How much is too much calcium?

[Tom]

There has always been much debate about how much calcium supplementation one should be giving to their tortoises. Some use none. Some use a lot every day. Some allow their torts to self-administer. When people ask how much they should use, I frequently answer "somewhere between a lot, every day and none". Both of these extreme strategies seem to produce healthy torts for the people who use them. I, personally, opt for the little bit goes a long way strategy and just use a little a couple of times a week for young tortoises, in conjunction with a high calcium diet.

Some people believe that you can't give too much calcium, because it is water soluble and excess will simply pass out through the kidneys. I have always maintained that too much calcium can contribute to some bad stuff, including interference with absorption of other vitamins and minerals. Here is something that I just pulled off of the http://africantortoise.com website in their article on pyramiding. I don't agree with the whole page and everything on it, but there is some useful and pertinent info on there. Knowledge has advanced quite a bit since that article was written, but it is still a lot on good info on how to raise a healthy tortoise. Here's the relevant paragraph:


"Calcium is also an important factor. In the wild the main sources are from the plants, the soil and in the water. Phosphorous plays a limiting role in calcium utilization. High levels of phosphorous leads to calcium being leached from the bones. A recent study showed that teenage girls are now showing signs of early osteoporosis. The relate it to drinking soda which are high in phosphoric acid. For our tortoises the main dietary source of phosphorous is protein. So once again high protein diets tie in. To counter act this and to get the calcium/phosphorous ratio to a healthy 2:1 , its is often recommended to dust all food with calcium (usually calcium carbonate). While superficially it does seem to have benefit, it has its own problems. Too much calcium results in secondary deficiencies of zinc, copper and iodine, malabsorption of essential fatty acids, and formation of calcium-containing bladder stones. Lack of calcium results in soft shells that often accompany pyramiding."

Everything between the above quotes was copied and pasted directly from the Africantortoise.com website. If its not okay to do this, Mods please delete this portion of the post and I'll just refer everyone to go to the website and find it themselves.

The second to last sentence is primarily what I am referring to here. Please share your opinions.

 

[webskipper]

I just sprinkle some calcium or vitamins on their greens. Alternating between the 2 powders. Also trying to get them eating more Opuntia. If I ever see a stone then I'll cut back.

 

[dolfanjack]

I don't give any supplements. My russian is an adult and doesn't need as much calcium ( he does have excess to a cuttlebone). My juvinile boxies get lots of worms and bugs and also have a cuttlebone. I havn't seen any signs the cuttlebone has ever been used though.

 

[Tom]

I'm not saying that's anyone's routine is right or wrong and I'm not making any recommendations here. It seems that everyones style of keeping works for them. I am just passing along what I know to be true about too much of a good thing.

 

[terryo]

I never gave calcium to Pio until he was about 7 months old. Then I started to sprinkle a little on his food every other day. Now he has the cuttlebone, and maybe I put a little on his food when I think of it. I never gave any to my boxies but they munch on cuttle bone all the time.
I have seen very bad results in water turtles that had too much protein. I got a rescue once that was very deformed as the owner used to give only worms and chicken. Never had a commercial food or any greens. I'm really not big on too much calcium for mine, and Pio rarely gets protein now that he's outside and can find some for himself.

 

[firework]

I can only speak of desert torts as I don't know much about other species.

In the wild, torts get Ca only from natural diet which is mainly green plants, and that should be enough for them. I don't know the percentage of Ca in the commercial powder, I guess they added other vitamins and additives, but still, that white powder is a LOT Ca. I can't imagine a tort having access to that concentrated Ca resources in the wild.

I use a small art brush, brush a little Ca powder on the greens, just enough to see the leaves turned a bit whitish. I do this every day but not on every leaf, only one or two leaves each time. The advantage of using a brush is it gives you better control over the amount. I used to use a salt shaker, but always shaked too much.

 

[Yvonne G]

I've always assumed that you can't give too much calcium. Its the D3 that you have to watch out for. I've heard that the calcium that they don't use is excreted in the urine. Someone correct me if I'm wrong.

