Fructose is both a natural sugar and a manufactured sweetener that is a major constituent in goods like sodas, processed foods, breads and desserts. A pediatric endocrinologist with the University of California San Francisco says fructose consumption in the United States is an epidemic. As an added sugar, Dr. Robert Lustig says, fructose is a "primary contributor" to human disease, including hypertension.
Facts on Fructose
Fructose is a simple sugar found naturally in honey and in the juices of many fruits. It's also known as levulose. Fructose is also artificially created. Food and beverage makers add it to a variety of products to sweeten, thicken, stabilize, brown, raise or preserve them. You probably know it as the main ingredient in the controversial high-fructose corn syrup, a ubiquitous added sugar implicated in obesity, diabetes, metabolic syndrome, high blood pressure and chronic kidney disease.
Blood Pressure
Blood pressure refers to the amount of force pressed against the walls of your arteries. Blood pressure is measured in mmHg, or millimeters of mercury. The National Heart, Lung and Blood Institute advises that a healthy reading for blood pressure is at or below 120/80 mmHg. A reading higher than that puts you in a prehypertensive state, and if your blood pressure reading surpasses 140/90, you've entered stage 1 hypertension. High blood pressure is a risk for heart disease because it causes your heart to work too hard and get too little rest. In addition, hypertension can stretch and weaken your blood vessels, which allows plaques to build up and block blood flow. A full one-third of American adults have high blood pressure, the Centers for Disease Control and Prevention says, and some scientists think the increasing consumption of fructose-sweetened food and beverages plays a role in this health problem.
Fructose and Hypertension
In a review of existing data, a group of kidney researchers publishing in the December 2010 "Journal of the American Society of Nephrology" said fructose intake was significantly correlated with the presence of elevated blood pressure and, a step further, "fructose-rich drinks" raise blood pressure. For example, the authors noted that in their previous research, administering 200 g of fructose daily for two weeks significantly raised blood pressure in men, and just 60 g -- the equivalent of two 12-oz. soft drinks -- just one time was enough to raise blood pressure in otherwise healthy young adults. The group concluded that excessive fructose consumption ought to be considered an "environmental toxin with major health implications."
Possible Mechanisms
The way the body metabolizes fructose may explain why it has an effect on blood pressure. Although most fructose travels directly to your liver by way of a special transporter, a small portion also travels through your kidneys. There it can raise uric acid levels. Uric acid is a waste product that goes through your kidneys as your body tries to break down certain foods. Uric acid is often an early warning for hypertension. Researchers publishing in the April 2011 "Hypertension" further explained that uric acid may in turn lower your levels of nitric oxide, a chemical compound that plays a role in keeping your blood vessels dilated. Moreover, they explained, sugar consumption has been linked to excess sodium retention.
References
- "The Bariatrician"; The Fructose Epidemic; Robert Lustig, M.D.
- "Journal of the American Society of Nephrology;" The Effect of Fructose on Renal Biology and Disease; Richard J. Johnson, et al.; December 2010
- Elmurst College "Virtual Chembook"; Fructose; Charles Ophardt; 2003
- National Heart, Lung and Blood Institute: High Blood Pressure
- "American Journal of Clinical Nutrition"; Potential Role of Sugar (Fructose) in the Epidemic of Hypertension, Obesity and the Metabolic Syndrome, Diabetes, Kidney Disease, and Cardiovascular Disease; Richard Johnson, et al.; October 2007
- "Hypertension"; Sugar-sweetened Beverage, Sugar Intake of Individuals and Their Blood Pressure; Ian J. Brown, et al.; April 2011
