8 Best Low Magnesium Cat Foods with Reviews

At Glance: Best Low Magnesium Cat Foods

Understanding urolith stones

Urolith stones are one of the causes of feline lower urinary tract disease (FLUTD) and many pet food manufacturers often try to modify cat diets to ensure they foster good urinal tract health.

The common uroliths in cats are the calcium oxalate and struvite (magnesium ammonium phosphate) stones.

Urolithiasis (the process urinary stone formation) is influenced by urine pH, the presence of calculogenic material, the urine concentration of the various urolith constituents (especially if present for long durations) and some metabolic factors.

Also, as Hill’s Pets notes, “an abundance of certain minerals such as calcium (Ca), phosphorus (P) and magnesium (Mg) found in certain cat diets can cause crystals to form in the urine, which sometimes leads to urinary stones.”

Pets.WebMd concurs adding high ammonium concentration besides magnesium and phosphate as a potential cause of these uroliths.

Finally, for optimum health, proper calcium, phosphorus, and magnesium ratio of Ca:P:Mg of 1.3:1:0.06 is also very essential. Therefore, these minerals need to be balanced.

Why food low in phosphorus and magnesium

Although a high concentration of calcium, magnesium, and phosphate is one of the causes of urolith, going for magnesium-free cat food is not a good idea. Magnesium has many vital roles and a deficiency will lead to some deficiency symptoms.

Initially, lower pH manufacturers added ammonium chloride and restricted magnesium which worked well for struvite stones. Unfortunately, this resulted in acidosis characterized by bone calcium mobilization which when combined with a low magnesium diet for cats spurred calcium oxalate stones formation. Therefore acidification alone was not a complete solution.

However, without diet acidification using ammonium chloride or other acidifying agents, the University of Minnesota’s College of Veterinary Medicine recommends the lowering of magnesium and phosphorus to help promote urine acidification and reduce chances of sterile struvite stones.

Secondly, controlling the various components of uroliths including magnesium, ammonium, phosphate, and calcium can help reduce both struvite and oxalate stones.

Thirdly, to reduce urine concentration, go for cat diets that increase the volume of urine such as wet or canned food since they have higher moisture content when compared to dry ones. Also, encourage your feline friend to drink more water.

Most canned foods have over 78% moisture content while dry ones have between 5-10% moisture content.

Furthermore, those with lower ash are also recommended especially for dry foods. The low ash indicates there are little inorganic minerals of which calcium, magnesium, phosphorus makes the bulk.

Additionally, avoid cat treats (unless you go for brands such as Royal Canin Urinary Feline Treats) as well as fish diets – they high in phosphorus and magnesium.

Finally, avoid commercial alkaline foods (high in pH). For instance, dry kibble diets with high grain and vegetables tend to raise urine pH that contributes to struvite uroliths. Note that an optimum pH which is between 6.0-6.5 is ideal in avoiding urolith stones.

Best low magnesium cat food brands

We have separately covered the best foods low in phosphorus. Here, we intend to focus on those low on magnesium where we will not list but review low magnesium brands including canned or wet as well as dry ones.

As we review the various brands, note that ME will stand for Metabolizable Energy, a cup is about 250 ml or 8 oz. and all calorie content and guaranteed analysis is on as fed basis unless stated otherwise.

a). Best low magnesium wet cat food – canned

If you prefer wet feline food, some of the brands that are low in magnesium include the following:

1. Royal Canin Veterinary Diet Urinary SO in Gel Canned Cat Food

Life stage: Adult felines

Royal Canin Veterinary Diet Urinary SO in Gel Canned Food will help support your cat’s urinary tract and bladder health by reducing calcium oxalate and struvite stones.

Key benefits

• Like most wet diets, it will boost hydration while diluting urine produced. This lowers the concentration of various minerals and diminishes the chances of crystal formation.
• Lower magnesium level vital in preventing the formation and dissolving struvite stones.
• Uses the Relative Super Saturation (RSS) methodology to minimize urinary stones formation by lowering ion concentration in urine, which in high level contributes to the creation of these stones.
• Reduces chances of struvite crystals recurring
• Your pet will not struggle during urination or have litter box behavior issues, such as urinating outside their litter trays, which may be due to pain.

Additional information

• First ingredients: Water sufficient for processing, pork by-products, pork liver, chicken by-products, chicken liver, chicken, and pork plasma.
• Calorie Content (calculated) (ME):  820 kcal ME/kg or 135 kcal ME/can.
• Guaranteed analysis:  Crude protein (min): 10.5%, crude fat (min): 2.5%, crude fiber (max): 2.0%, moisture (max): 81.0%.

2. Purina Pro Plan FOCUS Urinary Tract Health Adult Canned Wet Cat Food

Life stage: Adult cats

This Purina Pro Plan FOCUS Urinary Tract Health Formula will help maintain a healthy urinary tract by lowering pH.

Key features:

• Delicious and great tasting. Your kitties will love it.
• Fortified with all essential vitamins, minerals, and taurine to ensure it supports your cat’s immunity system.
• Has reduced magnesium at content 0.022% (0.09% on dry matter basis) and will lower urinary pH.

