Reprinted with permission from Vicki of Jack Pine Guinea Pig Rescue and sine_quanon, B.S. Genetics, Cell Biology, Chemistry; Former researcher for the US Dept of Agriculture Laboratory Services Coordinator, U of MN:
After reading a couple of postings from people concerned about overdosing their
cavies on vitamin C, I talked to my vet - who specializes in exotics (such as cavies). I
asked her if owners had to be careful about giving a daily vitamin C supplement and
fresh fruits and vegetables, was there a risk of overdosing? She said she has not
seen or heard of this being a problem. She said vitamin C is one of the safest
vitamins as it is water soluable and whatever a cavy doesn´t need is excreted in the
urine. My vet felt a cavy would have to be grossly overdosed to have a problem.
Giving a daily supplement with a good diet and fresh produce isn´t going to do it. I
also checked through my veterinary manuals but found only one sentence on the
subject, and this was in Diseases of Domestic Guinea Pigs, "Hypervitaminosis C is not
a recognized problem as any ascorbic acid which is excess to requirements is
excreted through the kidneys."
If anybody does have information from a reputable source on pseudo scurvy (or
hypervitaminosis C) in cavies I would love to see it. Preferably veterinary articles or
lab studies. Please contact me directly if you have such information - JPGPR@aol.com
There seems to be a wide range for daily vitamin C doses. One of my veterinary
manuals (Ferrets, Rabbits and Rodents - Clinical Medicine and Surgery) recommends
10-30 mg/kg daily for maintenance and up to 50 mg/kg for treatment of deficiency.
When putting vitamin C in water this book recommends 200-1000 mg/L. Another
manual (Diseases of Domestic Guinea Pigs) recommends up to 100 mg/kg for
treatment of deficiency. A few years ago one of my vets recommended 30-50 mg
vitamin C daily per adult cavy - depending on size, diet, conditions, stress. See what I
mean about wide range? If you only have a few cavies I think Liquid C, made by Twin
Labs, is a very easy effective way to go. One of the exotic´s vets in the Twin Cities
sells small bottles of this and recommends a dose of 1/2 cc daily per average sized
adult cavy - which is 30 mg vitamin C. This is a pleasant tasting syrup which many
cavies take willingly. It is also reasonably priced. You can buy Liquid C at GNC stores,
other health/nutrition stores, and at
www.mothernature.com. The product sold by Nutritional Research Associates,
Quintrex Aqua C, is approx. 1000 mg vitamin C per 1/4 t. Mixing directions are 1/4 t.
per 1 gallon of water. Adding vitamin C to cavy´s water is not as accurate or effective
as giving a measured oral dose. Vitamin C is a weinie vitamin - and is gradually
weakened by time, minerals in the water and perhaps even by the metal sipper tube.
The amount of vitamin C a cavy gets depends on how much water he drinks and can
vary from day to day.
Vicki - Jack Pine Guinea Pig Rescue, MN
EFFECTS OF MEGADOSES
The controversy about whether megadoses of vitamin C are healthful began in 1970
when Noble Prize winner Linus Pauling published his controversial book Vitamin C and
the Common Cold. This controversy is still very alive today. However, for most
purposes, vitamin C is nontoxic. Gram amounts are widely used as the treatment for
several conditions such as the common cold, cancer, schizophrenia, drug addiction, and
improvement of immune resistance. Vitamin C is not store appreciably in the body and
excess amounts are eliminated rapidly through the urine. Amounts over 10 grams per
day are associated with some side effects, though none are serious.
Most of the claimed clinical adverse effects of high doses are anecdotal and result from
uncontrolled studies. It has been claimed that ingestion of excessive quantities can
contribute to kidney stone formation, "rebound" scurvy, vitamin B12 destruction,
mutagenicity, impaired copper utilization, transient diarrhea, and laboratory testing
errors. Only the latter two effects appear to be supported by some published literature.
High intakes of ascorbic acid were postulated to contribute to kidney stone formation
because oxalate, a component of stones, is produced during catabolism of the vitamin.
