Coffee's characteristics:
- Rich in antioxidants,
- vitamin and mineral source
- It promotes intestinal transit.
- It contains stimulating caffeine.
The nutritional and caloric values of coffee
Contrary to popular belief, the benefits of a cup of coffee are not limited to the sole presence of caffeine. On the contrary, coffee contains a significant number of vitamins, minerals, antioxidants, and bioactive substances. Among these micronutrients, we can cite:
- Magnesium: espresso coffee is an excellent source of magnesium for women and a good source for men (men's magnesium needs are higher than women's). Magnesium participates in bone development, building proteins, enzymatic actions, muscle contraction, dental health, and the functioning of the immune system. It also plays a role in energy metabolism and in the transmission of nerve impulses.
- Espresso coffee is an excellent source of vitamin B3. Also called niacin, vitamin B3 participates in many metabolic reactions and contributes particularly to the production of energy from the carbohydrates, lipids, proteins, and alcohol that we ingest. It also collaborates in the process of DNA formation, allowing normal growth and development;
- Brew coffee and espresso coffee are good sources of vitamin B2 for women and for men (men's vitamin B2 needs are higher than those of women). Vitamin B2 is also known as riboflavin. Like vitamin B1, it plays a role in the energy metabolism of all cells. In addition, it contributes to the growth and repair of tissues, the production of hormones, and the formation of red blood cells;
- Espresso coffee is a source of copper. As a constituent of several enzymes, copper is necessary for the formation of hemoglobin and collagen (a protein used in the structure and repair of tissues). Several copper-containing enzymes also contribute to the body's defense against free radicals;
- Pantothenic acid: Brewed coffee is a source of pantothenic acid. Also called vitamin B5, pantothenic acid is part of a key coenzyme that allows the body to properly use the energy from ingested food. It also participates in several stages of the production of steroid hormones, neurotransmitters, and hemoglobin; and
- Coffee contains more than a dozen bioactive compounds, most of which are formed during the process of roasting (roasting) the bean. Three of them are found there in high concentrations and are important from a physiological point of view. These include caffeine, diterpene alcohols, and phenolic compounds known for their antioxidant effects.
- Caffeine This compound is by far the one that has been best characterized so far in coffee. In the United States, it is estimated that 75% of the caffeine consumed comes from coffee. In Canada, this amount has been estimated at 60%. The rest comes from tea, chocolate, energy drinks, etc. However, the caffeine content of coffee varies depending on the type of beans, the roasting method, and the method of preparation of the coffee (for more details, see our Caffeine sheet). Caffeine is known primarily for its stimulating effects. In healthy adults, a small amount can increase alertness and concentration. In other people, however, it can cause adverse biological effects such as insomnia, headaches, irritability, and nervousness. According to Health Canada, in adults, caffeine consumed in moderation (three cups of coffee a day) does not cause adverse effects, particularly in behavior (anxiety, attention capacity), cardiovascular health, or cancer;
- The coffee bean naturally contains significant amounts of diterpene alcohols, including cafestol and kahweol. These compounds, present in the oils of coffee beans, are released in contact with hot water. They would raise cholesterol levels. Depending on the mode of preparation, the coffee will contain more or fewer diterpenes. For example, boiled coffee contains 1.2mg to 18mg of cafestol and kahweol per 100ml, while espresso coffee contains 0.2mg to 4.5mg. Filter coffee, on the other hand, contains practically none (from 0 mg to 0.1 mg).
- Antioxidants: Coffee contains several antioxidant compounds. Given the frequency of its consumption, it can contribute significantly to the antioxidant capacity of the diet. In this regard, a Norwegian study shows that coffee is the food in the diet that contributes the most to total antioxidant intake in this population. A study has shown that the antioxidant capacity of plasma increases significantly following the ingestion of a single cup of filter coffee (200 ml). This suggests that coffee would probably exert its preventive effect on certain diseases thanks to its antioxidant power. Among the antioxidant compounds in coffee are phenolic compounds, including certain volatile substances produced during roasting. The characteristic odor of coffee is attributed to these volatile substances.
- Coffee contains large amounts of phenolic compounds, including caffeic and chlorogenic acids. A 200ml cup of coffee provides 70mg to 350mg of phenolic acid. By way of comparison, blueberries, cherries, plums, apples, and kiwis, which are the fruits richest in phenolic acids of the same family as those in coffee, contain from 10 mg to 230 mg per serving of 100g to 200g. Several researchers believe that caffeic and chlorogenic acids are largely responsible for the antioxidant effect of coffee.
