Alcohol Effects on the Cardiovascular System
Introduction
Over the past years, there has been great deal of media attention describing the menace of overboard alcohol consumption on the health and wellness of the society: the media, health professionals as well as the government has been advocating for modest consumption of alcohol due to its harmful effects on human organs and systems such as heart and cardiovascular system. Lucas et al (2005) noted that some people drink alcohol with the intention of improving their cardiovascular health due to the perception that it performs. Lucas D. L conducted a research determining challenges and opportunities of alcohol consumption of the cardiovascular system. They further asserted that it is not recommended to consume alcohol with this intention because it leads to numerous bad effects on the cardiovascular system.
Due to the result of bountiful research done by scientist and medical professionals over the past century, they have collectively considered alcohol as a toxic substance to the heart and the overall cardiovascular system. Several scientist and researchers such as Agarwal (2002), Britton and McKee (2000), and O’Keefe, Bybee, and Lavie (2007) have confirmed that heavy drinking of alcohol is one of the greatest of cause of a diverse range of cardiovascular diseases such as high blood pressure, cardiomyopathy, coronary artery disease, and stroke among others. Agarwal, Britton, McKee, O’Keefe, Bybee, and Lavie are medical researchers who have published several papers in Journal of the American College of Cardiology. By as early as 1926, pioneer epidemiology scientists such as Raymond Pearl have established that there is a connection between life expectancy and alcohol consumption. For instance, he noted that abstainers have longest life expectancy followed by moderate alcohol drinkers and then heavy drinkers respectively. Another study conducted 12 years later established that heavy drinkers are more likely to die as compared to abstainers.
However, other research study has indicated that there are beneficial effects of moderate alcohol consumption for instance increased life expectancy. A common argument put forward by health experts is that the effect of alcohol on cardiovascular system can be either beneficial or harmful depending on the characteristic of the consumer and the amount consumed. Based on this argument, this paper describes the effects alcohol on the human cardiovascular system. However, before discussing the effects, it is essential to understand what constitute alcohol.
Alcohol
Alcohol is a colorless, volatile, and flammable liquid that has intoxicating effects – it is consumed in form of wine, beer, sprit and other forms of alcoholic drinks. When consumed in low dose, it reduces anxiety, causes euphoria as well as sociability: however, in high doses it causes intoxication commonly referred to as drunkenness, unconsciousness and stupor. In United States of America, more than 89% of adults drink alcohol as a recreational drug in major social places and at home in form of beer, wine and spirits. Apart from human consumption, it is used as solvents and fuels for a wide range of industrial purposes.
In chemistry, alcohol is referred to as ethanol or ethyl alcohol and is formed when yeast ferments sugar found in different types of foods such as grapes, malted barley, cider, apple, potatoes, and beets among others. In chemistry, ethanol is an organic compound that contains hydroxyl (-OH) as a functional group: methanol and ethanol are the simplest and important class of alcohol group. The general formula for alcohol is CnH2n+1OH where C, H, and O are carbon, hydrogen, and oxygen atoms respectively. The following are sample structure of primary, secondary, and tertiary alcohol.
Description of the chart: organic structure of primary, secondary, and tertiary alcohols
Effects on Cardiovascular System
Cardiovascular system consists of the heart and a network of blood vessels and its primary function is transportation of blood to other body organs. A heart is slightly bigger than a human fist and its function is to pump blood and make it flow around the body thereby transport oxygen and nutrients. A heart generates its own electrical signals that coordinate its ability to pump blood. It is a vital organ in the human body of survival and the cessation of its beats is commonly associated with death. A number of things can go wrong with the heart such as heart attack, angina, atherosclerosis, and coronary artery disease among others. Some of these may be enhancing by introduction of toxic compounds such as alcohol to the system as discussed below.
(a) Alcoholic Cardiomyopathy
According to O’Keefe, Bybee, and Lavie (2007), long term and heavy consumption of alcohol leads to cardiomyopathy, which is the enlargement of the heart. When the heart is enlarged, it subsequently loses some of its ability to contract. This this type of condition occurs when there is a reduction in the amount of blood supply to the heart. Scientists such as Agarwal (2002), Bradamante, Barenghi, and Villa (2004) have confirmed that the common cause of nonischemic cardiomyopathy is long-term heavy alcohol drinking. This condition, in its worst form, always leads to heart failure and subsequently death of the affected person.