But as far as my own tortoises are concerned, if I sprinkle their food with calcium powder, they won't eat that day. So I've taken up (I think it was Tyler, but it might have been Chad or Gary GB)'s idea about placing a small dish of calcium powder in the habitat. They do a lot of walking through it and messing it up, but they DO eat it when the spirit moves them.

 

[Madkins007]

Excess calcium is passed in the urine (edit 11/23/2010- apparently, most excess calcium is passed in the feces.) IF the animal is properly hydrated, otherwise it can concentrate, along with other salts and minerals, in the kidneys and bladder, contributing to stones. Since most captive tortoises are at least somewhat dehydrated, I would not count on this (OURS are not, of course, since we are just so dang good, aren't we?? )

No one knows how much calcium a tortoise actually needs. If we base it on the recommended human doses, we would aim for about 1mg of calcium, per 30grams (1oz) of tortoise, per day. Actually, since a tortoise metabolism runs at about 1/2 the rate of a mammals, it could probably be 1/2 of that- 1mg of calcium per 60gr (2oz) of tortoise.

IF this anywhere near right, and I AM NOT saying it is, then a typical 10cm (4in) tortoise weighing about 190gr (7oz) would need about 3.5mg of calcium a day- or about the calcium dose found in 10gr (about 1/3rd ounce) of turnip greens a day!

Reminder #1- that is based on a theory, not proven research.
Reminder #2- healthy tortoises and skeletons need more than just calcium- some phosphorous (about half as much, in general), some vitamin D, heat, water, and an assortment of other nutrients are all important.

SO... the actual dosage may not be that big, and should be easy to hit with just a decent diet. Offering a bit extra for insurance should not be a problem as long as we don't overdo it. I treat my calcium powder as if it was some sort of radioactive salt- not much and not often.

 

[dmmj]

I will admit I feed mine lots of milk to provide plenty of calcium........
J/K I actually allow mine to self adminster their calcium with cuttlebones, I figure they will eat it if they need it. Mine also would not eat their food if they had a lot of calcium powder (ground up cuttlebone) on their food.

 

[N2TORTS]

As far as too much calcium…just some interesting information for everyone.
There are other components in food such as phytic acid and oxalic acid, these are found naturally in some plants, they bind to calcium and can inhibit its absorption ( eventually passed as waste) [/u]. Foods with high levels of oxalic acid include most greens including, red/green leaf , spinach, collard greens, sweet potatoes, rhubarb, and beans. The extent to which these compounds affect calcium absorption varies among weeds/plants consumed. Some absorbed calcium is also eliminated from the body in urine and feces.
JD~

 

[Ceilidh_Eliza]

I am also worried about calcium as I've only had my baby Hermann for a couple days. ive been told to sprinkle a small amount on his greens each day and use Nutrobal twice a week but on different days to the calcium. Is this correct, I obviously don't want to overdose the poor thing!

thanks

 

[Madkins007]

I am also worried about calcium as I've only had my baby Hermann for a couple days. ive been told to sprinkle a small amount on his greens each day and use Nutrobal twice a week but on different days to the calcium. Is this correct, I obviously don't want to overdose the poor thing!

thanks

If you are using an intelligent diet, it should get most of the vitamins and minerals it needs in the food.

Once you are doing the diet right, you can offer a bit of calcium once or twice a week (or so, depending on what you are offering for food), and a bit of vitamin powder once every week or three- just as insurance.

 

[LadyGreek]

As far as too much calcium…just some interesting information for everyone.
There are other components in food such as phytic acid and oxalic acid, these are found naturally in some plants, they bind to calcium and can inhibit its absorption ( eventually passed as waste) [/u]. Foods with high levels of oxalic acid include most greens including, red/green leaf , spinach, collard greens, sweet potatoes, rhubarb, and beans. The extent to which these compounds affect calcium absorption varies among weeds/plants consumed. Some absorbed calcium is also eliminated from the body in urine and feces.
JD~

Broccoli, Brussels Sprout, Cabbage, Collard Greens, Kale, Horseradish, Rutabaga, Turnip, Chinese Cabbage, Cauliflower, Broccoli Rabe, Daikon, Bok Choy, Radish, and Spinach are all high in Oxalic Acids and binds calcium.....not Red/Green leaf Lettuce. Everything in this list of vegetables is distinguished by its high oxalic acid and cellulose content. Most Mammals and Reptiles do not have the ability to break it down and absorb nutrients from it easily.

