food is presumed to help because it lowers total ratio of minerals in cat food.

Why is there ash in pet food?

Ash is listed on the food label to indicate the amount of minerals the pet food contains. Ash content is needed to offer a balanced diet and encourage the healthy development of the pet’s body by maintaining fluid balance and promote stronger bones and teeth.