Nutrition's Role in Enhancing Aging Horses' Immunity

Nutrition's Role in Enhancing Aging Horses' Immunity

It has been well-documented that the aged, including horses, have increased susceptibility to and prolonged recovery from infectious diseases, poor responses to vaccination, and increased incidence of various cancers.

Photo: Anne M. Eberhardt/The Horse

Over the past century, improvements in health care and advancements in biology, chemistry, and medicine have extended the average lifespan of humans and companion animals, including horses. However, we are now facing new challenges with the paradox of an older population with increased longevity, while confronted with the potential for many years of poor health. A better understanding of the mechanisms leading to a decline in physiologic function with age would provide new predictive biomarkers and potential therapeutic targets.

It has been well-documented that the aged, including horses, have increased susceptibility to and prolonged recovery from infectious diseases, poor responses to vaccination, and increased incidence of various cancers. Furthermore, it is now accepted that chronic inflammation (inflamm-aging) is a major underlying condition of many age related diseases, such as arthrosclerosis, arthritis, cancer, diabetes, osteoporosis, dementia, vascular diseases, obesity, and metabolic syndrome.

ONarutal Dietary Compounds with Anti-Inflammatory Mechanisms

Group Compound
Carotenoids Beta-carotene, lycopene, lutein
Flavonoids Quercetin, catechin, epigallocatechin-3-O-gallate, theaflavin
Isothiocyanates Sulforaphane, phenethyl, isothiocyanate
Terpenoids Limonene, retinoic acid
Omega-3 fatty acids Eicosapentaenoic acid, docosahexaenoic acid
Polyphenolic compounds Curcumin, gingerol, resveratrol, pterostilbene

In anti-aging research, much attention is focused on nutritional interventions as practical, cost-effective approaches to mitigating this age-related breakdown in immune function. These natural dietary compounds found in a variety of fruits, vegetables, nuts, and seeds are promising candidates in helping to combat the effects of aging. They possess broad biological activities: anti-oxidative, anti-inflammatory, detoxification, regulating signaling pathway, and modulation of enzyme activities (see sidebar at left).

Since aged horses (those 20 years and older) have increased levels of inflammation, and treatment with long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) such as flunixin meglumine and phenylbutazone can pose health problems, we are interested in nutritional interventions to counteract this inflamm-aging process.

Flavonoid (quercetin) and polyphenolic compounds (curcuminoids, resveratrol, pterostilbene, and hydroxypterostilbene) were compared to phenylbutazone and flunixin meglumine to determine differences in equine cytokine production in cell culture. White blood cells from aged horses were isolated and incubated overnight with each compound of NSAID at multiple concentrations. Inflammation production was measured when white cells were stimulated.

At varying doses (measured in micromolar units [µM]), each of the compounds and NSAIDs significantly reduced cellular inflammation: curcuminoids (20 µM), hydroxypterostilbene (40 µM), pterostilbene (80 µM), quercetin (160 µM), resveratrol (160 µM), flunixin meglumine (40 µM), and phenylbutazone (>320 µM). Interestingly, curcuminoids at a concentration of 20 µM reduced inclmmation to the same level as higher doses of flunixin meglumine (40 µM) and phenylbutazone (>320 µM). All natural compounds outperformed phenylbutazone by being effective at lower doses.

This preliminary research has led into two studies using aged horses to determine, 1) if a relationship exists between circulating vitamin and fatty acid levels to systemic inflammation and muscle mass, and 2) if anti-inflammatory supplementation affects immune responses to vaccination. These are preliminary steps to identify effective nutritional intervention regimens to improve function of the immune system in the aged horse.

CONTACT: Amanda Adams, PhD—859/218-1097——University of Kentucky Maxwell H. Gluck Equine Research Center, Lexington, Ky.

This is an excerpt from Equine Disease Quarterly, funded by underwriters at Lloyd's, London, brokers, and their Kentucky agents.

About the Author

Equine Disease Quarterly

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More