Antioxidant supplementation to the exercising horse

Abstract

Evidence of oxidative stress in horses has been described in reports dealing with intense and endurance exercise. Oxidative stress occurs when antioxidant systems are insufficient causing oxidation to potentially damage DNA, proteins, and lipids, and contribute to degenerative changes. Vitamin E is the most commonly supplemented antioxidant in horses and has been shown that horses in exercise conditioning may require higher intakes of vitamin E than recommended. Also in various species vitamin C potentiates the effects of vitamin E; however, under maintenance conditions horses have the ability to synthesize sufficient ascorbate, the demand increases as stress on the body is increased. Competitive endurance horses were estimated to consume 1.2 to 5-times higher levels of vitamin E than recommended intakes. In these horses a negative correlation was found between the vitamin E intake and creatine kinase, and aspartate aminotransferase. Similarly, three-day event horses have vitamin E average intakes about 50% over recommended levels, and it was also found that intake of vitamin E negatively correlated with inflammatory markers. However, large doses of vitamin E at about 10-times the recommended levels could potentially interfere with beta-carotene absorption. While some studies have shown benefits of lipoic acid supplementation in endurance trained horses similar to that of vitamin E, other studies failed to show any benefit of supplemental superoxide dismutase in intensely exercising horses. The implications from this broad scope of work show potential benefits for supplementing various antioxidants however, before assuming efficacy from other species horse specific studies should be performed.

Exercise-Induced Oxidative Stress and Dietary Antoxidative

“…A recent study suggests that vitamin E and α-lipoic acid supplementation may in fact suppress skeletal muscle mitochondrial biogenesis, regardless of training status ( 70 ). Some studies have shown the benefits of lipoic acid or vitamin E supplementations in endurance trained horses ( 71 ).…”

Oxidative profiles of endurance horses racing different distances

“…The literature available on oxidative stress induced by training or competition in endurance horses is scarce and is focused on food supplementation (Williams et al, 2004;GomesCabrera et al, 2006;Williams, 2010;Smarsh et al, 2010). However, the products of lipid peroxidation, such as MDA, can be used as indicators of free radical activity, i.e., lipid peroxidation, in the body (Kirschvink et al, 2007).…”

Efeito da suplementação com vitamina E sobre os metabolismos oxidativo e cardíaco em equinos submetidos a exercício de alta intensidade

“…Os marcadores de lipoperoxidação e a vitamina E são os mais extensivamente estudados quanto à formação e redução do estresse oxidativo, respectivamente, induzido pelo exercício físico (Deaton e Martin, 2003;Williams, 2010). Entretanto, há uma ampla variação de resultados e não foram estabelecidos ainda os benefícios reais da utilização desse antioxidante (Duberstein et al, 2009;Yonezawa et al, 2010a).…”