How Much Calcium Is Really Necessary?

[ianedward1]

@Tom
Certain plants are more well known to take up calcium than others (such as the greens we often use a staples). True, these numbers can vary due to the environment they are grown in, but truly can we accept more than what we are given unless we have a lab of our own :/. The best we can do is hope that they are close to the data we have

@Boah
Stones may not be made up of only calcium, but large amounts of calcium in a humans diet is related to the development of stones and that could likely also be related to herps

---

Something I wonder a lot though....I see it commonly that "its all grown in different soils". Well, obviously it is, but think of the fact that, those places growing in produce it in massive numbers. I can only imagine they would need somewhat fertile soil to achieve the production of these greens, am I right?

The calcium content of some some soils is much higher, and fertilization doesn't address that. For instance the sandy soil here in Florida probably holds a lot less calcium than some clay soils in africa

Honestly, some of the sand in florida soils is actually calcium sand. There are many places very high in calcium in Florida. But most leafy green produce is not grown in Florida.

Calcium levels are actually high in Florida because of acid rain releasing Calcium into the soil from dissolving the limestone that makes up the barrier of the Florida aquifer. (A whole bio problem on its own)

 

[Baoh]

Baoh,
"Stones cannot be composed of calcium alone. The anion that complexes with it is the greater issue as it relates to precipitation (the act of which is the basis for a stone involving calcium)". Could you explain that statement a little more, possibly "dumb it down" a little? I can't quite get the gist of it...
It is absorbed? It seemed absurd to me it could be identical, or even similar to that synthesized endogenously, but I really have no background in this kind of stuff, so I didn't know for sure. The fact just seemed absurd to me.
Could you elaborate, also, on the K2 comment? What is it, and what would it do? I think several members here, including myself, would find it interesting.
In biochemical standards, its like baking a cake I'm sure. For ME, it is pretty darned complex . Or at least seems that way.
Thanks so much for the graphic illustration, I'll have to keep that. Very interesting stuff.....

The anion is what forms the other component of the stone that involves calcium and is what is required for the calcium to precipitate (come out of solution) in that complexed salt form. Ca2+ will not realistically precipitate on its own in the body at a physiological level without that anion.

Structure is structure. Synthetic or natural, the structure is the same. Identical. In the same molecular arrangement with the same composition and placement of the same types of atoms in the same number with the same charge at the same energy level.

As mainey34 posted, it is involved in the uptake by and deposition in bones (among some other things). This is opposed to mineralized deposits on organs or within vascular walls.

 

[EKLC]

Something I wonder a lot though....I see it commonly that "its all grown in different soils". Well, obviously it is, but think of the fact that, those places growing in produce it in massive numbers. I can only imagine they would need somewhat fertile soil to achieve the production of these greens, am I right?

The calcium content of some some soils is much higher, and fertilization doesn't address that. For instance the sandy soil here in Florida probably holds a lot less calcium than some clay soils in africa

Honestly, some of the sand in florida soils is actually calcium sand. There are many places very high in calcium in Florida. But most leafy green produce is not grown in Florida.

Interesting. I just remember looking into the soil surveys for my county and seeing low amounts of calcium, magnesium, potassium, etc. Maybe in northern florida the lower water table in some parts means the calcium doesnt make it to surface soils.

 

[Baoh]

@Boah
Stones may not be made up of only calcium, but large amounts of calcium in a humans diet is related to the development of stones and that could likely also be related to herps

Related, yes. Causality is another level.

 

[wellington]

Well, a topic i have to agree with peter on. Many of the greens i feed my 2 torts are calcium enriched. Therefore i do not see the need to add extra calcium to their diet. But i too add Miner-all. For the minerals....



As for the comment below. Really, You couldn't be further from the truth. Not sure how you got that from me wanting a good discussion without member bashing. In the last few days, this forum has had three, and thats just what I seen, threads turn into mud slinging. It helps no one and does no good for new members. There seems to be a common denominator within those threads. I didn't want another to go in that direction. Have you seen my thread? Maybe check it out. You'll get a better idea of what I don't do . http://www.tortoiseforum.org/thread-64884.html

Quote "As for the "mud slinging" comment Barb i dont think that was called for unless you were egging it on."


I believe k2 has something to do with:

Maintaining bone mineralization

This thread is very interesting and confusing at the same time. Gives a lot to think about and decipher. Maybe even some things to try and change.

