High blood pressure, or hypertension, is common in the United States, affecting approximately 60 million people. Hypertension is usually defined as a systolic pressure reading greater than 140 and/or diastolic pressure greater than 85, although other factors are important too. Hypertension is linked to high cholesterol levels, atherosclerosis and stress, among other factors, and increases the risk of heart attack and stroke. Curcumin’s affect on hypertension has not been studied in people, although it does affect the properties and constituents of blood. Consult with your doctor if your blood pressure is high.

Curcumin is the biologically active component in turmeric root, which is often dried and ground into a yellow powder and used either medicinally or as a spice. Curcumin is a widely used herbal remedy in Indian Ayurvedic medicine, and to a lesser extent in traditional Chinese medicine. Curcumin displays a number of medicinal properties and is sometimes recommended to promote digestion, reduce the symptoms of arthritis and to protect the brain from Alzheimer’s disease, as cited in “The Way of Ayurvedic Herbs.” Curcumin’s effect on blood pressure has not been directly studied, although its ability to lower blood cholesterol, reduce inflammatory reactions and slow down blood clotting may contribute to preventing or combating high blood pressure.

According to “Medical Herbalism,” research has shown that curcumin lowers circulating levels of cholesterol and triglycerides in the blood and works as well as the drug Clofibrate, but without the side effects. Lowering blood cholesterol, especially the harmful LDL type, is assumed by the medical community to reduce the risk of atherosclerosis, which is clogging and hardening of the arteries. Atherosclerosis is a known cause of high blood pressure.

Curcumin displays strong anti-inflammatory properties, primarily because it is a powerful antioxidant that scavenges nitric oxide and free radicals in your bloodstream and inhibits the pro-inflammatory substance COX-2, as cited in the book "Biochemical, Physiological and Molecular Aspects of Human Nutrition." As such, curcumin can be of benefit for arthritis symptoms, but also for reducing the inflammatory reactions that occur within your blood vessels in response to damage. The formation of atherosclerotic plaques with cholesterol is essentially an inflammatory response in reaction to fissures in blood vessels or damage caused by free radicals. Unlike other COX-2 inhibitors, such as Celebrex, curcumin is nontoxic and produces no serious side effects.

Curcumin has a tendency to “thin” your blood, which means it reduces the ability of your blood platelet cells to aggregate and form clots, similar to the effects of vitamin E. Blood thinning is of benefit in reducing the risk of atherosclerosis and preventing many cardiovascular diseases, but it also increases blood-coagulation time and is not recommended if you have a bleeding disorder or are on anticoagulant medication, according to the book “Human Biochemistry and Disease.” Although curcumin seems to affect the blood in many positive ways, high blood pressure is a serious condition that should be supervised by your primary-care physican.