vitamin d3 sources bearded dragons

Simplifying Calcium and Vitamin D3

How well do you think you would score on getting calcium and vitamin D3 for bearded dragons in the right balance? Do you know what can throw the balance out?

Dr Amna Ahmad is a Doctor of Veterinary Science graduated from the University of Agriculture, Faisalabad, Pakistan.

Many bearded dragons end up with preventable diseases through lack of understanding the basics of calcium and D3 supplementation.

Schmidt et al (2017) conducted a survey on 529 bearded dragons presented to three different exotic animal clinics in Central Europe. Of those which were given blood tests, 57% showed a deviation in the calcium-phosphorus ratio and 63% showed hypocalcaemia. Almost 19% of the bearded dragons had musculoskeletal disorders with the most prevalent being osteodystrophy and limb fractures.

Should I Feed my Bearded Dragon Calcium?

Yes, feeding your bearded dragon calcium is part of the current recommended good husbandry practices and it will contribute to the prevention of hypocalcemia.

However, if you are feeding your bearded dragon 50% or more of the total diet with commercially prepared diets, supplementation should not be required (Stahl and Donoghue 2010). Check the ingredients of the food before supplementing.

Just like humans, calcium performs a wide array of bodily functions in bearded dragons. Most importantly:

  • Mineralisation of bone matrix,
  • Skeleton formation,
  • Blood clotting, and
  • Muscle contraction.

It serves as an essential electrolyte of the heart, brain, skeletal muscles and nervous system functioning.

Does my Bearded Dragon Need Vitamin D?

In a conversation on calcium, vitamin D cannot be left out. Bearded dragons do need Vitamin D as it is essential for the metabolism and absorption of calcium and phosphorus. The body cannot use calcium unless it has vitamin D3.

Vitamin D supports the immune system, development and maintenance of bones, cardiovascular heath, functioning of nerves and muscles, and reproduction.

There are more ways to get Vitamin D3 Than Using a Supplement

There are 2 ways to get vitamin D3. One, through the UVB interaction with the epidermis (skin) and two, orally through food and supplementation.

Bearded Dragons skin naturally produces vitamin D when exposed to UVB.

The liver metabolises vitamin D2 into 25-hydroxyvitamin D2, and vitamin D3 into 25-hydroxyvitamin D3. Together they are referred to as calcifediol.

Vitamin D2 (ergocalciferol) occurs in plant sources vitamin D3 (cholecalciferol) from plant and animal sources. Providing foods with vitamin D2 does not replace the need for vitamin D3.

Absorbed vitamin D can be stored in the body such as the fat tissue, liver and kidneys.

vitamin d3 sources bearded dragons
Sources of vitamin D3 (cholecalciferol) supplementation in bearded dragons and synthesis.

What Happens when Bearded Dragons Don’t Get Enough Calcium

Hypocalcaemia is low levels calcium in the blood. It is mainly due to:

  • Inadequate UVB exposure and heat for calcium absorption
  • Low dietary calcium
  • Excessive levels of vitamin A which competes with vitamin D3
  • High phosphorus diet or improper calcium to phosphorus ratio
  • Excessive dietary protein

This low level of calcium in bearded dragons can have serious effects on health. The effects of hypocalcemia mostly involve the muscles being more excitable. Symptoms include:

  • Hyper excitability,
  • Twitching of digits,
  • Seizures,
  • Abnormal movement,
  • Paralysis Disorientation,
  • Spinal and bone deformities (like scoliosis),
  • Fractures,
  • Soft pliable bones,
  • Weakness,
  • Constipation,
  • Prolapse of cloaca, and
  • Death.

Calcium deficiency also leads to nutritional secondary hyperparathyroidism (aka NSHP, metabolic bone disease). This is a much similar but more severe disorder to that of osteoporosis in humans. The most susceptible to NSHP are:

  • Juveniles typically facing low dietary calcium intake or Calcium deprivation. Calcium is critical during their development; and
  • Gravid females (due to their egg laying nature).

