Coffee is the second most popular beverage in the world after tea and water. It is consumed from the comfort of one's home to sumptuous restaurants. There are countless ways to prepare coffee and its varieties, and its taste, smell, and appearance vary depending on the variety. It is no exaggeration to say that most people cannot imagine a morning or even a whole day without it. About 3 billion cups of coffee are consumed worldwide every day, and in Poland, coffee consumption fluctuates between 1 and 1.5 cups per day per inhabitant of our country. It is valued for its stimulating effect and a range of health-promoting properties. However, amidst all this coffee turmoil, unroasted green coffee is increasingly standing out and will be today's heroine.
What exactly is coffee?
Coffee is nothing more than the fruit of the coffee tree. These are evergreen trees and shrubs that grow primarily in Africa, South America, and Asia. According to historical sources, coffee was already known in Africa around 550 AD. Currently, up to 104 unique coffee varieties have been classified. Depending on the variety and weather conditions, the taste of coffee can vary. The roasting process and brewing time, as well as the brewing method, all have an influence {1,2).
Roasted coffee
The actual process of roasting coffee is important for its flavor and nutritional content. Coffee roasting takes place at a specific temperature and under controlled conditions. It's worth noting that this depends on the coffee variety, its acidity, the grain size, and the roaster themselves. This extracts the coffee's intense flavor and aroma. Furthermore, the coffee's acidity decreases during this process.
Properties of roasted coffee
The first thing that comes to mind when you hear the word "coffee" is undoubtedly caffeine. In fact, it's estimated that a single shot of espresso prepared with ground coffee contains about 100 mg of caffeine, and the therapeutic dose is 200 mg. This substance is a common ingredient in medicines and preparations for migraines, asthma, analgesics, and stimulants. As for minerals, coffee doesn't contain any vitamins, but it does contain micronutrients such as sodium, potassium, magnesium, and calcium.{3}
It improves memory and concentration through substances such as the aforementioned caffeine, theobromine, and theophylline. Their influence on the nervous system cannot be overestimated, as they accelerate the transmission of nerve impulses in the brain. Furthermore, it supports memory processes, especially short-term memory, shortens reaction time, and facilitates concentration. Also worth mentioning is the effect of coffee on weight loss. Caffeine accelerates metabolic changes and can therefore be a complement to a healthy and balanced diet aimed at reducing body weight{3}.
The use of coffee in medicine
It can also be helpful in certain diseases, including Alzheimer's disease, Parkinson's disease, and type 2 diabetes.
Researchers at the University of Illinois at Chicago (USA) conducted extensive research into the relationship between Parkinson's disease and Alzheimer's disease and coffee consumption. They showed that the risk of these diseases decreased significantly if you consumed three cups of ground coffee daily. Statistically, these diseases appeared eight years later in coffee drinkers than in non-drinkers (aged 64 and 72). This phenomenon was more pronounced in men than in women, and, furthermore, increased coffee consumption beyond three cups did not reduce the risk of these diseases any further.
Allergies and asthma
The latest research on caffeine also reports that it may be an interesting addition in the treatment of asthma and allergies. Caffeine has been shown to reduce histamine levels, which are responsible for the allergic reaction, and, during asthma attacks, its beneficial effect is attributed to bronchodilation. This reduces attacks and shortens their duration.{3}
As far as minerals are concerned, coffee basically does not contain vitamins, but it does contain micronutrients such as sodium, potassium, magnesium and calcium{3}.
Coffee and magnesium
This article could not ignore the eternal question, namely, does coffee “leach” magnesium?
It is widely believed that coffee flushes magnesium from the body. Yes, after drinking coffee, there is a slightly increased excretion of magnesium in the urine, which lasts for several hours. Caffeine is responsible for this. However, this action should not be demonized. Remember that coffee also contains magnesium and, more importantly, it provides more than it excretes. It is estimated that 100 grams of brewed roasted coffee provides 7 to even 24 mg of this element{4}.
Its increasing popularity is due to a return to nature and a healthy lifestyle. It has been found that green coffee can have even greater beneficial effects on the body than roasted coffee. This is all due to the lack of nutrient loss during the smoking process. This applies primarily to antioxidants and chlorogenic acid. It is also found in potatoes, eggplants, and tomatoes, but in tea and coffee, it is present in much higher concentrations. Unfortunately, the amount of phenolic compounds decreases during smoking at high temperatures. It improves the reactivity of blood vessels and can have a positive effect on carbohydrate metabolism, which is important in the prevention of diabetes and obesity, as well as metabolic syndrome.