Finally, coffee contains significant amounts of lignans, phenolic compounds that are very common in plants. Lignans are converted into enterolignans by intestinal bacteria and then enter the bloodstream. Lignans act as antioxidants and are associated, in humans, with a reduced risk of cardiovascular disease and certain cancers.
The benefits of coffee
Most of the data on the link between coffee consumption and the reduction of chronic diseases has been obtained from epidemiological studies. According to some researchers, these results should be interpreted with caution as they may contain methodological biases. For example, the way to calculate the amount of coffee and caffeine consumed daily can vary greatly from one study to another (variation in the size of a cup of coffee, the duration of infusion, the type of beans used, etc.).
In addition, certain "confounding" factors such as alcohol consumption and cigarette smoking, often associated with heavy coffee consumption, are not always well assessed.
It should be kept in mind that coffee is only one of the risk factors for certain diseases. Despite certain benefits associated with its consumption, it remains prudent, in a public health context, to recommend moderation. This means, in more concrete terms, consumption of three cups of coffee per day or 400 mg to 450 mg of caffeine per day.
Diabetes type 2
The majority of epidemiological studies published to date indicate that coffee, consumed in large quantities, would reduce the risk of suffering from type 2 diabetes. A meta-analysis has identified data from nine prospective studies involving nearly 200,000 participants. It shows that drinking six cups of coffee a day or more reduces the risk of type 2 diabetes by 35%, compared to less than two cups a day. Consumption of four to six cups reduces the risk by 28%.
In addition, a recent literature review coupled with a meta-analysis has shown that the risk of type 2 diabetes decreases until it reaches maximum protection of 6 cups of coffee per day.
It is not possible, from the data from this type of study, to propose a mechanism of action, nor to establish a causal link. However, it has been speculated that the chlorogenic acid present in coffee could interfere with the action of an enzyme whose function is to release glucose into the blood. Chlorogenic acid could also decrease the intestinal absorption of glucose by blocking its transport to the intestinal membrane. As for caffeine, it would not be responsible for the beneficial effect provided by coffee since decaffeinated coffee also reduces the risk of type 2 diabetes.
Clinical studies are rather divided as to the effect of coffee consumption on certain indicators of diabetes. This is what the authors of a review article published in a 2006 report. Thus, certain data show that coffee would improve the sensitivity of cells to insulin and the metabolism of glucose following the intake of a meal. or a sweet drink. Other data rather indicate that coffee consumption would not affect fasting glucose or insulin concentrations and even on markers of insulin sensitivity. Most of these studies were done over a short period (one day). Only controlled and randomized clinical studies, carried out over longer periods, will make it possible to establish the link between coffee consumption and type 2 diabetes.
Cardiovascular illnesses
The effect of coffee consumption on the risk of cardiovascular disease has been the subject of a large number of studies over the past forty years, but the subject remains controversial. It is still unclear whether coffee is harmful or beneficial for heart health.
Coffee contains a multitude of chemical compounds whose effects can be opposite. The studies seem to show that the presence or not of a protective effect could depend on the quantity consumed. In addition, the mode of preparation of the coffee (filtered or boiled) would influence the cardiovascular risk. The results of a meta-analysis of 14 studies show that boiled coffee, compared to filtered coffee, increases total cholesterol and LDL ("bad") cholesterol levels. This increase is more significant in people whose cholesterol is already high. Boiled coffee contains high amounts of cafestol and kahweol. These two compounds would be responsible for the increase in cholesterol in the blood. The use of filter paper during the preparation of the coffee makes it possible to significantly reduce the concentrations since the filter captures the majority of cafestol and kahweol.
Coffee contains antioxidants and other substances that are believed to help reduce the risk of cardiovascular disease in people who consume filter coffee in moderation. At least that is what the authors of a review article published in the 2007 report suggest. A recent meta-analysis carried out in 2014 once again demonstrated that moderate coffee consumption (3 to 5 cups per day) was associated with cardiovascular risk. It would be mainly the polyphenols in coffee that would have a beneficial effect on cardiovascular health.
Caffeine, on the other hand, would not bring any benefit in this regard. Some researchers say it would even have deleterious effects. A recent study has highlighted the major role of caffeine in increasing cardiovascular risk. Caffeine would also be associated with an increase in blood pressure, a cardiovascular risk factor. However, the consumption of coffee (which does not only contain caffeine) would not have a negative impact, probably because of the protective effect of its other compounds.
In conclusion, it seems increasingly clear that large consumption of unfiltered coffee (more than six cups a day) is bad for the heart. However, moderate consumption of coffee, mainly filtered coffee, could lead to some benefits. This would be due, among other things, to the presence of antioxidant compounds such as polyphenols. These counteract the harmful effects of caffeine and compounds present in coffee oil (cafestol and kahweol).