To protect your bearded dragon from the totally preventable disease ‘nutritional secondary hyperparathyroidism’ (NSHP) or metabolic bone disease in bearded dragons, see the linked post by Dr Buchanan (DVM).

bearded dragon in late stages of mbd
Bearded dragon suffering from NSHP, an avoidable disease.

Overdosing on Calcium

Is it possible to give your bearded dragon too much calcium? Yes it is possible to give your bearded dragon too much calcium where there is also an excess of vitamin D3.

Is too much Calcium Bad for Bearded Dragons?

Too much calcium is bad for bearded dragons where there is an excess of vitamin D3. Vitamin D promotes the absorption of calcium. Calcium is pretty useless without D3.

Too much calcium in your blood is referred to as Hypercalcemia. Hypercalcemia will result in your bearded dragon becoming sick and, in some cases, it is fatal.

Overdosing lowers the use of fat, protein and minerals like zinc, iodine, manganese, iron and phosphorus. Soft tissue mineralisation, muscle calcification and hardening of muscles occurs.

Hypercalcemia is seen in bearded dragons with excessive exposure to UVB light along with excessive oral supplementation with calcium and vitamin D3. Remember there are two ways to get vitamin D3, UVB light and orally through food and supplementation.

In artificially lit environments, just as it is important that the light is putting out enough UVB it is equally important not to overdo it. In the right environment, bearded dragons can move in and out of the UVB light as they need it. The UVB tube length for your bearded dragon house should not cover the entire length of the house.

Setting up the lighting and heating well provides a solid foundation to build a healthy bearded dragon from. See the post on setting up lighting and heating for more information.

Signs of Calcium Overdose

Signs of calcium overdose in bearded dragons includes lethargy, muscle weakness and constipation.

How do I give my Bearded Dragon Calcium?

Outside of the calcium already provided in the foods naturally, you can give your bearded dragon calcium by:

  • Dusting food (insects and vegetation),
  • Gut loading, or
  • Bone meal.

Another means to give your bearded dragon calcium is to provide bone meal tablets (small or crushed) or powder (Stahl and Donoghue 2010). Some wild bearded dragons were found with bone pieces in their stomach, see the section below on why do we dust calcium when they don’t get it in the wild. With this being the case, bone meal may be a more natural means to give bearded dragons calcium.

The bone meal powder will make it easier to ration the amount used. The exact content of the bone meal tablets varies with manufacturer. The ratio of calcium (calcium carbonate from bone meal) to phosphorus is high, triple the amount of calcium or more.

Dusting

Dusting refers to coating food (both vegetables and insects) with powder supplements before being eaten. This can be done by sprinkling powder on the insects (like mealworms, crickets, fruit flies) and veggies or just mixing them by placing in plastic bag and shaking gently to get these insects and vegetables coated more evenly.

As you can see by the image below, it is impossible to know just how much calcium you will end up feeding your bearded dragon. Outside of a laboratory, it’s going to be impossible to be sure on how much of the calcium dusted onto insects will actually end up consumed.

Give them a light dusting and feed them. Excessive calcium will lead to overdose and calcium can be unpalatable. Foods dusted with too much calcium will probably be refused. See the frequency for dusting (feeding calcium) further down this post.

dusting feeder insects with calcium and vitamin d3 for bearded dragon
Dusting feeder insects with vitamin d3 and calcium ready for bearded dragons dinner. These insects are heavily dusted. Lighter dusting will be more suitable and be more palatable to your bearded dragon.

Why Do We Dust Calcium When They Don’t Get it in the Wild?

Why do we dust calcium? Bearded dragons don’t get calcium dusting in the wild but they are very good at converting UVB radiation (sunlight) into vitamin D3. In the wild, this aids them in being able to use calcium efficiently.

Vitamin D3 supports the metabolism and absorption of calcium and phosphorus. Since in the wild they are able to effectively convert UVB radiation to into vitamin D3, they are able to make use of the calcium they can absorb in their diet.

