The major contender for hot drink supremacy, coffee, raises many questions when it comes to its effects on human health. While its defenders praise its benefits on cardiovascular health, cancer and neurodegnerative disease prevention, its opponents fear that coffee drinking may do more harm than good. Coffee is brewed from coffee beans, the seeds of the coffee cherries. There are dozens of coffee species, some only recently having been discovered.
However, most of the world’s production and finest coffee beans come from the Coffea arabica (around 75%) and Coffea canephora (up to 20%) species, the latter having a slightly higher caffeine content and a stronger flavor. Despite now being cultivated throughout the world, coffee plants originated in subtropical Africa and southern Asia. What do coffee plants look like? Coffee plants are flowering plants that grow to the size of shrubs or small trees, usually 3-4 meters tall, but no more than 10. The plant has beautiful, waxy green leaves, ample white flowers and produces edible, colorful berries called ‘coffee cherries’. The seeds of the coffee cherries are the coffee beans used for making coffee.
What do coffee cherries and beans look like? Coffee cherries are actually the berries or fruit of the coffee plant. They are small (15-35 mm), round fruit and come in a variety of colors, ranging from bright green to yellow, when unripe, bright red when ripe with tints of brown when overripe. The flesh is usually yellowish in color and the fruit grow in clusters. Each cherry generally contains 2 big, pale green seeds called beans, with a small percentage of them having only one seed. The seeds are dried and roasted to obtain the dark coffee beans we grind to brew coffee.
What do coffee cherries taste like? Fresh coffee cherries have a sweet taste and both the colorful skin and thin layer of flesh surrounding the seeds or beans are edible. They take around 9 months to ripen. What do coffee beans taste like? Green (or unripe) coffee beans have a bitter taste and a grassy, slightly woody, pungent aroma. Coffee brewed from them tastes more like caffeinated tea than coffee itself. Roasted coffee beans, on the other hand, possess the characteristic coffee flavor: a caramelized, deep aroma with a bitter, yet rich taste.
How is coffee made? Coffee is made by brewing roasted coffee beans. The fruit must first ripen, after which their seeds are dried, roasted and ground. The degree to which coffee beans are roasted greatly influences the final flavor of the drink. Sugar, milk, steamed milk foam, cream as well as spices such as cinnamon or even cocoa and chocolate may be added in varying amounts to alter taste or enhance flavor.
There is an incredible volume of research on the both positive and negative effects of coffee consumption on human health. While part of the scientific literature asserts that drinking coffee is highly beneficial for us, there are just as many scientific studies which condemn coffee consumption on the grounds that it is toxic or unhealthy for us. Here is what the myriad of scientific studies advocating the benefits of coffee consumption has to say about the beneficial effects coffee has on human health:
1) Excellent stimulant, protective of the nervous-system. Adenosine is a neurotransmitter that inhibits central nervos system activity. The caffeine in coffee inhibits adenosine receptors, allowing dopamine and glutamate levels to rise, hence its stimulating effects and the reason why we feel less tired, more energetic and more positive after one or two cups of coffee in the morning. The same brain and nerve stimulating effect is also the reason why coffee consumption improves cognitive performance and concentration.
Moreover, it has been suggested that coffee consumption may offer protection against Parkinson’s disease, as revealed by a Honolulu study conducted on 8,000 men and published in the 15 May 2015 issue of the Journal of Neuroscience. This health benefits are attributed to compounds in coffee which may help prevent dopamine loss.
2) Boasts cardiovascular benefits. Coffee is a mild natural diuretic, meaning it helps the body get rid of excess water through urination. This can be a positive thing because diuretics help reduce high blood pressure (hypertension), exercising a protective effect on cardiovascular health in the long-run. A 2009 study on 83,700 female subjects came to the conclusion that women who drank two or more cups of coffee a day had a 20% lower risk of stroke (stroke.ahajournals.org, ‘The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population’).
Similarly, a 2013 Harvard analysis of 36 studies performed on over 1 million individuals concluded that coffee consumption does not increase cardiovascular disease risks. At the same time, numerous papers show that the caffeine in coffee actually raises blood pressure levels, increasing heart disease risks, one of many issues which will be addressed in a following article on the side effects of coffee consumption.
3) Reduces diabetes risks. Various studies performed on large numbers of healthy subjects showed that daily coffee consumption reduced type 2 diabetes risks by 8%, 20% and even 50% or 67%, with differences being highly dependent on daily coffee intake. Although the exact mechanisms have not been identified yet, it is believed that the phenolic compounds in coffee (such as chlorogenic acid) are responsible for altering glucose metabolism which would translated in a lower type 2 diabetes risk.
Chromium and magnesium, two minerals found in coffee beans, are believed to help the body make better use of insulin, contributing to a lower type 2 diabetes risk as well. Caffeine on the other hand was found to play no part as subjects consumed both regular and decaffeinated coffee.
4) Helps treat headaches. The caffeine in coffee stimulates both nervous system activity and blood circulation and can help relieve minor and moderate pain caused by headaches and migraines.
5) Strong laxative properties. Caffeine was found to stimulate intestinal muscles to contract, facilitating the occurrence of a bowel movement and thus temporarily relieving constipation. However, coffee is also a mild diuretic which means it promotes the elimination of water from the body, including water that is supposed to make stools soft and easy to pass. So while it may send you to the bathroom, it will not relieve constipation like drinking water and eating fiber-rich foods will, nor will it really solve the problem.
6) Aids with depression management. According to recent findings, coffee consumption is said to help lower depression risks in women. A 2011 Harvard study registered a 20% lower depression risk among women who drank 4 or more cups of coffee daily. The mechanism of action probably has to do with the fact that caffeine inhibits adenosine levels in the brain, allowing for dopamine (and glutamate) levels to rise and for a better control over emotional responses.
However, coffee encourages the elimination of essential dietary minerals, notably magnesium, which may contribute to accentuating depression symptoms as severe magnesium deficiency has been directly correlated with higher depression rates.
7) Boasts anticancer properties. Avid coffee drinkers have been found to have an overall lower risk of developing liver, colon and invasive prostate cancer as a result of the antimutagenic properties of coffee and coffee beans. But while part of the scientific literature advocates for the amazing anticancer properties of coffee, there are studies that show the drink also exhibiting mutagenic effects. Coffee may also increase the risk for estrogen induced cancers.
8) Does not influence overall mortality risks. An 18 and 24 year-old follow up study showed that moderate coffee consumption does not increase overall mortality risks, according to a June 17th, 2008 study published in the Annals of Internal Medicine (‘The Relationship of Coffee Consumption with Mortality’). This study counting 41 736 men and 86 214 women hopes to appease the harsh accusations of coffee consumption opponents and possibly stop the damage the coffee industry has been suffering lately. However, despite such an impressive list of health benefits, emerging research shows that the dangers of coffee consumption are just as varied and noteworthy as the health benefits, ranging from miscarriages and insomnia to infertility and even increased stroke and cancer risks.