However, the oxalate produced from vitamin C is insignificant in comparison with
oxalate from dietary sources. This is a rare case and only people with kidney disease
should be concerned.
The suggestion of "rebound" scurvy, the appearance of scorbutic symptoms following
the withdrawal of high dose vitamin C intake, has no experimental evidence for such an
effect in humans. Guinea pig studies in this area have been negative or inconclusive.
The theories that large amounts of ascorbic acid destroyed vitamin B12 and that
vitamin C is mutagenic were shown to be a result of error in experimental testing.
Controlled studies have also shown no support for the claim that vitamin C impairs
Diarrhea is the only major side effect of large doses for the otherwise healthy person.
Diarrhea is usually the first sign that the body´s tissue fluids have been saturated with
ascorbic acid. These disturbances are due to the laxative action of vitamin C. Most
people will not experience this effect with under 5 10 grams of vitamin C per day.
It also have been proven that megadoses of vitamin C may cause interference with the
clinical analysis of blood and urine. Excess intake gives false positive results for tests of
diabetes and interferes with tests for hemoglobin.
Other minor side effects include nausea, stomach cramping, and vomiting.
For high exposure levels, be aware that chewable tablets are full of sugar and the
acidity of vitamin C is hard on tooth enamel.
The authors list MANY reputable published sources for their information on their web
site. For further info please reference these materials.
Although the research above was gathered for human health purposes, much of the
testing was done on cavies as they react to vitamin C so similarly.
Most of my exotic veterinarians think a daily vitamin C supplement is beneficial,
especially since the most popular fresh foods given to cavies by the average pet owner
don´t contain enough vitamin C to consistantly provide the 10-30 mg/kg recommended.
I have never read or heard from any professional veterinary source that vitamin C
supplements can be EASILY overdosed. According to most exotic veterinarians and
exotic veterinary manuals scurvy (vitamin C deficiency) is a common cavy illness. Little is
said or written about vitamin C overdose except that it is not a common problem as a
cavy simply excretes excess vitamin C in it´s urine. It is not stored in the body, so does
not build up.
Warnings of the danger of psuedo scurvy from too much vitamin C or vitamin C
supplements with fresh foods have been posted on various boards. Because vitamin C
is so essential to a cavies health, and because vitamin C supplements are often the
easiest and most dependable way for many owners to rest assured their pet is getting
what he needs - I hate to see warnings against them without reliable evidence being
offered. Especially when these warnings are contrary to what I´ve learned from
experts. Scurvy is a very real and documented problem and instances could rise if
people believe vitamin C can be easily provided with any househould veggie or can be
easily overdosed. I was glad to see the following statements in the documented
research provided by sine_quanon: "The suggestion of "rebound" scurvy (or psuedo
scurvy), the appearance of scorbutic symptoms following the withdrawal of high dose
vitamin C intake, has no experimental evidence for such an effect in humans. Guinea pig
studies in this area have been negative or inconclusive." Check out the URL listed for
more information on this study.
A couple folks referred me to psuedo scurvy information from Eva´s Cavy Page.
Eva´s Pseudo Scurvy Page
disappointed to see that while Eva mentioned the condition was known and studied,
she did not provide any direct quotes or references from professional statements or
studies. I emailed Eva asking if she could direct me to her sources but haven´t received
I was also surprised to see this recommendation, "As much cabbage and carrots as the
guinea pig can eat every day will give more than enough vitamin C for a healthy guinea
pig." It is fairly well known that carrots contain little vitamin C. Several vets have
warned me about giving much cabbage. This is a "gassy" food and can cause bloat in
cavies. According to the exotics manual, The Biology and Medicine of Rabbits and
Rodents, "Carrots and lettuce are not good sources of vitamin C, and cabbage may
contain goitrogens." Goitrogens are substances that interfere with production of
While the Internet is often a terrific source of information, it can also be a source of
rumors, incomplete or inaccurate information, and old wives tales. Before taking any
advice that could possibly affect your pets health and safety, please check with a cavy
Breakdown of vitamin C in tap water
Vitamin C, aka ascorbic acid or even more correctly L-ascorbic acid, has been thoroughly
researched by the chemical companies that make it for scientific research purposes.
