Anemia is a predictor of mortality from high blood pressure, atherosclerosis, and heart disease . But only recently have medical researchers begun to realize that anemia sometimes is a treatable cause of hypertension, hardening of the arteries, and cardiovascular illnesses .
How Anemia Can Lead to High Blood Pressure and Heart Disease
In retrospect, it shouldn't be too hard to understand how a low red blood cell count (anemia) and low hemoglobin levels could lead to cardiovascular disease. Hemoglobin in red blood cells carries oxygen throughout the bloodstream. High hemoglobin concentrations in more red blood cells enable the bloodstream to carry more oxygen. When tissues are easier to provide with oxygen because red blood cells carry more oxygen, the heart doesn't have to work as hard to keep the various tissues in the body oxygenated. Sometimes anemia alone is enough to explain the effects of high blood pressure on the brain , especially in sickle cell disease .
It's only been recently, however, that a majority of researchers have concluded that anemia causes the high blood pressure that leads to heart and brain disease, rather than possibly just occurring at the same time due to an otherwise undiscovered cause. Correcting anemia sometimes is what is needed to correct high blood pressure. Before your doctors prescribe a second, third, fourth, or even fifth medication for you to take every day for hypertension, or you begin heart failure treatment, make sure that they have taken a second look at your complete blood count to confirm that you don't (or you do) have low hemoglobin or low red blood cell count. Sometimes iron supplementation is all you need for the higher hemoglobin levels that enable your heart to perform its function without working as hard.
What's the Protocol for Treating Anemia to Lower Blood Pressure?
You'd think it would go without saying, but it doesn't: Don't treat anemia until a lab test confirms that you have it. And don't assume you have iron-deficiency anemia until a lab test confirms, that, too.
It's possible to have an iron deficiency without having anemia, which is defined as a deficiency in red blood cells, not a deficiency in iron. This kind of iron deficiency usually doesn't cause symptoms, although about half the people who have it will develop a habit of pagophagia, craving ice to suck or chew. Some people with this kind of iron deficiency will develop cravings for cold vegetables, like ice cold celery sticks and carrot sticks straight from the crisper of the refrigerator. 
It's also possible to have anemia without an iron deficiency. Sometimes the body can't make functional molecules of hemoglobin. This condition is known as sickle cell disease. Sometimes the body can make enough red blood cells (remember, the red blood cell count defines anemia) but can't make enough hemoglobin. This condition is known as thalassemia. Sometimes the body can't make the "heme" (iron) part of hemoglobin. This condition is known as porphyria, which is apocryphally associated with vampirism. Or maybe the body simply can't use the iron is has. This condition is known as sideroblastic anemia . Or maybe the problem is an inability to absorb vitamin B12 to make the enzymes that ensure that red blood cells are the right shape and only normal size. This condition is known as "pernicious" anemia (so-called at one time because its cause was unknown and the condition was fatal) or megaloblastic anemia. 
You shouldn't assume that because you have "anemia" that the answer is iron supplementation for high hemoglobin levels. Even if you don't see a doctor, you still need to make your treatment decision on the basis of laboratory tests, and if you don't understand them, you do need to see your physician. But once you know you need iron, then there are some options from which to choose:
- Ferrous sulfate is economical and effective. There are other forms of iron that are more completely absorbed, but the downsides of using these chemical forms of iron with better absorption are that they cost a lot more, and they can be a lot more toxic if you overdose. 
- Ferrous sulfate, ferrous glycinate, and ferrous fumarate are better absorbed that "ferric" forms of iron. However, sometimes iron-deficiency anemia is treated with other forms of iron. Iron bis-glycinate is used to treat anemia in children. It's no more toxic than the less expensive ferrous sulfate, but it builds up better in the child's body . Iron sucrose (Venofer) is used for high blood pressure with anemia in people who have kidney disease . Iron dextran is a potentially dangerous form of iron supplementation (it can cause fatal allergic reactions) that is used to replenish iron in the red blood cell-making cells in bone marrow. Carbonyl iron (Feosol) is used when a slow-release form of iron is needed to prevent stomach upset.
Chances are that ferrous sulfate (also known as iron sulfate) is what will work for you. Your doctor may not even order a prescription iron supplement, because ferrous sulfate is available over the counter and It cost as little as US $0.03 a dose. In the right icircumstances, it can be an easy and inexpensive way to get your hemoglobin levels higher so your blood pressure will be lower. Just make sure it's iron that you really need before you start using iron supplements.