# Vitamin D supplements- dosage info



## Madkins007 (Dec 2, 2010)

Edited and updated 12-6-2010

A commonly seen comment is that we should be careful with vitamin D supplements to avoid overdoses. I found a reference in Mader's "Reptile Medicine and Surgery" that gives us a guideline for the dosage. (Please note that Mader is clear about this being a guideline, not the result of careful research!)

The target range is 200-2000 International Units (IU) per kilogram of tortoise a day. That would be roughly 100-1000 IU per pound for those who do not understand that metric is the superior system for this sort of thing .

(Note- for the purposes of this article, figure that a kilogram, or 1000 grams is about 2 pounds, and 100 grams is about 3.5 ounces)

The danger zone is about 5000 IU/kg) a day. Overdoses can have nasty consequences, but to hit the danger zone, you would really have to work at it- although something like a high-dose vitamin D table for a very young tortoise would probably do it. The main symptoms of an overdose are hard to see and include things like calcification of soft tissues.

I cannot figure the dosage you get from the sun because there are far too many variables, but if your tortoise has free access to sunlight strong enough to give you a good tan, then you don't need to worry about this. If you live so far north that it is hard to tan in the winter, you may need to supplement with either UVB light or vitamins.

UVB light is a HUGE question mark right now- what is the best way to offer general UVA for vision and behaviors, and UVB-295nm range for D3 fabrication? Heck if I know. I would suggest that if you are using UVB lighting in your set-up (and you should, for several reasons), then you may STILL want to offer some supplemental vitamin D, but probably at the lower dosage end.

Most reptile products are oddly quiet about the dosages in their products, but some numbers I can find for common sources are:

IU's of Vitamin D in 100 grams of food:
- Cod liver oil- 8840 IU (or about 74 IU per drop, but may also be high in mercury)
- Fresh mushrooms- 14 IU
- Fresh mushrooms exposed to UV- 500 IU (note that this is vitamin D2, a less potent or effective version of the vitamin. It may only count as about 1/4th to 1/3rd as useful)
- Mazuri Tortoise Diet- 299 IU 
- Canned tuna in oil- 235 IU
- Beef liver- 15 IU

Some other options are-
- Whole egg- about 20 IU in a medium egg
- One a Day Vitamin Tablets- 400 IU per tablet, or about 10-40 IU in a pinch of a crushed tablet (a common serving size for tortoises)
- Reptical with D3- 13.7 IU per gram of powder

Comments about 'forest-dwelling tortoises get all the D they need in the diet' are obviously inaccurate- unless there is a wild source of D that we do not know about. A half-pound (500gram) tortoise would need to eat the equivalent of 2 pounds of beef liver a day to get the recommended dose of D in the diet! (Granted, some Hinge-backs eat fish, and all forest species eat some mushrooms, but enough to completely satisfy the dose. There is also a lot of solar UV hitting them as well that close to the equator.)

Some vitamins are washed out of the body daily and need constant replenishment- B, C, K, etc. Vitamins A, D, and E are stored in the fat and used as needed. Since they are needed every day by a growing or active tortoise, we do not want the fat reserves to get too low, so need to help ensure an on-going dosage.

(Note that the flip side of this is that the tortoise needs a healthy amount of body fat to store energy in as well! A good argument for making sure they get enough food.)

As you think about vitamin D supplements, remember that 'wet' is better than 'dry'. Vitamin D in powder or dry tablet form is less effective than it is in actual food or in a oil base, like gel-caps. Some sources even suggest that 'dry' D does not count. The supplements in Mazuri, cat food, etc. are often stored in a oily base, but they will loose effectiveness over time, which is one reason for expiration dates on them.

DOSAGE SUGGESTION:
I think the most convenient version would be liquid vitamin D, which comes in 500 IU to 5000 IU strengths, usually taking 5 drops to accomplish. This lets you drizzle it fairly easily over the meal.

For the dosing, I would aim for-
- 1000 IU per kilogram for tortoises without supplemental UVB
- 500 IU per kilogram for tortoises with UVB lighting

BOTTOM LINE:
A good balance of calcium and D (and, of course, some other stuff) are vital to a tortoises health, especially in the early years. There is no reason to be afraid to offer supplemental calcium and vitamin D to give our tortoises the best chances for success.

Like any good thing, you can go too far. If you are giving a tiny tortoise an entire high-dose (2000 IU) D gel cap every day, you may be overdoing it. Short of that, we should be OK.



SOURCES:
Vitamin D in Wikipedia
Dr. Douglas Mader's "Reptile Medicine and Surgery"
www.uvguide.co.uk
and a note of thanks to EgyptianDan for the inspiration!


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## Balboa (Dec 2, 2010)

Thanks Mark!
As you well know I've been wondering about this. Now to do the math to see if I can apply it successfully.

I recall while looking over old threads that at some point Danny had commented that he'd never heard of a tortoise suffering from D overdose, but plenty suffering MBD. Of course, I wonder how would you really be able to tell if you did overdose.


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## Madkins007 (Dec 2, 2010)

Balboa said:


> Thanks Mark!
> As you well know I've been wondering about this. Now to do the math to see if I can apply it successfully.
> 
> I recall while looking over old threads that at some point Danny had commented that he'd never heard of a tortoise suffering from D overdose, but plenty suffering MBD. Of course, I wonder how would you really be able to tell if you did overdose.



I'll edit a description of an overdose back in.


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## Tom (Dec 2, 2010)

I saw the note about manufacturers not listing the amount of D3, but does anyone have any idea about how much is in Rep-Cal?


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## Madkins007 (Dec 2, 2010)

Tom said:


> I saw the note about manufacturers not listing the amount of D3, but does anyone have any idea about how much is in Rep-Cal?



