Coffee and heart, can caffeine be positive?

Let’s talk a little about the effects of coffee on the heart. There is always concern of whether coffee is harmful to the heart. There are those who think that it is bad for health and others point out that it does not harm. Actually, its effect on the cardiovascular system is not the same for everyone, since for the majority it probably does not have a harmful effect and in certain amounts it can be beneficial. In recent studies it has been seen that the consumption of 3 to 4 cups of coffee per day may be favorable for health. In this article we will try to explain all this in a simplified way.

Good morning coffee cup!

Why the popularity of coffee?

Coffee is one of the most popular drinks in the world, most people feel welcome when they enter a place where coffee is being prepared and its smell fills the environment. After all, caffeine is the stimulant substance with the highest consumption rate worldwide and the most socially accepted.

Caffeine has positive, even social, reinforcing properties. Part of its popularity is due to its stimulating effects on mood, the decrease in fatigue, the improvement of intellectual capacity and even physical performance, not to mention its secondary social gain as a favorite drink at the desk, many expect there to be a time dedicated to finish eating and to chat relaxed with a coffee. Alone or accompanied to taste a cup of coffee or feel its aroma represents for most a pleasant moment of the day.

It should be noted that caffeine is a substance that produces tolerance, that is, when we get used to it, we can fall in the dose increase without noticing the same effects that someone who is not accustomed would show. With cessation of consumption a specific withdrawal syndrome also appears, who has not seen someone having a headache because he did not drink coffee that day?

How much coffee do we drink?

It varies from location to location, but as a point of reference I can tell you that in Spain it is estimated that 80% of the adult population consumes an average of caffeine between 200-300 mg per person / day (2-3 cups of coffee daily)

How does caffeine work?

Caffeine has one of its main mechanisms of action in the nervous system, there it competes to occupy the so-called adenosine receptors, a neuromodulator that causes inhibitory effects so that the antagonism on adenosine that caffeine exerts usually brings stimulating effects.

Another effect of caffeine is that it also favors certain processes mediated by other substances that are neurotransmitters such as acetylcholine, dopamine, glutamate, norepinephrine, serotonin and GABA. Caffeine belongs to a group of substances known as methylxanthines, including theophylline (used for asthma) and theobromine. They also act on the respiratory system by relaxing the bronchial smooth muscle (caffeine has been used as a bronchodilator). They also have musculoskeletal effects, stimulate the central nervous system where they are psychostimulants, and also have action on the heart muscle and act as diuretics in the kidneys.

There was a time during which patients with certain coronary problems were banned from drinking coffee, I remember more than one asking for a cup of coffee in a coronary care room after a heart attack and when after their requests were denied it was possible to find them close by sipping a cup in secret. Over time it has been seen that moderate coffee consumption with caffeine is associated with a lower risk of mortality from coronary heart disease, specifically in older subjects. Below we can see how it acts on the heart after a heart attack.

Why doesn’t everyone think the same about the effect of coffee?

The lack of a consensus in the information on its use probably results in its action varying between people. There are those who are fast metabolizers of caffeine and others who are slow metabolizers (55% of the Caucasian population is a slow metabolizer of caffeine).

Thus between different people we can have different plasma concentrations after administering the same dose of coffee due to variations in metabolism, with also different effects. These facts have resulted in both positive and negative information about it.

The effects of caffeine are complex and depend largely on the state of health at the time of administration, the dose used, the interaction with other substances and the history of exposure to methylxanthines since a person who regularly consumes coffee, who has surely developed a certain tolerance for the product, is dramatically different to someone who has not consumed coffee for a long time.

Does drinking coffee modify mortality?

There are studies in which coffee consumption in certain quantities was inversely correlated with total mortality, that is, it seems to reduce it, it also does so with mortality due to a specific cause such as that due to heart disease, respiratory disease, stroke and diabetes. encouraging many to continue consuming it. On the other hand, NO positive correlation has been found with cancer-related deaths.

Effects of caffeine on the heart

It has been seen that caffeine could improve mitochondrial function and protect heart cells from damage. There are studies that indicate that caffeine increases the action of mitochondrial p27 (the cyclin 1B-dependent kinase inhibitor) that protects cardiomyocytes against apoptosis and acts on cellular respiration. P27 is also necessary for the conversion of fibroblasts into mechanically strong contractile myofibroblasts, a critical process after myocardial infarction. (

However, caffeine has a positive chronotropic and inotropic effect, that is, it increases the heart rate (number of times the heart beats per minute) and the contractile force of the heart because it causes inhibition of cardiac adenosine receptors.