As revealed by many recent studies, alcoholic cardiomyopathy is highly prevalent amongst the male drinkers. However, some studies have also established that the effect is also common amongst the female alcohol drinkers. One major thing noted is that the sensitivity of female to the toxic effect of alcoholic on the heart is high therefore; they have the highest risk of developing alcoholic cardiomyopathy. In addition, alcoholic cardiomyopathy is the leading cause of mortality due to alcohol drinking and is more rampant among heavy regular drinkers as shown in the chart below.
Description of the chart: the rate of mortality against age-specific consumption of alcohol
It is interesting to note that some people usually survive alcoholic cardiomyopathy for longer duration than expected as compared to cardiomyopathies caused by viral infection or pregnancy. According to a research study by Hines et al (2001), found that approximately 81% of people who contract alcoholic cardiomyopathy were still alive 5 years later as compared to only 48% of people with other forms of cardiomyopathies despite the severity of the symptoms and similar structural changes in the heart. Hines has published several medical research papers in New England Journal of Medicine.
Alcoholic cardiomyopathy has so many effects on the cardiovascular system. For instance, it damages the heart muscle there leading to lower inability of the heart to pump blood effectively. This further leads to lower heart rate and poor health of the affected person. According to Zeigler et al (2005), alcoholic cardiomyopathy also affects the cardiovascular system of the alcohol drinker by increasing the abstention. Over time, the person with alcoholic cardiomyopathy experiences a reducing or disappearing levels of antimyosin antibodies.
Over the past century, several scientific research studies have been conducted to determine the cellular as well as the molecular mechanisms through which alcohol affect the heart. According to Naimi et al (2005), alcohol affects the heart muscle by inducing damage to the membrane on the surface of the heart muscle cells as well as the myocytes. In addition, it also damage essential intracellular organelles of the heart as well as the apparatus that controls the contraction mechanism. Other research studies indicate that alcohol directly alters the ability of myocytes to synthesize proteins and enzymes thus affecting the heart functions. T also affects the ability of the myocytes to integrate, contract and self-repair thus leading to the ultimate death of the cell. The toxic effect of alcohol also detrimentally changes receptors lying on the surface of the myocytes, which are responsible for the regulation of intracellular function.
When in the blood, alcohol leads to the production of Reactive Oxygen Species (ROS), a dangerous molecule that contributes to the damage of heart cells. This molecular fragment is highly reactive and is produced as a result of metabolism of alcohol in the body. If it is overproduced, the ROS actually kill cells. Heavy consumption of alcohol subsequently increases the level of ROS thus the damage of heart cells begin. ROS start this process of damaging the cell by targeting phospholipids, which is the backbone of cell membranes. Once the ROS has destroyed phospholipids, the damage continues to the myocytes. It is the loss of myocytes that in turn results in the cardiomyopathy condition.
(b) Arrhythmias
Arrhythmia is another common disease of the cardiovascular system associated with heavy drinking of alcohol. It is the irregularity in the heart rhythm due to lose of ability of the heart muscle to contract and relax normally. Agarwal (2002) asserted that heavy drinking of alcohol causes the heart to lose its ability to contract its muscles synchronously thus it could not effectively pump blood regularly. For the heart to pump blood regularly, it must maintain its ability to contract its muscles synchronously. When alcohol is taken in large quantities, it subsequently disrupts the intrinsic pacemaker system of the heart thus reducing the ability of the heart muscles to contract synchronously. This eventually causes abnormal changes in the heart rhythm both acutely and chronically thus increased risks of arrhythmias.
There are two most common types of arrhythmias associated with heavy drinking namely the ventricular tachycardia and atrial fibrillation. Ventricular tachycardia is a life-threatening type of arrhythmias and is associated with very rapid beating of the heart. The rapid heartbeat originates from the ventricular chambers, which gives it the name. On the other hand, atrial fibrillation is characterized by rapid and irregular heartbeat – it originates from the atrial heart chambers. Both types of arrhythmias occur from alcohol’s destruction of the pacemaker system of the heart.
Alcohol causes atrial fibrillation and ventricular tachycardia by intoxication of the person. When in the blood, alcohol induces disturbances in the electrical discharge from the myocytes through its intoxication effects. In addition, it cases disturbances in the conduction of the produced electrical impulses from the myocytes through the heart muscles. For instance, it may cause the duration of electrical conduction through the heart’s atrial chambers to be prolonged. In essence, alcohol intoxication generally disrupts the contraction mechanism of the heart muscle thus leading to these two conditions.
