Coffee is one of the most widely used, and well known herbal beverages available. It's the second leading export product in developing countries after oil and its production employs over 25 million people in over 60 countries .
As such, it comes in a massive amount of variety with different flavours, styles, and combinations with other substances depending on where it's sold. We're all familiar with lattes, cappuccinos, long and short black's, espresso shots, and many of the other forms in which coffee is found. At the base of all this, is one herb. The coffee plant (Coffea arabica).
There are a few different species of coffee, but the most common are arabica and robusta. Arabica is more preferred for its flavour and is by far the most popular species world wide. Robusta has a less favourable taste, but contains more caffeine (which may be more important so some people!). Coffee brands that market themselves as a high energy coffee, often use this species, or a mix between the two, but generally speaking the best quality coffee is in fact Coffea arabica.
Coffee originated in Ethiopia, but has spread the world over due to the high demand for this delicious stimulant. To this day it competes with tea for the most widely consumed stimulant in the world.
Coffee is highly regarded by many people in the modern world for its wonderful flavour, however, this amazing seed happens to have a wide range of medicinal actions.
The benefits of coffee include reducing mental fatigue, increase athletic and cognitive performance, prevention of Parkinson's disease and type 2 diabetes, improves low blood pressure, combats gastrointestinal, lung and breast cancers, reduces headaches, supports weight loss, and manages ADHD.
Some recent studies have shown that long term coffee consumption is associated with a longer lifespan .
Justin Cooke recommends a healthy intake based off his own research to be between 2 and 6 cups a day, though some other studies suggest more specifically to consume between 3 and 4 per day.
- Vasodilator (with tolerance)
- Vasoconsrictor (Without tolerance)
- General health tonic
Other species includes:
Syn: Coffea canephora, Coffea bukobensis
Syn: Coffea arnoldiana
Dried roasted seed, green raw seed, berry shell, leaves
2-6 cups of brewed coffee a day over a long period of time is best.
- Maintain wakefulness
- Liver detoxification
- Low blood pressure (Short term)
- Altitude sickness
- Narcotic poisoning
- Heart disease
- Decrease inebriation
- As a diuretic
- Prevent onset of diabetes (Type 2)
- Coffea arabica L.
- Coffea robusta
Coffee use dates back thousands of years in Ethiopia where it originated. It was initially restricted to the Arab world, and was primarily grown in Yemen around the 15th century. Sufi religious practices (related to Islam) promoted the popularity and spread of coffee in this time. This religious group used coffee as a way to promote wakefulness and trance-like states in their ceremonies, which often lasted all night. .
After domestication, it became popular among the Arab world within about a century. By this time, its spread was due less by religious practices, and more by the new social concept of coffeehouses. These became (as they still are) a place for people to meet and socialize over coffee. During this time it was a practice exclusive to men. Women were socially excluded from all of these establishments. By the end of the 17th century, Cairo had become the central coffee market for the far east. .
Coffee was introduced to Europe through European travellers passing through Arab cities. This is quite different from many of the other traditional and medicinal plants introduced into Europe, which were mainly introduced through brutal colonial conquest instead. Upon introduction to European culture, it was reserved for medicinal use, however over time people began to develop a taste for the beverage and coffee consumption took off with the general population and soon became commonplace in the home. Coffee Shops popped up all over Europe, as they adopted the Arab practice for themselves. .
Coffea arabica, is an evergreen Shrub, growing to about 5m tall. Leaves are opposite, large, elliptical, glossy, and dark green. The flowers are white, and produce a fragrance reminiscent of jasmine. The fruit is classified as a drupe, that is elliptical, and about 1.5cm long. They start green, and gradually ripen to a bright, or dark red color .
C. arabica prefers tropical climates, with high amounts of rain, and little or no frost .
Habitat, Ecology, Distribution:
Indigenous to mountainous areas of Yemen, and Ethiopia, growing at altitudes of about 1400-1800m. Cultivation, and subsequent naturalization has occurred throughout the world including Indonesia, South America, Central America, The West Indies, and India . The coffee belt, it the aptly named range of latitudes where coffee can be grown to produce high quality coffees. This belt goes from 25 degree north to 30 degrees south and covers many parts of central and South America, Africa, the Middle East, Indonesia, Australia, and Asia.
