Although the death rate from coronary heart disease (CHD) has declined rapidly during the last few decades, CHD remains the most common cause of death in most countries around the world. The reduction in death rate is partly due to fewer people being diagnosed with CHD and partly due to a better prognosis of those affected.
However, the tide may be turning and if we look closely we might see some dark clouds on the horizon. The recent obesity epidemic and the rapid increase in type 2 diabetes may have ignited a new pandemic of chronic disease. Obesity and diabetes are strong risk factors for heart disease, many cancers, and Alzheimer’s disease.
In order to understand where the winds are blowing it may be helpful to analyze the modern-day heart patient and compare him/her with the typical heart patient of the 1980’s.
What does the modern-day heart patient look like? Is he/she different from the typical heart patient of the 1980’s? If so, should we still give the same dietary and lifestyle recommendations as 30 years ago?
Official dietary guidelines tend to change very slowly. In order to catch up and be able to reverse the rapid rise in metabolic disorders associated with obesity and unhealthy dietary habits, we may have to react very quickly. We may also have to admit that we’ve made a number of mistakes along the way. Otherwise we may be facing problems of enormous proportions.
Of course, there is no typical heart patient. Heart patients are young and old, male and female, skinny and obese, lazy and active, there are all possible varieties. However, trying to define the typical heart patient may help us understand whether there is a pattern or not.
Looking 25 years back to the days when I was starting my training as a cardiologist I see the typical heart patient as a normal weight, middle aged, smoking man with family history of heart disease and sometimes raised LDL-cholesterol (LDL-C). At that time, therapy was relatively conservative compared with today, and prognosis was generally worse. Of course abstaining from smoking was a key issue for these patients. Other recommendations included a prudent low-fat diet, quite similar to the one still recommended by many medical professionals. Statins were not available at that time, but dietary recommendations were primarily aimed at reducing blood levels of cholesterol.
As a young doctor, my first scientific project was to collect data from patients younger than forty years old who suffered an acute heart attack (acute myocardial infarction) during the time period 1980-1984.
Fortunately, heart attack was fairly uncommon in this age group and most patients were men. Among those admitted to hospital, 97 percents were smokers and slightly more than 50 percent had a parent or sibling with a history of CHD.
The mean level of total cholesterol in these individuals was 244 mg/dL (6.32 mmol/L) which was the same as the mean cholesterol among healthy people in the same age group. However, triglyceride (TG) levels were higher among the heart attack patients than in the general population. Mean body mass index (BMI) was 26.1 which was not significantly different from the general population.
We generally consider the main risk factors for CHD to be smoking, high blood pressure, high blood levels of LDL-C, diabetes, obesity and emotional stress. Low levels of HDL-cholesterol (HDL-C) and high TG may also be important. In they eighties, obesity and diabetes were much less prevalent than today. Therefore our main emphasis was on controlling blood pressure, getting the patient to quit smoking, and urging him/her to lower cholesterol through dietary measures.
The Modern-Day Situation
Recently an analysis of patients 40 years and younger who suffered an acute heart attack during the time period 2005-2009 was performed at our institute. As in the 1980-1984 study, there was a high prevalence of smoking and family history was common. However, body mass index was 28.6 which is significantly higher than in the eighties study.
The mean level of total cholesterol was 197 mg/dL (5.1 mmol/L), significantly lower than in the eighties.Interestingly, this cholesterol level was also significantly lower than the total cholesterol of individuals of similar age in the general population. HDL-C was significantly lower among the patients than in the general population.
Thus, compared with the eighties, young heart attack victims today seem more overweight and have lower HDL-C than the general population. Interestingly, high LDL-C does not appear to be a problem among these patients. This pattern was also found in the large “Get With the Guidelines” study which showed that a large proportion of patients admitted to hospital in the U.S. in the years 2000-2006 because of CHD didn’t have elevated LDL-C. However, HDL-C was generally low among these patients.
These data suggest that metabolic syndrome is becoming more prevalent among individuals with CHD. Metabolic syndrome is characterized by a large waistline, high blood levels of TG, low HDL-C, and sometimes diabetes.
High TG/HDL-C ratio generally reflects insulin resistance and is often associates with preponderance of small LDL-particles. This pattern is associated with increased risk of cardiovascular events. The metabolic syndrome is strongly associated with the risk of heart attack and stroke.
A recent EAS (European Atherosclerotic Society) Consensus Panel paper has highlighted a lipid pattern that is likely to cause atherosclerosis and thereby increase the risk of CHD. The combination of elevated triglyceride-rich lipoproteins and low HDL cholesterol are key factors driving risk in individuals with the metabolic syndrome.
An analysis of a large international registry showed that individuals with increased body mass index (BMI) had a more severe coronary artery disease than could be explained by the presence of traditional risk factors. Another study showed that waist-to-hip ratio was significantly associated with the risk of heart attack, highlighting the risk of abdominal obesity.
Researchers from the University of Oxford recently followed the health of 1.2 million women from England and Scotland for almost a decade. Analysis of the data showed that the occurrence of CHD increased with BMI. Every 5 unit increase in BMI, increases the risk of coronary artery disease by 23 percent.
A report from a French registry showed recent increase in the number of younger patients with heart attack, particularly women. The proportion of women with heart attack, younger than 60 years increased from 12 to 26 percent within fifteen years. The prevalence of risk factors among these women is worth thinking about. In fifteen years, smoking increased from 37 percent to 73 percent, and obesity from 18 percent to 27 percent among women younger than 60 years who had a heart attack. The proportion of young patients not having high blood pressure, diabetes, or high blood levels of cholesterol also increased markedly.
Is the Prudent Low Fat Diet Outdated?
Two-thirds of U.S. adults are overweight or obese. Obesity rates have more than doubled in adults and children since the 1970’s. The same trend is seen in many countries around the world making obesity a worldwide problem. Such an enormous change in such a short time is both astounding and frightening, considering the strong relationship between heart disease, stroke, diabetes and certain types of cancer.
So, obviously we will see a new wave of chronic diseases, it’s only a question of time. However, everything indicates that this is a man-made pandemic. But, therein lies the solution. Obesity is a preventable disorder. It’s a lifestyle issue. However, that doesn’t mean the solution is simple, only that it is potentially preventable.
Today preventing heart disease should aim at preventing obesity and the metabolic syndrome. It’s not about choosing low-fat and prescribing cholesterol-lowering drugs (statins) anymore. Although preventing obesity is not a simple task, some of the targets are obvious. If the over-consumption of refined sugars doesn’t stop, we don’t stand a chance.
Keep in mind Dr. John Yudkin’s word from his great book Pure, White and Deadly: “There is no physiological requirement for sugar, all human nutritional need can be met in full without having to take a single spoon of white or brown or raw sugar, on it’s own or in any food or drink”.
But, how do we deal with the modern-day heart patient? Does a prudent low-fat diet still apply? Probably not. A lot of evidence indicates that carbohydrate restriction with a relatively high consumption of fats is more likely to reduce insulin resistance, decrease TG, increase HDL-C and improve LDL-particle size and number.
The changing risk profile of patients with coronary heart disease illustrates the need for re-evaluation of our dietary recommendations. Albert Einstein’s is believed to have said: “Insanity is doing the same thing over and over again and expecting a different result.”