Thanks to the bioactive molecules that it contains, coffee is more than just a hedonistic beverage – in addition to being a pleasure to drink, coffee can have a positive impact on our bodies and our health.
Before going into the details, a few general factors that can affect the beneficial properties of coffee must be taken into consideration:
- The composition of the blend that is being prepared. Specifically, the percentage of Coffea arabica and Coffea canephora (robusta) in a blend not only has an influence on the flavour but also on the effects that the coffee has on our bodies and health since the two species contain different amounts of active compounds.
- The technique used to prepare the beverage and the amount of ground coffee used per serving.
- Consumption of other beverages that contain bioactive molecules, particularly caffeine.
- Consumption of alcohol and tobacco while drinking coffee.
Bioactive molecules in coffee
In addition to being the best-known molecule in coffee, caffeine (discovered approximately 180 years ago) is also the most studied. As was mentioned above, the quantity of caffeine in a coffee depends on many different factors.
What is caffeine from a chemistry perspective?
Caffeine is an alkaloid (an alkaline organic molecule of plant origin) found in coffee beans. It is similar to theobromine in cocoa and theophylline in green tea. Coffee plants produce this substance for defence, primarily from insects. Caffeine is found not only in the berry, but also in other parts of the plant like the leaves, which are frequently attacked by pathogenic insects. Green Arabica and Robusta beans contain different amounts of caffeine, generally 1.2% and 2.4% respectively (and in certain cases more). Therefore the type of blend has a significant impact on the amount of caffeine consumed by the drinker. These percentages remain almost unchanged after roasting. In general, a properly prepared espresso (see section on preparation) made with 100% Arabica contains about 2.5 mg/ml of caffeine, while a hypothetical espresso made with 100% Robusta would contain approximately 3.8 mg/ml (1 mg = 0.001 g). When preparing espresso, professional machines force water through the puck of ground coffee in the filter holder. This allows numerous molecules found in the coffee, including caffeine, to be extracted. Compared to other preparation methods, like moka coffee pots and drip machines, espresso machines produce a “denser”, more concentrated coffee, but in a small quantity (about 25-30 ml). Since coffee prepared with a drip machine or moka coffee pot is served in larger quantities, the amount of caffeine consumed when drinking an espresso is actually smaller. When estimating the caffeine content of a coffee-based beverage, it is necessary to consider such factors as the ratio of coffee to water, the brewing time, the physical separation of the ground coffee, and the percentage of Arabica and Robusta. Taking these factors into consideration, it is clear that a mug of drip coffee or a cup of coffee prepared with a moka coffee pot contains more caffeine than an espresso.
Caffeine is absorbed in the stomach and the intestines and reaches the bloodstream in 30 to 40 minutes, with a peak at 60 minutes. Enzymes in the liver metabolize the caffeine and the metabolites are eliminated in the urine. The half-life of caffeine (the time it remains in the body is approximately 4 hours in an adult male. It was recently discovered that some people have a gene that slows the metabolism of caffeine. Effectively, people that have this gene in their DNA eliminate caffeine much more slowly.
Moderate daily caffeine intake (from 200 to 600 mg, or 4 cups of espresso) has NO toxic effect and allows the drinker to enjoy the beneficial effects of caffeine. In addition, caffeine is NOT addictive – the average drinker rapidly becomes accustomed to its effects, does not need to increase the “dose” and can give it up quickly.
Toxicity only occurs in extreme cases. Acute toxicity requires consuming 5 to 10 grams of caffeine (120 espressos in 30 minutes). Chronic toxicity (agitation, tremors, nausea, restlessness, irregular performance) requires prolonged daily consumption of a high quantity of coffee (consuming more than 800 mg of caffeine). Regular, moderate consumption has no negative effects. Moderate consumption is about 300 to 400 mg of caffeine per day, which equals about 4-5 mg of caffeine per kilo of body weight.
A point should be mentioned regarding decaffeinated coffee. Different methods are available to decaffeinate coffee. Hausbrandt has its coffee decaffeinated by leading companies in the sector in Italy. The technique utilized by these companies involves using a solvent that is a gas under normal atmospheric conditions, but under high pressure and temperature becomes a liquid with a strong affinity for caffeine, almost entirely extracting it from green coffee beans. Once the process is complete, the solvent is entirely removed and the decaffeinated coffee is roasted and ground like any other coffee. If the process is performed correctly, there is very little difference between a regular coffee and a decaffeinated coffee, aside from the caffeine content being close to zero. In addition, there are precise Italian and European regulations regarding decaffeinated coffee, and Hausbrandt verifies (through an accredited laboratory that conforms to UNI CEI EN ISO/IEC 17025:2005 standard) that every lot of decaffeinated coffee meets regulatory parameters and limits. The following regulatory parameters are verified:
- Analysis of residual caffeine content: no more than 0.1 % (Ministerial Decree 20/5/76 and subsequent modifications)
- Analysis of solvent residues – no more than 2 mg/kg in roasted coffee (Decree 4/8/11 No. 158 – Directive 2009/32/EC)
- Analysis of moisture content: no more than 11 % (Ministerial Decree 20/5/76 and subsequent modifications).