Harvesting, Collection, and Preparation:
Depending on where coffee is grown, the flavour profile will change, altitudes, humidity, soil conditions, and growing techniques will all influence flavour. Generally the best species to use for flavour is arabica, which is grown world wide. Each region tends to offer its own general characteristic, however this can also vary quite a bit within the region.
Coffee takes about 3-4 years for the coffee plant to produce berries, after which yearly harvests generally take place. The berries ripen at different times throughout the plant, which makes harvesting a very long and intensive process where harvesters must pick the fruit by hand over the course of a few weeks.
The processing of coffee generally consists of drying, and roasting. Which is very similar to the other famous caffeine containing stimulants such as yerba maté, tea, and guarana. This process is suggested to reduce the bitter flavour, add a roasted flavour, prevent further oxidation of the polyphenols through destruction of the enzymes responsible, and free the caffeine and other xanthine alkaloids from the chlorogenic acids. In doing so, the constituents of the seeds change.
Caffeinated coffee is an incredibly complex beverage, containing well over 1000 components. The most important are suggested to be caffeine, diterpene alcohols, and chlorogenic acids. [30, 31].
The major xanthine alkaloid found in Coffea spp. (seeds) is caffeine, but also contains theobroma, and theophylline in varying amounts depending on the species . One species however Coffea liberica, is different in that its major xanthine alkaloid is theacrine, liberine . The leaves are suggested to include even more caffeine than the seeds and are sometimes consumed as a tea .
The most commonly consumed species however, Coffea arabica, which contains about 0.4-2.5% caffeine in its seeds [2, 62]. Coffea spp. is considered to contain about 3.5% tannin, and 1.25% trigonelline as well (supposedly contained at similar levels as caffeine but unstable and degrades during heating, into pyridines that also provide coffee flavor). While the coffea seeds are being roasted, the caffeine is liberated from the inactive combination with chlorogenic acid. The signature aroma of coffee is due to the caffeol (50% furfurol, traces of valeranic acid, phenol, and pyridine). Herbalist Terry Willard suggests this is what causes the unwanted hangover from coffea.
Caffeine is synthesized in plants as a method of chemical defense in the plant and often builds up in the seeds, leaf edges, and sometimes in the stems depending on the species . It can be found in 13 orders of the plant kingdom. Somer other well known plants containing this chemical includes the tea plant (Camellia sinensis), guarana (Paullinia cupana), and yerba maté (Ilex paraguariensis). Caffeine is considered a xanthine alkaloid, which begins as xanthosine, and is converted in the plant to 7-methylxanthine, and subsequently theobromine. This chemical is very similar to caffeine and is contained in high amounts in other stimulating plants such as cacao theobroma. In the coffee plant, this theobromine undergoes another conversion to become caffeine. . The molecule itself is highly soluble in solvents such as chloroform, but only slightly soluble in water and ethanol .
Green coffee seeds are very rich in chlorogenic acids (6-10% dry weight), and contain the largest variety (72), plus 3 separate cinnamic acids . This chemical is found in much higher amounts in green coffee beans than roasted coffee. This chemical supposedly bonds to caffeine making it inactive, and upon heating these chemicals are released and thus the caffeine becomes active. It is considered a phenol, specifically, an ester formed between caffeic-acid and L-quinic acid. It is also suggested to have mild hypotensive effects. .
Green unprocessed coffee beans contain a rich source of polyphenols (especially 5-, 4-, and 3-O-caffeoyl quinic acid), as well as the alkaloids trigonelline and caffeine. Upon roasting, chlorogenic acids undergo significant degradation which results in a new set of products including caffeoyl quinides, caffeic acid, and catechol. Trigonelline degradation breaks down into N-methyl-pyridinium and niacin, but still remains in fairly high amounts in even highly roasted espresso coffee beans (~5.3mg/g). Trigonelline and N-methylpyridinium are readily absorbed after coffee consumption and reach peak plasma levels after 2.5 and 1 hours respectively. Caffeine is fairly heat stable and remains mostly intact upon heating. .
Caffeic acid is also found in coffee but only in modest amounts (0.03mg per 100 ml). It can be found in a wide range of other botanicals. Despite the similarity in its name, caffeic acid is unrelated to caffeine. It possesses its own range of medicinal effects including antioxidant, immunomodulatory, anti inflammatory, anticarcinogenic (controversial).
