Vitamin D Deficiency - questions, questions

I came across a presentation on food by BAR (British Association of Rodentologists): http://66.102.9.132/search?q=cache:...ege+of+veterinary+surgeons&cd=6&hl=en&ct=clnk (It's available as a PDF, but I couldn't get it to load fully.)

As I was reading through it and came across Vitamin D, I couldn't help but wonder if when a guinea-pig is diagnosed with calcium deficiency, it's really Vitamin D deficiency instead (as the symptoms appear the same), because it's harder to get from food. Also, magnesium is just as essential for strong bones as calcium (even though it doesn't get any hype), but the two 'fight' for absorption; so an excess of one in the diet at any time will lead to a deficiency in the other.

I know that Vitamin D deficiency in humans has now been implicated with heart disease, Multiple Sclerosis (lack of sunlight in childhood), depression and certain cancers, so I was I wondering if similar problems had been linked to Vitamin D deficiency in guinea-pigs? [http://www.vitamindcouncil.org/researchHeartDisease.shtml]

The BAR article sites sunlight as the main source of Vitamin D (ditto for humans) - so what do guinea-pigs who live indoors do? I know that Oxbow guinea-pig food is fortified with Vitamin D, so presumably others are too, but is it enough - is it absorbed well enough?

Interesting thread, I've not come across that article before. I image there could be potential problems with guinea pigs who live in basements and garages that don't have windows, but the large majority of indoor pigs live in a room lit by natural light.

May I suggest that you Google "Vitamin D and calcium metabolism", this will answer your question. Likewise for zinc and magnesium.

A pig obtains Vit D from the diet and/or from sunlight. It is only when both sources are missing that problems occur

Physiological biochemistry is fascinating, if you like that sort of subject!

Laura-CCC4 said:

Interesting thread, I've not come across that article before. I image there could be potential problems with guinea pigs who live in basements and garages that don't have windows, but the large majority of indoor pigs live in a room lit by natural light.

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I'm not sure whether sunlight from a window would work, as people are told to get direct sun exposure in the late Spring, Summer and early Autumn, when the sun is sufficiently strong (depending on latitude). I think the glass pane absorbs a lot of the UV radiation.

alcesterpigs said:

A pig obtains Vit D from the diet and/or from sunlight. It is only when both sources are missing that problems occur

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Natural foodstuffs are a poor source of Vitamin D. My point was, if a guinea-pig lives indoors and therefore has no access to sunlight (presuming insufficient is absorbed through a window-pane), is all guinea-pig food supplemented with Vitamin D and if so, is it properly absorbed? This is not such a silly statement as it may sound; most calcium supplements for people contain calcium carbonate which is a poorly absorbed source of calcium.

It is very difficult for people to get sufficient Vitamin D from their diet and with the recent taboo on sun exposure, a lack of this vitamin is now being linked to a whole host of serious health issues (heart disease, certain cancers, MS, depression, mental illness, autism (possibly)). I was therefore making parallels between the problems now being seen in humans and whether e.g. heart disease in guinea-pigs could also be linked to a lack of this vitamin.

Try Google, again....
I have never knowingly seen a pig that is calcium, Vit D deficient.
Have the tabloids been publishing health scares again!?

alcesterpigs said:

Try Google, again....
I have never knowingly seen a pig that is calcium, Vit D deficient.
Have the tabloids been publishing health scares again!?

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Vitamin D is essential for the absorption of calcium from the GI tract in a guinea-pig, so both need to be present to prevent calcium deficiency. I have read on here about guinea-pigs where the owners thought their guinea-pig may have calcium deficiency (Gucci springs to mind) and the symptoms of calcium deficiency are the same as Vitamin D deficiency (according to the BAR article), so I was merely wondering if calcium deficiency could be diagnosed, when it was really a lack of Vitamin D.

Not tabloids, published papers:

http://circ.ahajournals.org/cgi/content/abstract/circulationaha;117/4/503

"Conclusions— Vitamin D deficiency is associated with incident cardiovascular disease."

http://journals.lww.com/smajournalo...itamin_D__Important_for_Prevention_of.15.aspx

"Vitamin D: Important for Prevention of Osteoporosis, Cardiovascular Heart Disease, Type 1 Diabetes, Autoimmune Diseases, and Some Cancers."

There are hundreds more on Google Scholar.

This is an issue I've thought about recently too (I might have even started a thread - can't remember). You are right that vitamin D can't be absorbed through windows - has to be sunlight on the skin. My pigs have always been indoors, and I really can't help but wonder whether it's better for pigs and rabbits too to be outdoor, with protection from excess heat and cold. :{ Mine are indoors though, and always have been.

If that's accurate, wouldn't all pigs who live indoors (and are not taken outdoors) then be ill with calcium/Vit D deficiency?

I understand the lines of thought here, but my own pigs are healthy and just don't get let outside. If they are getting zero Vit D from sunlight, then it must be obtained in the diet, which would lead to AP's point. Which then leads onto your question of Vitamin D levels in all guinea pig foods...an interesting research project.