Heart disease is a serious health problem faced by postmenopausal women. Heart disease and stroke account for 43 percent of all deaths among American women, representing the top two killers. With the loss of estrogen, a woman’s risk of getting heart disease increases four-fold and continues to rise with age.
Compared to men, women are more likely to die in the year following their heart attack. This is largely due to the fact that women get heart disease when they are older and they have more advanced heart disease by the time they are diagnosed. Symptoms like chest pain tend to be ignored or overlooked in women. Both women and their doctors may attribute these symptoms to indigestion, stress or gallbladder problems. As well, women tend to get to a hospital much later after having a heart attack than do men, and they also tend to receive less aggressive therapy.
What Causes Heart Disease?
“Heart disease” is a general term that includes coronary heart disease, congenital heart disease (the kind you’re born with), congestive heart failure and malfunctioning heart valves. We’ll discuss only coronary heart disease, a disease that affects the blood vessels that feed the heart. Coronary heart disease is caused by atherosclerosis, a gradual process that narrows the heart’s arteries and leads to a heart attack.
Atherosclerosis can begin in adolescence when fatty streaks, which may one day cause heart disease, can appear on the lining of arteries as cholesterol sticks to the arteries. The next stage of atherosclerosis is an injury to the lining of an artery. An infection or virus, high blood pressure, cigarette smoke or diabetes may cause this damage. Your body attempts to heal itself, just like it would with any wound. Immune cells are attracted to the injured artery wall and accumulate. Over time, the fatty streaks enlarge and become hardened with minerals, tissue, fat and cells, forming plaques. As plaques form beneath the artery wall, they stiffen arteries and narrow the passage through them. Most people have well-developed plaques by the time they are 30 years old. If atherosclerosis progresses, it can restrict blood flow to the heart.
Blood cells called platelets respond to damaged spots on blood vessels by forming clots. A clot may stick to a plaque and gradually enlarge until it blocks blood flow to an area of the heart. That portion of the heart may die slowly and form scar tissue. But a clot can also break loose, and circulate in the blood until it reaches an artery too small to pass through. When a clot that’s wedged in a vessel cuts off the supply of oxygen and nutrients to a part of the heart muscle, a heart attack results.
Who’s at Risk?
Risk factors for heart disease are usually classified as either modifiable or non-modifiable. Non-modifiable factors—like getting older or having a strong family history of early heart attacks—are risk factors that you can’t change. But you can reduce your risk by changing modifiable risk factors. You can change your diet, exercise more or quit smoking. You can even control risk factors such as high blood pressure or diabetes. Here’s a glance at the factors that put you at risk for heart disease (the more risk factors you have, the greater your risk):
Non-modifiable Risk Factors
• You’re over 40. As you get older your body becomes less efficient at clearing cholesterol from the bloodstream. With advancing age, many women develop high blood pressure and diabetes, two other risk factors for heart disease.
• You’re at or past menopause. Both natural and surgical menopause are associated with an increased risk. Before menopause, estrogen protects the heart by keeping cholesterol levels in check and blood vessels more flexible.
• You have a family history of heart attack prior to age 60. Your risk is even greater if you have a female relative who suffered heart disease.
Modifiable Risk Factors
• You have high blood cholesterol or you don’t know.
• You have high blood triglycerides or you don’t know.
• You have low HDL cholesterol or you don’t know.
• You have high blood pressure or you don’t know.
• You smoke cigarettes. Smoking is a more important predictor of heart attack in middle-aged women than it is in men. Women who use oral contraceptives and smoke cigarettes have an even higher risk. Smoking damages the lining of the arteries, increasing the likelihood of plaque formation. Inhaling cigarette smoke also produces free radicals in the body, which then damage LDL cholesterol, making it stick to the artery walls. Finally, smoking increases blood pressure and makes blood clot formation more likely.
• You have a poor diet.
• You don’t exercise regularly. Regular exercise helps you maintain a healthy weight. It lowers LDL cholesterol and raises HDL cholesterol, and it strengthens the heart and blood vessels.
• You have diabetes. A woman with diabetes is three times more likely to experience heart disease than a non-diabetic woman. In diabetes, fatty plaques develop and progress much more rapidly.
• Your BMI is more than 25 (see page 45 in chapter 2 to determine your BMI). Carrying extra weight puts stress on your heart and circulatory system. Being overweight can also lead to high blood pressure and elevated blood cholesterol. Excess weight around the waist is much more dangerous to your heart than excess lower body fat.