- Decaffeinated coffee is good, contains almost no caffeine and poses no health risk.
Antioxidants can be either endogenous molecules (synthesized by our bodies) or exogenous molecules (introduced through diet). They convert free radicals (very reactive molecules that are the primary cause of cell damage) into relatively harmless compounds, reduce the destructive potential of oxidizing substances and repair macromolecules that have undergone oxidation.
Free radicals form “by mistake” in our bodies and their danger lies in their reactivity. These molecules can oxidize cell structures, increasing both the speed of aging processes and the likelihood of developing chronic degenerative diseases like cancer.
Although the human body has defence systems, it is necessary to also maintain a healthy diet.
The most important antioxidants that we obtain from food are certain vitamins and two groups of compounds of plant origin – carotenoids and phenolic compounds. Phenolic compounds, chlorogenic acids in particular, comprise 6 to 10% of the dry weight of ground coffee. The phenolic compounds content varies from 200 mg to 500 mg per cup. Coffee contains 10 different isomers of chlorogenic acid. It is therefore not surprising that coffee is included in the list of the 50 products with the highest content of antioxidants, particularly phenolic compounds and melanoidins. Melanoidins are coloured substances that form during the roasting process. Since they are soluble in water, they are present in large quantities in coffee. In certain areas of the world, coffee is the primary source of melanoidin and therefore the primary source of antioxidants that are obtained through the diet.
It is worth noting that decaffeination has little effect on antioxidant content, so people who cannot tolerate caffeine can still obtain antioxidants by drinking decaffeinated coffee.
Finally, methyl pyridine rounds out this brief list of antioxidants in coffee. Methyl pyridine forms during the roasting process from trigonelline. It is an excellent antioxidant that can, in theory, defend the human body from certain types of tumours.
Cardiovascular diseases are one of the leading causes of death in the Western world and are directly connected to lifestyle.
In the past, coffee was considered a bitter enemy of the heart. However, this was because studies never took into account the patients’ lifestyle, including such aspects as sedentariness, alcohol abuse, smoking and an unhealthy diet.
Also, the type of coffee consumed must be taken into consideration – a cup of instant coffee may have very different effects on the body than a cup of espresso, since they contain different bioactive molecules. Finally, when studying correlations between the heart and coffee, it is necessary to consider whether the patient is a regular or infrequent consumer, since regular consumers develop a tolerance for the effects of caffeine (which begins after three days and is lost after one day). It should be pointed out that tolerance does not mean dependence.
Numerous studies have shown that excessive coffee consumption is dangerous, but “normal” consumption is not.
While research is still ongoing, the current results suggest that moderate coffee consumption (from 200 to 600 mg of caffeine, approximately 4 espressos) in a healthy person does not pose a serious risk of cardiovascular disease and in fact may have a protective effect.
- Coffee and blood pressure: moderate consumption of coffee, including caffeinated coffee, has no significant effect on blood pressure.
- Coffee and cholesterol: there is no link between coffee consumption and an increase in LDL cholesterol (bad cholesterol) in the blood.
- Coffee and diabetes: several recent epidemiological studies have demonstrated a close correlation between regular coffee consumption and a decreased risk of Type II diabetes, although the mechanism is not fully understood. In addition, coffee is a significant source of magnesium and therefore has a beneficial effect on glucose metabolism in the blood.
- Coffee and antioxidants: as a source of antioxidants, coffee defends against the oxidative damages of bad cholesterol, protecting the body from atherosclerosis and cardiovascular disease.
In the past, it was believed that coffee interfered with blood pressure and had an intense diuretic effect that could cause dehydration of the body. This is absurd since the studies only observed the subjects for a couple of hours after consuming the coffee, without considering the entire day. The increased amount of urine passed during the three hours immediately after drinking coffee is balanced with a lower amount passed during the rest of the day.
Coffee can be viewed as a source of minerals and it has even been demonstrated that coffee consumption is just another way to obtain the liquids and minerals that our bodies need.
It has been recognized that coffee has a slight “dietetic” effect when it is consumed without sugar, milk or cream.
Coffee is categorized as a “non nutritive dietary component”, meaning that it is not a significant source of nutrients or energy. A cup of coffee has about two calories (practically none). In addition, research has shown that moderate regular coffee consumption causes a 10% increase in metabolic activity (reducing the absorption of calories and increasing energy expenditure). This effect on the metabolism is even greater in slender individuals. It improves the use of fat as an energy source when performing physical work. This means that fat deposits in the body are burned to produce energy.
In short, coffee has a slight “dietetic” effect, even without taking into account the fact that by feeling less tired coffee drinkers are able to perform more physical activities and therefore expend more energy.
- Coffee and the stomach: Caffeine stimulates the production of saliva (an initial stage of digestion in the mouth), the secretion of stomach acid (promoting faster digestion), the secretion of bile and intestinal motility. Overall, it contributes to better and faster digestion. Since it increases the amount of gastric juices, it should be consumed in small quantities by those who suffer from gastritis. However, it must be emphasized that there is no relationship between the onset of gastric diseases and coffee consumption. It is recommended that people who suffer from this problem should limit not only coffee, but also tea, beer, soft drinks and carbonated beverages.
