Keep The Beat
When functioning properly, the human heart beats more than 100,000 times and pumps about 2,000 gallons of blood through your vessels every day. Millions of sophisticated heart cells intri-cately orchestrate the continual pumping of blood and oxygen through your veins. Your heart is about the size of your hand, and all of your arter-ies and blood vessels, if laid end-to-end, would circle the earth twice.
The beating of the heart keeps oxygen and nutrient-rich blood flowing throughout the body. The heart circulates blood and oxygen out to the body's tissues and organs and then circulates it back to the lungs where it can be reoxygenated. After the lungs reoxygenate the blood, some of the blood is filtered through the kidneys and liver. The kidneys cleanse the blood of waste products and then eliminate the waste via urine. The heart is divided into two sides. One side pumps "fresh," oxygenated blood out to the body, and the other side receives the oxygen-deficient blood. While the heart fills up with oxygen-deficient blood, it is considered "at rest." The heart contracts as it pushes the oxygenated blood out.
The seemingly simple operation of the heart is rife with risks that can dam-age our health and cause death. The single most dangerous outcome to the heart and your health is the blockage of an artery. The most common form of heart disease is known as coronary artery disease, which simply means that blood flow through the arteries has become blocked or obstructed. This reduces blood flow to the heart and can cause other heart problems such as angina (chest pain) and myocardial infarction (heart attack).
Your arteries start out flexible and elastic. Over time, the arteries can become thick, stiff, and susceptible to plaque buildup. This is known as atherosclerosis or hardening of the arteries. No one is born with harden-ing of the arteries. It is caused by a gradual, silent buildup of plaque that can eventually be deadly.
Plaque is a combination of substances including fat and cholesterol. Without plaque, blood can flow freely as the heart maintains its healthy beating. When plaque builds up, the artery narrows, constricting blood flow to the heart. Plaque can even build up to the point where blood flow is completely blocked. When there is too much cholesterol in the body, plaque can accumulate. High cholesterol is a risk factor for the develop-ment of heart disease. Other risk factors include:
- High blood pressure
- High homocysteine levelsBlood Flow
- Increased and uncon-trolled stress and anxiety
- Poor diet
The next chapter will review diet and lifestyle factors asso-ciated with high cholesterol. While it is not the only risk factor for developing heart disease, high cho-lesterol remains a key concern for many Americans. There is no question that elevated cholesterol can disrupt the rhythmic beating of the heart. Re-searchers have discovered, however, that it is the combination of elevated cholesterol with high homocysteine levels that presents an increased risk for heart problems.
Oxidation And Your Heart
According to groundbreaking researcher Kilmer McCully, MD, high cholesterol levels alone do not cause heart disease. "When it [cholesterol] is taken up into the arterial wall, it becomes oxidized or modified, and it has damaging effects on cells in the arterial wall," says McCully. Ho-mocysteine is one reason why cholesterol may build up in the artery to dangerous levels.
Homocysteine is a nonessential amino acid that results from a defi-ciency of three B vitamins: B6, B12, and folic acid. In addition, too much dietary protein and too little of these B vitamins can convert methionine, an essential amino acid, into its toxic byproduct, homocysteine. Some re-searchers believe high homocysteine poses a greater risk for heart disease than high blood pressure, smoking, or high cholesterol.
As researchers dig deeper into the issue of elevated homocysteine, they are finding that the health ramifications of this condition are broad. It could, in fact, be the catalyst cholesterol needs to begin blocking the artery. Both homocysteine and cholesterol levels should be considered when creating a health plan. But before we can construct that plan, we need to first understand what cholesterol is and why it is so important to keep levels in a healthy range.