In the heart muscle, electrical conduction occurs when there is movement of ions such as calcium, sodium, and potassium across the surface of the myocyte cell. This eventually causes the electrical potential across the myocyte cell membrane to change a process that is known as depolarization thus generating electrical impulse. The generated electrical impulse then moves across the myocytes leading to synchronous contraction of the heart. However, when alcohol in the cell reaches large concentration, the overall movement of calcium ions across the myocyte cell membranes decrease suddenly. The decrease in movement of calcium ions subsequently alters the conduction of the electrical impulse and depolarization process through the heart thus cause arrhythmias. In addition, high intake of alcohol also interferes with the movement of sodium ions in the similar process leading to the same results.
(c) Effects of Alcohol Withdrawal
Several studies have also indicated that alcohol withdrawal has drastic effects on the cardiovascular system. Interestingly, analysis of several cases of sudden death due to ventricular arrhythmias has indicated that the mortality occurs at when alcohol levels in the blood are very low or undetectable. Further analysis indicates that sudden deaths due to ventricular arrhythmias often occur during the abstinent periods suggesting that it might be related to alcohol withdrawal. In addition, higher cases of development of arrhythmias usually occur during the withdrawal period when the person is quitting drinking alcohol.
During the withdrawal period, the person undergoes detoxification – during this period, the cell start producing higher level of noradrenaline and adrenaline hormones in the body. Higher level of these hormones increases the sensitivity of the heart to arrhythmias and sudden death may occur. In addition, alcohol withdrawal also lowers the amount of magnesium and potassium stored in the body, a change that subsequently increases the chances of developing arrhythmias.
(d) Effects on the Vascular System
On the vascular system, alcohol has a diverse range of effects such as causing coronary heart disease among others. One of the major effects of heavy alcohol drinking is the increased risk of coronary heart disease. For instance, heavy drinking increases the episodes of pain in people suffering from various heart diseases thus increased risk of fatal heart attack. In addition, heavy drinking of alcohol causes frequent and great hangover affecting the coronary heart diseases. While many studies have suggested that prolonged heavy drinking of alcohol is associated with coronary heart disease, some have shown that moderate alcohol drinking lowers the risk of the disease in some groups. Some recent studies indicate that moderate alcohol drinking actually reduces the risk of heart attack and chest pain.
The mechanism through which alcohol reduces the risk or protects against coronary heart disease is not clearly understood. However, one possibility suggested by several researchers is that alcohol may act by impeding the process of accumulation of fatty deposits in the heart arteries thereby causing changes in the cholesterol profile. It also reduces the way atherosclerotic plaques develop in the coronary arteries – it lowers the level of LDL cholesterol. High level of this cholesterol in the heart muscle is associated with increased risk of heart diseases (Rehm et al, 2003).
High consumption of alcohol decreases the activity of Cholesteryl Ester Transfer Protein (CETP), a process that is responsible for increasing the level of HDL-cholesterol in the heart muscle. In addition, it acts by altering the production of certain variants of CETP at different activity levels. This change decreases the level of HDL cholesterol as well as CETP activity. These findings actually indicate that one mechanism through which drinking of alcohol moderately reduces the risk of coronary heart disease is by altering the cholesterol level in the body.
Another suggested mechanism is that moderate drinking of alcohol may improve survival after heart attack thus lowering the mortality of coronary heart diseases. Moderate drinkers of alcohol have higher probability of surviving myocardial infarction thus reduced risk of coronary heart diseases. In addition, alcohol increases the level of chemical adenosine in the blood thus protecting the heart cells against any likely damage. This process also reduces the risk and mortality of coronary heart diseases. For a long time, researchers have known that alcohol increases the level of adenosine in the blood. Alcohol also does this by blocking the adenosine docking sites on the myocytes a process that also contribute to increased level of adenosine in the blood.
(e) Stroke
Recent research studies suggest that there is a relationship between stroke and alcohol drinking especially in people suffering from coronary heart disease. Hines et al (2001) asserted that heavy drinking of alcohol increases the risk of both hemorrhagic and ischemic strokes, which are caused by blocked supply of blood to the brain. Mechanism through which alcohol leads to increased risk of stroke is likely to be the same as the case of coronary heart disease.
(f) Blood Pressure
Another serious negative effect of alcohol drinking is that it is associated with increased blood pressure. Recent studies in different cultures have shown that heavy drinking of alcohol increases blood pressure. When present in the body in high concentration, alcohol elevates blood pressure thus causing hypertension. According to a research by Bradamante, Barenghi, and Villa (2004), approximately glass of alcohol every day has the potential of chronically increasing the blood pressure – the effect is great more in the elderly people.