Red/green leaf lettuce do not fall into that category of high oxalic acids. They contain a small amount of fatty acids in a state suitable for use by the body. They are one of the ideal staples to feed strictly herbivorous Torts because of the level of vitamins and minerals. That's why a healthy bag of Organic Spring mix Salad is a good staple for many Torts with added variety here and there like romaine, dandelion, rose leaves and petals....ect ect.

Just thought I would help out!

 

[chadk]

... but are there benefits to providing foods high in Oxalic Acid? Are there benefits from those high Oxalic Acid plants, such as being high in various viatims and minerals essential for that well rounded diet we wish to provide? Can you go for a diet that emphasizes Ca absorbtion on some days, then switch to some foods high in Oxalic Acid others?

 

[LadyGreek]

... but are there benefits to providing foods high in Oxalic Acid? Are there benefits from those high Oxalic Acid plants, such as being high in various viatims and minerals essential for that well rounded diet we wish to provide? Can you go for a diet that emphasizes Ca absorbtion on some days, then switch to some foods high in Oxalic Acid others?

Moderation and variety is the key!

The fact that these vegetables are high in Oxalic Acid doesn't mean they cant be fed sparingly, but I wouldn't call it a benefit just a variety. Feeding your Tort Collard Greens once every 2 weeks isn't going to do a thing. As a matter of fact they might relish it. However, there are just some greens I personally would never feed my Torts. Spinach is one I stay away from all together just to name a few, but again that's just me.

 

[chadk]

Mine eat a well rounded diet that includes collards, mustard greens, and some spinach. I also ensure they are well hydrated and eat a variety of things.

This offers some perspective on the topic:
http://russiantortoise.org/nutritional_analysis_of_kale.htm#oxalates
This is interesting too:
http://russiantortoise.org/diet_research.htm

 

[Tom]

Some interesting stuff in the replies here.

Mine will eat their greens no matter how much calcium I sprinkle on there.

My point of the whole thread is that a lot of people use Ca every day and say that you can't use too much, because any that is not needed will just pass through and be excreted. That may be true.

I'm saying that you CAN use too much because too much calcium interferes with the absorption of zinc, copper, iodine and essential fatty acids, among other things.

 

[Madkins007]

Broccoli, Brussels Sprout, Cabbage, Collard Greens, Kale, Horseradish, Rutabaga, Turnip, Chinese Cabbage, Cauliflower, Broccoli Rabe, Daikon, Bok Choy, Radish, and Spinach are all high in Oxalic Acids and binds calcium.....not Red/Green leaf Lettuce. Everything in this list of vegetables is distinguished by its high oxalic acid and cellulose content. Most Mammals and Reptiles do not have the ability to break it down and absorb nutrients from it easily.

Red/green leaf lettuce do not fall into that category of high oxalic acids. They contain a small amount of fatty acids in a state suitable for use by the body. They are one of the ideal staples to feed strictly herbivorous Torts because of the level of vitamins and minerals. That's why a healthy bag of Organic Spring mix Salad is a good staple for many Torts with added variety here and there like romaine, dandelion, rose leaves and petals....ect ect.

Just thought I would help out!

The research I have done gives me different answers with several of these points. For example, these foods have this many mg of oxalates per 100g of food-
Broccoli- 0mg
Cabbage- 0mg
Collard Greens- .07mg
Kale-.02mg
Turnip (greens?)- .05mg
Chinese Cabbage/Bok Choy- .09mg
Spinach- .69mg

The 'brassicas' are known for good calcium bioavailability (http://www3.interscience.wiley.com/journal/119293677/abstract?CRETRY=1&SRETRY=0) and low oxalates.