 

[paludarium]

There are a few studies regarding calcium supplements for tortoises:

In the study Influence of the calcium content of the diet offered to leopard tortoises (Geochelone pardalis) the authors concluded that the tortoises that received three times the recommended calcium supplementation had the highest growth rate and were thriving. However, after reading the article thoroughly, I still did not know the exact Ca/P ratio in their experiments, therefore I could not come to a conclusion that depletion of calcium in the body of the tortoises receiving no calcium supplement was merely due to low calcium diet instead of improper Ca/P ratio.

In another study Influence of different dietary calcium levels on the digestibility of Ca, Mg and P in Hermann's tortoises (Testudo hermanni) the author found out that when Ca/P ratio in the diets rasied from 3:1 to 6:1, the digestibility of Ca and Mg also increased, while the digestibility of P decreased. The author also pointed out that until now, the role of the kidney in reabsorption of minerals is not clarified in tortoises. They also suggested that it may be prudent to feed a lower yet adequate level of dietary Ca, because higher levels may risk the pathologic accumulation of calcium somewhere in the animal.

In the study Long term observations on the alimentation of wild Eastern Greek Tortoises Testudo graeca ibera (Reptilia: Testudines: Testudinidae) in Dobrogea, Romania the authors noticed the ingestion of earth, especially clays containing limestone, or even degraded, friable limestone rock by the tortoises and this behavior was mostly noticed in juveniles and sub-adults and should probably be connected to their special mineral needs (mostly calcium).

Maybe we only have to leave some limestone containing clays or rocks for the tortoises, and the tortoises will take what they need.

 

[Tom]

D3 is very well absorbed and is molecularly identical to D3 that is synthesized endogenously (within the body).

Very well absorbed where and how? Are you saying tortoises can ingest it, and it gets into the bloodstream where they can use it?

The one study I saw many years ago involving green iguanas said they could not use dietary D3 and that no amount of D3 taken orally in any form made it into the bloodstream. Blood samples were taken before and after D3 was administered orally, and the D3 levels did not change. Other animals in the study were exposed to artificial UV or natural sunlight, respectively, and their D3 levels DID go up after UV exposure.

Have you seen a study on tortoises showing otherwise?

 

[Baoh]

D3 is very well absorbed and is molecularly identical to D3 that is synthesized endogenously (within the body).

Very well absorbed where and how? Are you saying tortoises can ingest it, and it gets into the bloodstream where they can use it?

The one study I saw many years ago involving green iguanas said they could not use dietary D3 and that no amount of D3 taken orally in any form made it into the bloodstream. Blood samples were taken before and after D3 was administered orally, and the D3 levels did not change. Other animals in the study were exposed to artificial UV or natural sunlight, respectively, and their D3 levels DID go up after UV exposure.

Have you seen a study on tortoises showing otherwise?

Your premise is unfortunate. On the other hand, I actually worked with the substance in a professional setting for years.

http://www.anapsid.org/pdf/jody-hibma-uvb.pdf

 

[paludarium]

Very well absorbed where and how? Are you saying tortoises can ingest it, and it gets into the bloodstream where they can use it?
......
Have you seen a study on tortoises showing otherwise?

I ma not sure about tortoises, but there was a study regarding red-eared slider turtles:
http://vetmed.illinois.edu/mmitch/pdf/red eared slider.pdf

Please read the discussion section of the study.

 

[Tom]

Your premise is unfortunate. On the other hand, I actually worked with the substance in a professional setting for years.

http://www.anapsid.org/pdf/jody-hibma-uvb.pdf

Well I don't see what is unfortunate about my premise, but that is your usual opinion, isn't it?

I read the study carefully and there are two flaws. It also references the study I saw so many years ago in the early 90's, which was apparently carried out in 88' and 89'.

The two flaws with this study: 1. D3 levels in the blood were never measured. They only measured growth rates. 2. D3 was supplied via a 50/50 mixture of Repcal with D3 and a vitamin supplement that also had D3. The cited group that grew the least got NO vitamin supplementation at all, D3 or otherwise, so I would expect them to grow more slowly. This may or may not have anything to do with D3.

The discussion also mentions the danger of artificial UV exposure and the inadequacy of the bulbs in use at the time, but this study is from 1996. Bulb development has come along way since 1996, has it not? I wonder if something similar has been attempted with current fl. bulbs or MVBs? You would be the man who would know where to find such a study.

You say that you worked on the subject for years. I am willing to simply listen to what you discovered, based on your experience, with or without studies to cite. Did your years of working on the subject teach you that tortoises OR green iguanas CAN absorb dietary D3, in contrast to the 1988 study that I saw so many years ago? The only scientific info I have ever seen on the subject is the study I mentioned, so I am certainly no expert on the subject. My personal experience has not demonstrated anything one way or the the other to me on this subject since all of my reptiles are regularly exposed to real sunshine and I've never had any reason to measure the blood levels of D3 in any animal. Here is your chance to share some knowledge with us. Please.