Caffeine does not induce or worsen the severity of ventricular arrhythmias and does not increase the risk of certain supraventricular arrhythmias such as atrial fibrillation or flutter, except at very high doses.

The most common adverse effects of caffeine are palpitations, tachycardia, gastric discomfort, tremor, nervousness and insomnia. While it is attributed beneficial effects, if consumed in excess and without individualizing the case it can be harmful.

And with regard to blood pressure and diabetes risk, what can coffee consumers expect?

Regular coffee consumption has been associated with a lower risk of developing type 2 diabetes (the so-called adult diabetes) as it increases insulin sensitivity.

About the elevation of systolic blood pressure with the use of caffeine today we know that it can happen in those who are not habitual consumers, while habitual consumers do not usually present it. An elevation of 11 to 14 mmHg has been seen with the consumption of 3 cups of coffee in people who have spent some time without consuming any caffeine, but not in frequent consumers who will not see significant elevations by taking their two or three cups a day.

Will coffee produce arrhythmias?

Apparently only excess caffeine induces increased arrhythmias. With a moderate dose of caffeine, the danger of inducing arrhythmias in normal subjects is small, that is, those without known heart disease. Individuals with ischemic heart disease (irrigation failure of their coronaries) or pre-existing ventricular extrasystoles tolerate moderate amounts of caffeine without a noticeable increase in the frequency of arrhythmias.

As a curious fact, it seems that habitual coffee consumers do not show significant changes in vagal activity, but they do so when the dose of caffeine is abruptly decreased when they consume decaffeinated coffee in a total and abrupt manner.(

Will coffee damage my coronaries?

In a study in which the presence of coronary calcium (risk factor for heart attacks) was examined by tomography, it was observed that those who consumed coffee three or four cups per day had less coronary calcium with a reduction of 41%, the results were:

  • Drinking 1 cup of coffee / day reduced the risk by 23%.
  • 1-2 cups of coffee / day reduced the risk by 34%.
  • 3-4 cups of coffee / day reduced the risk by 41%.
  • 5 or more cups of coffee / day reduced the risk by 19%.

Thus to consume coffee in moderate quantities, not only does it not increase cardiovascular risk, but it could decrease it (care must be taken as not all cases will be similar).

If you like coffee very much and your consumption is higher than that mentioned, you can drink decaffeinated coffee that contains a smaller amount of caffeine, always in moderate quantities and avoiding abrupt changes.

What substances in the diet contain caffeine?

Caffeine is not only in coffee, the sources of caffeine are several. It has been isolated in more than 60 species of plants, we easily get it in our daily diet in coffee, tea, chocolate and cola.

These are the approximate amounts of caffeine that some drinks contain per serving:

  • Coffee (per 150 ml cup) instant, roasted and ground: 80-200 mg of caffeine / serving (depending on origin and preparation)
  • Decaffeinated coffee (per 150 ml cup) both roasted and ground as well as instant: 3 mg of caffeine / serving
  • Tea (per 150 ml cup): 40 mg of caffeine / serving
  • Cola (per 330 ml can): 30 mg of caffeine / serving
  • Chocolate in pills (50 g): 20 mg of caffeine / serving

In addition to caffeine, coffee contains substances such as cafestol, kahweol, chlorogenic acid that are attributed antioxidant and protective properties as well as some micronutrients such as magnesium, potassium, niacin, trigenoline and tocopherols.

Consequences of drinking a lot of coffee

Drinking three or up to four cups of coffee per day does not seem to cause harm; on the contrary, it could bring benefits, except in exceptional cases. Caffeine has many other effects that are beyond the scope of this article, as well as problems caused when the dose of toxicity is reached. As everything in excess is harmful, caffeine in very large quantities can cause adverse effects, poisoning and even death.

Is it good to drink decaffeinated coffee?

As we saw earlier, decaffeinated coffee has a small proportion of caffeine. Moderate consumption of normal coffee (3-4 cups per day) has been associated with beneficial effects, or at least not adverse effects, in most cases. But if you are one of those who drink excessive amounts of coffee (more than four cups per day) or if you have adverse symptoms with a lower intake due to problems with your metabolization, you may be able to lower the dose of caffeine, however as we have already seen sudden changes are not usually recommended.


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