Needless to say, knowing what foods are toxic to bearded dragons is a basic part of animal husbandry. But, it’s not just about knowing what is toxic to bearded dragons, there are also antinutrients.
Antinutrients aren’t considered toxic but some of them reach levels beyond the capacity of the bearded dragons to deal with safely. This article is about identifying what foods bearded dragons can’t eat and and looking at what science has to say about processing foods we want them to eat to reduce the levels of antinutrients.
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Foods that are Toxic to Bearded Dragons
| Food | Description |
|---|---|
| Amaranth hybridus | May contain toxic levels of nitrates. |
| Animal products | Seafood and poultry are not suitable for bearded dragons due to their inability to digest these foods properly. |
| Apple, apricot, cherry – seeds & plant | Seeds and plant are cyanogenetic. |
| Avocado leaves (and fruit) | Avocado contains persin, which is toxic to many pets, including bearded dragons. |
| Cassava | Leaves and roots are cyanogenetic. |
| Chives | Similar to onions and garlic, can be toxic and cause digestive issues. |
| Citrus fruits | High acidity can upset the digestive system and lead to long-term health issues including: |
| -Lemons | |
| -Limes | |
| -Oranges | |
| -Grapefruits | |
| -Tangerines | |
| -Pomelos | |
| -Citrons | |
| -Clementines | |
| -Key limes | |
| -Ugli fruit (a type of tangelo) | |
| Clover White or Yellow sweet clovers | May have toxic levels of nitrates. |
| Clover – Trifolium spp | May cause photo sensitization and contact dermatitis. |
| Dairy products | Bearded dragons cannot eat dairy products, they cannot digest the lactose. |
| High fat foods can disrupt the metabolism of calcium, essential for bone health. | |
| Eggplant leaves | Eggplant, being a member of the nightshade family like tomatoes and potatoes, also has leaves that contain solanine. |
| Garlic greens | Similar to onions, garlic and its greens contain compounds that can be harmful to bearded dragons. |
| Grasses – Arrowgrass, Mesquite grass, Sudan grass, Witchgrass | Leaves and plant are cyanogenetic and some may contain toxic levels of nitrates. Witchgrass is hepatogenic and may have toxic levels of nitrates. |
| Iceberg lettuce | Although not toxic, iceberg lettuce is discouraged as it is associated with diarrhea due to its high water content. |
| Leeks | Can cause digestive issues and potentially lead to blood abnormalities. |
| Oats | Non toxic unless infected with fungi. |
| Onion greens | Onions and their green parts can be toxic to bearded dragons, potentially leading to digestive issues and blood abnormalities. |
| Potato leaves | The leaves of the potato plant contain solanine, a toxin that is harmful to bearded dragons. |
| Rhubarb | Leaf and plant have cathartic toxins including oxalic acid. |
| Sage | Some varieties may have toxic levels of nitrates. |
| Shallots | Contains compounds that can be harmful, similar to onions and garlic. |
| Sweet potato vine | Contains LSD related hallucinogens and possibly toxic levels of nitrates. |
| Mushrooms wild varieties | Potential toxicity, specific varieties can be poisonous. Bearded dragons natural diet does not typically include fungi, and the calcium to phorphorus ratio is poor. For example: |
| -button mushrooms have 5mg calcium and 93mg of phorphorus being a ratio of 0.1:1; and | |
| -portabello mushrooms have a calcium content of just 3mg with 87mg of phosphorus at a ratio of 0.0:1. | |
| Sourgrass | Plant is cyanogenetic. |
| Tomato vines and leaves | Tomato plants, particularly their leaves, contain solanine and other toxic alkaloids that can be harmful. |
| Insects | Boxelder bugs (lygaeid bugs) |
| Fireflies (Photinus spp) | |
| Monarch butterflies (Donaus plexippus) | |
| Queen butterflies (D. gillipus) | |
| Lady Beetles (particularly Harmonia axyridis) | |
| Insects that are known to have venom, as they can pose serious health risks. | |
| Deceased insects may no longer possess nutritional value and might harbor bacteria. | |
| Undernourished insects (not fed or not fed gut loading diet). |
1. Vegetables and Herbs that are Toxic to Bearded Dragons
Certain vegetables contain compounds that are toxic to bearded dragons. Here’s some toxic plants beardies shouldn’t eat:
- Onions, garlic, and chives: Can damage red blood cells and cause digestive problems.
