Eating peanuts -- unsalted peanuts, of course -- is a good nutritional approach for lowering blood pressure. The amino acid l-arginine is the responsible constituent of the peanut for this pressure-lowering effect. L-arginine has been shown to lower blood pressure in salt-sensitive hypertension, but it had little or no effect on other types of hypertension.
L-Arginine
L-arginine content of the peanut is 3.085 g per 100 g of peanuts. This is high compared to its content in other arginine-rich foods such as the walnut, with 2.270 g per 100 g, and the almond, which has 2.446 g per 100 g. L-arginine is a semi-essential amino acid found in both animal and plant sources. L-arginine is called semi-essential because there are times and conditions when the body can not manufacture this amino acid in the absence of precursor nutrients from food. Non-essential amino acids can be produced by the body from other nutrient sources in your body, while essential amino acids must be supplied in your diet or in supplements.
Hypertension
Hypertension can be divided into two major categories; essential hypertension and secondary hypertension. Essential hypertension occurs by mechanisms that are largely unknown; secondary hypertension has well-defined organic causes, such as kidney damage. Examples of essential hypertension are salt-sensitive hypertension and isolated systolic hypertension. Hypertension from adrenal tumors and hyperthyroidism are examples of secondary hypertension.
Salt-sensitive Hypertension
Salt-sensitive hypertension is a type of hypertension that can respond well to peanut consumption. Salt-sensitive hypertension is a genetic hypertension seen in its pure form in the Dahl salt-sensitive rats. Dahl rats are selectively bred for this type of hypertension. When placed on a high salt diet, Dahl rats develop very high blood pressures that lead to death in a few weeks.
Nitric Oxide
The blood pressure-lowering effect of l-arginine is mediated through nitric oxide. Nitric oxide is a vasodilator that is produced and released from the vascular endothelium. The endothelium is a layer of cells that lines the inner walls of the blood vessels. When nitric oxide dilates the blood vessels, it lowers vascular resistance and improves blood flow to various organs. This is the primary mechanism by which it lowers blood pressure.
Unsalted Peanuts
Reduction of salt consumption is one of the common and effective nutritional approaches for controlling salt-sensitive hypertension. Therefore, it is not surprising that the blood pressure-lowering effect of l-arginine would be enhanced by unsalted peanuts.
References
- "Cardiovascular Research"; Lessons from rat models of hypertension; Pinto, Y.M. et al.; July 1998.
- 2."American Journal of Physiology"; Regional blood flow in Dahl-Iwai Salt-Sensitive Rats and the Effects of Dietary L-Arginine Supplementation. Tomohiro, A. et al.; April 1997.
- USDA Agricultural Research Service: Nutriet Data Laboratory
- University of Arizona; Chemistry of Amino Acids
- "The American Society of Nutritional Sciences J. Nutr."; L-Arginine and Hypertension; Noyan Gokce; October 2004.
