The Effect of Ramadan Fasting on Arginase Activity in Healthy Volunteers

The practice of fasting is performed by many communities for religious or spiritual reasons. Additionally, in the recent years many health benefits were associated with different kinds of fasting. These include: controlling blood glucose levels , reducing insulin resistance, reducing inflammation, improve heart health, lowering blood pressure and boosting brain function while prevent neurodegenerative disorders. Moreover, there is proven evidence on the effects of Ramadan fasting, performed by muslims for one month, on improving vascular health, blood flow and enhancing endothelial function in patients with cardiovascular disease. Fasting was reported to increase nitric oxide (NO) levels and decrease asymmetric dimethylarginine (ADMA); a novel cardiovascular risk factor. Nitric oxide, a potent vasodilator and vascular protective molecule, is produced by endothelial cells by the action of endothelial nitric oxide synthase (eNOS) on L‐arginine. Arginase, an enzyme implicated in many cardiovascular diseases, can compete with eNOS for their common substrate, L‐arginine to produce urea and ornithine. We and others have reported the effects of arginase inhibition on improving endothelial function and NO levels in different cardiovascular diseases and in diabetes. Our project aims to study the effect of Ramadan fasting on arginase activity in healthy individuals. We measured arginase activity one day before the start of fasting and on the last day of fasting for thirteen young male adults, ages between 18–35 years old. The fasting performed is to withhold from eating, drinking and smoking from sunrise to sunset (about 15 hours) everyday for a period of one month. Plasma arginase activity is measured using a colorimetric reaction of urea production. Our results show a modest though significant decrease in arginase activity of 15.7 ± 4.2%. We also determined basal urea levels and observed no change in these levels. Our results propose one important benefit of fasting through lowering arginase activity thus reserving available L‐arginine for NOS and increasing NO levels. We also noted that basal urea levels did not change. It was expected that not drinking water for long hours could increase chances of dehydration which can increase plasma urea concentrations, but this did not occur. In conclusion, our result show another added health benefit of fasting to the vascular system which is lowering arginase activity. Fasting under doctor supervision can be used in selected patients with vascular diseases to maintain and promote NO levels. We yet have to determine the effects of fasting on other systems of the body such as liver and kidney to preclude any deleterious side effects of this practice. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .