The absorption of natural vitamin C in horses and anti-oxidative capacity: a randomised, controlled study on trotters during a three-month intervention period.
The primary aim of this study was to evaluate whether a low-dose vitamin C supplement given in a natural form—specifically as a dried powder of a selected rose hip species (Rosa canina)—would lead to a measurable increase in blood vitamin C concentration in horses supplemented daily for three months. A secondary objective was to measure the supplement's antioxidant effect.
Sixteen horses participated in the study and were randomly divided into two groups. The horses were given either 25 g of rose hip powder daily (equivalent to 125 mg natural vitamin C) or 50 g of rose hip powder daily (equivalent to 250 mg vitamin C). Serum vitamin C concentration was measured before supplementation began and again after 14, 28, and 84 days.
Antioxidant capacity was assessed by measuring the amount of oxidative anions released by polymorphonuclear leukocytes before supplementation and again at days 14 and 84.
Although intake of 125 mg of natural vitamin C appeared to increase serum vitamin C concentration after 84 days, the change was not statistically significant. In contrast, the daily 250 mg dose led to a significant increase in serum vitamin C concentration already after 14 days (P < 0.02), and the concentration increased further at days 28 and 84 (both P < 0.02). In addition, serum vitamin C concentration was statistically significantly higher at the 250 mg dose compared with 125 mg (P < 0.03).
The higher vitamin C dose also led to a significant reduction in the release of oxidative anions (P < 0.001).
The results suggest that natural vitamin C derived from rose hip is absorbed sufficiently to increase serum vitamin C concentration and reduce oxidative stress in horses receiving less than 500 mg vitamin C daily.
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A randomised placebo controlled double blind study on the effect of subspecies of rose hip (Rosa canina) on the immune system, working capacity and behaviour of horses
Study objective: The purpose of the study was to determine whether rose hip powder (Rosa canina) affects the immune system, working capacity, and behavior of horses during training.
Study design: 44 trotters participated in the study. The horses were randomly divided into two groups: one received rose hip powder, and the other received a placebo. The study lasted three months and was double-blinded and placebo-controlled.
Key findings:
Rose hip powder was observed to have anti-inflammatory and antioxidant effects in horses.
The supplement improved the horses' vitamin C status.
These results suggest that rose hip powder may be a useful addition to equine feeding, especially during training, supporting the immune system and improving working capacity.
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The role of rose hip (Rosa canina L.) powder in alleviating arthritis pain and inflammation – part II: animal and human studies
The fruits of Rosa canina—rose hips—have been used in herbal remedies since ancient times.
Animal and human studies are particularly important in evaluating rose hip's true biological effects. In vivo studies conducted over the past two decades show that rose hip powder (especially the R. canina subspecies "Lito"), which contains a specific galactolipid (GOPO), can reduce joint pain, improve daily functional ability, and even reduce the use of common pain medications.
Because multiple compounds contained in rose hip have been shown to have anti-inflammatory effects, it is assumed that these anti-inflammatory actions explain part of rose hip's benefits in managing joint disease.
Although only a limited number of randomized, placebo-controlled clinical trials on rose hip have been published so far, existing evidence supports the idea that preparations containing both seeds and shell parts are more effective at reducing inflammation than products containing shell parts only.
Studies in horses and dogs
Trotters and greyhounds exposed to intensive training are interesting research targets for the prevention of inflammatory conditions, because intense physical exertion has been shown to produce oxidative stress. Oxidative stress also plays a role in the development of several equine diseases, such as recurrent airway obstruction and joint problems. A decline in vitamin C level in horses is considered an early sign of stress.
Synthetic vitamin C is poorly absorbed in horses, and its effect on blood vitamin C concentration may only be seen after up to three weeks of continuous use (20 g daily). For this reason, it is important to find feeding approaches where the horse can obtain plenty of vitamin C in an easily absorbed form.
A randomized, placebo-controlled study in which 44 trotters received rose hip powder (containing seeds and shell parts) for three months showed that Rosa canina has similar anti-inflammatory effects in horses as in humans. Chemotaxis of neutrophils isolated from rose-hip-supplemented horses (movement toward the site of inflammation) decreased significantly compared with placebo horses.
In addition, rose hip powder significantly improved the antioxidant capacity of horses when assessed using neutrophil chemiluminescence. Treated horses improved statistically significantly in running speed—the 1000-meter distance was completed on average 1.1 ± 1.5 seconds faster. No such improvement was seen in the placebo group. Horses receiving rose hip were also clearly more supple the day after exertion. Improvements in speed and suppleness were also linked to a significant rise in plasma vitamin C level.
The study also observed a dose response: even a daily dose below 250 mg of rose hip powder reduced the release of oxidative anions and increased blood vitamin C concentration.
In greyhounds that received the same rose hip powder for three months, similar results were observed: the dogs were more supple the day after hard training, they had better speed, and they had better coat quality compared with same-age, same-breed placebo dogs. In addition, leukocyte (white blood cell) count decreased significantly after three months of treatment—no such decrease was seen in the placebo group. The dogs' running speed improved statistically significantly (P < 0.027).
The study concluded that rose hip has anti-inflammatory and pain-relieving properties. In addition, studies* have found that rose hip improves coat quality and reduces the risk and prevalence of gastric ulcers.
In summary: Studies in horses and dogs suggest that rose hip has anti-inflammatory effects, it can improve performance, and animals are more supple after heavy exertion.
