Improper Diet Cascade
Improper Diet Cascade (IDC) is a theory by bird veterinarian Greg J. Harrison, DVM that links a wide variety of illnesses, behaviors, etc. to problems in the diet. It is similar to proposals made about human and other animal diets as we find that more and more issues are interconnected. The over-simplified version is “you are what you eat”. If we offer foods that are too high or too low in nutrients (even “micro- nutrients” like selenium) or foods that have lost nutritional values or gone “bad” due to poor handling or storage, etc. then it will have real effects on whatever eats it.
The effects may start small – pH imbalances, cellular issues, etc. – but the “cascade” part kicks in as effects snowball and little issues start building into major problems.
We already know that the foods we offer tortoises in captivity are nothing like what they get in the wild: most wild foods are much higher in available calcium and fiber for example. We try to make up for this with additional variety or pelleted diets, and yet we still see many issues that can be traced to diet: soft shells, pyramiding, respiratory illnesses, listlessness, unusual growth patterns, reproductive failures…
The visible symptoms of IDC do not show up until things have been going wrong on a cellular level for some time.The first signs often show up in the feathers in birds, so probably show up on the skin on tortoises, although we probably cannot easily see it. There may be small changes such as dry, flaky skin, loss of color, loose scales, excess
IDC is fatal in severe cases, but would more likely cause long-term problems, like shorter lifespans, increased susceptibility to disease or parasites, reduced reproduction, increased medical problems, and so on.
While there is no single, quick fix to IDC, the original article makes several suggestions that we can adapt for use with tortoises. While many of these are mentioned elsewhere on this site, here are the main ideas: