Coffee is the second most popular drink in the world, after water. People drink coffee for the taste and the boost provided by the caffeine. Although coffee drinkers usually don’t consciously think or care whether it is healthy or not, coffee has over time become a subject of medical research and studies.
While coffee seems to have therapeutic benefits, it depends on the brew and how you drink it. Drinking it doused with milk, creamer, sugar, sweeteners and flavourants, however, takes away many of these benefits.
There are many varieties of coffee available, as various cultivars of coffee trees are grown in different climates and soil conditions around the world. Arabica is a more expensive coffee species than Robusta, which is easier to grow, but Robusta is regarded as a lower quality bean with a harsh taste and with a higher caffeine content. Arabica beans offer a wide variety of taste characteristics with more nuanced flavours when roasted, but is a cultivar that is more difficult to cultivate.
The most expensive coffee in the world is called kopi luwak. A cat-like animal, the civet, is indigenous to Indonesia and feeds on coffee cherries. The coffee cherry and pulp are digested, but the coffee seeds remain intact and undergo unique fermentation during the digestion process. The civets’ feces are collected by farmers and then washed, dried, sorted and roasted. This unique fermentation process gives kopi luwak its distinct flavour.
Many factors play a role in the taste of your brew, such as different species, different blends, different origins, and different roasts. The taste is further influenced by the age of the coffee, the processing method, the grind, and the brewing method.
About 80% of the world’s coffee is produced by 25 million smallholder farmers. The main coffee-producing countries by market share in 2017 were: Brazil (32%), Vietnam (18%), Colombia (9%) and Indonesia (7%).
The coffee tree is a tree shrub that bears fruit which are referred to as coffee cherries. The two beans found in the cherry are actually the seeds.
Some nations consume more coffee per capita than others, especially in colder climates, with Finland being the world’s top coffee consuming nation with an average of 12 kilograms of coffee consumed per capita per year, and followed closely by Norway and Iceland.
Which type of coffee offers health benefits?
Only quality coffee will offer any therapeutic benefits, with quality referring to organic whole-bean black coffee. Organic coffee means it is pesticide free, as most commercially produced coffee can be heavily contaminated with pesticides from crop spraying. It is also best to buy whole-bean coffee and grind it yourself to ensure it is fresh and not rancid. Coffee should be properly dried and roasted, and an indication of rancidity and poor quality is coffee that does not have a pleasant aroma. For the most health benefits, coffee should be consumed black and without sugar or sweeteners. Also use non-bleached filters in drip machines, as the bright white filters may contaminate the coffee with the chlorine used as bleach.
Which is healthier – dark roast or light roast coffee?
Light roast and dark roast coffee are quite different in taste, flavour and complexity.
Light roast coffees have a light brown colour and light taste. When the coffee beans are lightly roasted it reaches an internal temperature of 180ºC – 205ºC. Dark roasted coffees have a dark brown colour with a smoky, bitter taste when brewed. Dark roasted coffee beans are roasted to an internal temperature of around 240ºC.
While the degree of roasting affects the taste of coffee, the roasting process also alters the chemical substance of the coffee beans, resulting in different health benefits for different roasts.
Chlorogenic acid is a potent antioxidant that is naturally found in green coffee beans (and incidentally also in black tea). (Antioxidants are substances that may prevent or delay some types of cell damage.) A Korean study done in 2017 has found that during the roasting process much of the chlorogenic acid is retained in a light roast, but mostly lost in a dark roast due to the higher temperatures. As a result a light roast has more antioxidants with anti-bacterial and anti-inflammatory properties.
A study done in 2011 has found that dark roast coffee is rich in N-methylpyridinium ions (a chemical compound formed during the roasting process), which improve the antioxidant status of the hormone erythropoietin, secreted by the kidneys, that stimulates red blood cell production. N-methylpyrdinium also restores blood levels of the antioxidants vitamin E and glutathione (an antioxidant that is capable of preventing damage to important components of the cells in the body). N-methylpyridinium ions are deemed to also have anti-carcinogenic properties, which means a tendency to inhibit or prevent the development of cancer.
In summary, a light roast preserves the anti-inflammatory properties of coffee, while a dark roast, with its higher levels of N-methylpyridinium, improves the anti-oxidant status of the body.
Other health benefits of coffee:
Research has linked coffee to various health benefits, not only from the ingredients mentioned above, but also from the non-caffeine components, which include multiple nutrients.
- A Dutch study with 17 000 men showed that those who consumed 7 or more cups of coffee per day had a reduced risk for developing Type 2 diabetes.
- A study undertaken by Harvard University with 80 000 women has found that those who consumed 4 or more cups of coffee per day had a 28% lower risk of developing gallstones, while consuming one cup per day did not reduce the risk significantly.