Caffeol is an umbrella term for the aromatic constituents of coffea, that give it the signature aroma. Caffeol is made up of many constituents (roughly 850 different volatiles constituents), most of which are formed during the heating (roasting) process. Consists mainly of furfuryl alcohol. It is formed from the degradation of sugars, and pyrolysis of woody fibers.
Coffee contains: Oil, wax, caffeine, aromatic oil, tannic acid, caffeotannic acid, gum, sugar, protein. .
Caffeine is absorbed quickly, and efficiently through the digestive tract and rectal mucosa (Barceloux et al., 2009). It is measurable in blood serum as soon as 5 minutes after consumption, and reach peak absorption levels in the blood as soon as 30-60 minutes [2, 64]. Within about 6 hours in healthy adults, caffeine has been broken down into secondary metabolites (namely paraxanthine), through the cytochrome P450 in the liver, and subsequently excreted through the kidneys. After intake, caffeine, is demethylated through cytochrome P450, yielding the secondary metabolite, paraxanthine, making it the chief metabolite of methylxanthines in the body . Small amounts of caffeine (<10%) is excreted unmetabolized in the urine, which is the near exclusive mode of excretion of caffeine .
Paraxanthine is not produced by plants and is only observed in nature as a metabolite of caffeine, theobromine, and theophylline in animals. This metabolite, has been shown to produce a wide variety of actions throughout the body, many of which are similar to caffeine, theobromine, and theophylline. These effects include adenosine receptor antagonist, lipolytic effects, Competitive nonselective phosphodiesterase inhibitor, increase in Ca2+ in muscle, and effects on Na+/K/ATPase. [2, 8].
Pharmacology and Medical Research:
Effects on Altitude sickness
Still compiling research.
Caffeine has been fairly well studied in its effects in the prevention of Alzheimer's disease. It has been found through murine animal testing to pass the blood–brain barrier and inhibit γ-secretase initiated cleavage of amyloid precursor protein, which is considered a key process in accumulation of aggregated plaques of Aβ in the brain . Alzheimer's is characterized by an accumulation of beta-amyloid deposits which build up over time, and lead to the eventual death of the synapse. Several cohort and case studies have suggested a clear relationship between regular coffee consumption and a lower incidence of Alzheimer's . More recent studies have suggested a significantly higher activity in roasted coffee when compared to pure caffeine . This suggests a synergy between other components of coffee in regards to the prevention of cognitive decline and Alzheimer's. This synergy has also been found when investigating neuro-inflammation in mice. It was discovered that caffeine combined with polyphenols had a much stronger effect in reducing and preventing neuro-inflammation than the pure alkaloid .
Diabetes is the 4th leading cause of death in industrialized countries, and affects roughly 177 million people world wide resulting in about 4 million deaths per year. This number is expected to double by 2025 if current trends continue. [40, 41].
There have been hundreds of studies within the past 20 years on coffee in relation to diabetes, with most of them occuring in the past 10 years. The overwhelming majority of these studies have indicated that regular, moderate consumption of coffee reduces the risk of type 2 diabetes. These effects are noted to be independant of race, gender, and ethbicity, and geographic distribution. In fact these studies were conducted all over the world with many different ethnic backgrounds and geographical distributions. .
More specifically, regular, moderate coffee consumption has been shown to produce a lower prevalence of impaired glucose tolerance, hyperglycemia (fasting and after glucose load), hyperinsulinemia, and insulin sensitivity [43-46]. It has been found to have a poitive association with adiponectin as well, which is a hormone that regulates the catabolism of glucose and insulin sensitivity. This hormone is reduced in diabetics and thus is considered a protective agent against diabetes. [47-49]. Other factors that may be at play with the mechanism of action of coffee is through thermogenic effects of caffeine (increase in energy expenditure and metabolism), [50,51], and increases satiety (feeling of being full) [52,53].
The alkaloid trigonelline, which can be found in relatively high amounts in green (unroasted) coffee beans, and in smaller amounts in roasted coffee beans, is also found in the herb Trigonella foenum graecum. This herb is a traditional medicine that has commonly been used to treat diabetes, and contains substantial amounts of this trigonelline alkaloid. This same alkaloid, extracted from pumpkin seeds, has been found to produce anti-diabetic actions in mice, but has not had any testing done in this regard on humans . It is possible, that this alkaloid is at least partly responsible for the preventative effects on type 2 diabetes, although clearly more research is needed in this area.