According to the Material Safety Data Sheet (this is a form required by law to be
completed about every chemical that is available to the scientific lab, both research and
teaching), it is not necessarily stable in tap water. The following is an exerpt from the
Material Safety Data Sheet (MSDS) put forth by Hach Chemical Company. MSDS are
HACH -- ASCORBIC ACID
MATERIAL SAFETY DATA SHEET
Manufacturer´s CAGE: 91224
Part No. Indicator: B
Part Number/Trade Name: ASCORBIC ACID
Cond To Avoid (Stability): MOISTURE.
Materials To Avoid: CONTACT WITH OXIDIZERS, DYES, ALKALIES, IRON, COPPER.
Hazardous Decomp Products: ACRID SMOKE AND IRRITATING FUMES IN FIRE.
Hazardous Poly Occur: NO
Conditions To Avoid (Poly): NOT RELEVANT.
It is common to find copper and iron in your tap water if your pipes are copper or iron
like in many old houses. The other chemicals that cause major problems with ascorbic
acid are oxidizers, these are very strong and very reactive chemicals like the chloride
ion. This is where the debate sets in about chlorine in tap water. Since according to the
Chlorine Chemistry Council http://www.c3.org/newsroom/whitepap...rcl.html#awater
most of our tap water is chlorinated with chlorine gas, it is not loaded with the highly
reactive form of chloride. This is because in addition to being an oxidizer, chlorine is also
what is known as a diatomic element, meaning it likes to bond to itself like in the case
of chlorine gas. In this form it is not as strong of an oxidizer. Since at this point I wasn´t
satisfied that I knew the answer to the debate of chlorine breaking down vit C, I called
the technical support lines for both Fisher Scientific and Sigma Chemical Company (both
also produce ascorbic acid). At both companies I spoke with a PhD in chemistry who´s
only job is to know how the chemicals their companies sell will react. In both cases I
was told that the chlorine in the tap water would not be as much of a problem as the
iron and copper that are also present. They also said that the chlorine gas used to
chlorinate our water is not as strong of an oxidizer as say perchlorate (also a form of
chlorine). They also said (as the following MSDS exerpt from Fisher Scientific states:
**** SECTION 10 - STABILITY AND REACTIVITY ****
Stable at room temperature in closed containers under normal storage and handling
Conditions to Avoid:
Incompatible materials, light, ignition exposure to air, excess heat.
Incompatibilities with Other Materials:
Hazardous Decomposition Products:
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.
Hazardous Polymerization: Has not been reported.)
that the light and air would probably break it down before the chlorine would.
Also according to Nutritional Research Assoc who manufacture and sell Quintrex
Aqua-C, a vit C supplement specific for cavy´s drinking water, "light, warmth, moisture,
and the oxygen present in the water tend to destroy its value. So Quintrex Aqua-C
water should be made up daily. Copper in the water system is destructive to Vit C, so a
copper-free watering system is necessary." They make no mention of chlorine.
My conclusion from the data I have seen could be summarized as follows:
While the chlorine MAY degrade the vit C, it should be doing so no faster than the
copper and iron that is most likely present in all of our water systems. Taking this into
account, setting water out to let the chlorine "evaporate" is NOT effective in protecting
the quality and quantity of the vit C in your cavy´s water bottle. Both light and air also
aid in vit C´s degradation, so you should refresh your cavy´s vit C at least once daily
using a filtration system that removes copper such as a Brita, Pur, or reverse osmosis
water purification system.
Use common sense with vitamin C.
Cavies are unlikely to suffer vitaminosis C or psuedo scurvy (overdose of vitamin C)
when given a daily vitamin C supplement at recommended doses with or without fresh
fruits and vegetables. Studies show vitamin C to be one of the safest vitamins and not
easily overdosed. However, anything can be overdone if recommendations are ignored.
