Reference Links - Goitrogens
Feeding goitrogenic foods as a significant part of the diet, human and iguana, can thus lead to hypothyroidism. This leads to reduced activity levels, reduced metabolic rate, muscle and joints aches and pains." [1] Personally, I have hypothyroidism and it sucks. Proper thyroid function is incredibly important to almost every single system in the body.
One problem with isolating good information, 'goitrogens' are not an isolated nutrient/chemical/compound. They are actually a number of substances that have the effect of thyroid suppression due to interfering with the uptake of iodine. [2] Due to how common hypothyroidism is in humans, most research and information is related to us. Cruciferous vegetables has popped up time and again though, and there is a problem with that, for me. Searching for the compound 'glucosinolate' had a lot more vauable information than 'goitrogen' did. This is stated as being the primary compound that brassica family plants have. [3]
These plants include most of the 'good' leafy greans. This includes the typically "recomended" cultivars: Arugala (Rocket), Collard Greens, Mustard Greens and Turnip. I haven't been able to locate much information quantifying what a 'high' goitrogen content in a plant is.
The previous source gave the following information:
Broccoli: 61 mg/100g
Cabbage: 78 mg/100g
Kale: 100 mg/100g
Mustard Greens: 282 mg/100g
There also apears to be a link between age and levels of the substances of concern, one study indicated that young broccoli have 10-100x more glucosinolates than older plants. [I can't find this source again right now] This has me VERY confused, and I hope to eventually uncover the differences in the levels.
Anyway, Here are some links for my personal reference or your own edification.
anapsid.com - hypothyroidism in green iguanas (2000)
Hypothyroidism and goitrogens have nothing to do with calcium deficiency (metabolic bone disease), the mineralization of soft tissues (due to high levels of calcium oxalates or oxalic acid intake), thiamine deficiency, or kidney failure.
Reptilian Endocrinology (2008) - This source has some study based information regarding the endocrinology and the way it works in reptiles, with out specific relation to diet as far as Goitrogens are concerned. This seams like a rather interesting if dry read.
Phytochemical and Ethnobotanical Databases
Animal Science - Plants Poisonous to Livestock (No reference to Reptiles)
These compounds often contribute a bitter, "hot" taste to condiments (mustard, horseradish) and may exhibit goitrogenic or antithyroid activity.
Isothiocyanates (2008) - This is a great detailing the chemical reactions/exchanges
Food Lists - I have not confirmed the contents of these. I am using them to help build a matrix of information to see if any agrees on anything.
Food for Herbivorous Reptiles
Beautiful Dragons - A frequently cited/referred resource in the BD community.