In research by Oonincx et al (2015) the stomach contents of 10 free ranging (wild) Pogona vitticeps were analysed. A very small portion of indigestible material (2.3% of stomach content) was found in the stomach, some of which included degraded bone as was attributed to potentially aiding the intake of dietary calcium. This could give an explanation as to how bearded dragons get calcium in the wild, at least for these specimens.

Other sources for how bearded dragons get calcium in the wild include dried bones, snail shells and potentially chalky rock dust. (Baines, 2017).

Some pet owners report their bearded dragon eat rocks. The reason is not clear but there is potential for it to be for a dietary reason including access to minerals.

In captivity, they are typically kept indoors in artificial lighting. Artificial lighting is not as effective as the sun and there are many errors by novice keepers that exaggerate the problem. So we attempt to correct the imbalance with oral calcium and vitamin D3 supplementation.

Gut Loading

Gut loading insects for bearded dragons is another useful method to feed a highly nutritious diet with calcium supplements. The insects are fed a diet that is nutritious for your bearded dragon 24 hours prior to feeding them to your dragon. This diet is not necessarily good for the insects health.

Some invertebrates, such as crickets, cannot be kept alive on calcium gut loading diet for over 3 days as it causes impaction in the cricket and subsequently it dies (Thompson, 2016).

How Much Calcium do I give my Bearded Dragon?

The amount of calcium you give your bearded dragon can be a bit of guesswork for pet owners. There are a couple of ways to go about this:

  • One, ask your vet who will be able to assess the relevant factors specific to you so they can make a recommendation.
  • Two, follow the recommended dosage provided by the supplement manufacturer.

You probably would have preferred I gave you an outright amount. An 1/8 of a teaspoon or a pinch might be useful, but here is the thing, calcium supplements can only be effective in the right conditions.

Some supplement manufacturers such as Vetark have brought their measures down to ‘pinches’, This may make it easy to follow however keep in mind some of the variables that influence how much calcium supplementation is required:

  • Environmental factors like UVB lighting and heat including amount of exposure to direct sunlight versus artificial UVB.
  • Biological stage of the animal.
  • The amount of calcium that sticks to the food.
  • How well insects were gut loaded.
  • The calcium supplement being used.

Ratio of Calcium to Phosphorus

It is not enough to just give calcium to your bearded dragon; it must also be in the right ratio. For growing reptiles, the required calcium to phosphorus ratio is 2:1. The nutritional demands of adults is 1.5:1 and in egg laying periods it reaches up to the level of 10:1.

The following table shows this data with the amount of calcium to be fed as a percentage of the dry matter and the calcium to phosphorus ratios:

NUTRIENTSGROWING BEARDED DRAGONSADULT BEARDED DRAGONS GRAVID BEARDED DRAGONS
Calcium1-1.5% (% of dry matter)
Phosphorus0.5-0.9%
Calcium:Phosphorus2 : 11.5 : 1Up to 10 : 1

How Often do you Give a Bearded Dragon Calcium?

How often you give your bearded dragon calcium with D3 greatly depends on the amount of UV light exposure. Bearded dragon’s that are provided with time outdoors in direct sunlight will need lower supplementation, unlike those kept indoor.

UVB light and calcium d3 quantity
Bearded Dragons with exposure to unfiltered sunlight should require less supplementation. Bearded dragons only receiving artificial UVB light will require more supplementation.

Bearded dragons do not need calcium every day. As a generalisation, the recommendation of numerous veterinarians, researchers and herpetologists, suggest you should give your bearded dragon calcium and vitamin D3 supplement as follows:

STAGEFREQUENCY
HatchlingsDaily
Juvenile 3-4 times a week
Adult At least once per week
Reproductively active females3-4 times a week
Adult receiving sunlightOnce every 2 weeks

Bearded Dragon Calcium with or without D3

Should I Give my Bearded Dragon D3?