Cavies require 10-30mg/kg of vitamin C daily. If sick or pregnant their requirements
may be a little higher. Huge megadoses of vitamin C are not needed and should not be
given. Somebody asked me about giving a 250 mg vitamin C chewable daily as a treat -
or giving a sick cavy 500mg daily. Definitely NO! That is grossly overdosing, giving the
cavy many more times the recommended amounts. While studies show large doses of
vitamin C can be given without causing problems, we do not know exactly how much IS
too much. Owners need to educate themselves and show common sense when taking
care of their cavy´s needs.
Sine_quanon, thank you again for such well researched information. Sounds like vitamin
C is a wieny vitamin that weakens in water - BUT, this is a gradual process and not
something instantaneous. As I suspected! Also sounds like metals in the water are
harder on vitamin C than chlorine.
Vicki - Jack Pine Guinea Pig Rescue, MN
In response to a question of whether the body absorbs synthetic C differently from
It´s not that an organism can´t use a manufactured vitamin, it´s that not all of the
vitamin is actually usable. When vitamins are manufactured, your product will show a
characteristic known as isomerism. Isomerism means that you´ll get many chemical
compounds that have the same molecular formula (meaning they´ll have the same
atoms in the right numbers), but different arrangements of the atoms. Most organisms
will only be able to use one arrangement of a particular vitamin. What that means to us
is that if you (or your cavy) takes a synthetic vitamin, the body will only use the one
arrangement found in the mixture of many different arrangements. The other non
usable ones will just be excreted. When you take a natural vitamin often there is only
the one usable form present. Either way, the natural or the manufactured vitamin, will
still give you what you need, but there is a bit more waste using a synthetic vitamin.
Lynx Posted on: 03-17-2000 05:02 AM:
While for me this is not an issue, because I prefer not to put C in water (my cavies
consume remarkably little) I would like to comment on copper plumbing systems and
home wells. With acidic water, as I have, as time progresses, the copper is slowly
leached into the water. However I routinely run the water long enough (for me a
gallon, ecologically saved for the washing machine) before use in coffee or mixing
juices. I feel this is adequate for the average home owner who has a well system and
plastic piping to the source and has a good idea of where any metal piping is located in
the water system.
Another site that mentions megadosing with C
Scroll down to: Can There Be Too Much of a Good Thing?
scroll down to scurvy
scroll down to VII. METABOLIC DISEASES - A. Scurvy
scroll down to Vitamin C Deficiency
scroll down to Vitamin C Deficiency
C and calcium content of vegetables
THE TANG FALLACY
These are the ingredients for sugar-free Tang,(couldn´t find the
ingredients for the regular kind which I assume are probably close
except for the aspartame).
Ingredients: Citric acid, potassium citrate (controls acidity),
maltodextrin (from corn), calcium phosphate, aspartame (Phenylketonurics:
contains phenylalanine), ascorbic acid (vitamin C), natural flavor,
artificial color, xanthan bum, orange juice solids, cellulose gum,
magnesium ocide, acesulfame potassium, yellow 5, yellow 6, niacinamide,
alpha tocopherol acetate (vitamin E), vitamin A palmitate, vitamin B6,
artificial flavor, riboflavin (vitamin B2), BHA (preserves freshness).
Calcium is not a desirable addition to a pig diet. Nor is BHA. Somehow,
I don´t think the other ingredients are all that great either
considering, you can use Tang to remove rust from the dishwasher.
An 8 fluid ounce serving of Tang contains 100% of the Daily Value (DV)
of Vitamin C. The Daily Value amount is 60mg. Therefore, presumably, a
serving of Tang contains 60mg of Vitamin C.
Depending on how much a pig drinks, Tang in the water could be an extremely
poor source of C.
If you want to give them additional C thru juice - unsweetened cranberry
juice is a much better choice. Tang is junk food for pigs.
Note: BizyLizy reports that her vet advised her to use 0.1cc - 0.2cc (10 mg - 20 mg) for a guinea pig who is just under two pounds. The vet had some concerns about a higher dose due to the Niacin content.