Additional information                             

• First ingredients: Water, meat by-products, chicken, wheat gluten, corn starch-modified, artificial and natural flavors, soy flour, potassium chloride.
• Calorie Content (calculated)(ME): 886 kcal/kg or 25.1 kcal/ounce
• Guaranteed analysis:  Crude protein (min): 12.0%, crude fat (min): 3.5%, crude fiber (max): 0.2%, moisture (max): 78.0%, ash (max): 1.5%, potassium (K) (min): 0.20%. Magnesium (Mg) (max): 0.022%, taurine (min): 0.05%

Besides the Chicken Entree in Gravy, you can also get the beef and chicken, classic salmon or Turkey and gibbets in either 12, 24, or 36 carton packs.

3. Hill’s Prescription Diet c/d Feline Multicare Urinary Track Chicken & Vegetable Stew

Life stage: Adult maintenance

Your feline’s tender palates will find the Chicken & Vegetable Stew that supports urinary health irresistible.

Key benefits

• It has controlled calcium, phosphorus, and magnesium levels, which effectively reduces mineral levels in urine that predisposes your kitty to urinary stones.
• Features the S+OXSHIELD™ intended to ensure the right urine pH levels and a urinary environment that doesn’t favor the formation of urinary stones.
• It is fortified with omega-3 fatty acids, antioxidants, and potassium citrate for optimum health.
• It will lower the chances of the common urinary signs by a whopping 89%.
• Dissolves urinary stones

Additional information

• First ingredients: Water, pork liver, chicken, carrots, wheat gluten, rice, corn starch, spinach, chicken liver flavor, chicken fat.
• Calorie content: 69 kcal / 2.9 oz. (82 g) can
• Guaranteed analysis: Protein: 41.0%, fats: 19.1%, carbohydrate (NFE): 33.6%, crude fiber: 0.6%, calcium: 0.80%, phosphorous: 0.68%, potassium: 0.92%, sodium: 0.33%, magnesium: 0.060%, taurine: 0.40%, vitamin C: 7 ppm, vitamin E: 731 IU/kg, total omega-3 FA: 0.87%, total omega-6 FA: 3.91%, Carnitine: 25.4 ppm, on dry matter basis.

There is also the Hill’s® Prescription Diet® Metabolic + Urinary Feline Vegetable & Tuna Stew and Hill’s® Prescription Diet® c/d® Multicare Feline with Ocean Fish options you can go for.

4. Dave’s Pet Food Restricted Diet Magnesium & Phosphorus Grain-Free Pork Recipe Canned

Life stage: Adult maintenance

This prescribed diet will help create a perfect urinary environment that prevents the formation of urinary stones.

Key benefits

• It is flavorful and protein-rich.
• Has restricted calcium, phosphorus, and magnesium but not below the AAFCO guidelines
• Grain-free and doesn’t have carrageenan to benefit kitties with sensitivities.
• Supports your cat’s wellbeing, thanks to the added vitamins, minerals and taurine

Additional information

• First ingredients: Pork, pork broth, pork liver, potatoes, pea fiber, natural flavor, salmon oil, tricalcium phosphate, agar-agar, parsley, and carrots.
• Calorie content: 1179 kcal/kg or 184 kcal/can.
• Guaranteed analysis:  Crude protein: 9.5%, crude fat: 6.75%, crude fiber: 3.0%, moisture: 78.0%, ash: 1.50%, phosphorus: 0.18%, sodium: 0.08%, magnesium: 0.01%

b). Best low magnesium dry cat food

If you favor dry foods for one or the other reason, you have several brands to buy that will serve you well. They include:

1. Royal Canin Veterinary Diet Urinary SO Dry Cat Food

Life stages: Adult cats

The Urinary SO veterinary diet will help you nutritionally address the various urinary tract and bladder health issues that your feline pal has by creating a perfect environment that doesn’t allow the formation of struvite or calcium oxalate urinary stones.

Key benefits

• Controlled magnesium levels will help dissolve any pure struvite urinary stones present.
• Your kitty will have reduced urine ion concentration and, consequently, chances of urinary stone formation, thanks to the Relative Super Saturation (RSS) methodology.
• Minimize the recurrence of lower tract urinary tract problems.

Additional information

• First ingredients: Chicken by-product meal, brewer’s rice, corn, corn gluten meal, chicken fat, and wheat gluten.
• Calculated ME calories: 3659 kcal of metabolizable energy (ME) per kg or 315kcal ME per cup.
• Guaranteed analysis:  Crude protein (min): 32.5%, crude fat (min): 13.0%, crude fiber (max): 4.0%, moisture (max): 8.0%, calcium (max): 1.5%, phosphorus (max): 1.26%. Magnesium (max): 0.1%.

2. Hill’s Prescription Diet c/d Feline Urinary Tract Multicare with Chicken

Life stages: Adult cats

The Diet C/D Feline Urinary Tract Multicare with Chicken has an ideal balance of nutrients while keeping some minerals that promote urinary crystals at minimums.