Shortest answer is yes you should give your bearded dragon D3 (cholecalciferol). Calcium deficiency is often accompanied by vitamin D3 deficiency. Vitamin D3 given as a supplement orally is not as effective as it is from giving access to sunlight without any barriers between the UVB and the bearded dragon.

Vitamin D3 is required for calcium absorption and metabolism. Supplementing the diet with calcium alone is of no value unless you provide UVB exposure to your bearded dragon.

Bearded dragons may be fed calcium with or without vitamin D3. However, where sunlight is provided on a regular basis (i.e. multiple hours per week), oral D3 supplementation should be reduced or not fed at all.

Be aware that you can overdose on vitamin D3. Overdosing can result in mineralisation of tissues, including the kidneys, which can lead to renal disease.

Vitamin D3 Oral Supplementation is a Poor Substitute for UVB

Research on juvenile bearded dragons found that supplementing with vitamin D3 in doses as high as 4 times the average dietary recommendation was ineffective whereas UVB exposure to the skin was significantly beneficial (Oonincx 2010).

Which Calcium Powder Should You Buy for Bearded Dragons?

For bearded dragons kept indoors, buy calcium powders with cholecalciferol, also known as vitamin D3.

For bearded dragons kept outdoors or a combination of indoor and outdoor housing, it is likely that lower levels of D3 cholecalciferol will be needed.

Buying calcium powder both with and without cholecalciferol will provide options for alternate dusting. Avoid any calcium powder that has phosphorus in it. Calcium supplement meant for humans can also be used.

Calcium Carbonate without cholecalciferol
Bearded dragons can be provided Calcium Carbonate without cholecalciferol intended for human consumption.

Fixing the Diet

Some tweaks to the bearded dragons diet that will help with getting calcium right are:

  • Reverse the inverse Ca:P ratio of insects by gut loading and dusting. As a matter of interest, unlike most other feeders, soldier fly larvae have a higher calcium to phosphorus ratio (Divers 2018).
  • Keep your bearded dragon needs to be kept hydrated. Dehydration can decrease the level of nutrients absorbed. Water aids in digestion, utilisation of nutrients and elimination of waste products.
  • Select foods that can improve the Ca:P ratio and that don’t have high levels of anti-nutrients that can block absorption.

15 Foods High in Calcium

Foods high in calcium that you can feed as part of a varied diet include:

  • Turnip greens
  • Collard green
  • Mustard greens
  • Endive/Chicory
  • Escarole
  • Dandelion Greens
  • Parsley
  • Romaine lettuce
  • Escarole
  • Cilantro
  • Mulberry leaves
  • Watercress
  • Alfalfa
  • Blackberries
  • Fig

Watch Out For These Foods

Foods with an inverse Ca:P ratio cannot always be avoided but some are higher than others and should be used with caution, if at all.

Foods high in phosphorus should generally be avoided. Small portions occasionally may be okay for a healthy bearded dragon.

  • Day old chicks
  • Pinkie mice
  • Muscle meat
  • Squash and pumpkin seeds
  • Pea sprouts
  • Celery
  • Peas
  • Banana

Foods High in Oxalic or Phytic Acid

Foods high in oxalates and phytates can inhibit the uptake of calcium and caution must be used.

Oxalic and phytic acids bind to calcium making it unavailable. These foods can be added in small portions occasionally to a healthy bearded dragons diet (Stahl and Donoghue 2010). If they are fed, feed in small portions alternating with other foods.

Broccoli, Kale and Bok Choy are rich in calcium but also have high oxalate and goitrogen content that negatively affect their nutritional importance.

  • Broccoli,
  • Kale
  • Bok Choy
  • Spinach
  • Peas
  • Beans
  • Beetroot

Causes of Calcium DEFICIENCY

Causes of calcium deficiencies include:

  • Environmental factors like UVB lighting and heating
  • Biological stage of the animal, i.e. growing, gravid
  • Dietary issues:
    • The amount of calcium that sticks to the food
    • Ineffective or absent gut loading of insects
    • Calcium to phosphorus ratio
    • Amount of phosphorus o Level of anti-nutrients that can bind calcium (oxalates) or decrease absorption (phytic acid)

Phosphorus rich diets can also cause calcium deficiency

Calcium to phosphorus ratio is crucial to understand in the bearded dragons’ diet. Both are inversely related and negatively affect the level of each other.