- Coffee and the liver: Coffee consumption substantially reduces the risk of cirrhosis of the liver (both in alcoholics and non-alcoholics). Several studies have shown a significant decrease in the incidence of gallstones in coffee drinkers. Caffeine causes an increase in contractions of the gall bladder and therefore reduces the risk of stone formation (for those who regularly drink two or three cups per day). Finally, certain diterpenes present in coffee, such as cafestol and kawheol, have antimutagenic properties. This means that they are involved in protecting our bodies against mutagenic agents. Specifically, coffee consumption reduces the risk of colon and rectal tumours. Other molecules found in coffee (melanoidins) defend the gastrointestinal tract from external oxidative aggression.
The possible beneficial link between coffee consumption and tumors has been widely researched. Numerous studies on various types of cancer (oral cavity, esophagus, stomach, liver, breast, ovarian, kidney, pancreatic, colon, rectal and bladder) have had promising results.
A large number of the studies on coffee and tumors have shown positive results. While some of these studies simply show that there is no relationship between coffee consumption and the development of tumors, others demonstrate that coffee plays a protective role.
Coffee, caffeine and antioxidants play an important role in defending against degenerative diseases. A brief overview of the most notable diseases:
- Parkinson’s is a degenerative disease that involves part of the central nervous system. Although a definitive cause has not yet been discovered, it is clear that the development of this disease is probably related to many factors: genetic anomalies, lifestyle and environmental factors. However, one conclusion has been drawn from all of the studies conducted to date – moderate coffee consumption can have a protective effect against the development of this disease, particularly consumption of 100-300 mg of caffeine per day (coffee, tea, cocoa, etc.). Unfortunately the mechanism of action is not yet fully understood.
- Alzheimer’s is a degenerative disease that progressively destroys brain cells. This disease, which affects 26 million people around the world, has no cure and is still poorly understood. Laboratory tests on guinea pigs have demonstrated that giving caffeine to the animals slowed the onset of the disease and also brought about a significant improvement in animals with the disease, providing hope for a cure in humans.
- Multiple Sclerosis is a degenerative disease of the central nervous system. In this case as well, recent studies on rodents have demonstrated that caffeine consumption slows or prevents the onset of this disease. The studies are still in the beginning stages, but this is undoubtedly a promising result for researchers.
Drinking coffee increases attention and concentration, and helps reduce fatigue and tiredness. It stimulates brain activity, decreases reaction time, increases attention span and improves endurance. A quick search yields thousands of studies that deal with coffee and the mind. There are many practical cases in which caffeine plays an extremely beneficial role. It increases memory capacity, speeds up information processing, has a very beneficial effect on mood (some scientists even believe it may have a preventive effect on depression and drug use), helps with getting over jet lag, and improves driving and attention span.
Caffeine decidedly enhances athletic and physical performance. Numerous studies have been conducted and are underway that are looking into the effects on trained athletes, as well as regular people who occasionally take part in sports. Unfortunately the mechanisms of action are not yet fully understood. The research to date has demonstrated that caffeine is an ergogenic aid, or rather a substance that produces energy when it is transformed and that is able to improve a muscle’s ability to perform work. It therefore allows people to enhance endurance during physical activity.
Although studies are insufficient and methodologically limited, it has been clearly demonstrated that caffeine does not exacerbate pre-menstrual syndrome.
In recent years, there has been increasing interest in food consumption in pregnant and breastfeeding women, including the effects of coffee consumption during these delicate stages. Caffeine metabolism is slower in pregnant women, meaning that it has a longer bioavailability and is therefore absorbed in larger “doses” (the half-life of caffeine in a woman who is 5 months pregnant can be as long as 7 hours).
Drinking coffee during pregnancy becomes risky when consumption exceeds 4-5 cups per day (of American coffee) and becomes very risky when it exceeds 8 cups per day. As has been discussed in the preceding pages, high caffeine consumption for long periods of time is unhealthy for any individual and 8 cups of coffee per day is certainly not within the normal range.
Most international scientific bodies recommend not exceeding 300 mg of caffeine per day (approximately three cups of American coffee). The majority of studies have also demonstrated that there is no link between coffee or caffeine consumption and miscarriages and foetal deformities. In addition, recent research has shown no correlation between coffee consumption and foetal growth.
In conclusion, it is always best to exercise good judgement and not exceed the recommended intake.
Particular care must be taken when breastfeeding, since caffeine appears in breast milk. It is therefore best to opt for a good decaffeinated coffee and limit substances that are rich in alkaloids, such as tea, chocolate and other beverages that contain central nervous system stimulants.
To round out the discussion on “women and coffee”, a final topic must be considered – menopause. In the past, studies focused on the relationship between coffee and osteoporosis. Moderate coffee consumption does not interfere with increasing bone mass, nor does it cause any changes.
With respect to menopausal women, there is no clear relationship between caffeine intake and loss of bone mass and calcium. Osteoporosis is a complex multifactorial disease that involves many other factors, including diet, lifestyle and genetics.