Abstract
Because of the vast medical literature which produced a negative image for the effect of coffee on the health of regular coffee consumers, and the obvious contradictions created by the more recent publications, a large prospective study is needed to investigate the effects of coffee and caffeine on the hardest end-point to any study, mortality from all causes. Several epidemiological studies have already shown an absence of any effect of coffee consumption on mortality in total communities.
This paper will focus on strong association between recent coffee drinking and the incidence of cardiovascular disease. The relationship of coffee consumption with the risk of myocardial infarction.
Coffee Consumption and Coronary Heart Disease
Coffee is consumed by 110 million Americans. Its effects on blood pressure and heart function have been investigated extensively, with little consensus among the results of multiple studies. While some have found that caffeine raises sympathetic activity and blood pressure in many coffee drinkers, these effects seem to disappear in those who have been drinking coffee regularly for prolonged periods of time.
But how does coffee affect the risk of developing heart disease? Previously, there has been some evidence that caffeine may raise the levels of LDL, otherwise known as the bad cholesterol, and thereby raise the incidence of coronary artery disease. Some studies have not been able to confirm this finding, while others argue that only heavy drinking (more than 5 cups per day) is associated with any risk of developing heart disease. In Finland, coffee consumption is one of the highest per capital in the world, interestingly, so are their rates of heart disease.
One study looked at a possible relation between coffee consumption and development of heart disease. Over 20,000 Finnish men and women participated in a cross-sectional risk factor survey in 1977, or 1982. The study assessed caffeine consumption, major risk factors for heart disease, and other important medical history. Patents were then followed for a period of 10 years.
The results differed between men and women. Men who did not drink coffee at all had highest incidence of heart disease. There was a slightly increased risk of heart attacks in men consuming caffeine. However, the same men also had a higher incidence of smoking and worse cholesterol profiles.
In Finnish women, all-cause mortality actually decreased with increased coffee consumption. Coffee may or may not change the risk of developing heart disease or high blood pressure; the studies show mixed results. It is likely that other factors are contributing as confounding factors and the topic needs further investigation. Drinking in moderation may be the ultimate answer here.
On the other hand, the debate over the possible association between heavy coffee consumption and myocardial infarction has been fought in the literature for 25 years. Opinions on the health consequences of coffee consumption changed even more frequently than those concerning alcohol. The debate goes back over more than 200 years. A threatened ban on coffee consumption in women provoked Johan Sebastian Bach into composing his only secular cantata, the “coffee cantata.” But the majority of data up to the present time indicate that there is no relationship between coffee consumption and coronary artery disease.
Hayden demonstrated no increased mortality from coronary heart disease in heavy coffee drinkers, and the Framingham study absolved coffee drinking as a factor in the development of atherosclerotic cardiovascular disease. MacCornack as well as Curatolo equally found no association between coffee drinking and ischemic heart disease. Hennekens suggested that the risk, if any, of death from coronary heart disease associated with coffee drinking is small.
There are however a few voices which blame caffeine for the development of coronary artery disease. Studies from Finland maintain that the incidence of coronary heart disease is high in the part of the population with high coffee consumption. The conditions are not different in neighboring Sweden, where Wilhelson found a significant association between coffee consumption and myorcardial infarction. It was reported in 963 a positive association between coronary heart disease and coffee. But the overwhelming evidence is that coffee drinking is not causally related to coronary artery disease.
This however does not detract from the fact that coffee drinking has acute effects on the cardiovascular system. The father of classical psychiatry, Kraepelin, emphasized the protean manifestations of caffeinism and noted quickening of the pulse, palpitation and uneasiness in the region of the heart. Dobmeyer reviews the arryhthmogenic effects of coffee and discovered that although caffeine caused no significant changes in conduction intervals, the effective refractory period of the high and low right atrium, the A-V node, and right ventricle were shortened. Theophylline, the active ingredient in tea and coffee acts much like a ?-adrenergic agonist.
Meanwhile, many studies could not find the link between cardiovascular disease and consumption of coffee and caffeine. A prospective study conducted by Harvard University researchers concluded that caffeine consumption causes no substantial increase in the risk of coronary heart disease or stroke. The study included 45,589 men between the ages of 40 to 75 years old and adjusted for major cardiovascular-risk indicators including dietary intake of fats, cholesterol and smoking. Additionally, a case-control study on the effect of filtered-coffee consumption on plasma lipid levels indicated that coffee consumption led to a small increase in the level of high-density lipoprotein cholesterol that is believed to protect against and lower the risk for coronary heart disease.
Results from the Scottish Heart Health Study, published in 1993, support the finding that filtered-coffee consumption was not linked to an increase in cholesterol concentrations or coronary heart disease (CHD). This study of 9740 men and women in the United Kingdom concluded that neither tea nor not coffee consumption was linked to CHD. The majority of coffee consumed in the United Kingdom is instant, and the researchers noted that previous studies indicating a positive relationship between coffee and CHD were focusing on unfiltered and boiled coffee which is consumed in Scandinavia, but rarely in the US. The result of a study published in the Journal of the American Medical Association, which is the largest study on caffeine and CHD ever conducted on women, found no evidence of a positive relationship between coffee consumption (regular or decaffeinated, current or past consumption) and risk of CHD. The study also pointed out that there was no observable difference in effects between genders.
The effects of caffeine on blood pressure have been the subjects of various hypotheses, many of which have been disproved. A number of studies have shown that any temporary rise in blood pressure due to caffeine consumption is less than the elevation produced by normal, daily activities. The result of a double-blind randomized trial including 69 healthy participants indicated that caffeine has no adverse effect on cardiovascular risk by inducing unfavorable changes in blood pressure or serum lipids. Recent analysis from a multiple year intervention trial indicates an inverse correlation between caffeine intake and both systolic and diastolic blood pressure.