This means that when one is rich in the diet, the level of other will be low and vice versa. This is controlled by some hormones such as calcitonin, parathyroid hormone and vitamin D3 (an accessory hormone).

Be mindful over the level of phosphorus in the diet. Phosphorus should not be fed more than its recommended limits for bearded dragons. High levels of phosphorus cause harm.

Effect of UV exposure in calcium absorption

Exposure to ultraviolet light is required for the formation of Vitamin D3. Sufficient exposure to UVB light, is necessary. UVB exposure with or without vitamin D can treat Hypocalcaemia.

As previously discussed, there are two ways to provide UVB exposure to your bearded dragon. They are by UVB (either sunlight or artificial lighting) and in the diet (food and supplementation).

Do Bearded Dragons Need Sunlight?

Bearded dragons will do best with sunlight. There should be nothing blocking the sun light which includes any glass, plastic or otherwise. Being transparent (such as glass) does not mean it allows UVB rays to pass through it.

Mesh screens reduce the amount of UVB that transmits through it. The tighter the mesh, the less UVB it will allow through. Use aviary wire mesh or similar on outdoor housing. Second is, provide UVB bulbs in your bearded dragons housing.

mesh cover on bearded dragon house outdoor
The amount of UVB light that will penetrate wire mesh is proportionate to the spaces in the mesh. The smaller the space, the more wire there is to block the UVB.

Bearded dragons need full spectrum or high UVB reptile bulbs provided overhead. UVB radiations of only 280-320 nm wavelengths are useful for bearded dragons for vitamin D production in their skin. Lamps below 290 nm are of no use for bearded dragons.

Changing UVB lamps is expected to be between 6 to 12 months. Be diligent in changing out your UVB lamps as per the manufacturer’s instructions. Alternatively, you can buy a UV meter to the UVB output of the lamp. Check your lighting and heating setup against the post on setting up lighting and heating.

Lack of exposure to UVB source can lead to calcium deficiency in bearded dragons. This condition is more pronounced in baby dragons as need more amount of calcium to build their developing and growing skeleton.

Observations show that bearded dragons experience improved appetite, better growth, remain healthier and more active in provision of sunlight and/or UVB generating bulbs or fluorescent type tubes.

Remember, nothing beats natural exposure to sunlight even if only for a few hours a week.

Get These Things Right for a Healthy Bearded Dragon

Some good husbandry practices:

  • Keep diets low in phosphorus and calcium binding oxalates and phytates
    • Calcium and vitamin D deficiencies are mostly seen in dragons fed on diets high in fruits, celery etc.
    • Avoid foods such as spinach, beetroot and rhubarb leaves.
  • Dust insects, they are naturally low in calcium.
  • Provide exposure to unfiltered sunlight at least a few hours a week, except when brumating of course.
  • Provide artificial UVB bulbs for those housed indoors.
  • Add calcium rich foods to the diet. Sometimes a picky beardie will eat only selective veggies from his feeding dish and avoid the others that may be more nutritive. If your bearded dragon has stopped eating greens or perhaps never started then there are a few tricks you can put in place. For tricks of the trade (so to speak) to get your bearded dragon to eat greens see the post on 6 ways to get your bearded dragon to eat vegetables.
  • Dragons require high temperature for proper feed digestion so temperature of vivarium should be high enough to proper utilization of feed in intestine (heat lamps orlight generated heat source can be used as if needed) • Should be given free access to water to avoid dehydration. As dehydration decreases nutrient utilization.

