A few decades ago, few people could define or explain cholesterol, nor did they understand the way in which this substance is linked with heart disease.
Indeed, it has been a breakthrough in Western medicine to admit that diet, specifically fats in the diet, influence heart disease.
At one time, researchers and nutritionists who suggested a link between a variety of nutrients and a healthy heart were not taken seriously and were relegated to the fringes of the scientific community.
Nowadays, however, comparing cholesterol levels is the stuff of cocktail party conversation. Low-fat is in, and many of the largest food production companies in the world now print a banner on food labels declaring the product “reduced fat,” “fat free,” or “low fat.”
If preventing cardiovascular disease was a simple matter of counting fat grams, the mystery of this widespread and varied group of health concerns would be solved. But, like so many other health issues, cardiovascular disease is more complex. To understand the way in which soya products may protect against heart disease, it is necessary to gain an understanding of the way the heart and circulatory system works.
What is Heart Disease?
Just as there are many forms of cancers, there are numerous kinds of heart conditions and diseases, all of which have underlying causes. Oxygen, which circulates in the blood, is essential to the heart; when the heart becomes deprived of oxygen, problems appear. Angina (crushing pain experienced in the chest) results when the heart is deprived of oxygen for a brief period. But, when the heart is deprived of oxygen for more than a few minutes, an event that is commonly called a heart attack occurs. (The medical term for this is myocardial infraction.)
Quite literally, part of the heart muscle dies because it becomes oxygen deprived. Every year in the U.S., about one million people experience this serious event, and about one third of these incidents result in death.
There is no question that modern medical intervention has improved the survival rate of heart attack victims and a variety of treatments, including drugs and surgery, have given patients a second chance. Unfortunately, many of the treatments have done little to address the underlying cause.
Heart disease does not develop suddenly
When the American Heart Association advocated a low-fat diet, this represented a significant step in not only rebuilding the health of those affected by heart disease, but in attempting a prevention program as well. You see, heart disease does not develop suddenly; rather, it begins long before it manifests symptoms.
At one time, most of what was known about the heart was discovered by examining the organ during autopsies. Heart attack victims, and individuals who died from other causes, were found to have blockages in their coronary arteries.
While we have three major coronary arteries, these branch into smaller ones as they move away from the heart. The arteries are the pathways for the blood, and what we experience as a heartbeat is actually the pumping action of the heart muscle as the arteries feed the heart with oxygen rich (in ideal conditions) blood. So, if the arteries are blocked, the flow of blood and oxygen are obstructed.
One of the first clues that cholesterol was linked with heart disease came from the discovery that the blockages, referred to as plaque, contained, among other substances, cholesterol. So, like mineral deposits in water lines, plaque builds on the walls of the coronary arteries.
Evidence that this was a gradual process mounted when autopsies performed on young soldiers in the Korean and Vietnam conflicts revealed that most of these young, presumably healthy men, had at least mild early- stage plague formation. Other research has concluded that even pre-adolescent children may have plaque deposits in their coronary arteries.)
At one time, cardiovascular disease was believed to be a genetic issue, because Caucasians living in industrialized countries seemed to be afflicted more than any other population group, although other racial groups living in the Western world soon developed heart disease, too. The genetic connection, however, seemed like a simple cause and effect relationship, and high death rates from heart disease in Northern Europe, Canada, and the U.S. were considered unfortunate, but in large measure an inevitable consequence of one’s genes.
As the decades have passed, however, pharmaceutical and surgical interventions have prolonged life and improved the quality of life for those suffering from cardiovascular disease. Unfortunately, procedures such as angioplasty (the so-called “balloon” procedure) and by-pass surgery do not prevent plaque build-up from recurring, nor do they address the underlying issue of plaque formation.
Back to the Beginning
Blockages of the coronary arteries occur because the lining of the arterial walls are compromised or damaged. The body seeks to repair the damage by protecting the area with a kind of coating, much like a biological band-aid. A variety of substances and events damage the arterial walls, thereby triggering the body’s protective response. Cigarette smokers, for example, are at high risk for cardiovascular disease because nicotine can cause damage to the arterial walls.
One of the most important medical developments of our time has been the link between high cholesterol levels in the blood and cardiovascular disease. A related discovery was the relationship between a diet high in saturated fat and high cholesterol levels. So, genetic indicators aside, diet has taken its rightful place in both the cause of and a preventive measure for heart disease.
Low Fat Diets Come of Age
It is important to remember that cholesterol is an essential substance, involved in hormone production and other functions. It is produced by the liver, but also enters the bloodstream through food containing cholesterol, such as eggs and dairy products. The term lipoproteins refers to the particles by which cholesterol and other fats (triglycerides) are carried through the body.