 

[Baoh]

"Well I don't see what is unfortunate about my premise, but that is your usual opinion, isn't it?"

My usual opinion is that your premise is unfortunate?

"The two flaws with this study: 1. D3 levels in the blood were never measured. They only measured growth rates. 2. D3 was supplied via a 50/50 mixture of Repcal with D3 and a vitamin supplement that also had D3. The cited group that grew the least got NO vitamin supplementation at all, D3 or otherwise, so I would expect them to grow more slowly. This may or may not have anything to do with D3."

1. Serum D3 measurements not being taken is not a flaw. It is one of the selected parameters of the DOE or the "design space". 2. There were two factors manipulated here. D3 supplementation and light exposure with the light exposure having two versions or "sub-variables". The design parameters are such that they allow the observer to isolate variables per cohort and make an association with the selected output. This is also not a flaw and your expectations are not relevant to the quality of the study design because the idea to pre-conclude and therefore ignore is not science.

Did adding oral D3 supplementation improve the observation outcome with UVB? Yes. Did adding oral D3 supplementation improve the observation outcome without UVB? Yes, and to a somewhat comparable degree, while still a little less, to D3+UVB, which was interesting. Did UVB alone provide nearly as much of a growth benefit as oral D3 supplementation or oral D3 supplementation with UVB? No. What variable had the greatest positive impact in terms of mass gain and linear growth (which would directly involve the skeleton)? Oral D3 supplementation. In order for that to be the case from a biochemical standpoint, what is necessary by simple parsimony? Absorption.

"The discussion also mentions the danger of artificial UV exposure and the inadequacy of the bulbs in use at the time, but this study is from 1996. Bulb development has come along way since 1996, has it not? I wonder if something similar has been attempted with current fl. bulbs or MVBs? You would be the man who would know where to find such a study."

Do you have such a study showing the development of the improvements? It is still not relevant to this study.

"You say that you worked on the subject for years. I am willing to simply listen to what you discovered, based on your experience, with or without studies to cite. Did your years of working on the subject teach you that tortoises OR green iguanas CAN absorb dietary D3, in contrast to the 1988 study that I saw so many years ago? The only scientific info I have ever seen on the subject is the study I mentioned, so I am certainly no expert on the subject. My personal experience has not demonstrated anything one way or the the other to me on this subject since all of my reptiles are regularly exposed to real sunshine and I've never had any reason to measure the blood levels of D3 in any animal. Here is your chance to share some knowledge with us. Please."

A study was just provided with iguanas establishing an orally administered D3 variable and positive outcome. You have just seen scientific information, so asking me this question implies you either selectively ignored it or do not understand it. Your personal experience is irrelevant to the validity of the study which used actual metrics to reflect a biochemical relationship to physiological improvement outcomes instead of a set of personal assumptions that may abide by a logical fallacy known as an appeal to nature.

If you are asking me to give you confidential information, which is what I work on, then you are out of luck. In order to not just say I am an expert, which I guess I am by certain definitions, and pull an appeal to authority (logical fallacy), I will discuss what is available in public like I have been. I let the readers of this thread know that I have professionally worked with this substance for years because it provides a context and an exhibition of background, not so that it is a concluding factor or some sort of proof of being correct. When dealing in science, I let data drive the decisions. If I want even more refined answers, I had better have even more refined data. Here we have data showing oral D3 supplementation being effective at promoting mass gain and linear growth in iguanas, which is something that a party earlier in the thread had claimed to not be the case.

 

[ianedward1]

^ I agree. There were never any D3 blood measurements made which would be a very necessary piece of data with them giving D3 toxicity as a possible cause of death. That would be a very condemning piece of missing info for me if I was asked to review this paper for publication. They also state that they had no information or prior experience with the bulb they were using. Who knows what kind of levels of UV they may have been exposing the lizards to. Also, different species synthesize D3 differently depending on who available it is in their diet. Animals that are carnivorous endotherms receive most of their D3 from their diet while herbivorous ectotherms are usually much less efficient at absorption and typically produce their own.

 

[Baoh]

^ I agree. There were never any D3 blood measurements made which would be a very necessary piece of data with them giving D3 toxicity as a possible cause of death. That would be a very condemning piece of missing info for me if I was asked to review this paper for publication. They also state that they had no information or prior experience with the bulb they were using. Who knows what kind of levels of UV they may have been exposing the lizards to. Also, different species synthesize D3 differently depending on who available it is in their diet. Animals that are carnivorous endotherms receive most of their D3 from their diet while herbivorous ectotherms are usually much less efficient at absorption and typically produce their own.

