URIC ACID IS A SIGNIFICANT ANTIOXIDANT

Dr. Anil Batta*

ABSTRACT

Uric acid (UA) is the end product of purine metabolism in humans due to the loss of uricase activity by various mutations of its gene during the Miocene epoch, which led to humans having higher UA levels than other mammals. Furthermore, 90% of UA filtered by the kidneys is reabsorbed, instead of being excreted. These facts suggest that evolution and physiology have not treated UA as a harmful waste product, but as something beneficial that has to be kept. This has led various researchers to think about the possible evolutionary advantages of the loss of uricase and the subsequent increase in UA levels. It has been argued that due to the powerful antioxidant activity of UA, the evolutionary benefit could be the increased life expectancy of hominids. For other authors, the loss of uricase and the increase in UA could be a mechanism to maintain blood pressure in times of very low salt ingestion. The oldest hypothesis associates the increase in UA with higher intelligence in humans. Finally, UA has protective effects against several neurodegenerative diseases, suggesting it could have interesting actions on neuronal development and function. These hypotheses are discussed from an evolutionary perspective and their clinical significance. UA has some obvious harmful effects, and some, not so well-known, beneficial effects as an antioxidant and neuroprotector. High plasma uric acid (UA) is a precipitating factor for gout and renal calculi as well as a strong risk factor for Metabolic Syndrome and cardiovascular disease. The main causes for higher plasma UA are either lower excretion, higher synthesis or both. Higher waist circumference and the BMI are associated with higher insulin resistance and leptin production, and both reduce uric acid excretion. The synthesis of fatty acids (tryglicerides) in the liver is associated with the de novo synthesis of purine, accelerating UA production. The role played by diet on hyperuricemia has not yet been fully clarified, but high intake of fructose-rich industrialized food and high alcohol intake (particularly beer) seem to influence uricemia. It is not known whether UA would be a causal factor or an antioxidant protective response. Most authors do not consider the UA as a risk factor, but presenting antioxidant function. UA contributes to > 50% of the antioxidant capacity of the blood. There is still no consensus if UA is a protective or a risk factor, however, it seems that acute elevation is a protective factor, whereas chronic elevation a risk for disease.

Keywords: Uric acid Diet Protection Risk Metabolic syndrome.