It has also never been shown that oxalates are a big problem for a decently hydrated tortoise. Their contribution to bladder stones can just as easily be blamed on excess calcium and poor hydration. In fact, tortoises can eat plants so loaded with oxalates that they are considered toxic to humans.

Cellulose is broken down by many herbivores. Grass-eating animals need to at least partially digest cellulose in order to extract the nutrients. They may do this with a specialize digestion process, with the help of special micro-organisms, or other techniques or combinations of techniques, but it has been shown that baby Galapagos tortoises can get nutrients from cellulose pretty well. (http://www3.interscience.wiley.com/journal/110471755/abstract )

Cellulose is just a kind of fiber, and decent fiber is an important part of a healthy tortoise diet.

The leaf lettuces, like red and green, are certainly OK, but have mediocre Ca: P ratios (1.24:1 and 1.18:1 respectively), and nothing too exciting for other values. They are a decent addition to a balanced and varied tortoise diet, the main problem with them is a low level of fiber and their main benefit is water in fresh plants. Romaine lettuce is about the same.

However... the dreaded Iceberg lettuce is not really that different than the leaf lettuces- an almost 1:1 Ca: P (actually .95:1), not quite as much vitamin A, but more net carbs. If red and green leaf lettuce is a nearly perfect food, then that would make Iceberg pretty good.

Sources:
Most nutrient info- http:/www.elook.org
Oxalates- http://www.litholink.com/gateway.aspx?page=OxalateDiet and http://sun.ars-grin.gov/duke/highchem.html




Here is the deal for me... we are investigating this stuff to the point that we seem to be focusing on a lot of speculation and theory rather than actual fact. There are zoos that have fed what we would say is a mediocre to poor diet for their Red-foots, but get impressive longevity and breeding results.

The brassicas were considered evil because when they formed the major part of the diet of Galapagos tortoises, the torts developed goiters. It did not affect most species, and has not shown to be a problem when used in moderation- but we still tend to avoid them. Iceberg got a bad rep when it was used almost to the exclusion of anything else- and we still are reluctant to use it much.

For every nutrient, there is an anti-nutrient- calcium blocks iron absorption, some vitamins block other vitamins. We can go crazy dealing with it, or we can just offer a balanced, varied diet and not sweat small glitches.

 

[LadyGreek]

Excelent research Mark! This will be added to my notes! I wish I could have done as much reasearh, but I was going off the top of my head at work while I was supposed to be working. Haha!
My main point was to clear up the Red/Green leaf saga, because I didn't want Newbies thinking they had to stay away from them altogether. Another thing we have to keep in mind in the debate is we are debating a LARGE rage of Tort species with all different diets. What a Red-Foot can eat a Greek may not be able too and so forth.

But the main topic is Ca and I think a keeper should choose wisely based on the diet they feed their Torts and the quality of it's living spaces (Cuttlebone, UVA/UVB, natural sunlight.....ect. Just my own personal thought. Not trying to force it on anyone.

 

[Madkins007]

Excelent research Mark! This will be added to my notes! I wish I could have done as much reasearh, but I was going off the top of my head at work while I was supposed to be working. Haha!
My main point was to clear up the Red/Green leaf saga, because I didn't want Newbies thinking they had to stay away from them altogether. Another thing we have to keep in mind in the debate is we are debating a LARGE rage of Tort species with all different diets. What a Red-Foot can eat a Greek may not be able too and so forth.

But the main topic is Ca and I think a keeper should choose wisely based on the diet they feed their Torts and the quality of it's living spaces (Cuttlebone, UVA/UVB, natural sunlight.....ect. Just my own personal thought. Not trying to force it on anyone.

I agree completely. I DO think there is a 'core diet' that most commonly kept species can do well- the so-called 'Weed Diet', which would vary some based on where you are, what you have available, etc. I also completely agree that some of the lettuces that get overlooked in our quest for maximum calcium are a useful addition to the diet.

I DO really wish that someone would just finally do the research needed to determine at least a basic calcium (and vitamin D) need. It would make things so much easier!

(And I think I know which sites you have seen the information you gave at. Good sites, but I sometimes wonder about some of their information.)