Yeahhhh... no. I cannot find anything on-line about the dosage levels, but I would suspect that they are formulated to be on the low end of the spectrum, like cat kibble and Mazuri.

Plus, 'dry' vitamin D is not as effective as 'wet' is, so gel capsules with the oil in them are better than dry pills or powder... and I should probably put that in the article too, huh?


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## Tom (Dec 2, 2010)

Madkins007 said:


> Tom said:
> 
> 
> > I saw the note about manufacturers not listing the amount of D3, but does anyone have any idea about how much is in Rep-Cal?
> ...



Are we talking about those fish oil capsules? I take these for joint health and good cholesterol. Give them to my dogs too. That would be pretty hard to dose for a tiny hatchling, wouldn't it?


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## HarleyK (Dec 3, 2010)

I'm confused because on the guaranteed analysis it says 13,700 IU/kg for reptocal. This doesn't say how much per serving so I have to estimate how much per kg I am using? In this case the D3 levels seem in the safe limits right?

I guess what I am asking is how can I figure out how much D3 IU my tortoise is consuming based on the IU rating.


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## Livingstone (Dec 3, 2010)

Can someone post exactly what "gel cap" we are talking about, just so we are on the same page.



Tom said:


> Are we talking about those fish oil capsules? I take these for joint health and good cholesterol. Give them to my dogs too. That would be pretty hard to dose for a tiny hatchling, wouldn't it?



I would think if you stuck the capsule with a hypodermic you could work out the fluid capacity. Once you know the amount of fluid per capsule you can work out how much to give the tortoise based on weight and Mark's helpful ratio posted above.

However it might require a bloody small syringe. Maybe one they use for insulin would work.


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## Madkins007 (Dec 3, 2010)

Reptical- It would have been nice to have found this online somewhere, but 13,700 IU/kg means that there is that many IUs in about 2 pounds of powder. Since a pinch is about 1/4th of a gram, this works out to... about 3.5 IU per pinch. Not a whole lot.

Fish oil- not all fish oils have vitamin D in them, Check the label.

Gel-caps- these are any pills that are soft gelatin capsules filled with oil. You can extract the oil by using a small pair of scissors and cutting an end off and squeezing, but liquid D would be more convenient, and less messy/wasteful.

Sites like vitamins.com or vitaminshoppe.com have some great stuff at good prices. Not only D, but also things like calcium, fiber, A, E, etc.


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## Whinhill (Dec 3, 2010)

Great article

my 2 cents cod liver oil is usually low in mercury these days (cod don;t live very long anymore most are caught before they are 3 years old so don't have to opportunity to bioaccumulate large amounts of mercury unlike larger long lived (less frequently caught in this case) carnivores fish such as tuna.

cod liver oil from farmed fish is even better as their diets are mercury free.


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## stells (Dec 5, 2010)

I have always supplimented... and always used UV lighting... young tortoises get suppliments at every feeding... older tortoises get it 3 times per week... i have never had a problem with overdose... and have made the posts of this forum saying that... there are alot of posts on this forum from people with soft tortoises... but none about a tortoise with overdose...

I guess i am not as dated as some people think


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## kelarned (Dec 6, 2010)

So I found a liquid vitamin D-3 supplement at the Vitamin Shoppe. It claims that is has 400 Iu's per five drops. Could I safely assume that one drop is roughly 80 Iu's?

I have 2-100 gram leos. I'm a little rusty on the conversions, but I do believe that approx. 100 Iu's per day would be an adequate amount.

Does this seem appropriate? Please let me know your thoughts.


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## Madkins007 (Dec 6, 2010)

stells said:


> I have always supplimented... and always used UV lighting... young tortoises get suppliments at every feeding... older tortoises get it 3 times per week... i have never had a problem with overdose... and have made the posts of this forum saying that... there are alot of posts on this forum from people with soft tortoises... but none about a tortoise with overdose...
> 
> I guess i am not as dated as some people think



Yeah... I was a 'you'll overdose it!' guy until I saw a comment from Danny and took it as a challenge to prove my stance, and saw how wrong I was. The article is an attempt to undo some of that and a form of apology to others!




kelarned said:


> So I found a liquid vitamin D-3 supplement at the Vitamin Shoppe. It claims that is has 400 Iu's per five drops. Could I safely assume that one drop is roughly 80 Iu's?
> 
> I have 2-100 gram leos. I'm a little rusty on the conversions, but I do believe that approx. 100 Iu's per day would be an adequate amount.
> 
> Does this seem appropriate? Please let me know your thoughts.



80 IU/drop would be correct.

Conversion? If it is 200-2000 IU/1000g of tortoise, then just move the decimals over- 20-200 IU/100g of tortoise. 1 drop would seem safe, and even 2 if there is not a lot of UV light.


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## jackenDonald (Dec 16, 2010)

Vitamin D3 is not a vitamin at all but a necessary hormone that effects the immune system & nearly every aspect of health. Having low Vitamin D levels greatly increases risk of cancer, heart disease, diabetes, MS (& maybe even FMS)

I don't think that FMS, cancer, MS, etc. is a vitamin deficiency but being deficient can create or greatly exacerbate health problems.
Luckily you can buy vitamin D3 (cholecalciferol) over the counter and the upper limits are extremely high. Current recommendations are for 35iu per pound - a 150# person needs minimum of 5250iu per day & the rda is 400iu. This amount is for minimal needs and does not account for depleted stores. March is when stores are at their lowest.


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## juliadesusa (Dec 24, 2010)

Vitamin D is very much useful for our body the deficiency of it will causes the cancer, Heart troubles etc.Vitamin D will mostly we take from the sun rays at the morning time.It is more beneficial for us,Other wise we can take it from cod liver oil,Or from Mushrooms,or from Eggs.


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