- A Japanese study found that those who consumed coffee daily had about half the risk of hepatocellular carcinoma (a type of liver cancer) than those who never drink coffee.
- A study of nearly 50 000 men showed that men who drink 6 cups of coffee per day had a 60% lower risk of lethal prostate cancer, while those who consumed 3 cups per day had a 30% reduced risk.
- Studies have linked the regular consumption of coffee with lower rates of conditions such as dementia, Parkinson’s disease, stroke and heart rhythm problems.
- Coffee can help to curb sugar cravings, by binding to the opioid receptors in the brain, which are part of a primordial reward system. The modern Western diet is high in processed foods, which are loaded with sugar, and this has led to the opioid receptors becoming addicted to unhealthy foods, such as sugar. The caffeine in coffee can bind to the opioid receptors, occupy them and prevent you from becoming addicted to something else.
The caffeine kick:
Caffeine is an odourless (the typical flavour of coffee comes from the roasting) natural ingredient in the green coffee bean and is also found in plants such as tea, cocoa and kola. Caffeine is water soluble and is extracted during the brewing process. It is quickly absorbed and enters the blood stream through the lining of the mouth, throat and stomach.
Caffeine is a psychoactive stimulant that speeds up the central nervous system. As such it can be viewed as an unregulated drug, although it is generally recognized as safe. Caffeine tolerance and its effects varies by individual, for example some people have no trouble sleeping after a cup of coffee, while others are unable to sleep soon after drinking coffee. For most people the caffeine in coffee results in enhancing their mood, increased alertness and improved ability to concentrate. Some people are sensitive to caffeine and it can cause headaches, irritability, jitters and insomnia.
Large amounts of pure caffeine, in the region of 1 gram (1 000 mg) for an adult, can be viewed as toxic. Fortunately the average brewed cup of coffee contains only about 120 mg of caffeine and in its natural form.
Caffeine content of different brews:
As caffeine is water soluble, hot water acts as a solvent to extract it into the brew. The ideal water temperature is near-boiling (95-105 ºC).
As Expresso is highly concentrated and consumed quickly, the caffeine is rapidly absorbed. This leads to the common belief that expresso has a higher caffeine content than a drip cup of coffee. The fact of the matter is that a double shot of expresso contains about 80 mg of caffeine, while a drip cup contains about 120 mg of caffeine, Because it is consumed slower than expresso, the immediate effect is different.
Virtually all the caffeine gets extracted during the first minute of the brewing process, while the caffeine gets extracted faster with a finer grind as there is a greater contact area.
Depending on the method of measurement, ground dark roast may have a slightly higher caffeine content than light roast. Bean for bean the light roast and the dark roast would have similar levels of caffeine. However, the beans lose some mass and density during the roasting process, and more so in the case of dark roast. This means that dark roast beans are lighter than light roast and if you weigh your measure of coffee, dark roast will have more caffeine as there will be more beans than in the equivalent measure of light roast. If you measure the coffee by scoop (meaning volume and not mass), the light roast will have more caffeine. These differences in caffeine content are minimal.
Drinking quality coffee:
Drinking organic whole-bean black coffee is an acquired taste, but to get the full health benefits, gradually reduce the amounts of milk and sugar over time. Once you get used to the taste of pure black coffee, anything you add to it will be guaranteed to spoil the wonderful flavor of good coffee.
Sources:
Dark roast coffee is more effective than light roast coffee in reducing body weight, and in restoring red blood cell vitamin E and glutathione concentrations in healthy volunteers. Published October 2011, 55(10): 1582-6. National Center for Biotechnology. U S National Library of Medicine. National Institutes of Health. (www.ncbi.nlm.nih.gov)
Can drinking dark coffee improve your health? Published online 18 August 2011. Dr. Mercola. (www.mercola.com)
Light roast vs dark roast coffee: Which packs more health perks? Published online 21 June 2017. Health. (www.health.com)
Is dark or light roast coffee healthiest? Published online 18 July 2017. Gamble Bay Coffee. (www.gamblebaycoffee.com)
No, dark roast coffee isn’t stronger than light roast. Published online 17 April 2017. Insider. (www.thisisinsider.com)
Chlorogenic acid in coffee. Comprehensive Natural Products 2010. ScienceDirect. (www.sciencedirect.com)
Chlorogenic acid: health benefits, possible side effects & risks. Published online. Consumer Health Digest. (www.consumerhealthdigest.com.)
10 Things you probably didn’t know about coffee. Published online 17 December 2018. Business Insider. (www.businessinsider.co.za)
Coffee. Annual Report 2017. IDH – The Sustainable Trade Initiative. (www.idhsustainabletrade.com)
HEALTH INSIGHT
January 2019