Pathophysiological Relationship Between Hypertension and Diet
Blood pressure is a function of the force that blood exerts against the inner walls of arteries as your heart pumps blood. Blood pressure is also a function of the resistance that artery walls exert against the blood pushing on the artery walls. Excess calorie intake leading to overweight and obesity can produce high blood pressure, or hypertension. Taking in too much sodium, primarily in the form of salt, also raises blood pressure in some people. Other dietary factors, including intake of minerals and sugar, can also influence blood pressure.
Blood Pressure Control
Your brain and kidneys are the primary organs involved in blood pressure control. Your brain can send signals through nerve fibers that increase blood vessel resistance and blood pressure. Nerve signals to the heart can increase or decrease heart rate, which can increase or decrease blood pressure. The kidneys regulate balance between fluid and salt intake and excretion, which controls blood volume. An increase in body fluid and blood volume raises blood pressure. A rising blood pressure normally causes the kidneys to increase salt and water excretion to lower blood pressure.
Overweight and Obesity
Most people with high blood pressure have primary, or essential, hypertension -- hypertension with an unknown cause. However, primary hypertension is strongly associated with taking in too many calories and becoming overweight or obese. In obese people, the normal function of the kidneys to increase water and salt excretion in response to an increase in blood volume and pressure is impaired. Thus the kidneys adjust to a higher blood volume and pressure level to support a higher body fluid volume. High levels of the hormone leptin -- produced in fat tissue in proportion to the amount of fat tissue -- is at least a partial cause of obesity-related hypertension.
Increasing salt intake stimulates the thirst center in your brain. Increasing water intake raises body fluid and blood volume and increases blood pressure. This normally causes the kidneys to increase water and salt excretion to lower blood pressure. However, some people with hypertension are salt-sensitive, meaning their blood pressure fluctuates broadly in response to dietary sodium levels. In people with salt sensitivity, the kidneys become tolerant to a larger body fluid and blood volume associated with excess sodium intake, which further elevates blood pressure. Increased levels of sodium in the brain are at least partly responsible for development of salt-sensitive hypertension.
Other Dietary Factors
Development of salt-sensitive hypertension may be partly related to consuming a diet that is relatively deficient in potassium and calcium. Increasing potassium intake lowers blood pressure in people with hypertension who also have a high salt intake. High intake of simple sugars may also promote salt-sensitive hypertension. Consumption of sugar-sweetened beverages, especially those containing fructose, was associated with higher blood pressure among participants of the International Study of Macro/Micronutrients and Blood Pressure, according to the April 2011 issue of "Hypertension." A low-fiber diet may promote high blood pressure and a fiber-rich diet may help protect against hypertension.
- Textbook of Medical Physiology, Eleventh Edition; Arthur C. Guyton and John E. Hall
- Hypertension: The Kidney, Hypertension, and Obesity
- Hypertension Research: Mechanisms of Obesity-Induced Hypertension
- Hypertension: Obesity, Sympathetic Overdrive and Hypertension -- The Leptin Connection
- Hypertension Research: The Central Mechanism Underlying Hypertension -- A Review of the Roles of Sodium Ions, Epithelial Sodium Channels, the Renin-Angiotensin-Aldosterone System, Oxidative Stress and Endogenous Digitalis in the Brain
- International Journal of Hypertension: Upregulation of the Renin-Angiotensin-Aldosterone-Ouabain System in the Brain Is the Core Mechanism in the Genesis of All Types of Hypertension
- The Journal of Clinical Investigation: Salt Handling and Hypertension
- Hypertension: Sugar-Sweetened Beverage, Sugar Intake of Individuals, and Their Blood Pressure -- International Study of Macro/Micronutrients and Blood Pressure
- Hypertension: Influence of High Glycemic Index and Glycemic Load Diets on Blood Pressure During Adolescence
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