Vitamin D is an essential nutrient for mineralization and skeletal growth. Both its deficit and its excess can cause injuries at the systemic level, hence the need for adequate supplementation in humans and pets.
Vitamin D is a compound naturally synthesized by plants and mammals in response to ultraviolet radiation. However, in the case of dogs, this process is more limited; It has to incorporate most of it through the diet.
Vitamin D provided with food is absorbed by the intestines, transformed by liver enzymes, and metabolized by the kidneys. The result is an active molecule, calcitriol, which is mainly stored in fatty tissue.
This nutrient, apart from being key to the bones, is essential for the muscular and nervous system. Thus, any mismatch in the recommended dose causes a biochemical imbalance that can lead to lethargy, the appearance of tumors, or even death.
Vitamin D associated disorders
Vitamin D requirements for dogs depend on calcium and phosphorus concentrations, age, and, to a lesser extent, sex and breed. Among the most recent estimated values are those of the Association of American Feed Controls Officials (AAFCO). This body stipulated in 2007 the approximate dose of 500 IU daily per kilogram of diet.
The most common disease associated with the deficit is rickets, a bone disorder that affects young animals. This is caused by the decrease in calcium and phosphorus concentrations in the organic matrices of bones and cartilage.
It is the overdoses of vitamin D that cause the most harmful conditions due to the so-called calcifications.
Among the most frequent symptoms of poisoning by this nutrient are vomiting, excessive urination, dehydration, and loss of appetite. In more severe cases, the damage may involve cardiac, renal, intestinal, and pulmonary bleeding and soft tissue mineralization.
The most common cause of vitamin D poisonings is due to feed intake with an excessive dose of said compound. However, the accidental consumption of rodenticide cholecalciferol, the chemical name of the active molecule of vitamin D., is also common.
Treatment against intoxication
The medical protocol to address the excessive increase in the body’s vitamin D levels in dogs depends on their amount, and the time elapsed. In milder cases, gastrointestinal lavage is performed, which can lead to vomiting and the administration of activated carbon.
In the event that more than six hours have passed after ingestion, it can be treated with calcitonin, prednisone, diuretics, and bisphosphonates. These compounds interfere with calcium absorption by increasing their excretion through the urine.
In December 2018, the Food and Drug Administration ( FDA ) published a series of poisonings in dogs that had ingested commercial feed. The common problem was the presence of a higher dose than recommended, which led to its withdrawal from the market.