What is coffee?
The coffee bean is the seed inside the fruit of the coffee tree, referred to as the 'coffee cherry'. Usually, there are two beans inside the cherry. When there is only one small, round bean, it is called a peaberry. Coffee grows in warm, humid climates at altitudes up to 6,000 feet above sea level. It is the second most traded commodity in the world after oil.
How Much Caffeine in a Cup of Coffee?
It can be even more confusing if you want to know how much caffeine is in a cup, because that varies depending on the beans, how they are roasted, and how the coffee is prepared.
For example, a restaurant-style serving of Espresso in a 1 oz (30ml) cup can contain from 40 to 75 mg of caffeine. Even a decaffeinated Espresso can contain up to 15 mg of caffeine.
On the other hand, an 8 oz (240 ml) cup of generic instant coffee can contain any amount from 27 to 173 mg of caffeine, while a Starbucks Pike Place 16 oz (480 ml) cup of brewed coffee contains 330 mg of caffeine.
How Much Is a Moderate Intake of Caffeine?
A moderate intake of caffeine is probably around 300 mg per day. This is roughly 3 to 4 cups of ground roasted coffee or 5 cups of instant. For pregnant women, this level would be considered excessive, and they are advised to keep their consumption below 200 mg a day.Coffee is not the only source of caffeine in the diet. 300 mg is also the amount of caffeine in 5 or 6 servings of tea and some colas, and the average chocolate candy bar has about 35 mg.
Coffee Drinking is good or bad for our health
There was a time when the only news about coffee and health was how it was bad for the heart, likely to give us ulcers and aggravate our nerves, but now it seems this popular beverage is receiving a more favorable kind of press.
However, the researchers uncovering the good news are all saying the same thing: while there appear to be some health perks from drinking coffee, there are also a few cautions, and the evidence is not solid enough to actively encourage people to go out and drink coffee.
Another reason to reserve some caution, is that although the evidence is shifting toward a more favorable view of coffee's effect on health, it is not based on cause and effect but on links for which there could be other explanations: it could be that regular coffee drinkers have something else in common, that studies have yet to discover, to account for the effect on health.
Harvard Study 2008 change the opinion
The results showed regularly consuming up to 6 cups of coffee per day (containing around 100 mg caffeine per 8 oz cup) was not linked with increased deaths in either men or women, from any cause, or death from cancer, or from cardiovascular disease.
This finding confirms the research picture that has been emerging in the last few years, says Rob van Dam, Assistant Professor in the Department of Nutrition, Harvard School of Public Health, one of the study researchers. For the general population, the evidence suggests that coffee drinking doesn't have any serious detrimental health effects," he adds. Mayo Clinic preventive medicine specialist Donald Hensrud suggests one explanation for the apparent reversal in thinking about coffee, is that, Earlier studies didn't always take into account that known high-risk behaviors, such as smoking and physical inactivity, tended to be more common among heavy coffee drinkers at that time
Coffee drinking is good for Cancer patient
Studies have also suggested coffee consumption is linked to a lower risk for some cancers, including endometrial, aggressive prostate, estrogen-negative breast cancer, liver cancer, and a common form of skin cancer, but not others (eg esophageal). In 2011, researchers working with data from the Nurses' Health Study published findings that showed coffee drinkers who consumed more than four cups a day had a 25% lower risk of developing endometrial cancer. Senior researcher Edward Giovannucci, professor of nutrition and epidemiology at the Harvard School of Public Health, said coffee is starting to emerge as a protective agent in cancers that are linked to obesity, estrogen and insulin.
He and his colleagues suggest antioxidant and anti-inflammatory substances in coffee may be responsible for anti-cancer activity. Giovannucci said lab tests show coffee has more antioxidants than most fruits and vegetables.
Coffee drinking is good for Heart Disease and Stroke
Some of the evidence that has emerged in recent years suggests coffee consumption may lower the risk of heart disease and stroke.
A Kaiser Permanente study presented at an American Heart Association conference in March 2010, found coffee drinkers were less likely to be hospitalized for heart rhythm disturbances. The researchers examined data on of 130,000 health plan members and found people who reported drinking between one and three cups of coffee a day had a lower risk than non-drinkers, regardless of other risk factors. Reported more recently, in 2012, a US study found that drinking coffee in moderation, may also protect slightly against heart failure. For women, coffee drinking may mean a lower risk of stroke.
