Hypertension (aka “The Silent Killer”) is so named because it doesn’t give us any signs or symptoms to throw a red flag in front of us to tell us that something is wrong with our circulatory system. It is estimated that about one out of every four people in this country have hypertension. Each year, there are 2 million new cases of high blood pressure diagnosed and the number seems to be rising. It is also the most chronic illness that we as Americans face today. So, what is going on in our blood stream to cause this rise in the tension of our arteries, and are there ways to fix it? To get a better idea, we must first understand what blood pressure actually is.
THE PHYSIOLOGY OF BLOOD PRESSURE
Blood pressure typically refers to the pressure (measured in millimeters of mercury “Hg”) of flowing blood against the arterial walls of the circulatory system. You might be familiar with readings such as XXX/XXmmHg, which simply means the ratio of systolic pressure to diastolic pressure. Systolic pressure can be thought of as contraction the part of the contraction/relaxation cycle of the heart. Conversely, diastolic pressure would be the relaxation part of the cardiac cycle.
In humans, normal blood pressure during periods of low stress/work is typically 120mmHg over 80mmHg. However, there are a number of variants that influence blood pressure. For example, peripheral resistance (the resistance that must be overcome to push blood through the arteries), volume of blood/unit time, and artery hardness caused by tissue oxidation, aging, and sclerotic tissue buildup. Furthermore, the nervous and endocrine systems have a direct influence on blood pressure. This is why fluctuations in blood pressure can occur multiple time per day. When the pressure of the circulating blood drops below normal levels it is called hypotension, and of course high blood pressure is so named hypertension.
Our bodies have a fascinating system of hormones, enzymes, and other endogenous factors that regulate blood pressure with extreme precision and intricacy. For one, we all have little pressure sensors in high pressure receptor zones of our spinal cord and the back of our necks called baroreceptors. These little sensors send signals to certain areas of the brain that tell the heart to force blood faster or slower by its contractions. This in turn adjusts the mean arterial pressure of our bodies. In fact, we can feel this system at work when we stand up too fast after sitting for long periods of time – the dizzy sensation we get is called the baroreceptor reflex.
Is important to have sensors to tell our bodies when pressure is low or high, but what about a mechanism that actually does something about it? This is where enzymes and hormones come into play. Renin is an enzyme that floats around the bloodstream and is activated on command and is responsible for the hydrolysis of angiotensinogen to angiotensin I. This just means that renin grabs onto a serum protein called angiotensinogen with one hand and with the other brings in a water molecule to rearrange this protein to form angiotensin I. This newly formed angiotensin I then makes the conversion to angiotensin II (a potent vasoconstrictor) depending on the blood pressure at the time. The rate at which these two proteins are formed depends on how our circulatory system will allow the kidneys to compensate for loss in blood volume or drops in arterial pressure. Thus, one of the major influencers of blood pressure in our bodies.
So, what happens when there’s too much salt, too little salt, or too much angiotensin II in our bloodstreams? This is where hormones come in. Namely, aldosterone. This steroid hormone is sent on its way from the adrenal cortex when it notices high levels of angiotensin II and potassium in the bloodstream. It will then tell the kidneys to hang onto sodium and get rid of potassium. Seeing as sodium is the main anion that decides the amount of water in blood vessels by osmosis, aldosterone will increase fluid retention, which then influences blood pressure. We’ve all heard of ACE inhibitors, well ACE stands for Angiotensin Converting Enzyme. These types of drugs help normalize blood pressure by stopping the conversion of angiotensin I to angiotensin II when angiotensin II concentrations begin to climb.
CAUSES OF HIGH BLOOD PRESSURE
Arterial hypertension plagues millions of Americans each year and can be caused by a multitude of different factors. It is also one of the major risk factors for heart attacks, arterial aneurysms, heart failure, and strokes. It is such a health risk that it has been shown that if abnormally high pressure is left untreated, patients usually end up dying within just a few years1. Hypertension is diagnosed if the resting blood pressure is continuously at or above 130/80 or 140/90 mmHg2. High blood pressure is caused by excess body weight, too much salt in the diet, smoking, and alcohol use3 just to name a few. Secondary causes, which can bring on temporary high blood pressure, are usually a result of mental stress, kidney disorders, prescription medications, etc.
