Vitamin D is just one more way your cat’s food may be killing her.
Recently Rachael Ray Nourish wet cat food was recalled over elevated Vitamin D levels. This coincided with a conversation I just had with a veterinary nutritionist about study regarding Vitamin D in cats.
A study published May 13, 2015 found that the level of Vitamin D in the blood of hospitalized cats predicted their likelihood to survive. In fact, in this case it was low Vitamin D levels that indicated a higher risk of death in these sick cats.
Food is the only source for Vitamin D in cats. They do not manufacture it in their skin with the help of sunlight like people do. This led me to ask the nutritionist about Vitamin D levels in cat food. Could low levels in cat food be responsible for poor disease recovery? Might it be causing fatal disease in the first place?
The study did not answer these questions, it simply noted the correlation. Low Vitamin D levels could just be a marker of some other unknown factor. And the food may not be the culprit. Maybe some cats can’t absorb or metabolize Vitamin D properly. Maybe it’s the absorption or metabolism problems that led to the poor recovery of these cats.
A previous study found that cats with tooth resorption (a painful disease of cats that causes their teeth to dissolve at the gum line) have significantly higher serum concentrations of Vitamin D than do cats without this condition. In a separate study, these researchers also found that 41% of canned cat foods have in excess of 30 times the vitamin D requirement of cats.
Vitamin D is an extremely important vitamin. It acts as a hormone in the body and regulates calcium metabolism which is important in bone growth and maintenance. Vitamin D deficiency causes Rickets in the young and osteomalacia (softening of the bones) in adults. Vitamin D excess leads to too much calcium in the blood. This can cause calcification of body tissues and the formation of bladder stones. Either too much or too little Vitamin D in cat food is a serious problem.
It is truly the Wild West when it comes to Vitamin D for cats. The nutritionist I spoke to told me of her research into the Vitamin D contents of cat foods. She found that the Vitamin D in feline diets ranges from 98 – 1,305 IU/1,000 Kcal. The AAFCO guidelines allow for levels of 125 – 2,500 IU/1,000 Kcal.
Why such a wide range? Well for one thing, other components of the food affect Vitamin D metabolism. For example, dietary fiber decreases Vitamin D absorption. So you would expect a weight-loss diet that uses fiber to decrease calories to require a higher Vitamin D level.
But most of all, I think pet food companies are clueless about the appropriate level of Vitamin D for their foods. My suggestion; grind up a mouse, measure the nutrient levels, and mimic those. Mother Nature still knows best! I’ll let you know if anyone ever follows my advice (don’t hold your breath).
Do you trust your cat’s food? Why or why not?