- Mushrooms: Some varieties contain toxins harmful to reptiles.
- Rhubarb and avocados: Highly toxic, even in small amounts.
These plants contain chemicals or oxalates that interfere with calcium absorption, essential for bearded dragons’ bone health. These are certainly at the top of the list of what bearded dragons can’t eat.
2. Acidic Fruits: Foods Bearded Dragons Can’t Digest Easily
Highly acidic fruits like oranges, lemons, limes, pineapples, and tomatoes can irritate bearded dragons’ digestive systems. Feeding acidic fruits regularly can harm their stomach and intestinal lining.
3. Bearded Dragons Shouldn’t Eat High-Sugar Foods
Bearded dragons don’t metabolize sugar as humans do, so high-sugar foods can lead to obesity and health complications. Avoid fruits with bananas and grapes leading the list.
Flowers that are toxic and extremely dangerous are azaleas, daffodils, and tulips. Marijuana is also toxic to reptiles.
Mader (2006)
Anti-Nutrients & Toxins: Which to Avoid or Manage
Some common foods for bearded dragons can contain compounds that may harm their health. While certain anti-nutrients like goitrogens and oxalates are manageable in small amounts with careful food rotation, others, such as cyanogenic compounds or persin, are outright toxic and should never be included in their diet. Below is a guide to understanding these compounds and knowing which foods to avoid entirely, along with those to offer in moderation for a balanced, safe diet.
1. Goitrogens
Goitrogens are in foods like kale, cabbage, and broccoli. Goitrogenic foods can strain the thyroid gland, required for hormone production and regulation. Although goitrogenic foods aren’t off the table (pardon the pun), they should be fed sparingly, particularly if your bearded dragon has thyroid-related health issues. Consult a vet for specific advice if needed.
However, the great news is that goitrogens are somewhat destroyed during cooking.
Research by Panduang et al., (2023) provides great insight into how to reduce goitrogens. They found that when cabbage is steamed at 100°C for 4 minutes its goitrogen levels drop a staggering 82%. When blanched for 2 minutes at 100°C the goitrogens drop 78.9%.
Panduang et al. (2023) also provides insights on Chinese kale. When Chinese kale was steamed at 100°C for 2 minutes the goitrogens dropped by approximately 32%. However, blanching Chinese kale at 100°C for 2 minutes slightly increased goitrogen levels due to enzymatic reactions, making steaming the better option for reducing goitrogens in this vegetable. For more information on blanching and steaming bearded dragons meals for the article on freezing vegetables with bulk meal preparation.
| Component | Goitrogen Level (Goitrin) ng/mL |
|---|---|
| Cabbage Raw Value | 251.5 |
| Cabbage Blanched (100°C, 2 min) | 53.2 |
| Cabbage Blanched (100°C, 4 min) | 48.2 |
| Cabbage Steamed (100°C, 2 min) | 45.2 |
| Cabbage Steamed (100°C, 4 min) | 45 |
| Cabbage Steamed (100°C, 6 min) | 55.3 |
| Chinese Kale Raw | 82.3 |
| Chinese Kale Blanched (100°C, 2 min) | 90.4 |
| Chinese Kale Steamed (100°C, 2 min) | 56.1 |
| Chinese Kale Steamed (100°C, 4 min) | 62.2 |
2. Oxalates (Oxalic Acid)
Oxalate can be found in relatively small amounts in many plants.
Noonan & Savage (2002)
Oxalates, also known as oxalic acid, are compounds found in certain leafy greens and vegetables. Oxalate is considered both an antinutrient and a toxin (Libert and Franceschi, 1987).
Oxalates bind with minerals like calcium, iron and magnesium which reduces their absorption. The main concern is the disruption to the ideal calcium-to-phosphorus ratio (1:1 or 2:1) necessary for bone health in bearded dragons.
Oxalates are present in two forms: soluble oxalate (sodium, potassium and ammonium salts), and insoluble oxalate (calcium, iron and magnesium salts)
(Noonan and Savage, 1999)
Plants like soursob (Oxalis spp), curly dock (Rumex crispus), Acacia spp., and purslane (Portulaca oleracea) contain high levels of oxalates (Rahman et al., 2012). None of these plants should be fed to bearded dragons.