Even though the association between alcohol and hypertension is well recognized, the cellular mechanism through which it affects the blood pressure is not clearly understood. In addition, it is confusing given the fact that alcohol has an effect of dilating blood vessels; a phenomenon that should actually lower the blood pressure. However, most studies consider the long-term effect by looking at how it affects the autonomic nervous system. For example, when alcohol is consumed heavily, there would be an increased release of stress hormone known as noradrenaline and adrenaline. The release of these hormones subsequently causes the blood vessel to constrict resulting in increased blood pressure. It also decreases the sensitivity of baroreceptors, sensory neurons responsible for sending signal from large arteries and heart to the brain: these baroreceptors are responsible for regulating the blood pressure.
In addition, heavy drinking of alcohol directly affects blood pressure by altering its peripheral regulation by affecting the smooth muscles. Alcohol also inhibits the operation of endothelial cells that is responsible for relaxing smooth cells for control of blood pressure. In summary, the chart below illustrates the effect of alcohol on blood pressure.
Description of the chart: changes in blood pressure on various components of cardiovascular system caused by alcohol consumption
Conclusion
Heavy alcohol drinking is a common practice in the contemporary society and it is seen as an important element of social activities. In the modern society, it is not seen as a vice as it was long time ago. It has become a threat in the pillars of our society. Some of the problems associated with heavy drinking of alcohol include its effects on the cardiovascular system. The research study has indicated that the effect of alcohol on the cardiovascular system depends on the level of concentration and amount consumed. In addition, it produces both negative and positive effects.
In summary, some of the effects of alcohol on cardiovascular system are associated with alcoholic cardiomyopathy, arrhythmias, alcohol withdrawal, coronary heart disease, stroke, and blood pressure. For instance, it increases the risk of coronary heart disease, heart attack, stroke, high blood pressure, cardiomyopathy, as well as arrhythmias among other. Withdrawal of alcohol consumption also has effects on the cardiovascular system. For instance, it leads to production of higher level of noradrenaline and adrenaline hormones that subsequently leads to increased sensitivity of the heart to arrhythmias and sudden death.
References
Agarwal, D. P. (2002). Cardioprotective effects of light–moderate consumption of alcohol: a review of putative mechanisms. Alcohol and alcoholism, 37(5), 409-415.
Bradamante, S., Barenghi, L., & Villa, A. (2004). Cardiovascular protective effects of resveratrol. Cardiovascular drug reviews, 22(3), 169-188.
Britton, A., & McKee, M. (2000). The relation between alcohol and cardiovascular disease in Eastern Europe: explaining the paradox. Journal of Epidemiology and community Health, 54(5), 328-332.
Hines, L. M., Stampfer, M. J., Ma, J., Gaziano, J. M., Ridker, P. M., Hankinson, S. E., … & Hunter, D. J. (2001). Genetic variation in alcohol dehydrogenase and the beneficial effect of moderate alcohol consumption on myocardial infarction. New England Journal of Medicine, 344(8), 549-555.
Lucas, D. L., Brown, R. A., Wassef, M., & Giles, T. D. (2005). Alcohol and the cardiovascular system: research challenges and opportunities. Journal of the American College of Cardiology, 45(12), 1916-1924.
Naimi, T. S., Brown, D. W., Brewer, R. D., Giles, W. H., Mensah, G., Serdula, M. K., … & Stroup, D. F. (2005). Cardiovascular risk factors and confounders among nondrinking and moderate-drinking US adults. American journal of preventive medicine, 28(4), 369-373.
O’Keefe, J. H., Bybee, K. A., & Lavie, C. J. (2007). Alcohol and cardiovascular health: the razor-sharp double-edged sword. Journal of the American College of Cardiology, 50(11), 1009-1014.
Rehm, J., Gmel, G., Sempos, C. T., & Trevisan, M. (2003). Alcohol-related morbidity and mortality. Alcohol Res. Health, 140, C00-C97.
Thayer, J. F., Yamamoto, S. S., & Brosschot, J. F. (2010). The relationship of autonomic imbalance, heart rate variability and cardiovascular disease risk factors. International journal of cardiology, 141(2), 122-131.
Zeigler, D. W., Wang, C. C., Yoast, R. A., Dickinson, B. D., McCaffree, M. A., Robinowitz, C. B., & Sterling, M. L. (2005). The neurocognitive effects of alcohol on adolescents and college students. Preventive medicine, 40(1), 23-3