Monocalcium and Dicalcium Phosphates for Dogs

There is something very important about Phosphorus in regards to how much dogs need and how much they actually receive.

Dogs, like other farm animals such as poultry, have been documented to be receiving significantly less phosphorus than they need. What they can get from greens such as vegetables is only 30% of what they need and only 50% of the 30% gets finally absorbed.

Low phosphorus can cause;

  1. Poor growth
  2. Poor appetite
  3. Bone mineralization disorders
  4. Dental malformation
  5. Muscle weakness
  6. Lethargy
  7. Inability to reproduce
  8. Anemia

Pet food manufacturers rely on inorganic phosphates, specifically monocalcium, dicalcium or tricalcium phosphates to increase the Phosphorus in dog and cat food.

Monocalcium phosphates and dicalcium phosphates are the most frequently used as additives in pet foods. The major distinction between these food phosphates is their phosphorus content.

How Monocalcium phosphates is made:

To make monocalcium phosphate, calcium carbonate is treated with phosphoric acid. The end result of this process is two byproducts: calcium sulfate (gypsum) and monocalcium phosphate.

Gypsum is a common industrial product that has many uses, including being used as an additive in pet foods. Monocalcium phosphate, on the other hand, is not commonly found in nature and must be manufactured for use in food products.

The process of manufacturing monocalcium phosphate begins by treating calcium carbonate (CaCO3) with phosphoric acid (H3PO4). This reaction produces two byproducts: calcium sulfate (CaSO4) and monocalcium phosphate (Ca(H2PO4)2).

The calcium sulfate is then separated from the monocalcium phosphate, and the monocalcium phosphate is dried and ground into a fine powder. This powder can then be used as an additive in pet foods.

How Dicalcium Phosphates is obtained:

Dicalcium phosphate is made by treating calcium carbonate with phosphoric acid. The end result of this process is two byproducts: calcium sulfate and dicalcium phosphate.

Dicalcium phosphate differs from monocalcium phosphate in that it contains less phosphorus. It is also not as commonly used in pet foods, as it is more expensive to produce than monocalcium phosphate.

Monocalcium phosphates Regulation as a food additive

According to the FDA’s notice under Code of Federal Regulations 21CFR182.8217, FDA approved Monocalcium phosphates as a food additive generally recognized as safe (GRAS).

Advantages of monocalcium phosphate over dicalcium phosphate and tricalcium phosphate;

This website did the hard work of compiling the following advantages of the mono- over di- and tri-calcium phosphates;

  • It is a neutralizer for a number of chemicals, including salt, potassium, magnesium, and others.
  • It encourages the proper functioning of the heart, nervous and muscular systems, as well as other organs.
  • By stimulating digestive enzymes, it improves digestion by boosting their activity.
  • It strengthens the immune system
  • It aids in the movement of lipids, protein synthesis, and the removal of harmful chemicals from the intestine.
  • It improves the body’s carbohydrate, protein, fat, mineral, and energy metabolism
  • It has a protective effect on enzymes and vitamins, as well as an inhibitory action on proteins and the amino acids.
  • It contains the highest degree of digestibility (bioavailability)
  • The mineral contents of this formula are low, ensuring maximum digestibility and minimal environmental pollution.

Phosphates are inorganic salts of phosphorus. The three primary types of phosphates used in pet food are tricalcium phosphate, dicalcium phosphate, and monocalcium phosphate.

Phosphorus is an essential mineral for dogs and is needed for proper bone and teeth development. It is also involved in many other metabolic processes including energy production, cell growth and repair, and muscle contraction.

Digestibility of Monocalcium, Dicalcium and Tricalcium Phosphates:

Absorption of phosphorus from tricalcium phosphate is about 28%, while absorption from monocalcium phosphate is about 70%. Dicalcium phosphate absorption falls somewhere in between at 40-60%.

The table above is in line with another study that saw higher digestability of calcium and phosphorus in monocalcium(mCaP) compared to in dicalcium phosphate(diCaP).

Monocalcium Phosphate in dog food:

Monocalcium phosphate is a highly digestible form of phosphorus that is commonly used in dog food. This type of phosphorus is easily absorbed by the body and helps to maintain healthy bones and teeth. Monocalcium phosphate also supports proper kidney function and helps to keep the immune system strong.

Dogs that are not getting enough phosphorus in their diet may show signs of weakness, lethargy, and poor appetite. If you think your dog may be deficient in phosphorus, talk to your veterinarian about supplementing their diet with monocalcium phosphate.

Dicalcium phosphate(DCP) in dog food:

Dicalcium phosphate is another form of phosphorus that is commonly used in dog food. This type of phosphorus is not as well absorbed as monocalcium phosphate, but it is still a good source of this essential mineral.

According to this 1999 Research, dicalcium phosphate is a mix of varying amounts of dicalcium and monocalcium phosphates, phosphoric acid, calcium carbonate, and impurities, depending on the origin of the raw material and procedures employed in its industrial production.

DCP is a common supplement and tartar control aid that’s also used to improve cat and dog food texture. It is however insoluble, nonabsorbent, and cannot take in water. It has been linked to kidney stones in humans as well as calcification of soft tissue in pets.

The table shows the higher rates of digestibility of dicalcium phosphate compared represented below as DCP1 to monocalcium phosphate (represented below as MCP1). This is according to a recent 2021 Study on Digestability of Calcium Phosphate compounds;

Tricalcium phosphate in dog food:

Tricalcium phosphate is a form of phosphorus that is less well absorbed than other forms of this essential mineral. This type of phosphorus is often used in dog food as a cheaper alternative to monocalcium phosphate or dicalcium phosphate.

Is monocalcium phosphates safe for dogs?

It is safe and is often added to boost the amounts of Phosphorus in dog diets as most commercial dog food lack them. Experts recommend getting monocalcium phosphate supplements if your dog is not getting enough phosphorus in their diet. FDA has approved it as a food additive for pets and humans.

Ideal calcium, and phosphorus ratio for dogs:

The ideal ratio of calcium to phosphorus in the diet of dogs is 1.2:1 to 1.3:1. The Ca:P ratio in tricalcium phosphate is 1:1, in dicalcium phosphate 2:1, and in monocalcium phosphate 0.5:1. This means that tricalcium phosphate contains more phosphorus than calcium, while monocalcium phosphate contains more calcium than phosphorus.

When choosing a phosphorus supplement for your dog, it is important to consider the absorption rate of the phosphorus as well as the ratio of calcium to phosphorus. Monocalcium phosphate is a highly digestible form of phosphorus that is easily absorbed by the body. This type of phosphorus is ideal for dogs that are not getting enough phosphorus in their diet or for dogs that are at risk for phosphorus deficiency.

Side effects of monocalcium phosphate:

The main side effect of monocalcium phosphate in dogs when consumed in excess is cardiovascular issues and problems with calcium homeostasis. When not in the right ratio with calcium, phosphorus can cause these adverse effects. If you think your dog has consumed too much monocalcium phosphate, contact your veterinarian immediately.