Vitamin and Mineral Supplementation for Herps
©1996, 2002 Melissa Kaplan
There are two types of supplements you need for your iguana: a multivitamin supplement and a calcium supplement. Most multivitamin supplements have some calcium but not enough to counterbalance the phosphorous naturally found in the food - even when sticking to foods high in calcium. That's just one of the not insurmountable problems when feeding a vegetarian diet....actually, it is a vegan diet as many vegetarian humans eat eggs and dairy products, both sources of calcium that are not available to iguanas (because animal protein is unhealthful for them).
The reptile multivitamin supplements out there are about the same. You can buy a reptile multivitamin supplement (names like Herptivite, Reptivite, Reptisol, etc.) or you can buy a bird vitamin such as Avitron, or a general animal vitamin like Vionate, buy and crush the canine Pet Tabs, or get a human vitamin - Centrum contains more vitamins and trace elements than any of the reptile and pet vitamins on the market. I use Vionate because not only is it a good quality vitamin but I can buy it in 4 lb jars (I, uhm, make a lot of iguana salad...)
There are lots of calcium supplements on the market - Repcal, Reptical, Osteoform, Miner-All, and Os-Cal to name a few. Many brag about the D3 or D they have added to it, and many have A, D and E in them. While vitamins A, D, E and phosphorous are necessary to the body for use in calcium metabolism, they are already included in the multivitamin supplement (which contains many other vitamins and minerals the fortified calcium supplements do not have) and from the food. With one exception. D3 (cholecalciferol) is essential to calcium metabolism, and is made in the iguana (and human, for that matter) skin by contact with sufficient UVB wavelengths. Plants contain another type of vitamin D, called D2 (ergocalciferol). D2 is not nearly as efficient, close, in fact to being worthless, at metabolizing calcium, hence the need for D3.
To m,ake things more interesting, some research suggests that iguanas may not utilize much or any of the D3 they ingest (as given in a vitamin supplement), only that made by the UVB-skin interaction; other research suggests that iguanas are able to utilize at least some dietary D3.
Therefore, buying a calcium supplement that contains only D3 may not be useful for the calcium metabolism. Products such as Solar Drops and Moon Drops is a waste for iguanas (and possibly other diurnal and nocturnal reptiles as well, especially omnivores and carnivores who get most of their D3 from the prey they eat) as it misleads people who think that they are making up for the lack of sun or other proper UVB access, and harms the iguana who ultimately suffers from metabolic bone disease from inadequate calcium being metabolized. Since vitamins and minerals act synergistically with one another, it is essential that, in the absence of a specific, documentented vitamin or mineral deficiency (as tested by your veterinarian), we provide a good multivitamin supplement, not just a D3 supplement.
I use plain old calcium carbonate, relying on the variety of fresh foods and multivitamin (Centrum or Vionate) to provide the A, E, and other vitamins and minerals, to ensure that they are getting enough calcium to balance out the phosphorous and calcium oxalates in their food, and natural sun, augmented with UVB-producing fluorescents as necessary, for the natural production of D3 and for the visual stimulation provided by the UVA in these lights.
One needs to read the labels when choosing a vitamin supplement for reptiles. The ratio of vitamin A to vitamin D to vitamin E should be 100:10:1. One popular "reptile vitamin" (with the word "rep" in the name!) has an A to D ratio of over 600:1 instead of 100:10!!
Unfortunately, label reading doesn't always guarantee you are getting what the label says. Reptile vet/nutritionist Susan Donoghue found when doing analysis of reptile and mammal vitamins that Nekton Rep didn't include four of the minerals the label said it did, including calcium! She also states that no multivitamin has enough calcium for green iguanas, and that what ever multivitamin supplement is used, they will need to be additionally supplemented with a calcium supplement.
I take the lazy way and mix the vitamins in with the food when I prepare large batches of it. If I am making food on a day to day basis, I will mix the vitamins in right before serving. You can also make large batches and mix the vitamins in right before serving.
Mix the vitamins in - don't sprinkle them on top. If your iguana is eating everything or most of what is on his plate, the vitamins mixed into the food will be mostly tasteless (there are some that igs don't like, and occasionally batches of vitamins may spoil - they really have a very short shelf life - and taste off. If your ig is not eating well, getting him to eat the vitamins by sprinkling them on top is not going to keep or make your iguana healthy. You must address the underlying problem.
Based on what I have read in many different books and articles, here's what I've been recommending as a likely supplement schedule. Note that it is tailored to the age or condition of the iguana based on the different needs of these iguanas at these times.
Vitamin Supplementation, Days Per Week
Other Questionable Vitamin Products/Sources
T-Rex 2:1 Cal/Phos
T-Rex Bone Aid
Caveat About Vitamin and Mineral Products
Just because the pet product manufacturers are making vitamins, doesn't mean they really know what they are doing or that they have actually conducted rigorous tests or relied on any such tests in developing their product.While some is good, more is not necessarily better...
Oversupplementation of vitamins can be harmful. Vitamins A and D can cause serious problems, including liver, skin, and eye problems, and metabolic bone disease.
Excessive amounts of calcium, previously uncommon in iguanas, may become an increasing problem as owners, scared of MBD, overcompensate and give too much calcium. Hypercalcemia may also occur in conjunction with protein/hydration induced kidney failure, can cause bone defects, cardiac changes, hyperthyroidism, shock, renal hypertension and failure and death.
It should be noted that vitamins A and D are heavily laced into dog and cat foods, another reason why they are so harmful to iguanas. Fat (both that found in commercial mammal foods and many human foods derived from animal protein or made with oils and fats, as well as the fat in soy products such as tofu) can also impede calcium metabolism, causing metabolic bone disease.
The best way to find out how you are doing supplement-wise is to have an annual blood test done on your iguana.
Donoghue, S. and J. Langenberg. (1996) Nutrition. In, Reptile Medicine and Surgery. D. M. Mader, DVM (Ed.) WB Saunders Company, Philadelphia PA, pp. 148-174.
Barten, S.L. 1996. Personal communication.
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