The speculation on cause of death was listed as speculation and, strictly defined, is possible. There is no need to perform any kind of testing to infer possibility, since possibility is pre-existent and inherent. Likewise for the speculation of UV-induced irritation. These are possibilities speculated and not probabilities asserted, so there is no requirement to test them in the framework of this study. It would be useful for a follow-up study, but is not the point of this one. Their obligations are to provide evidence for the aspects they test so that a conclusion can then be drawn regarding the nature of the relationship between pre-designed inputs and the resultant outputs post-implementation of whatever limitations of methodology are chosen and executed.

I would like to see testing of serum D3 levels. However, what I would like is irrelevant, as the study is not intended to observe serum D3 levels. It is intended to add particular variables to subjects and observe any differences in the designated metrics. It achieved what it was intended to achieve. It establishes direct and simple relationships. It does not seek to weave a tapestry of relationships into a pleasingly comprehensive story. I would love all sorts of scans, histological sampling, and more, but my love is irrelevant and it was never the point of this piece of research. It satisfies the point of the study whether or not it satisfies a bystander's irrelevant opinion.

 

[ianedward1]

Honestly, this thread seems to have slightly deviated form Calcium to D3. Yes, those two are closely related. My entire point though was, if we give a naturally high calcium diet, is there any need for extra supplementation (D3 or not)? I'm not talking about making our torts grow faster, I am talking about making them grow healthier with a natural calcium source. Fast does not always mean healthy

 

[Tom]

I should have known you'd be difficult about this. A few simple questions:

Does orally administered D3 make it into the blood of a tortoise?

Since they didn't just give D3 in your study, (they gave a vitamin/calcium with D3 mixture), and no supplementation of any kind to the group that grew the least, how do we know that some other component of the vitamin/calcium mixture did not contribute to the growth and it has nothing to do with D3.

Just because they grew, does not necessarily mean that D3 got to the blood through the gut. It just means they grew. I've lots of iguanas, tortoises and beardies in various states of MBD that could still grow. Why does growth mean that D3 got into their blood?

 

[jaizei]

Since they didn't just give D3 in your study, (they gave a vitamin/calcium with D3 mixture), and no supplementation of any kind to the group that grew the least, how do we know that some other component of the vitamin/calcium mixture did not contribute to the growth and it has nothing to do with D3.

Doesn't it specifically state that they ordered a special batch of calcium with d3, but without the d3. I read this as all groups received supplementation, some just didn't get d3.

 

[paludarium]

Personally I will not apply the data obtained from lizards on the turtles or tortoises.

In the study Effects of ultraviolet radiation on 25-hydroxyvitamin D3 synthesis in red-eared slider turtles (Trachemys scripta elegans) the authors reported that 25-hydroxyvitamin D3 concentrations increased significantly in all turtles from the time they were removed from aestivation until the end of the study. Although we cannot eliminate ambient UV-B radiation as a possible cause for this increase, half of the turtles had exposure to only insubstantial amounts of UVB radiation (< 0.01 W/cm2). Therefore, absorption of vitamin D3 from the diet is the most likely explanation for the observed increase.

The turtles in the control group did not receive UVB but diets (probably with animal matters), anyway, the serum D3 increased significantly after 4 weeks.

 

[Nay]

Hi, I just love that people have the incentive to pursue something way past what most of us would do, be it work, or just for fun.Man I had hard enough time just reading it from the OP' post. Very very neat and thank you for posting.
May I add a very non scientific, even to go as far as non tort observation?
I have been involved with horses and horse people for way longer that torts and have watched as many well meaning people load up their horses with every new supplement on the market. That being said, I have always watched most of those same people have multiple problems with their horses, (To be fair, a few went the supplement route after a problem occurred looking for an solution.) But it seems once they started something, they always had more issues. I am clear that loads of variables make up loads of issues, (stabling, feed, blanketing(or not) amount of exercise, and you cannot make a blanket statement. It's just myself and one or two others have that "if it ain't broke don't fix it" mentality,and our horses are old and relativity problem free. (My Arab is 31 and our pony is well into his 30's.)We also have 2 other younger horses and I plan on continuing the same route. I have read and read about about the calcium addition/controversy in torts and use it primarily when my leopard seems to be wanting to lay. It's hard to really know.
Thanks for the wonderful input.
Nay

 

[deadheadvet]

So far there is no evidence that excess calcium causes bladder stones in tortoises. The stones that have been analyzed at the University of Minnesota Urolith Center have routinely come back as Uric Acid stone. So it appears that there is another mechanism going on causing stones and it is not calcium.
They have studied calcium levels in the California Desert Tortoise, and they run extremely high normally. So it is my opinion that we are worrying way to much about how much calcium in our tortoise diet. Agreed that supplementation may not be necessary if commercial tortoise food is given routinely. That's my 2 cents.