Key benefits

• Clinically proven to lower the commonly noted urinary problem signs by 89%
• Features restricted levels of calcium, magnesium, and phosphorus
• It will help dissolve struvite stones after about 27 days on average
• Hill’s nutritionists & veterinarians use the S+OXSHIELDTM formulation to ensure perfect urinary tract and bladder environment that doesn’t favor struvite or calcium oxalate stones.  

Additional information

• First ingredients: Chicken, whole grain corn, corn gluten meal, whole grain wheat, brewers rice, pork fat, chicken meal, and egg product.
• Calorie content: 3846 kcal/kg (349 kcal/ 8 oz. cup
• Guaranteed analysis: Protein: 33.4%, fats: 16.1%, carbohydrate (NFE):43.8%, crude fiber: 1.1%, calcium: 0.78%, phosphorous: 0.76%, potassium: 0.66%, sodium: 0.37%, magnesium: 0.080%, taurine: 0.2%, vitamin E: 749 IU/kg, total omega-3 FA: 0.70%, on dry matter basis.

3 Purina Pro Plan Dry Cat Food Formulas – Urinary Tract Health Dry Cat food

Life stages: Adult maintenance

Purina Pro Urinary Tract Health Chicken and Rice Formula dry feline diet is an excellent choice if you need a low magnesium diet that supports urinary health.

Key features

• It has lower dietary magnesium content (0.0755), and it will help reduce urinary pH.
• Great tasting and doesn’t have any artificial flavors or colors
• Enriched with omega 3-fatty acids and quality protein from chicken to ensure your pet’s skin is healthy, and it has a shiny coat.

Additional information

• First ingredients: Corn gluten meal, chicken, wheat flour, brewer’s rice, ground yellow corn, animal fat preserved with mixed-tocopherols, and egg product,
• Calorie content: 4365 kcal/kg or 487 kcal/cup
• Guaranteed analysis:  Crude protein (min): 31.0%, crude fat (min): 14.0%, crude fiber (max): 2.0%, moisture (max): 10.0%, ash (max): 6.5%, calcium (min) 0.7%, phosphorus (min): 0.6%. Magnesium (Mg) (max): 0.075%, Linoleic acid (min): 1.6%.

4. Blue Buffalo Natural Veterinary Diet W+U Weight Management + Urinary Care Grain-Free Dry Cat Food

Life stage: Maintenance of adult cats

If you have felines that struggle that are overweight or gain weight quickly that suffer from urinary care, the W+U Weight Management + Urinary Care is all you need.

Key benefits

• The food has an ideal fat level and higher in fiber to help in managing weight.
• Controlled mineral levels to support urinary health
• No grains, by-products meals of chicken or poultry, artificial preservatives, soy, wheat, corn or artificial flavors
• The diet has precise antioxidants, minerals, and vitamin levels to support immunity and create a healthy oxidative balance.

Additional information

• First ingredients: Deboned chicken, chicken meal, pea protein, tapioca starch, and powdered cellulose
• Calorie content: 3,257 Kcals per kg or an equivalent of 52 Kcals per cup
• Guaranteed analysis: Protein (min): 38.0%, crude fats (max): 11.0%, crude fiber (max): 13.0%, moisture (max): 9.0% magnesium (max): 0.1%, sodium (min): 0.25%, sodium (max): 0.45%,  vitamin E(min):  300 IU/kg, taurine (min): 0.3%, soluble fiber (min): 0.5%, and omega 3 fatty acids (min): 0.5%.

Other good cat foods for healthy urinary tract

Other both dry and wet foods good for your cat’s urinary tract include the following:

• Feline Urinary SO® Moderate Calorie Morsels in Gravy – Canned
• IAMS PROACTIVE HEALTH Adult Urinary Tract Health – Dry
• Wysong Uretic Feline Formula -Dry
• Wysong Uretic with Organic Chicken Feline Diet -Canned/Wet
• Hill’s® Science Diet® Adult Urinary Hairball Control
• Science Diet® Adult Urinary Hairball Control Chicken Entrée Can
• 9Lives – Dry

Cat food low in phosphorus and magnesium

If you are interested in brands with low P and Mg levels, go for those from Hill’s pets we have listed. They also have lower oxalates and calcium.

Low ash and magnesium cat food

It is common to get people looking for feline food low in ash and magnesium especially as a way of dealing with urolith formation.

Initially, magnesium and ash content (total inorganic minerals after organic content has been burnt off) was associated with feline lower urinary tract disease including urolith formation.

This made many manufacturers lower ash and magnesium. However, later it was discovered that the various factors we have mentioned led to urolith formation.

Diets for struvite and oxalate stones

One research on the Association Between Dietary Factors And Calcium Oxalate and Magnesium Ammonium Phosphate Urolithiasis In Cats published in the Journal of the American Veterinary Medical Association concludes that diets high in “higher protein, sodium, potassium, moisture, calcium, phosphorus, and magnesium contents and with decreased urine acidifying potential may minimize formation of calcium oxalate uroliths in cats.”

On the other hand, those with low proteins but higher in fat and those that make the urine more acidic potentially reduce the chances of struvite uroliths.