Foods like spinach and beet greens also have high oxalates but may be fed in small, rotational amounts if your bearded dragon has no underlying health issues. Consult your vet if you are unsure.
To give some context as to what level of oxalate is in various plants, based on per 100 grams of fresh weight, as per research by Noonan and Savage, (1999):
- Rhubarb 275-1336 mg
- Purslane 910-1679 mg
- Spinach 320-1260 mg
- Beet leaves 300-920 mg
- Amaranth 1087-1586 mg
- Apples 0-30 mg
- Cabbage 0-125 mg
- Parsley 140-200 mg
- Lettuce 5-20 mg
Soaking and cooking of foodstuffs high in oxalate will reduce the oxalate content by leaching.
Noonan & Savage (2002)
Some oxalates are water-soluble, meaning they dissolve in water (like sodium, potassium, and ammonium oxalates). Other oxalates are insoluble (like calcium, iron, and magnesium oxalates) so they do not.
Treating foods high in soluble oxalates with blanching and steaming can reduce some of their oxalate content, as these processes help leach out the soluble portion. Just as we saw previously with goitrogens. Insoluble oxalates, however, are not affected by these methods.
3. Cathartic Toxins
Cathartic toxins are compounds that stimulate the intestines, causing a strong laxative effect. These toxins are found in plants like rhubarb leaves, which contain anthraquinones that can lead to severe digestive distress, diarrhea, and dehydration if ingested.
Aloe vera also contains anthraquinones, particularly aloin, which can have similar strong laxative effects. The presence of both oxalates and cathartic toxins makes rhubarb especially dangerous for bearded dragons, and it should never be fed to them.
4. Other Phytochemicals
In addition to goitrogens and oxalates, some foods contain phytochemicals like saponins, tannins, terpenoids, and glycosides. While these can be safe in small amounts, excessive consumption may interfere with nutrient absorption. For example, saponins can reduce the absorption of fat-soluble vitamins like A and E. If feeding various live plants, be sure to balance with vitamin-rich foods for comprehensive nutrition.
4.1. Saponins
Saponins are found in alfalfa, quinoa, and some varieties of legumes. While alfalfa sprouts can be in a bearded dragon’s diet, as with all food, it should be rotated with other greens to avoid nutrient absorption issues.
For humans, saponins are known to offer potential benefits, such as cholesterol-lowering and anticancer effects, by binding to bile acids and inhibiting certain cancer cells.
However, saponins can also reduce the absorption of minerals like iron and zinc, which may impact nutrient intake if consumed in high amounts. Research by Livingston, et al., (1984) shows that harvesting alfalfa sprouts within 2-4 days of sprouting lowers the levels of saponins.
| Sprouting Stage | Caliverde Saponin (%) | Moapa Saponin (%) | Ranger Saponin (%) |
|---|---|---|---|
| Seed (Day 0) | 0.14 | 0.12 | 0.11 |
| Day 2 | 1.78 | 2.01 | 2.25 |
| Day 4 | 2.11 | 3.24 | 2.24 |
| Day 6 | 3 | 7.27 | 2.78 |
| Day 8 | 3.59 | 7.24 | 3.14 |
4.2. Tannins
Tannins are present in foods like kale, collard greens, and dandelion greens. Tannins can bind with proteins and minerals, which may hinder nutrient uptake if fed in large amounts. Offering these foods in moderation ensures they’re part of a balanced diet.
Weeds that commonly have high nitrate concentrations are pigweed, lamb’s quarter, thistle, Jimson weed, fireweed (Kochia), smartweed, dock, and Johnson grass.
Thompson, (2020)
4.3. Terpenoids
Terpenoids are found in many herbs, such as basil, oregano, and parsley. While safe in small quantities, overfeeding herbs with terpenoids could impact your dragon’s digestion and should be balanced with other greens.
4.4. Glycosides
Glycosides are present in foods like apple seeds (which should be avoided entirely) and sweet potato leaves. Apple seeds contain harmful cyanogenic glycosides and should be kept out of your bearded dragon’s diet, while the sweet potato leaves should be limited due to their mild toxicity.
