Why coffee is good for almost everyone

For Captain Kathryn Janeway in the Star Trek: Voyager series, coffee is “the finest organic suspension ever devised,” a statement with which many of us appear to agree. According to the Spanish Coffee Association (AECafé), 65.5 million cups of coffee are drunk in Spain every day, 80% of which contain caffeine: 46.5 million of these are consumed in Spanish homes and 19 million in hotels, restaurants and coffee shops. If we were to include the consumption of minors, the figure would stand at 1.4 cups of coffee a day per inhabitant. Spain is not, however, the biggest coffee consumer: the per capita consumption – 3.81 kilos a year – is half that of Italy, the Netherlands and Finland. In fact, the relationship of humanity with this stimulant, native to northern Ethiopia and whose consumption dates back to at least the 13th century, borders on the delirious. “In my opinion, it is inhumane to force people who have a genuine medical need for coffee to line up behind people who apparently consider it some sort of recreational activity,” quipped American humor columnist and Pulitzer Prize winner, Dave Barry.

Although not yet considered a medical necessity, a compilation of more than 200 meta-analyses published in 2017 in the BMJ medical trade journal found that coffee consumption appears safe at normal levels of consumption, with a greater reduction in risk for various pathologies when consuming three to four cups a day.

The benefits include a reduction in mortality in general and a lower risk of cardiovascular disease, several types of cancer, neurological conditions, metabolic conditions – such as type 2 diabetes – and liver disease, such as cirrhosis. Fortunately for people whose sleep is disturbed by caffeine, and who desist after mid-day, decaffeinated coffee also carries these benefits. One drawback: the benefits mean consuming coffee like Captain Janeway; black, no sugar.

While that research concluded that moderate coffee consumption is “more likely to benefit health than harm it,” its authors also pointed out that most of what was analyzed was observational and that robust clinical trials are needed to understand whether there is a real cause-and-effect link. They also warned of possible undesirable effects. For example, coffee consumption during pregnancy could be associated with low birth weight, premature births or miscarriages. Pregnancy apart, it could increase the risk of bone fractures in women, though not in men.

A group of specialists attached to the Center for Biomedical Research on the Pathophysiology of Obesity and Nutrition Network (CIBEROBN) found coffee consumption was associated with greater longevity, particularly among those over 54, after observing 20,000 volunteers over 10 years. “The bulk of chronic diseases occur in advanced years and that is where coffee can have a more beneficial effect,” Estefanía Toledo, one of the authors of the study and researcher at the Navarre’s Institute for Health Research (IdiSNA), told EL PAÍS.

Another group of Spanish experts from the Consortium of Biomedical Research on the Public Health and Epidemiology Network (CIBERESP) analyzed coffee consumption in more than 3,000 people over 60 and found that two or more cups a day could be beneficial in women and in people with hypertension, obesity and diabetes. “A lot of scientific evidence regarding diet comes from population studies, which is enough to give nutritional advice to the population; sometimes we don’t need more,” Esther López-García, co-author of both studies and professor of Preventive Medicine and Public Health at Madrid’s Autonomous University, tells EL PAÍS. “As far as coffee is concerned, the data from population studies is already so strong that right now there is no need for a clinical trial to show that coffee reduces the risk of heart attack. In fact, many dietary guidelines already include it as a healthy drink.”

Produced from the beans of the coffee plant, which are then roasted, the consumption of coffee has also been linked to a reduced risk of Alzheimer’s and Parkinson’s, but how this neuroprotection mechanism operates is unclear. In 2018, Canadian researchers said that some of its components inhibit the formation of proteins whose accumulation is associated with these diseases, such as β-amyloid, although they noted that “it is likely that the neuroprotective effect is due to a combination of factors.”

Although caffeine is assumed to be behind coffee’s effects on the body – incidentally, the most consumed psychoactive agent in the world – roasted coffee is a complex mixture of more than 1,000 bioactive phytochemicals, some with potentially therapeutic effects. It contains, among others, polyphenols such as chlorogenic acid and lignans, the alkaloid trigonelline, melanoidins formed during roasting and modest amounts of magnesium, potassium and vitamin B3 (niacin).

The bulk of chronic diseases occur in advanced years and that is where coffee can have a more beneficial effect

Spanish researcher Estefanía Toledo

Some of these compounds have antioxidant, anti-inflammatory and anti-carcinogenic properties, improve the intestinal microbiome and modulate glucose and fat metabolism. But the biochemical composition and effects of each cup vary according to the varieties of coffee – arabica versus robusta – and how it is processed from the green, unroasted bean, the degree of roasting and the method of preparation. For example, unfiltered coffee, such as that served boiled like Turkish coffee or pressed in a French piston coffee maker, contains diterpene cafestol, a compound that increases cholesterol, while filtered coffee gets rid of this substance.

As Toledo and López-García point out, the fact that coffee is often consumed with products that cause cancer, such as tobacco or alcohol, has obscured the knowledge of its benefits. In fact, for years, the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) considered coffee as “possibly carcinogenic to humans” based on limited evidence of a link to urinary bladder cancer.

However, an analysis of the increasingly abundant research published in 2016 in The Lancet Oncology concluded that for that type of cancer, there was “no consistent evidence of a link to coffee consumption.”