References and Further Reading

  1. Frances Baines (MRCVS). 2017. Your First Bearded Dragon Care Information.
  2. Bruce, H.M.; Parkes, A.S. 1950. Rickets and osteoporosis in Xenopus laevis. Journal of Endocrinology: 64-81.
  3. Cusack, L., Rivera, S., Lock, B., Benboe, D., Brothers, D., & Divers, S. (2017). Effects of a light-emitting diode on the production of cholecalciferol and associated blood parameters in the bearded dragon (pogona vitticeps). Journal of zoo and wildlife medicine48(4), 1120-1126.
  4. De Vosjoil, P., Sommella, T. M., Mailloux, R., Donoghue, S., & Klingenberg, R. J. (2016). The Bearded Dragon Manual: Expert Advice for Keeping and Caring For a Healthy Bearded Dragon. Lumina Media.
  5. Diehl, J. J. E., Baines, F. M., Heijboer, A. C., van Leeuwen, J. P., Kik, M., Hendriks, W. H., & Oonincx, D. G. A. B. (2018). A comparison of UV b compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons. Journal of animal physiology and animal nutrition102(1), 308-316.
  6. Divers, S. J., & Mader, D. R. (Eds.). (2005). Reptile medicine and surgery. Elsevier Health Sciences.
  7. Divers, S. J., and Stahl, S. J. (2018) Mader’s Reptile and Amphibian Medicine and Surgery- E-Book. Elsevier Health Sciences.
  8. Donoghue, S. ARAV Companion Reptile Care Series. How to Keep Your Iguana Healthy, Happy and Safe! NAVO Revised 2015.
  9. Girling, S. (2003). Veterinary nursing of exotic pets. Oxford, United Kingdom: Blackwell.
  10. Klaphake, E. (2010). A fresh look at metabolic bone diseases in reptiles and amphibians. Veterinary Clinics: Exotic Animal Practice13(3), 375-392.
  11. Oonincx, D.G.A.B., Stevens, Y., Borne J.J.G.C. van den., Leeuwen J.P.T.M. van., Hendriks W.H. 2010 Effects of vitamin D3 supplementation and UVb exposure on the growth and plasma concentration of vitamin D3 metabolites in juvenile bearded dragons (Pogona vitticeps). Comparative Biochemistry and Physiology, Part B156 (2010) 122–128
  12. Oonincx, D. G. A. B., Van De Wal, M. D., Bosch, G., Stumpel, J. B. G., Heijboer, A. C., van Leeuwen, J. P. T. M., Hendriks, J. P. & Kik, M. (2013). Blood vitamin D3 metabolite concentrations of adult female bearded dragons (Pogona vitticeps) remain stable after ceasing UVb exposure. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology165(3), 196-200.
  13. Oonincx, D. G. A. B., Leeuwen, J. P. van., Hendriks, W. H., Poel, A. F. B. van der. (2015) The Diet of Free-Roaming Australian Central Bearded Dragons (Pogona vitticeps). Zoo Biology 34:271-277. Wiley Periodicals Inc.
  14. Schmidt-Ukaj S., Hochleithner M., Richter B., Hochleithner C., Brandstetter D., Knotek Z. A survey of diseases in captive bearded dragons: a retrospective study of 529 patients. Veterinarni Medicina, 62, 2017 (09): 508–515. doi: 10.17221/162/2016-VETMED
  15. Stahl, S., and Donoghue, S. Nutrition of Reptiles. In: Hand MS, Thatcher CD, Remillard RL, et al, editors. Small Animal Clinical Nutrition. Topeka (KS): Mark Morris Institute; 2010.
  16. Thompson, K. S. 2016. Applied Nutritional Studies with Zoological Reptiles. (Doctoral Dissertation) Oklahoma State University
  17. Watson, M. K., & Mitchell, M. A. (2014). Vitamin D and ultraviolet B radiation considerations for exotic pets. Journal of Exotic Pet Medicine23(4), 369-379.
  18. Yeates, J. (Ed.). (2019). Companion animal care and welfare: The UFAW companion animal handbook. John Wiley & Sons.

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