The risk of cardiovascular disease is in part measured by the proportions of different kinds of lipoproteins in the blood, hence, the common terms “good” and “bad” cholesterol. High-density lipoproteins (HDL) appear to protect against heart disease, while low-density lipoproteins (LDL) increase risk.
Fat is not all bad
One of the confusing issues surrounding heart disease and the necessity to decrease dietary fat concerns the misconception that fat is by definition harmful. Chemically, fats are compounds consisting of fatty acids and a substance called glycerol. The difference between saturated and unsaturated fats is found in the proportion of hydrogen atoms occurring in the substance.
Fortunately, we do not need to count hydrogen atoms in order to recognize a saturated fat. Animal fats are solid at room temperature, and tend to be highly saturated with hydrogen; vegetable fats are liquid at room temperature, indicating that they are not saturated with hydrogen. However, vegetable fats–usually called oils–are not all alike and they vary in their degree of saturation. Some fatty acids cannot be formed in the body and these are known as the essential fatty acids.
In general, the emphasis on a low-fat diet has centered around the importance of decreasing saturated fats, but cutting overall intake of fat is emphasized, too. As the average person views it, reduced fat in the diet means reduced circulating cholesterol in the blood, particularly the “bad” cholesterol, LDL.
Sometimes it is not that simple, however, and cholesterol levels in our population remain stubbornly high, perhaps because reducing fat is not always easy to accomplish, or because other factors contribute to keeping cholesterol levels elevated. Some people appear to have a genetic tendency to have high cholesterol levels.
Drugs to Rescue?
In recent years, drugs to lower cholesterol have received wide attention and have been viewed as an answer to reducing risk of high cholesterol and plaque build-up. By-pass surgery and angioplasty might have reversed the problem of arterial blockages in the short-run, but did not address the problem over the long term. It has been documented, for example, that an artery cleared of blockage through angioplasty may contain plaque build-up only three or four months after the procedure.
In other words, the procedure may not be a long-term solution.
A pharmaceutical approach is quite common nowadays, mainly because there are powerful drugs that indeed lower cholesterol, at least some of the time. The question remains, however, at what cost–or costs–do these drugs work? First, the drugs are very expensive, and many patients simply cannot spare well over 100 dollars a month to buy them. The side-effects experienced by some people are unpleasant at best and dangerous at worst.
From abdominal pain and nausea to liver damage, it is safe to say that taking the drugs is a decision that must be made after considering the risk-benefit ratio. It is no wonder researchers and the general public are looking for a safer solution to the cholesterol problem.
Soya may be the Heart’s Friend
There is overwhelming evidence that soya protein lowers cholesterol levels in the blood. In this case, we need not rely on epidemiological studies, that is examining the incidence of diseases and conditions across populations.
However, population studies indicate that cultures who rely primarily on vegetable protein rather than animal protein have lower incidence of cardiovascular diseases, from elevated blood pressure (hypertension) to atherosclerosis (arterial blockages). Asian cultures in particular have a much lower death rate from cardiovascular diseases, and of course, we now know that soya is an important source of protein in the diets of many Asian countries.
Animal studies first showed that soya protein could lower cholesterol in the blood, and because soya is inherently safe, not to mention inexpensive, research protocols involving humans are not difficult to construct. In one study, patients with elevated cholesterol showed an average reduction of 21 percent in blood serum levels after only three weeks on a diet in which animal protein was replaced with soya protein. This regimen outpaced a group placed on a standard low-fat diet that included some animal protein. Other studies have shown that if we want to reduce cholesterol levels quickly, using soya protein is a safe, inexpensive, and effective way to proceed.
Frankly, when one looks at the risk of taking cholesterol – reducing drugs as compared to the safety and effectiveness of using soya protein, one can only wonder that soya has not become a mainstream therapy. From what we now know, soya protein can help lower LDL while not affecting beneficial levels of HDL. I could cite dozens of studies that demonstrate soya’s role in preventing and treating heart disease, but most consumers have not heard about this important development.
It is ironic that only a few years ago criticism was directed to the medical establishment about the tendency to ignore the risk of heart disease among postmenopausal women. Not only were many drug trials restricted to male research subjects, but women were less likely to be screened for developing cardiovascular conditions. The criticism was well-founded, but the solution to the problem is misguided. Over the last two or three years, women’s magazines and other media reports directed to women are dominated with data promoting cholesterol-lowering drugs.
Rarely, if ever, is adding soya to the diet mentioned as an option for preventing heart disease or lowering cholesterol levels.
Soya has gained some recognition for its beneficial role in easing menopausal symptoms (discussed in chapter nine), but its protective role in preventing heart disease is rarely mentioned. So, the same drugs that cause side effects in men are now being offered to women in the name of redressing past exclusion.
Of course, soya is rarely mentioned in articles and reports directed to men either, an issue that should disturb us all.