Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Green Iguana Diet: Not Just A Matter Of Calcium:Phosphorous Ratios

©2000 Melissa Kaplan

The question of why my recommended green iguana diet (known around the Internet as the "MK salad" or "MK diet") includes plants that don't have 2:1 Ca:P ratio periodically comes up. It's a question that reflects a lack of understanding about diets and overall health in general.

As humans, we consume a widely varied diet - or should. With the exception of those who are on strict diets due to health problems, and perhaps vegans, most people eat a range of foods that can be classified as "very healthy" to "lousy for health but good for the soul". While the former category may include fresh vegetables, whole grain breads, and heart-healthy salmon, the latter may include things like a slab of heavily frosted, triple-layered Death By Chocolate cake. If all you ate was Death By Chocolate, your soul might be very happy, but your heart and the rest of your body wouldn't be doing so well. By the same token, if all you ate was a big pile of broccoli and carrots every day, your body would eventually suffer from malnutrition.

A healthy diet for iguanas must include far more than just the right amount of calcium and phosphorous (and UVB exposure). To grow, develop and maintain muscle tissue, organ tissue, and keep everything running properly, and deal with the stresses of daily life and seasonal cycles, iguana, like all animals, need protein, carbohydrates, some fat, lots of fiber, and the full range of vitamins, minerals, and trace elements. The vegetables and fruit in my recommended diet are selected to provide the nutrients iguanas need, when fed in conjunction with the proper selection of leafy greens and supplemented with vitamins as needed. For a more complete analysis of what the MK salad is, please see "MK Diet" Composition. While some people don't use any vitamin supplementation, other than additional calcium starting just before their female's breeding season starts to ensure she has enough calcium in case she becomes gravid, since the actual vitamin and mineral content of plants can vary depending on where they are grown, and because chronic stress depletes many vitamins, minerals and trace elements more rapidly, many vets and experienced herp keepers recommend a regular schedule of vitamin supplementation.

Thus, if you construct your iguana's diet solely from foods listed from the plants that are high in calcium and low in phosphorous, you will end up with a malnourished iguana. If you use a variety of foods selected to provide the protein, carbohydrates, fiber, and fat, as well as moisture and color to make the food more palatable and attractive to the iguana, the iguana's nutritional needs will be met, growth and development will progress normally, and you'll have a far healthier iguana, nutritionally speaking.