Another study on coffee consumption, it has been found to be associated with risk of coronary heart disease but not in others. A recent review, a meta-analysis and a commentary together identify many of the relevant studies and summarize current knowledge. Coffee has been in use for about 1000 years, and as of the mid-1980s was consumed by 52% of the US population. It is the major source of caffeine for those who drink it, delivering between 200 and 300 mg/day. Coffee is chemically complex, however, and may contain 100 or more active substances, depending on the manner of its preparation.
This consideration has led to identification of two specific components, kahweol and cafestol, which in human experiments have been found to increase blood cholesterol, particularly LDL-cholesterol, concentrations. Because these compounds are trapped by paper filtration in the brewing process, only coffee prepared by boiling and drunk without filtration would be expected to have this effect. Increased risk of coronary heart disease commensurate with this demonstrated blood lipid effect of unfiltered coffee would be expected if there were no opposing influences of other constituents of coffee.
Review and meta-analysis of 8 case-control and 14 cohort studies concluded only that a relative risk from drinking five cups per day was unlikely to exceed 1.5 and that ambiguity of the evidence left doubt about the existence or size of the true effect. As in other contexts, the need for longer-term studies with more than baseline assessment of coffee intake was noted, including both regular and decaffeinated coffee drinking. Different preparation methods and the greatly increased variation in types of coffee consumed in some segments of society also require consideration.
Although coffee has long been vilified, recent research has practically elevated it to the status of a health elixir. Moderate consumption of America’s favorite beverage has been shown to yield a number of perks for the brain and body. Because it’s made by brewing beans, there’s no denying that coffee is a plant-based beverage. Like other plant foods, including fruits and vegetables, coffee is rich in dsease-fihgting antioxidants.
While fruits, vegetables, and grains are undoubtedly more nutritious sources of antioxidants, the unfortunate reality is that few Americans eat the recommended amounts of these wholesome foods. In fact, studies have shown that coffee is the largest source of antioxidants in the typical American’s diet.
Although many foods, including red beans and blueberries, have far higher antioxidants concentrations than a cup of coffee, most Americans don’t eat beans and berries regularly enough to drive their disease-fighting benefits. More than 80 percent of U.S. adults consume coffee at least occasionally, and over half of us drink it every day.
Coffee’s greatest claim to fame may lie in its ability to boost brain power. After a jolt of java, individuals tend to perform better on tests that measure concentration, memory, and learning. Coffee may have even greater benefits in the human brain, protecting it from degenerative processes that lead to dementia. Recent studies suggest that habitual coffee drinkers have a lower risk for Parkinson’s disease and Alzheimer’s than individuals who abstain. Researchers once suspected that coffee might increase the risk for a variety of cancers, but this theory has been disproved.
As it turns out, regular consumption of the brewed beverage appears to afford a measure of cancer protection. Coffee has been shown to reduce the risk of colorectal cancer by as much as 25 percent. Because coffee hastens the elimination process, cancer-causing toxins in digestive waste material are in contact with the intestinal lining for shorter periods. Coffee also appears to increase the activity of enzymes responsible for the detoxification of carcinogens in the body.
At least one study has demonstrated that coffee drinking can have a protection effect against some types of breast cancer as well. Among women with breast cancer causing gene mutations, those with high levels of coffee consumption were found to have a reduced risk of developing breast cancer.
Coffee has long been implicated in the development of osteoporosis, but there’s never been any convincing scientific evidence to support the theory. Studies examining the effects of moderate coffee consumption on bone loss in postmenopausal women reveal that as long as dietary calcium intake is adequate, drinking one to three cups of coffee a day has no detrimental effect on bone health. Recent research also refutes the notion that drinking coffee is bad for your heart. in a study funded by the National Institute of Health, scientist analyzed caffeine consumption among more than 100,000 adults, and found that drinking coffee was not associated with an elevated risk of coronary heart disease. Coffee may offer a measure of protection against diabetes. in an 18-year-long study of more than 120,000 adults, Harvard scientists concluded that regular coffee consumption was associated with a significantly lower risk of developing type II diabetes.
Coffee can help improve the staying power of exercisers, equestrians, and other athletes the caffeine boots endurance by delaying the onset of fatigue. When athletes drink three or four cups of coffee about an hour before they complete, they can outlast their caffeine free competitors by up to 20 minutes. This effect on athletic performance is real, in fact, that the International Olympic Committee classified caffeine as a restricted drug. Olympic competitors are allowed to use caffeine, as long as they don’t overdo it.
In conclusion, this paper has discussed the aspects of coffee consumption. Coffee is one of the most popular beverages in the world and is consumed by millions of people every day. Coffee’s most intriguing and studied ingredient is caffeine. Both coffee and caffeine have been studied in a variety of situations, from psychomotor effects to performance enhancement effects in exercise, to drinking coffee to prevent a number of diseases. As this research has demonstrated, coffee consumption is not dangerous by any means and in most cases can have a multitude of beneficial effects. Traditionally, these beneficial effects have been attributed to the caffeine content of coffee, but this is not the case in every situation, and the additional ingredients of coffee may also provide beneficial effects. In most cases, a functional food has a special effect on a particular population, but it is clear that the benefits of drinking coffee cover a wide spectrum of the population, and the benefits are not defined in isolated situations.
The role that coffee consumption has in preventing some of the most devastating and prevalent disease should justify the classification of coffee as a functional beverage.
Reference
Muray, S., Bjelke, E. & Robert, G. (1981). American Journal of Epidemiology (Vol.
113). Coffee Consumption and Mortality from Ischemic Heart Disease. MN:
University of Minnesota.
