December 19, 2016

Calcium Metabolism in Great Dane Dogs Fed Diets with Various Calcium and Phosphorus Levels

As part of a study to determine how Great Danes processed calcium at early stages, 47 Great Danes were fed from birth either normal diet, a high-calcium diet, or a low-calcium diet. Great Danes were selected because their weight and metabolism is roughly the same as a human and the results could prove useful for clinical knowledge. The dogs were allowed time to run outside for some of the day and spent the rest of their time in metabolic cages to collect their urine and fecal matter. They were given as much water as they wanted. The dogs were split into 7 groups with different diets. 2 groups were given different quantities of normal calcium diets, 2 groups were given high calcium diets with varying amounts of phosphorus, and three groups were given low calcium diets. The researchers checked the amount of calcium in the dogs’ plasma, urine, and fecal matter in 6 week intervals starting at 8 weeks of age. They used that data to calculate the amount of calcium absorbed by the body

They found that the dogs fed on low calcium diets by 26 weeks were able to absorb more than 80% of the calcium in their food, while dogs fed on the high calcium high phosphorus diets absorbed a significantly lower percentage than the low calcium diet dogs as well as the control group. However, the dogs fed on the high calcium normal phosphorus diet absorbed roughly the same percentage of calcium as the control group, leading to high calcium absorption during the entire experiment. This came as a surprise to the researchers, who expected a decrease in absorption. These dogs had insufficient amounts of phosphate and some developed hypophosphatemia, which affects bone growth and hormone production. The researchers hypothesize that this is the reason the calcium absorption did not decrease in this particular group.

At the end of the trial, they found that the calcium absorption in the group fed a high calcium diet eventually reached the same magnitude as the dogs in the control group. The researchers also suggest that young dogs fed a high calcium diet may be at a high risk for absorbing too much calcium because their bodies haven’t learned to adapt yet. They also found that great danes that ate calcium-rich food in restricted amounts developed less health problems than those that ate calcium-rich food as much as they wanted. This means that puppies shouldn’t be over-nourished. The study also determined that the minimum nutrient requirements for large dogs is likely too low, as the dogs on the low calcium diet developed osteoporosis.

Reviewed by Jason Hammerman.

Orginihal article: http://jn.nutrition.org/content/121/11_Suppl/S99.long

Hazewinkel, Herman A. W, Walter E. Van Den Brom, Arie TH Wan't Klooster, George Voorhout, and Ank Van Wees. "Calcium Metabolism in Great Dane Dogs Fed Diets with Various Calcium and Phosphorus Levels." Journal of Nutrition 121.11 (1991): S99-106. Web. 24 Oct. 2016.