In March 2011, research led by the Karolinska Institute in Stockholm, Sweden, that followed over 30,000 women for 10 years, found those who drank more than one cup of coffee per day appeared to have a 22 to 25% lower risk of stroke, compared to non-drinkers. The researchers also found that "low or no coffee consumption was associated with an increased risk of stroke in women”. The findings were the same, regardless of other factors such as smoking, alcohol, body mass index, history of diabetes, and high blood pressure. An earlier US study, published in 2009, involving 80,000 women from the Nurses' Health Study, had also found a 20% lower risk of stroke among coffee drinkers. None of the women had a history of stroke, coronary heart disease, diabetes, or cancer at the start of the study, and the researchers found the relative risk of stroke went down as coffee consumption went up.However, a recent Harvard Health newsletter warns that while moderate coffee consumption (3 - 4 cups a day) may be linked to a lower risk for stroke, among infrequent coffee consumers the risk of a stroke just after drinking coffee could be higher.
One reason coffee consumption may lower longer term risk for heart disease and stroke, is because it appears to reduce the chance of developing type 2 diabetes, which is itself a risk factor for these diseases.
Coffee drinking is good for Type 2 Diabetes
Frank Hu, nutrition and epidemiology professor at the Harvard School of Public Health, has been researching the effects of coffee on health since before the 2008 Harvard study, on which he was also a co-author.In 2005, he and his team published a paper in which they reviewed nine studies covering more than 193,000 people in the US and Europe that examined the link between coffee intake and type 2 diabetes. Their analysis found participants who reported drinking more than 6 or 7 cups of coffee a day were 35% less likely to have type 2 diabetes, compared with those who reported drinking under 2 cups a day. For those drinking 4 to 6 cups a day, the risk was reduced by 28%.
More recently, in 2009, an international study led by researchers in Australia, reviewed 18 studies covering nearly 458,000 people and found that for every extra daily cup of coffee consumed, there was a 7% reduction in risk for developing type 2 diabetes. There were similar reductions for tea and decaf coffee. However, the researchers warned that some of the studies they reviewed were small and less reliable, so the link between heavy coffee drinking and reduced risk of type 2 diabetes may be exaggerated. They called for randomized trials to investigate their finding more robustly.
Coffee drinking is good for Alzheimer's disease
In 2009, researchers in Finland and Sweden reported a study that followed over 1,400 people over 20 years, and found that those who drank 3 to 5 cups of coffee a day in their midlife years had a 65% lower chance of developing dementia and Alzheimer's disease compared with those who reported drinking no coffee at all or only occasionally. In June 2012, researchers from the University of South Florida (USF) and the University of Miami, published a paper describing how they monitored the memory and thinking processes of 124 people, aged 65 to 88, and found all those with higher blood levels of caffeine (mostly from drinking coffee) avoided the onset of Alzheimer's disease in the 2-4 year follow up. This was even true of those who had mild cognitive impairment (MCI), a precursor of Alzheimer's.
Lead author Chuanhai Cao, a neuroscientist at the USF College of Pharmacy and the USF Health Byrd Alzheimer's Institute, and colleagues, have been publishing papers on the links between caffeine, coffee and Alzheimer's disease since 2006.
Coffee drinking is good for Parkinson's disease
For Parkinson's disease, another neurodegenerative disorder, it appears there is also a link between higher coffee consumption and decreased risk. And like Alzheimer's, this also seems to be due to caffeine, but it is less clear how it works. However, one study of caffeine and risk of developing the two diseases that was published in Journal of Alzheimer's Disease in 2010, by Xuesong Chen and colleagues from the University of North Dakota in the US, suggest it might be something to do with a protective effect that caffeine has in preserving the blood-brain-barrier.
In another Journal of Alzheimer's Disease study also published in 2010, João Costa of the University of Lisbon, Portugal, and colleagues present an analysis of 26 studies that suggests an inverse association between coffee drinking and the chance of developing Parkinson's disease. For every increase of 300 mg per day in caffeine intake, they found a drop of 24% in the relative risk of developing Parkinson's. Among those who regularly drank two to three cups of coffee a day, there was a 25% lower chance of developing the disease compared to non-coffee drinkers. However, among women coffee drinkers only, this fell to 14%. The researchers said their findings could "hardly by explained by bias or uncontrolled confounding".