The first studies on the effects of coffee consumption began in the 1980s, when it was thought to be harmful. “When it comes to drinks, coffee has the highest consumption after water,” says López-García. “And around 2000, the focus was back on coffee because a lot of people had been drinking it for years without seeming to show any negative impact. When we removed the effect of tobacco from the equation, things changed a lot. I participated in studies where it was observed that coffee reduced the risk of cardiovascular disease and type 2 diabetes. It was also observed that it did not increase the risk of hypertension in regular coffee drinkers.”

Although one of the effects of caffeine which last about three hours is to increase blood pressure, “in regular consumers this effect decreases as habituation occurs and the beneficial effects of the other components of coffee prevail, especially in the metabolism of glucose, which is what reduces the risk of diabetes.” However, according to López-García, there are certain demographics to whom coffee could be harmful, such as those with unaddressed hypertension, those who have digestive problems as it is a gastric irritant, and insomniacs.

The challenge of conducting reliable and comparable studies is exacerbated by the difficulty of defining a cup of coffee, an ambiguous concept whose volume, preparation and additives vary widely around the world. “Is it an espresso, an American, filtered or unfiltered?” says Toledo, who admits to drinking three espressos or filtered coffees a day without sugar or sweeteners.

“A coffee drinker may drink different types of coffee throughout the day,” she says. “Maybe one at home when you wake up and then another one mid–morning, but the method of preparation may be different because you drink it at work or in a coffee shop, which means observational studies have their limitations.” The intensity and variety of roasting also affects quality. South Korean researchers have shown that a dark roast decreases the amount of antioxidant and anti-inflammatory substances, which would make a light roast more advisable.

Better natural than roasted

On the website directoalpaladar.com, the gastro blogger Liliana Fuchs argues that among the common coffees in the supermarket – natural, roasted and blended – roasted coffee, obtained by roasting the beans with sugar, is “a crime against good coffee.” Created by the Salamancan inventor José Gómez Tejedor at the end of the 19th century for his company Cafés La Estrella, the taste is a little more bitter but it became popular in Spain during the post-war period because it has a longer sell-by-date and allows more coffee to be extracted from the same volume of beans. Fuchs “strongly” recommends renouncing roasted or blended coffees, which are very common in the hotel and catering industry, and “always opting for natural roasted coffee.”

It is also not easy to know the amount of specific components in a cup of coffee. A 30-milliliter black or espresso coffee has about 60 milligrams of caffeine, but the arabica has less than the robusta variety, and even decaffeinated coffee may include a few milligrams. In a review in The New England Journal of Medicine, experts from the universities of Singapore and Harvard considered that drinking “three to five cups of coffee a day has been consistently associated with a reduced risk of several chronic diseases,” but warned that high caffeine consumption can have adverse effects, such as tremors or nervousness.

But, in moderate doses – from 40 to 300 mg – caffeine can reduce fatigue, increase alertness and reduce reaction time. In adults who are not pregnant or breastfeeding, the authors recommended not exceeding 400 mg daily, dropping to 200 mg in pregnant women.

Moreover, susceptibility to caffeine varies according to our genes and metabolism, which explains why there are those who cannot sleep if they have coffee after midday and those who can drink it even before going to bed, making adjusting the dose accordingly advisable. But, for the peace of mind of people who drink a lot of coffee, specialists from the US National Cancer Institute (NCI) have found that drinking coffee reduces mortality even among those who drink eight or more cups a day, whether they metabolize caffeine quickly or slowly.

On the other hand, well-designed studies sometimes expose contradictory nuances. For example, a recent study by Chinese researchers who followed 170,000 Britons in the UK Biobank cohort – a large biomedical database with global access for researchers – over a decade found that moderate consumption of instant, ground or decaffeinated coffee, with or without sugar, was associated with lower mortality, which was not as evident in coffee sweetened with artificial sweeteners.

López-García, who drinks up to four coffees a day with milk but no sugar, considers that “although in general terms diets with low sugar content are advisable, adding a teaspoon, as is often done in Spain, does not counteract the beneficial properties of coffee.” In fact, 2015 research found that those who added sugar, cream or milk enjoyed similar benefits to those who drank it black. But, she points out, adding a little is very different to consuming products from a number of coffee shop chains that are more like sugary drinks, something that “is no longer coffee, but a mixture of cream and sugar.”

Another group of Australian experts who undertook a study using the same British database found that two to three cups per day of decaf, regular or instant, were associated with less cardiovascular disease and mortality, although the benefit of reducing the risk of arrhythmia was not linked to decaf.

In any case, “the evidence that coffee is associated with lower mortality is fairly consistent,” according to NCI researcher Erikka Loftfield in The New York Times. Its benefits, in fact, are universal do not, as an NCI–funded study of the US population found, vary according to ethnicity – African–Americans, Japanese–Americans, Latinos and whites all show greater longevity. Nor are they exclusive to any one region of the planet: it has just been proven that both coffee and green tea prolong life in Asian populations.

Similarly, according to Italian, British and American researchers, “coffee can be part of a healthy diet.” In short, consumed in moderation, especially black with no sugar, coffee seems to be good for most people. As Clark Gable would say, “I never laugh until I’ve had my coffee.”

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