5. Additional Toxins to Avoid in Bearded Dragon Diets
5.1. Cyanogenetic Compounds
Cyanogenic compounds are naturally present in many foods, often in trace amounts that are too low to pose harm, especially when dealing with non-seed parts or properly processed items.
Being present in so many foods, cyanogenic compounds are simply impossible to avoid. Certain plant parts contain cyanogenic compounds at levels that release dangerous amounts of cyanide when digested. Foods that are toxic to bearded dragons include apple seeds; pits of stone fruits like apricots, peaches, and cherries; bamboo shoots; and cassava.
Cyanogenic glycosides are plant toxins that can release hydrogen cyanide (HCN) and are present in >2500 species of plants and their related foods. HCN is released from cyanogenic glycosides via two routes: within the plant itself or after ingestion of the plant material.
Park et al., (2024)
| Plant and Part Tested | Total Cyanogenic Compounds (mg/kg) | Comparison Level |
|---|---|---|
| Cassava (Root) | 85 | High |
| Prunus mume (Japanese Apricot, Seeds) | 60 | High |
| Apricot (Seeds) | 55 | High |
| Apple (Seeds) | 50 | Moderate |
| Peach (Seeds) | 50 | High |
| Loquat (Seeds) | 48 | Moderate |
| Cherry (Seeds) | 45 | Moderate |
| Plum (Seeds) | 42 | Moderate |
| Plum (Seeds) | 42 | Moderate |
| Bamboo Shoots | 40 | Moderate |
| Lima Beans | 35 | Low |
| Flaxseed | 30 | Low |
| Dried Apricot (Whole Fruit) | 20 | Low |
| Loquat (Pulp) | 15 | Low |
| Apple Pulp and Peel | 10 | Low |
| Grape Seeds and Peel | 8 | Low |
5.2. Hallucinogenic Compounds
Some plants, like sweet potato vine, contain mild hallucinogenic substances. These are known to cause confusion and abnormal behavior, so it’s best to avoid feeding plants with these compounds to prevent nervous system issues.
5.3. Nitrates
Nitrates are common in soil, water, and some vegetables, nitrates are safe in small quantities. Some foods high in nitrates are parsley and spinach (Salehzadeh et al., 2020). Excess nitrates can be toxic to bearded dragons and interfere with oxygen transport in the blood, so foods high in nitrates should be limited.
| Vegetable (Part) | Nitrate Level (mg/kg) | Relative Level |
|---|---|---|
| Parsley | 562 | High |
| Cabbage | 530 | High |
| Basil | 507 | High |
| Beet leaves | 439 | High |
| Radish | 381 | Moderate |
| Lettuce | 370 | Moderate |
| Carrot | 324 | Moderate |
| Tomato | 166 | Low |
5.4. Persin
Avocados contain persin, a toxin harmful to many animals, including bearded dragons. Even a small amount can cause serious digestive and health issues, so keep avocados entirely off their menu.
5.5. Solanine
Solanine is a natural toxin is found in green or sprouted potatoes and tomatoes. Solanine can cause digestive issues and, in larger quantities, may negatively affect the nervous system. Solanine cannot be destroyed by cooking.
Solanine is not removed by boiling, but it can be destroyed by frying.
Crews (2014)
5.6. Phytochemicals
Other phytochemicals, including saponins, tannins, terpenoids, and glycosides, can interfere with nutrient absorption if consumed in excess. For instance, saponins may reduce the absorption of essential fat-soluble vitamins like A and E.
How to Treat Foods to Reduce Antinutrients
Creating the right diet plan for bearded dragons can be challenging due to these anti-nutrients in many common foods.
The good news is that blanching vegetables can help reduce levels of goitrogens, oxalates, and other phytochemicals. For step-by-step blanching instructions and recipe examples, check out our post on Can Bearded Dragons Eat Frozen Food.
