# D3 and Overdosing



## Seiryu (Jun 22, 2010)

So there is always talk about D3 and people saying overdosing d3 is easy if you supplement it. Maybe I am completely off basis, but here is my line of thinking. This is for growing tortoises though, NOT adults.

So you take your tortoise outside for 10-12 hours a week. Many people think this to be plenty of sunshine for the tortoise to properly synthesis d3. Not all one day of course. So let's say 1.5 hours a day you take him out.

On the other hand, there are people who live in California, Arizona, Florida with higher UV index's than that of other states who can't house their tortoises outside year long. And they keep their tortoise out almost 365 days a year.

Obviously their tortoise is getting more sunshine than the rest of us taking ours out for an hour or two a day. 

How come adding a supplement of D3 (in a growing tortoise) in an area where the UV index is lower and we can't keep the tortoise out all day due to rain, winter, too cool weather is a BAD thing to do, when our tortoises are synthesizing far less d3 than those that are in warm climates year round? Not talking about a daily thing, but once or twice a week.

Are their tortoises getting overdoses of d3 because they are outside all the time? I think not. I know a supplement vs the real thing is a little different, but d3 is d3 is it not?

Also, our UVB bulbs we use, whether or not they are MVB or the Fluorescent tubes give off less UVB than the sun. Those who get a winter, or those who keep their tortoises indoors use these lights. Some people say the UVB bulbs are not enough, yet these are the same people that say to NEVER ever use a d3 supplement.

I don't get how you can overdose d3 unless your tortoise is outside all day long, all the time, when you bring them inside, put them under UVB bulbs that give off far less UVB than the sun.

There was a point brought up, saying that maybe our tortoises aren't getting enough vitamin/d3 supplementation and that can intern cause pyramiding as well.

Anyways what are your thoughts on this.


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## stells (Jun 22, 2010)

My growing tortoise's have suppliments containing D3 at every feeding when they are inside... outside they get it once per week... the UV rating over here (UK) is very low most days... so just to rely on UV bulbs i feel doesn't work for me... plus you would need to constantly monitor the decay of the UV bulb which with some can be very quick... people have done this on shelled warriors and some of the readings after a couple of months were quite shocking...
I have seen plenty of people on the forums saying they have soft tortoises... this in my opinion is from the lack of supplimentation given... seems on this forum to be very common with Sulcata's... i have though NEVER seen a post on a tortoise suffering with D3 overdose... if i am wrong and there are these kind of thread on here feel free to correct me...
I am going to carry on supplimenting my growing tortoises as i do as i haven't had a problem with growing them... hardening hatchlings... or overdose... all of my tortoises are thriving... so i ain't gonna fix what ain't broke...


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## Tom (Jun 22, 2010)

This is just one of those things.

Way too many unanswerable questions. How much do they need? At what life stage? How much do they produce on their own in one hour of CA summer sun? Michigan? Iowa? How much do they make under a MVB? How fast does their body use it up once they make it? Can they even use it if its ingested (saw a study that said iguanas can't)? Can they overdose on D3? We all talk about it, but has anyone ever seen a D3 overdosed tortoise? How different is it among the different species?

I think we all develop a "feel" for what's right for our situation. Mine are in the sun every day, so I don't use D3. Kelly uses it everyday when her's are inside. Everyones situation is different and every one does what works best for them.

And remember, the point about vitamin and D3 supplements having to do with pyramiding is in the debatable section. It might have everything to do with it or nothing at all. Too many unanswered questions on that one too.

I'm hoping that with forums like this and lots of shared experiences, we can start to get some of these questions answered...


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## egyptiandan (Jun 22, 2010)

In over 30 years of having tortoises, talking to people and being on forums, I have never seen an overdose of vitamin D3. 
In that same period of time, I've have seen or read about over a thousand tortoises (easy) that were deficient in vitamin D3.

Danny


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## Missy (Jun 22, 2010)

What is the best D3 to use???


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## Madkins007 (Jun 22, 2010)

Point of order- apparently there is a safety mechanism in the skin that prevents D3 overdoses from the sun, although no one seems sure if it also works for artificial light. (http://en.wikipedia.org/wiki/Vitamin_D, look under the section "overdose by ingestion" and other sources.)

Overdosing on D3 would mostly likely occur through supplements, and probably from thinking that if a little helps, a lot will help more- a very dangerous idea in supplements, diet, etc.

While it is not a common problem, it is one addressed by Dr. Mader. The most common signs of D3 overdose would seem to be a sunburn-like skin reaction.


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## Terry Allan Hall (Jun 22, 2010)

Madkins007 said:


> Point of order- apparently there is a safety mechanism in the skin that prevents D3 overdoses from the sun, although no one seems sure if it also works for artificial light. (http://en.wikipedia.org/wiki/Vitamin_D, look under the section "overdose by ingestion" and other sources.)
> 
> *Link no workee...*
> 
> ...



This common sign of D3 overdose would be in humans or torts?


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## Madkins007 (Jun 22, 2010)

Terry Allan Hall said:


> Madkins007 said:
> 
> 
> > Point of order- apparently there is a safety mechanism in the skin that prevents D3 overdoses from the sun, although no one seems sure if it also works for artificial light. (http://en.wikipedia.org/wiki/Vitamin_D, look under the section "overdose by ingestion" and other sources.)
> ...



Torts. The link is fine, I just stupidly added the comma after it instead of using the link tool or adding a space. http://en.wikipedia.org/wiki/Vitamin_D


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## Terry Allan Hall (Jun 22, 2010)

Madkins007 said:


> Terry Allan Hall said:
> 
> 
> > Madkins007 said:
> ...



OK, thanks for the clarification.


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## Tom (Jun 22, 2010)

Can a tortoise even get a sunburn? My adults walk around in the sun most of the day.


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## fifthdawn (Jun 23, 2010)

Yep, the reason why you can't overdose in the sun is because your body will only make enough d3 as it needs. When its supplemented orally, your body has to use it all up. While you can overdose on D3, it is extremely hard to overdose which is why you rarely hear about overdose in d3. Infact, you run a higher risk in overdose with other vitamins than you would with d3.


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## Madkins007 (Jun 23, 2010)

Tom said:


> Can a tortoise even get a sunburn? My adults walk around in the sun most of the day.



I dunno... I would suspect that a tort with no shade in full sun would eventually develop some sort of skin troubles, possibly along with sun blindness, dehydration, etc. but I'd also bet that different species have different degrees of protection in their skin.

We know, for example, that many reptiles have different kinds of scales, using thickness and coloration, to protect them while also processing needed levels of D3.


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