L-arginine may just prove to be that one nutrient that is lacking impacting the health and perfomance of horses. L-arginine supplementation may prove to be of significant benefit on many levels. Let’s take a look at the basics and what clinical research has to show.
Amino acids are the structural building blocks of protein, with each one having its own impact on health, sometimes from multiple levels. L-arginine is considered to be a ‘semi-essential’ amino acid in that the body is able to synthesize it from other amino acids. Arginine is also acquired from the diet from dairy and plant foods, in variable levels. What research has shown is that in most cases of healthy individuals, the achieved arginine levels between diet and natural synthesis are considered to be adequate, but we have to raise the question as to what the definition of a truly healthy individual is and what those levels are? Research is a little vague on this topic and has suggested normal levels, but there are too many variables to make this carry over from one individual to the next. What has been shown is that the natural synthesis of L-arginine by the body is insufficient to meet typical demands and thus diet is considered to be the sole source of the amino acid.
When we consider the basic diet that most horses consume, as well as the many health conditions that are becoming more prevalent, we need to question the value of supplementation. This holds true for equine athletes as they can be exposed to food sources may be deficient in many nutrients for various reasons. It could be possible that supplementing various amino acids in their diets, including L-arginine, could prove to be very beneficial for a host of conditions.
L-arginine supplementation has been shown in research to enhance physical exercise capacity and delaying onset of fatigue, possibly reducing lactic acid production which is often a limiting factor to intensity and duration. Supplementation has also been shown to improve antioxidant levels during exercise, which is often depleted and predisposes many athletes to illness.
Impact of L-Arginine on Health:
L-arginine is directly tied into nitrogen metabolism and ammonia detoxification within the body. Ammonia is generally a byproduct of protein metabolism and keeping levels low is critical to overall health.
L-arginine is the precursor to nitric oxide formation, which contributes to vasodilation (relaxation of blood vessels). This vasodilation then can contribute to overall lowering of blood pressures, enhance blood circulation and improve cardiac function.
L-arginine directly impacts immune function by enhancing natural killer cell and lymphocyte activity.
L-arginine impacts endocrine function directly, with one area in particular being Growth Hormone (GH).
Considering all of these benefits, let’s now take a look at what research has to show.
Tissue Healing and Repair:
It is well known that severe illness, sepsis, trauma and post operative healing can result in depletion of L-arginine within the body. This subsequent depletion has been theorized to contribute to overall poor recovery in a variety of conditions. In most cases of critical illness, Total Parenteral Nutrition, provided to the patients that are not eating has been of value, but often is void of critical L-arginine which may enhance overall recovery.
L-arginine supplementation has shown to increase healing time, reduce post operative infection risk, decrease length of hospital stay and enhance overall immune function in patients with critical injuries, illness or post-operative.
L-arginine supplements increased production of Nitric Oxide (NO) resulting in vasodilation and has been shown to benefit those patients with active hypertension.
L-arginine supplementation reduced clinical signs of angina in patients with active clinical signs and increased their exercise capacity.
L-arginine supplementation reduced the clinical signs of congestive heart failure (CHF) resulting in improved blood flow and condition stability.
L-arginine supplementation improved exercise duration in patients with CHF.
L-arginine supplementation also improved renal function and blood flow in patients with CHF.
L-arginine supplementation reduced factors associated with atherosclerotic plaque formation due to increased nitric oxide formation, decreased platelet aggregation, decreased monocyte migration, decreased smooth muscle proliferation and decreased vasoconstriction…all factors tied in with atherosclerosis.
L-arginine supplementation has been shown to enhance central nervous system function and reduce the impact of neurodegenerative conditions, likely through improved blood circulation and antioxidant defenses.
So why supplement with L-arginine?
Honestly, we have to look at two categories of equine athletes when it comes to supplementation; health preservation versus condition management. The difference between two is that one group is looking for prevention purposes to maintain optimal health, while the other group may actually have a health condition that creating excess demands on the body, creating a need for higher levels of supplementation.
In horses, L-arginine supplementation may enhance overall exercise performance, recovery, help to improve cardiac function and blood flow, while potentially reducing the impact of lactic acid. Considering the ability of arginine to enhance circulation and support the immune system, supplementation may prove beneficial in wound repair, surgical recovery and even tendon healing. By enhancing circulation, we can improve the delivery of nutrients to the tissue for healing purposes. The immune function is also needed in the process of tissue repair, which helps to clear dead tissue and fluid accumulation, all supported by L-arginine. L-arginine supplementation may also prove valuable in the management of laminitis, due to improved blood flow and vasodilation to the digital region. Doses again vary dependent on the level of condition being managed.