 

[Madkins007]

Some things to keep in mind.

1. How much calcium should my tortoise get? It is not about the Ca: P ratio, it is about the absolute amount needed, by weight or caloric intake. The formula is 1.3 to 8mg x Kcal (or, for every Calorie of food, there should be 1.3 to 8mg of calcium). Phosphorous should be the same as or about half of the calcium dose*. (Dr. Douglas Mader, Reptile Medicine and Surgery, p. 287). To make things easier, there is a chart here to help figure this out- https://sites.google.com/site/tortoiselibrary/nutrition/guidelines-and-dosages.

2. Should I offer supplements? No. The best thing is to provide a balanced, healthy, varied diet that is naturally rich in calcium, low in phosphorous, and offers other useful nutrients as well. After all, proper development requires lots of different nutrients- including iron (which, ironically, is blocked by calcium in the blood.)

3. What if my diet is not solid? Try to fix it, and consider adding as little supplement as you can. Supplements are NOT a replacement for good nutrition- they are insurance. Use it like it was poisonous and radioactive- more is NOT better!

4. Do they need vitamin D3 in the food or supplements? Uncertain. There is no question about needing vitamin D, but it seems pretty obvious that UVB from the sun is by far the best way to do this, and that UVB from a good lamp is better than dietary vitamin D, but D in the food or supplements would be better than nothing.

5. Can they overdose or have other side effects from excess calcium or vitamin D? Yes, sort of. In tortoises, bladder stones are often blamed on too much calcium, but the better culprit is probably dehydration (although no one knows for absolute sure). As Dr. Mader has noted elsewhere, most captive tortoises are dehydrated and underweight, which is more likely to trigger the stones than either calcium or oxalates (another common villain accused of causing stones). In a healthy, well-hydrated tortoise, excess calcium is excreted with no problem.

Vitamin D is a bit trickier. It takes a rather large dose to OD on (about 5x the usual dose over time) and most of the symptoms of an OD are excessive calcification. Vitamin A is a far more common health problem when OD'ed, causing eye and skin issues. I honestly think a lot of the fear of a vitamin D OD is because the person is thinking of vitamin A. Vitamins A, D, and E are stored in the fat tissues, so are not easily excreted in cases of overdosing. Also note- you CANNOT OD on vitamin D produced by the sun- there is a 'safety circuit' built-in to the process. (However, there is other damage you can get, human or tortoise, from over-exposure to UV light.)

6. So, do supplements help at all? Probably not as much as we hope. It turns out that a LOT of the nutrients in supplements is not very 'bio-available', that is, that a lot of it is not readily absorbed by the body. Iron is a good examples of this. For iron to be absorbed properly, it has to be in really, really tiny particles. If you take a bowl of iron-enriched cereal and mush it up in a lot of milk, then dip a magnet in it, you will see black filings gather. This is iron, and if you can see the particles, they are probably too big to get into the cells. The same applied to calcium particles- the best calcium supplement is a really, really fine dust.

But this also applies to a lot of other nutrients. Flax seeds are rich in omega 3 oils- but humans and tortoises cannot really digest the seeds correctly to get much of the oil out, so they tend to pass unused. Many of the other ingredients in ANY supplements or fortified foods (human or pet) are the same thing- they are just not as bio-available as we think or hope. (Just for a little squick factor- in a lot of 'fiber enriched' foods, cellulose is an ingredient, and cellulose means wood pulp. It is fiber, but not the kind that helps the most.)


*- Phosphorous ratios. Because of the emphasis on calcium, phosphorous often comes off as the 'bad guy'. This is not true! Phosphorous is a MAJOR nutrient that animals NEED for health. If an animal routinely gets too much calcium and not enough phosphorous, the bones become stiff and brittle. Phosphorous, in the right ratios, helps soften the bones a bit, adds a little give and makes them harder to break.

The problem is that a lot of old common turtle diets were really lopsided. The classic 'hamburger and lettuce' diet, for example, has a ratio of about 1:20! This creates soft bones that easily deform- lumpy shells on turtles, soft jaws and deformed limbs on lizards, etc.

Contrary to popular belief, the healthy ratio for a tortoise is the same as it is for any reptile, and even humans- about 1.5:1, but even 1:1 isn't horrible, even over time. Nothing wrong with 2:1, or even the occasional burst of 15:1- but over the course of a month or season, we should aim for about 1.5:1.