Cancer
According to epidemiological data, coffee consumption is linked to a reduced risk of certain types of cancer, including breast cancer, colorectal cancer, and gastric cancer.
Breast cancer data shows that, in premenopausal women, drinking four or more cups of coffee a day reduces the risk of suffering from this type of cancer by 40%. In this study, however, the same association was not demonstrated in postmenopausal women or in women consuming less than four cups of coffee per day.
A genetic study published in 2006 shows that women carrying one of the two genetic mutations that predispose to breast cancer and who consume six or more cups of coffee per day have a significantly lower risk of suffering from breast cancer than those who do not drink coffee. On the other hand, a recent meta-analysis on the relationship between coffee consumption and the risk of breast cancer showed no link except in women with non-hormone-dependent breast cancer, where coffee consumption reduced the risk.
Regarding the relationship between coffee and the risk of colorectal cancer, the authors of a meta-analysis mention that the data seems to indicate that coffee consumption reduces this risk. They warn, however, that the lack of consensus among the various epidemiological studies does not allow such a link to be established with certainty. Finally, a recent meta-analysis published in 2013 showed that coffee consumption was inversely related to the risk of endometrial cancer.
liver diseases
Several studies show that coffee consumption is associated with a reduced risk of liver damage, particularly cirrhosis and alcoholic liver cirrhosis. According to some authors, this effect is attributable to caffeine. Others associate the protective effect of coffee with its content of phenolic acids, antioxidant compounds that would act in concert with caffeine.
A large prospective study, carried out on a cohort of more than 125,000 subjects, shows that the risk of suffering from alcoholic liver cirrhosis is inversely related to coffee consumption. Heavy coffee drinkers (four cups or more per day) would be better protected than light drinkers (three cups or less per day). In this study, coffee consumption was also linked to a lower prevalence of elevated liver enzymes (markers of liver damage) in the blood. In a previous study, the same authors had shown a reduced risk of death from hepatic cirrhosis in coffee drinkers. The risk was reduced by 22% per cup of coffee consumed per day.
Data from a US national survey, the National Health and Nutrition Examination Survey, has linked high coffee consumption (more than two cups a day) with a lower risk of chronic liver disease in people at high risk of liver problems.
Finally, the results of a meta-analysis of nine studies published between 2002 and 2007 show that coffee consumption (an increase of two cups per day) is associated with a 43% reduction in the risk of liver cancer. It is important to mention that these are epidemiological studies and that no mechanism of action could be discovered in these studies, which limits the interpretation of the results. Moreover, even if the coffee was hepatically protective, the best approach to reduce the risk of alcoholic-type liver cirrhosis remains the reduction of alcohol consumption.
Gallstones
Coffee acts on several processes involved in the formation of lithiasis or gallstones (commonly called "stones"). Epidemiological data show that coffee and caffeine have protective effects against the formation of gallstones, but these results are not unanimous in the scientific community. While some authors report that high coffee consumption decreases the risk of gallstones, others instead observe an increased risk with high consumption.
A prospective survey carried out on a cohort of nearly 81,000 women followed for 20 years demonstrated that the consumption of four or more cups of coffee per day is associated with a 25% reduction in the risk of cholecystectomy (removal of the gallbladder biliary). In this study, a decrease in the risk of cholecystectomy was also observed with the consumption of caffeine but not with the consumption of decaffeinated coffee.
A prospective study of over 46,000 men shows a significant decrease in the risk of gallstones in those who consume four or more cups of coffee per day. However, this protective role of coffee has not been observed in all studies. For example, research carried out among Japanese men shows about twice the prevalence of gallbladder disorders among heavy consumers of coffee (more than five cups per day) or caffeine (more than 300 mg per day), compared to those who consume less than 100 mg per day. Data from a study carried out in the United States from 1988 to 1994 in nearly 14,000 subjects shows that the prevalence of gallbladder disorders is not associated with coffee consumption, as much in men as in women.
Several factors, both genetic and environmental, may be associated with the formation of cholelithiasis. The role of coffee or caffeine should be further analyzed to better assess its importance in the incidence of this health problem.
Parkinson disease
Most major epidemiological studies show that coffee consumption is associated with a reduced risk of Parkinson's disease, particularly in men. The results of a major meta-analysis point in the same direction.
Recently, researchers analyzed data from approximately 6,700 subjects who participated in a prospective study and whose follow-up spanned 22 years. They observed that drinking ten or more cups of coffee a day reduced the risk of Parkinson's disease by 74%. This decrease was 38% among people who consumed four to nine cups of coffee per day, compared to those who did not. This association was even stronger in obese people.
