What is hypertension?
Roughly one out of three adults in the United States have hypertension (high blood pressure). Only half of those with high blood pressure have it under control. High blood pressure can be a serious problem. It can damage your blood vessels, particularly in your kidneys and your brain. Eventually, it can also damage the valves in your heart. Pregnant women are prone to a form of high blood pressure called preeclampsia, which is dangerous to the woman and her baby. For these reasons, millions of people are taking medications to control their blood pressure.
However, medication is not necessarily the best way to control blood pressure. Yes, it can reduce the blood pressure. But it does not cure the vascular resistance that the heart is trying to solve by beating so hard. The best way to solve the blood pressure problem is to relieve this resistance by eating a low-fat vegan diet.
Blood pressure results from the force exerted by the heart as it beats. Blood pressure is measured in millimeters of mercury (mm Hg) because blood pressure was originally measured with a tube that contained mercury, which is a liquid metal. The higher the pressure, the higher the column of mercury in the tube would be. A blood pressure measurement consists of two numbers: the systolic and diastolic pressure. The systolic pressure represents the pressure that is exerted when the heart contracts and pushes the blood into the arteries. The diastolic pressure represents the pressure when the heart is relaxing and refilling between beats.
Hypertension is a sign of bad circulation
To understand blood pressure, you need to understand that the heart is trying to keep enough blood flowing through the blood vessels to serve the body’s needs. Hypertension (high blood pressure) is a sign that the heart is struggling to overcome high resistance in the circulatory system. In other words, the heart is beating really hard to try to push blood through tight, clogged blood vessels. You can use medication that can reduce your blood pressure. However, the blood pressure medication does not solve the problem of tight, clogged blood vessels. Fortunately, you can often solve the circulatory problems through a change in diet.
Blood is a fluid. Like other fluids, it follows the basic rules of physics, including a relationship called Poiseuille’s [pwah-zweez]) Law . Poiseuille’s Law is a mathematical equation that describes the relationship between the rate of flow of a fluid through a tube and the radius of the tube, the length of the tube, the viscosity (resistance to flow) of the liquid, and the drop in pressure from the beginning to the end of the tube. This relationship is usually shown as follows:
Pressure drop = (8 × viscosity × length × flow rate) / (π × radius4)
You can also express Poiseuille’s Law as follows:
Flow rate = (π × radius4 × pressure drop)/(8 × viscosity × length)
From this equation, you can make some important predictions:
- If you double the pressure, but keep everything else the same, you would double the flow. That’s why the heart beats harder to increase blood flow.
- If you double the viscosity of the blood (i.e., make the blood twice as thick) but keep everything else the same, you would cut blood flow in half.
- If you double the length of the blood vessels (which happens if the person gains a lot of weight) but keep everything else the same, you would cut the blood flow in half.
- If you double the radius of the blood vessel, but keep everything else the same, you would increase the flow by 2 × 2 × 2 × 2 = 16-fold! Likewise, if you decreased the radius of the blood vessel by half, you would decrease the flow by 93.75%!
How diet causes hypertension
Once you understand these relationships, you can see why people get high blood pressure. If you eat a fatty diet, you will likely gain some weight and make your blood a bit thicker. As a result, your heart will have to beat a little bit harder to keep your blood flowing. However, a fatty diet also clogs your arteries. Also, even a single fatty meal can make your blood vessels constrict. As a result, your heart will have to beat a lot harder to keep blood flowing. The weight gain and the thickening of the blood will make your blood pressure go up a little, while clogged arteries and vasoconstriction will make it go up a lot!
You can take medication to make your blood pressure go down, but this medication will not solve the underlying problem of poor circulation. To solve your circulatory problem, you need to keep your blood fluid and keep your arteries clean and flexible. The best way to do that is to eat a low-fat vegan diet. This kind of diet works so fast to reduce blood pressure that many people can immediately stop taking their blood pressure medication.
Pre-eclampsia is a form of hypertension in late pregnancy
The high blood pressure that occurs in late pregnancy (pre-eclampsia) is a different problem. It results from a shortage of protein in the blood plasma. This problem occurs if the woman is not getting enough to eat or if she is eating way too much fat. Either way, she will end up converting too much of her plasma proteins to sugar. As a result, she will not have enough plasma protein to hold enough fluid inside her blood vessels to support a healthy pregnancy.
To try to correct this problem of low blood volume, the kidneys will release renin, which will activate the renin-angiotensin-aldosterone system. The angiotensin will make the arteries constrict. The aldosterone will make the woman retain salt and water. But since she does not have enough protein in her blood to keep that extra fluid inside her blood vessels, it will leak out into her tissue. As a result, she will have dangerously high blood pressure as well as swelling.
The surprising solution to pre-eclampsia is to eat a lot of starch and very little fat. Women who eat a lot of carbohydrate will convert very little protein to sugar. As a result, they will have normal blood pressure as well as stable blood sugar levels. I explain this problem in Where Do Gorillas Get Their Protein?