There are two different kinds of cholesterol. Dietary cholesterol is found in foods and blood cholesterol is made by your liver. For most people, the two are unrelated. That means that dietary cholesterol has little or no effect on the amount of cholesterol in the blood. Cholesterol and fat are transported in your bloodstream on carrier molecules called lipoproteins. The lipoproteins that have received the most attention are low-density lipoproteins (LDL), high-density lipoproteins (HDL) and triglycerides. If you know your cholesterol levels, use the following reference guide to determine if your level is healthy, or if it puts you at higher risk for heart disease.
BLOOD LIPID DESIRABLE BORDERLINE RISK AT RISK
Total cholesterol <200 200-239 >240
LDL cholesterol <130 130-159 >160
HDL cholesterol 50-60 N/A <40
Triglycerides <150 150-199 >200
Blood lipids are measured in milligrams per deciliter (mg/dl).
Circulating cholesterol contributes to heart disease by becoming part of the fatty plaques that build up on artery walls. The more LDL cholesterol there is in the blood, the more cholesterol there is available to attach to artery walls. The longer you have high LDL levels, the greater the chance more cholesterol has built up in your arteries. While LDL is considered bad, oxidized LDL cholesterol is deemed even worse. Once LDL cholesterol becomes oxidized or damaged by harmful free radical molecules, it then is much more likely to accumulate in your arteries. You’ll read below how dietary antioxidants may help prevent such damage to LDL cholesterol particles.
Blood cholesterol levels rise quickly in women after menopause. By the age of 55, women have higher cholesterol levels than men. Having high total cholesterol does not pose as much risk for women as it does for men. What does increase your risk for heart disease is having both a low HDL cholesterol and a high triglyceride level. It’s estimated that this combination increases a woman’s risk of heart disease ten-fold. In order to get a more accurate picture of your risk for heart disease, it’s important to get all types of cholesterol measured, not just your total number. For instance, if your total cholesterol is 250, but your HDL is high, then your risk for heart disease is less.
Your ratio of total cholesterol to HDL cholesterol is considered a better predictor of heart disease risk than LDL or HDL values alone. This score is referred to as your risk ratio—your total cholesterol divided by your HDL cholesterol. Here’s a reference guide for women:
Total/HDL Cholesterol (Risk Ratio)
Below average risk <3.5
Average risk 3.5-5.0
Above average risk 5-10
Much above average risk >10
HIGH BLOOD PRESSURE
The higher your blood pressure is above normal, the greater your risk for heart disease. Arteries that are stiff from atherosclerosis strain as blood pulses through them. And if you have high blood pressure as well, your arteries are put under much greater stress. Stressed and strained arteries develop more lesions, and fatty plaques grow more frequently.
Blood pressure results from the pressure generated by your heart as it pushes blood through your arteries. When your heart beats, the blood pressure in your arteries rises. When the heart relaxes between beats, blood pressure falls. Your blood pressure is taken as two measures, a systolic and diastolic pressure. A healthy blood pressure in adults is 120/80 (systolic/diastolic). Doctors interpret the bottom number, the diastolic blood pressure, to determine if you have hypertension. Here are the standards used:
Diastolic Blood Pressure
Mild hypertension 90-99
Moderate hypertension 100-109
Severe hypertension 110-119
Very severe hypertension >120
Hypertension is more common in women over the age of 55 than it is in men of the same age. High blood pressure has no symptoms. The only way you can detect it is by having it checked regularly. Your blood pressure should be taken when you are relaxed, not stressed. When you’re anxious your blood pressure rises, but when you relax it returns to normal. High blood pressure is treated by weight loss, dietary modifications and often medication.
Today many studies are focusing on a compound called homocysteine. Homocysteine is an amino acid that our body produces during cellular metabolism. Normally we convert homocysteine to other harmless amino acids with the help of B vitamins. When this conversion doesn’t occur, homocysteine can accumulate in the blood and damage vessel walls, promoting the build-up of cholesterol. Homocysteine levels can accumulate as a result of an inherited genetic defect or a deficiency of B vitamins.
A number of studies have discovered that people with high homocysteine levels have a much higher risk of heart disease. Researchers from Boston found that, among 28,263 postmenopausal women, those with the highest levels of homocysteine had more than twice the risk of heart attack or stroke compared to women with the lowest levels.1
At this time, there is no clear definition of normal or healthy levels. But as you’ll read below, there are some simple dietary modifications to help prevent homocysteine from accumulating in your bloodstream.