Vitamin C

[mtj]

I'm considering putting my horse with spavins on a new arthritis supplement that is based on rosehips and has high levels of vitamin c. I haven't gone completely crackers - the supplement has undergone a published preliminary trial with humans.

His current joint supplement (flexaibility) also has vitamin c included. I appreciate that humans do not benefit from over high amounts of Vitamin C and wondered if there was a limit for horses.

Any thoughts?

 

[soloequestrian]

I don't know whether there is an upper limit on Vit C however it is water soluble so in theory the body can excrete excess relatively easily. There are certain schools that think the levels currently prescibed for human intake are far too low and that high levels of Vit C in the diet can have beneficial health effects - we evolved to eat much more fruit and veg than the average (Western anyway) human does now and somewhere along the line lost our ability to synthesise our own Vit C (along with other frugivores - guinea pigs, fruitbats, some birds and I think other great apes). I believe there are other schools that think high levels are not a good thing though....
Horses make all they need themselves like other mammals which is why it's not normally necessary to supplement.
If you can get hold of the NRC nutrient requirements they should tell you if there has ever been a safe upper limit for horses determined, but I wouldn't be surprised if there hasn't.

 

[scally]

Although the body will excrete excess Vitamin C damage can still be done prior to excretion. Complications include Kidney Stones, Vitamin B-12 deficiencies, Copper deficiciences, increased need for oxygen, diabetes, hypoglycemia. A human can take up to around 1000mg of Vitamin C a day with very little side effects (recommended dose is around 75mg) although long term use can result in the above illnesses, so what a horse can have I would have no idea.

Maybe discuss this with your vet and a nutritionist by human levels 10 x the recommended daily dose will not affect a human greatly if used for a short time, so this maybe the same for horses. You also need to take into account vitamin C in his normal diet also to give you the daily intake correctly.

Also overdosing on one vitamin can lead to deficiencies in others vitamins and minerals so I think professional advice is recommended.