ADVANCEMENTS IN TECHNOLOGY AND NUTRITION
Hypertension can be a scary thing, but along with diet and exercise it is nice to know that there are other options to take control of our high blood pressure. As mentioned before, ACE inhibitors like Lisinopril and Benazepril are very good at lowering blood pressure through the angiotensin I → angiotensin II pathway. Other prescription medications like Bumetanide help lower blood pressure by acting as a diuretic – thus decreasing blood volume. Conversely, drugs such as sodium nitroprusside act as vasodilators - relaxing arterial walls so blood can move more easily through the blood stream.
But what if one decides to go the naturopathic route and stay away from drugs? Interestingly, nature has provided a wonderful array of nutrients that act in a similar manner to these prescription meds.
Often wonder why fish never get high blood pressure? All kidding aside, certain types of fish contain unique lipids called Omega 3 fatty acids. These interesting little fatty acids are crucial to human physiology but ironically, we can’t make them on our own. So, we must rely on an outside source. Studies show that these good fats can actually lower blood pressure and reduce the risk of hypertension4. So, eat more fish… not just for healthy hair, skin, and nails but for your circulatory system.
Thankfully, our bodies can make something on its own that helps to lower blood pressure. L-arginine is a non-essential amino acid (essential in infants) that can produce nitric oxide as one of its metabolites. Nitric Oxide (NO) is a very potent vasodilator, relaxing arterial walls and thus lowering blood pressure. This has been shown in various studies using high doses of L-arginine5,6.
If you were to think of the mitochondria as the motor of each cell, then Co-enzyme Q10 (CoQ10) would be the spark plug to the motor. CoQ10 is a small molecule that our bodies make to keep the “motor” running. As we age however, we make less and less. This is one of the reasons why supplementation with CoQ10 is more popular with the elderly. Alternatively, CoQ10 seems to have benefits other than providing energy to the motor. With mechanisms still not completely understood, CoQ10 has been shown to lower blood pressure when taken in even relatively small amounts7-9. Although a little on the pricey side, CoQ10 may be a promising alternative to conventional blood pressure-lowering methods.
Saving the best for last, the age-old remedy for high blood pressure… garlic. This sulfur-containing pizza topping has been used for centuries to treat hypertension. Even current meta analytical studies show this to be true10. Interestingly, research does seem to have a mechanism for garlic’s ability to lower blood pressure, this being done by some of the polysulfides found in garlic actually stimulating the production of H2S and NO11, both of which induce smooth muscle cell relaxation, vasodilation, and BP reduction. Good new for us, bad news for vampires.
With millions of people each year falling victim to the Silent Killer, it seems comforting to know that there are means to lower the risk of and/or prevent high blood pressure altogether. Furthermore, as science and technology progresses, more and more of these means rise to the surface for us to benefit from for generations to come.
Chad Brey, a California State University, Northridge alumnus, has since worked as a chemist for various analytical and research facilities such as Amgen, Baxter, and Nusil Technology. Since 1997 he has worked in the dietary supplement industry for companies such as Earthwise Nutrition (formerly known as Great Earth Vitamins) and has earned a number of certificates as an IACET-certified dietary supplement specialist. Chad has written dozens of technical articles on the specifics of how certain dietary supplements work. Chad has formulated and developed small and large molecules in research and development laboratories since 2003 and continues to consult others in R&D today.
1. Textbook of Medical Physiology, 7th Ed., Guyton & Hall, Elsevier-Saunders, ISBN 0-7216-0240-1, p. 220.
2. Poulter, NR; Prabhakaran, D; Caulfield, M (22 August 2015). "Hypertension". Lancet. 386 (9995): 801–12.
3. "High Blood Pressure Fact Sheet". CDC. 19 February 2015. Archived from the original on 6 March 2016. Retrieved 6 March 2016.
4. Morris MC, Sacks F, Rosner B, Circulation. 1993;88:523–33.
5. Pezza V, et al, Am J Hypertens. (1998) 11:1267–70 [letter].
6. Calver A, Collier J, Vallance P, Clin Sci (1991) 81:695–700.