Short term effects of the caffeine contained within coffee actually cause an increase in blood pressure, however once tolerance is established, and modulation to the adenosine receptors is established, regular coffee consumption actually offers antihypertensive effects instead. Aside from many of the effects noted in the following section n cardiovascular effects, coffee contains compounds other than caffeine that offer blood pressure control such as flavonoids, melanoidins, magnesium, and potassium .
Coffee is an extremely rich source of antioxidants. It contains a good supply of phenolic compounds (200 mg - 550mg/cup). The main phenolic compound in coffee is chlorogenic acid , and melanoidins [58,59]. Caffeine has also shown a mild antioxidant effect [58, 59]. In a few different studies, brewed coffe has shown significant ntioxidant capacity, and is noted to be highly bioavailable [60,61].
In the past, coffee has been suggested to produce negative effects on the cardiovascular system, however more recent studies (past 5-10 years) it has actually been shown to produce the exact opposite, offering positive effects on the cardiovascular system in various ways. These older studies likely derived this suggestion through some of caffeine's short term effects, which includes an increase in blood pressure, and increase in anxious feelings and jitteriness, which could easily be perceived as a negative side effect especially with the surge in high blood pressure over the past century. However, these effects are subject to a fast developing tolerance, whereby modulation of the adenosine pathway (from which these original changes occur), causes these effects to be negated. Once a tolerance is developed, the long term benefits of coffee far outweigh the short term negative side effects.
There are an ever increasing number of recent studies that have demonstrated either a neutral, or beneficial effect on cardiovascular health from the long term consumption of coffee [12-29].
Some of the beneficial effects caffeine and its metabolites has on the cardiovascular system is through their actions on adenosine inhibition. Through this action these alkaloids have been found to improve renal function and enhance the action of diuretics, both of which directly lowers blood pressure .
Chlorogenic acid (another caffeine metabolite) are potent antioxidants as well, and improve endothelial and vascular function through increased availability of nitric oxide . These actions have a significant positive effect on the cardiovascular system, and likely play a role in the prevention of developing heart disease over the long term.
Decaffeinated coffee has not been found to deliver the same benefits on the cardiovascular system, however this may be due to the lack of scientific research in this area, as most of the study on coffee is done on the caffeinated, roasted or raw coffee beans .
There has been suggested a U shape association with the safe, and beneficial consumption of coffee. People who drank very little or no coffee (less than 2 cups a day), or excessive amounts of coffee (over 10 cups a day) had a higher incidence of high blood pressure, and cardiovascular disease than did medium-high coffee drinkers (3-6 cups a day). Therefore it is suggested that the safe and therapeutic dose with regards to cardiovascular disease is between 3-6 cups of coffee a day, over a long period of time.
Coffee is well known as a cognitive enhancer, however a recent study conducted on the effects of caffeine on cognitive performance  discovered surprisingly that caffeine does not offer any improvements in cognitive performance, but on the other hand has a negative effect on cognitive performance if chronic consumption is stopped. They noted that the likely perceived benefit on cognitive performance from caffeine, and subsequently coffee, is through reduced sleepiness rather than increased alertness. It was found that people who consume caffeine in medium to high amounts had almost no difference in anxiety, mental alertness, and cognitive performance after consuming caffeine. Non or low caffeine users had an increase in anxiety and wakefulness, however also did not have a significant increase in cognitive performance in this study.
It appears that if coffee really does improve cognitive performance, it is not due to the caffeine content, and may in fact simply be a perceived cognitive improvement due to a mere reduction in sleepiness instead.
One study found that with daily consumption of three or more cups of coffee, patients with HCV-related liver disease is associated with a significant (50%) reduction in oxidative damage indicators (8-OHdG). Oxidative DNA damage is closely correlated with DNA mutation and carcinogenesis. Therefore these results show a positive correlation between coffee consumption and a reduced risk for advanced liver damage [34-36].
In a different randomised study on patients with hepatitis C, found that by drinking 4 cups of coffee a day resulted in reduced collagen synthesis and oxidative DNA damage. This study also noted an increase in both telomere length and level of circulating markers for apoptosis. These are all markers for protective factors in liver disease. [34, 37, 38].
