Hypertension, or high blood pressure, is defined as persistently high systolic blood pressure of more than 140mmHg and a diastolic blood pressure of more than 90 mmHg. Readings are taken on three separate occasions to declare a patient as hypertensive. Hypertension is one of the modern epidemics having a high prevalence rate all over the globe. Every year, every 1 in 3 people is diagnosed as a case of high blood pressure. The rate of morbidity and mortality associated with hypertension is very high, mainly because of the complications that come in the wake of high blood pressure, mainly cerebral, cardiac and vascular disorders. This dramatic increase in the number of cases of hypertension is mainly due to high-fat dietary patterns. Fortunately, high blood cholesterol is among the modifiable risk factors of hypertension.
WHAT IS BAD CHOLESTEROL?
Cholesterol obtained from the dietary sources is of several types. The “good” cholesterol is the high density lipoprotein (HDL) cholesterol while the low density lipoprotein (LDL) cholesterol, very low density lipoprotein (VLDL) cholesterol and the triglycerides (TGs) constitute the “bad cholesterols”.
HOW DOES CHOLESTEROL CAUSE HYPERTENSION?
When the internal environment of the body is altered as a result of inflammation, certain inflammatory cells migrate into the walls of the blood vessels and start accumulating the low density lipoproteins thereby becoming laden with lipids. This condition is known as “atherosclerosis”. The flexibility of the blood vessel wall is, therefore, decreased. The vessel walls become less pliable and the ability to accommodate large blood volumes is reduced. The inevitable result is increase in the pressure of blood inside the hardened vessel walls. The blood pressure also increases due to the fact that the lumen of the blood vessels becomes obliterated and when blood passes through narrow lumen, its flow becomes speedy and turbulent, causing an increase in the blood pressure. Hypertension ensues. When these atherosclerotic plaques become too large in size and compromise the flow of blood to vital organs or when they accumulate platelets and form thrombi, fatal illnesses like stroke and myocardial infarction can result. HDL cholesterol is “good” in terms that it does not deposit in the blood vessels and clog them.
PLANTS THAT CAN LOWER BLOOD CHOLESTEROL TO CONTROL HYPERTENSION
Nature has endowed many plants with myriads of beneficial components that have the ability to prevent the oxidization of LDLs, the deposition of atherosclerotic plaques in blood vessels and to lower the risk of development of hypertension. Some of the plants that are widely used for controlling high blood cholesterol and high blood pressure are given below.
Oats are rich in beta glucans. They are well known hypocholesterolemic agents. Oat bran diets have been shown to decrease the circulating blood levels of total cholesterol by almost 19% and the LDL cholesterol by 24%, thereby lowering the incidence of hypertension (Varady, Krista A., and Peter JH Jones; 2005). Consumption of almost 5 grams of oatmeal on a daily basis has been reported to lower the concentration of cholesterol by 5%.
Lentils are rich sources of phytosterols, chemicals that inhibit the absorption of cholesterol in the body. They compete with cholesterol in the formation of “mixed micelles” that are formed by the action of biliary pigments on cholesterol to aid the digestion of cholesterol (Bazzano, Lydia A., et al. 2011).
Olives are rich sources of omega 3 fatty acids. They also contain oleic acid and polyphenols. Animal studies have shown a significant reduction in the circulating levels of LDLs, VLDLs and Triglycerides (De La Cruz, José Pedro, et al.; 2000).
Animal studies have demonstrated the artichoke extracts to inhibit the biosynthesis of cholesterol by the liver in an indirect manner quite efficiently. It causes the inhibition of enzymes that are involved in cholesterol biosynthesis, thus preventing hypercholesterolemia and thereby, hypertension. (Gebhardt, Rolf.2002).
An extensive experimental study was carried out to observe the effects of celery in rats which were initially fed high LDL diet to induce hyperlipidemia in them. Half of the rats were given the celery extracts while the rest were not. At the end of the trial period, a significant decrease in the amount of total serum cholesterol and LDL cholesterol was observed which highlighted the ability of celery to lower the serum concentration of cholesterol and thus prevent hypertension. (Mansi, Kamal, et al. 2009).
Fenugreek has known hypolipidemic effects. Its seeds were given to test subjects in whom remarkable decrease in the serum levels of cholesterol was noted (Prasanna, M. 2000). Fenugreek also has antioxidant effects that prevent the formation of cholesterol plaques in the blood vessels (Belguith-Hadriche, Olfa, et al. 2010).
Hawthorn berries have rich triterpenic acid content. Hawthorn decreases the serum concentration of cholesterol by inhibiting its absorption. It does so by down regulating the activity of intestinal Acetyl-Coenzyme A acetyl transferase (ACAT), an enzyme involved in the metabolism of cholesterol. One animal study showed hawthorn to cause 22% reduction in the level of cholesterol in circulation and in liver (Lin, Yuguang, Mario A. Vermeer, and Elke A. Trautwein; 2010).
Holy basil has the ability to scavenge the highly reactive free radical species that induce oxidative stress, leading to the formation of atherosclerotic cholesterol plaques in the blood vessels. In this way, Indian Holy Basil prevents hypercholesterolemia and consequently, high blood pressure (Kedlaya, R., and D. M. Vasudevan; 2004).
Flaxseed is a cholesterol lowering herb that is rich in lignans. It can help lower the levels of LDL cholesterol within the body and thus, lowers the risk of hypercholesterolemia (Bloedon, LeAnne T., and Philippe O. Szapary; 2004).
Many other plants naturally contain components that help lower the circulating levels of cholesterol in the body. These plant products have the added benefit of being completely safe for use, without any additional side effects. These plant based food substances should be incorporated in diet only after consultation with a doctor to avoid the exacerbation of any preexisting condition. Their regular consumption can cause significant reduction in the levels of cholesterol and thereby, prevent hypertension. The complications of hypertension such as diabetes mellitus, stroke, angina, heart attack, visual disorders and kidney diseases etc. can also be prevented with plant based diets.