What does green coffee taste like?
The taste of green coffee can be compared to green tea. It also depends on the variety. However, it is generally lighter, more bitter, and more acidic than roasted coffee. The caffeine content is almost identical to roasted coffee, as this alkaloid is not affected by the temperature or time of the roasting process.
Effects on carbohydrate metabolism
Maintaining normal blood glucose concentrations is one of the fundamental mechanisms influencing body homeostasis, and is even more important for people suffering from diabetes. The chlorogenic acid contained in green coffee has the effect of reducing glucose absorption from the digestive tract by up to 80%. Furthermore, due to this property, it lowers the glycemic index of foods, but only when ingested orally. Green coffee bean extracts also have a similar effect. After administering 1% chlorogenic acid extract to rodents, blood glucose levels decreased by 43% {5}.
Effect on blood pressure
High blood pressure is a problem that affects an increasing number of people, and its ineffective treatment significantly increases the risk of sudden cardiovascular events. Studies have shown that green coffee extract can be helpful in reducing high blood pressure. They were conducted on rats, and after administering this extract, its blood pressure-lowering effect was observed. It is worth noting that similar experiments have also been conducted on humans. Green coffee extract also showed a similar effect on our bodies. This was likely due to increased nitric oxide (NO) secretion and, consequently, vasodilation. There is also a theory that chlorogenic acid in green coffee extract lowers cortisol levels, which is otherwise called the "stress hormone." Its excess leads to a decrease in the amount of nitric oxide and, consequently, vasoconstriction and an increase in blood pressure.{6}
Contraindications
The research also examined whether green coffee, its extracts, and chlorogenic acid itself could cause side effects. In the vast majority of cases, these effects were ignored, and these substances were considered safe. However, there are a few cases in which one should not overdo it with green coffee. First, high caffeine intake can increase the risk of complications in people with diabetes and insulin resistance. The key here is to choose versions of green coffee that do not contain caffeine. Second, short-term and high doses of chlorogenic acid (over 2 g/day) can lead to an increase in homocysteine concentration and contribute to cardiovascular disease. The conclusion is simple: as with everything, moderation and common sense should be observed. {7}
Summary
Green coffee is currently gaining popularity, and a lot of water in the wort will pass through before it reaches the level of roasted coffee. In addition, its taste may be unacceptable at first, especially if we are used to the taste of this roasted. However, the effect of the substance it contains is considerable. It should also be remembered that its brewing is not the only way to provide chlorogenic acid or other health-promoting compounds it contains. There are many flavorless extracts and extracts on the market. They can be an interesting alternative to your daily diet. It should be remembered that this is not a medicine, but only a supplement for the possible treatment of the aforementioned conditions. Which does not change the fact that it is very helpful in this regard.
Bibliography :
- Geoffrey Burnie et al., Botanica: illustrated, in alphabetical order, describing more than 10,000 garden plants , Germany: Könemann, Tandem Verlag GmbH, 2005, ISBN 3-8331-1916-0, OCLC 271991134.
2 World Checklist of Selected Plant Families: Royal Botanic Gardens, Kew. [Accessed 03.12.2010].
- Zdrojewicz Z., Grześkowiak K., Łukasiewicz M., Is drinking coffee healthy?, “Medycyna Rodzinna” 2016, No. 3
- Jarosz M., Wierzejska R., Coffee drinking and the risk of type 2 diabetes, optimistic scientific reports, “Epidemiological Review” 2012, No. 66.
5. Li Kwok Cheong JD, Croft KD, Henry PD, Matthews V, Hodgson JM, Ward NC. Green caffeine polyphenols do not attenuate features of metabolic syndrome and improve endothelial function in mice fed a high-fat diet. Arch. Biochem. Biophys. 2014;559:46-52.
- Revuelta-Iniesta R., Al-Dujail E. Consumption of green coffee reduces blood pressure and body composition by influencing 11b-HSD1 enzyme activity in healthy individuals: a crossover pilot study using green and black coffee. BioMed. Resolution Int. 2014; http://dx.doi.org/10.1155/2014/482704
- Olthof MR, Hollman PC, Buijsman MN, Amelsvorrt JM, Katan MB. Chlorogenic acid, quercetin-3-rutinoside, and black tea phenols are extensively metabolized in humans. J. Nutr. 2003; 133:1806