Both of these studies suggest a hepatoprotective effect in the progression of liver disease, especially liver cancer, and hepatitis, but also likely offers protective benefits in such conditions as fatty liver disease, and cirrhosis.
Caffeine, once metabolized into paraxanthine, has been shown to act as an adenosine receptor agonist, which in turn leads to an increase in epinephrine, which is a powerful vasoconstrictor. This will lead to an increase in diastolic blood pressure. This mechanism is subject to tolerance however, and has been noted that the acute hypertensive effects of caffeine stop occurring through consistent use of the herb. In fact, in one study, researchers noted that 100-200mg caffeine produces symptoms in non caffeine users, with tolerance noticed in 1-4 days, and generally, moderate doses of caffeine (250-300mg) do not produce clinically significant cardiovascular alterations in people who consumed caffeinated beverages often . This tolerance is suggested to be through changes in the adenosine signalling pathway after repeated exposure to caffeine in order to combat these effects .
Weight Loss Supportive
Paraxanthine is also held responsible for the lipolytic properties of caffeine. As paraxanthine levels rise in blood plasma, levels of free fatty acids rise with it . Other studies have confirmed coffees ability to stimulate thermogenesis in humans as well , and coffee has also been shown to increase satiety [52,53], which in turn promotes smaller and less frequent meals. These effects were noted to be dependant on caffeine, but were also significantly increased with the presence of chlorogenic acid [55-57].
Caffeine appears to be the agent responsible for the athletic performance enhancement effects of coffee, and despite the development of a tolerance for many of the effects of this chemical, it appears to maintain its ability to improve physical performance in both non and low caffeine consumers, as well as medium to high consumers .
The sodium ion pumps located throughout the body, are found especially in nerve and muscle cells, and are used to change the concentration gradients on the inside and outside of the cells in order to produce a charge. Paraxanthine acts as an enzymatic effector of Na+/K+ ATPase, effectively increasing this activity and thus lowering plasma K+, which is associated with skeletal muscle fatigue .
Paraxanthine was shown to produce dose dependant increases in Ca2+ in skeletal muscle. This effect was transient, and also associated with theophylline, and theobromine. These effects were successfully reduced using a calcium channel blocker (procaine 10mM) .
Coffee's stimulant effects are mainly due to the xanthine alkaloids present, particularly caffeine. This alkaloid works as an antagonist to the adenosine A1, and A2A receptors, which results in a variety of physiological and behavioural effects. Some of these effects include wakefulness, increased blood pressure, tremors, mildly anxiogenic, and enhances physical performance .
These effects are suggested to be subject to a tolerance however, as with repeated exposure to caffeine, changes to the adenosine signalling pathway develop in order to oppose its effects. This explains some of the negative side effects of caffeine withdrawal which includes lowered mental alertness. This is an area highly disputed however and more research is needed to determine the exact mechanism of action involved with caffeine tolerance. .
Toxicity and Contraindications:
Although coffee has a low potential for abuse, it does lend itself to dependency, as seen when frequent users who cease consumption experience negative withdrawal effects. This is seen with caffeine in general and not necessarily specifically with coffee. The effects of this withdrawal includes lowered mental acuteness, and headaches, which may persist for a few days before returning to normal .
The caffeine contained in coffee has been found to produce anxiolytic effects, and jitter. These effects were only noticed in people who did not regularly consume caffeine, and were absent in people who consumed a source of caffeine regularly. It appears that in regular coffee drinkers (or other sources of caffeine), these adverse effects are avoided due to a development of a tolerance. .
Consuming coffee (or any caffeine containing herb), will have acute side effects such as nervousness, mild anxiety, and jitters if consumed in a high enough dose. It takes a few days of consumption for the body to develop the desired tolerance in order to recieve the most benefits from coffee.
Do not rely on coffee to keep you awake when operating a motor vehicle, as stated above, wakefulness is promoted, but actual concentration ability is not improved by caffeine.
Still compiling research.
A 200µg/ml dose of T. panurensis extract was shown to inhibit uo to 40% of uric acid production, possibly prolonging the effects of caffeine and its derivatives. (Source).
- The Sunlight Experiment
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