A recent literature review carried out in 2013 showed that coffee consumption reduced the risk of Parkinson's disease. This effect was greatest at 3 cups per day. Both genetic and environmental factors appear to be associated with the onset of Parkinson's disease. Oxidative stress could be one of the mechanisms involved in the evolution of the disease. Coffee, thanks to its antioxidant content, would provide some protection.
Positive effects on athletic performance?
Caffeine has demonstrated beneficial effects on sports performance, in particular by increasing lipolysis and preserving glycogen stores during exercise. Caffeine would also have possible effects on adrenaline, muscle contraction, and the central nervous system by reducing the feeling of fatigue and increasing endurance.
Caffeine would be effective during short efforts of very high intensity or endurance. The impact is felt within an hour of ingestion. It is very important to check your tolerance before consuming it because each person can react differently. Indeed, some side effects, such as irritability, tremors, and gastrointestinal discomfort, can occur in people who do not have good caffeine tolerance. Average consumption of 3 mg of caffeine per kg of body weight would be the optimal dose to obtain the desired effects.
The fiber in coffee?
Coffee beans are rich in dietary fiber. A certain amount would end up in the brewed coffee. At least that's what a group of Spanish researchers reported when evaluating the soluble fiber content of different coffees. Most Nutrition Facts tables state that coffee does not contain fiber. The data from this study instead shows that espresso coffee, filter coffee, and soluble coffee contain 0.65 g, 0.47 g, and 0.75 g of soluble fiber per 100 ml, respectively. It should be noted that the assay method used in the study (enzymatic method followed by dialysis) is not the common method used to assay fiber in foods.
According to this study, coffee is therefore one of the few drinks to contain dietary fiber. Since it is consumed frequently and in relatively large quantities (two to three cups a day), coffee could thus contribute to the daily fiber intake.
Indeed, coffee contains soluble fiber. Its content varies between 1.5 and 2.3 g per cup (250 ml). Soluble fibers can contribute to the prevention of cardiovascular diseases by notably reducing the absorption of bile acids. They can also help control type 2 diabetes, thanks to, among other things, a slowing down of the digestion of glucose from food.
Nutritionist's word
Regular filter coffee, with no added sugar, milk, or cream, provides just three calories per cup and no carbs. This is not the case with some specialty coffees, whose calorie and sugar content varies according to the ingredients that compose them. Thus, a mocha coffee, prepared with chocolate syrup, will contain up to 140 calories and 20 g of carbohydrates per cup. A cup of café au lait and a cup of café latte, prepared with 2% milk, will contain 67 and 97 calories, as well as 7 g and 9 g of carbohydrates (sugars from milk). These types of cafes provide at least a half serving of dairy.
How to choose the right coffee?
Coffee is a stimulating drink containing caffeine. Along with tea and mate, it is one of the most widely consumed caffeinated beverages in the world. Moreover, coffee represents a major source of income for producing countries. Coffee consumption developed in Europe in the 1600s, a few hundred years after its discovery in Yemen.
Coffee identification card:
- Family: Rubiaceae
- Origin: Yemen
- Season: year-round availability
- color range: green to brown
- The flavor : is strong and bitter.
Coffees for all tastes
In North America, the type of coffee most consumed remains regular or "traditional" brewed coffee. However, consumption habits are changing rapidly, and more and more amateurs are discovering new types of coffee, called "specialized." Here are a few examples:
Café Expresso: is a coffee prepared by percolating it under extremely high pressure from a fine, highly torréfied paste. A successful espresso is distinguished by the formation of an opaque cream of hazelnut color that adheres to the sides of the cup.
Cappuccino: coffee made up of one-third espresso, one-third heated milk, and one-third milk froth, sometimes sprinkled with cocoa or cinnamon.;
Coffee with milk: is a coffee to which an equal amount of hot milk and milk foam is added. It is usually served in a large cup, a bowl, or a cup and is made with a long or double espresso and sometimes a strong filter coffee.
Café latte: Café latte is the Italian variant of coffee with milk. It is made the same way as a latte but uses ¼ espresso and ¾ hot milk. The basic element of the café latte is always an espresso;
Espresso Macchiato: a coffee with a layer of milk foam on top.
Latté Macchiato. The Coffee is prepared by pouring hot milk over whipped cream in a tall, narrow, and clear glass. Following that, the espresso is gently poured between the lait and the mousse. The ingredients must not be mixed together. This coffee can be flavored with cacao, cinnamon, or other spices.
Mocha coffee: is a coffee drink made from espresso, cocoa powder or chocolate syrup, and hot frothy milk? Top with whipped cream and chocolate flakes to serve.
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