Mosha et al., (1995) demonstrated that the antinutrients in foods like oxalic acid, phytic acid and tannic acid can be reduced by blanching for 2.5 minutes. Here are some examples from the research.
| Vegetable | Cabbage | Collard | Sweet potato | Turnip | |||||
|---|---|---|---|---|---|---|---|---|---|
| Raw – Oxalic Acid | trace | 281.08 | 469.73 | trace | |||||
| Blanched – Oxalic Acid | no data | 269 | 448 | no data | |||||
| Raw – Phytic Acid | 1.01 | 3.97 | 0.46 | 2.11 | |||||
| Blanched – Phytic Acid | 0.67 | 3.84 | 0.35 | 2 | |||||
| Raw – Tannic Acid | 1266 | 941 | 491 | 518 | |||||
| Blanced – Tannic Acid | 286 | 418 | 293 | 275 |
Based on the results of this study, blanching can therefore be recommended as an effective method for reducing antinutritional factors in vegetables.
Mosha et al., (1995)
Are Wild-Caught Insects Toxic to Bearded Dragons?
Feeding wild-caught insects to bearded dragons has been recommended by many a vet. However, there are concerns raised with wild caught insects being potentially toxic to bearded dragons or carry the risk of pesticide contamination. The other side to wild caught insects is knowing what you have caught. Insects like fireflies (lightning bugs), ladybugs, and box elder bugs are toxic and can be fatal to bearded dragons.
If you are clear on what insects you have caught and that they are not toxic to bearded dragons or likely to have been contaminated by pesticides, then they can be a great option to offer variety.
For a list of bugs safe for bearded dragons to eat see the article Best Insects for Bearded Dragons: Nutrition and Feeding Guide.
What Foods are Toxic to Bearded Dragons: Final Tips
Clearly, we need to know when foods are toxic to bearded dragons so they can be avoided. But not all foods that bearded dragons shouldn’t eat are toxic. It can get a bit overwhelming when you realize almost everything you will feed your bearded dragon may have one antinutrient or another.
Fortunately, there is sufficient information available on bearded dragons diets from a scientific perspective and from history with reptile owners. You can find more information in the articles on food in the diet section.
Knowing what bearded dragons cant eat will help you make informed decisions, promoting a long, healthy, and happy life!
References
- Barnard, S. M. (1996). Reptile keeper’s handbook. Krieger Publishing Company.
- Crews, C. (2014). Encyclopedia of Food Safety. Natural Toxicants: Alkaloids. Encyclopedia of Food Safety, 251–260. Elsevier Inc.
- Livingston, A. L., Knuckles, B. E., Teuber, L. R., Hesterman, O. B., & Tsai, L. (1984). Minimizing the Saponin Content of Alfalfa Sprouts and Leaf Protein Concentrates. Advances in Experimental Medicine and Biology, 177, 253–268.
- Mader, D. R. (2006). Reptile medicine and surgery (2nd ed.). Saunders Elsevier.
- Panduang, T., Phucharoenrak, P., Karnpanit, W., & Trachootham, D. (2023). Cooking Methods for Preserving Isothiocyanates and Reducing Goitrin in Brassica Vegetables. Foods (Basel, Switzerland), 12(19), 3647.
- Park, H., Chung, H., Choi, S., Bahn, Y.-S., & Son, J. (2024). Evaluation of exposure to cyanogenic glycosides and potential hydrogen cyanide release in commercially available foods among the Korean population. Food Chemistry, 456, 139872–139872.
- Libert, B.; Franceschi, V. R. (1987) Oxalate in crop plants. Journal of Agricultural and Food Chemistry 35, 926–938.
- Mosha, T. C., Gaga, H. E., Pace, R. D., Laswai, H. S., & Mtebe, K. (1995). Effect of blanching on the content of antinutritional factors in selected vegetables. Plant Foods for Human Nutrition, 47(4), 361–367.
- Noonan, S., & Savage, G. (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition, 8(1), 64–74.
- Plants Poisonous to Livestock – Animal Science. (2018). Cornell University. College of Agriculture and Life Sciences.
- Rahman, M. M., Abdullah, R. B., & Wan Khadijah, W. E. (2012). A review of oxalate poisoning in domestic animals: tolerance and performance aspects. Journal of Animal Physiology and Animal Nutrition, 97(4), 605–614.
- Salehzadeh, H., Maleki, A., Rezaee, R., Shahmoradi, B., & Ponnet, K. (2020). The nitrate content of fresh and cooked vegetables and their health-related risks. PLOS ONE, 15(1), e0227551.
- Thompson, L. J. (2020, October). Nitrate and Nitrite Poisoning – Special Pet Topics. MSD Veterinary Manual.
