What Does Science Say About Caffeine?

There are divided opinions about caffeine intake. However, scientific studies have determined that a moderate intake has positive effects in most healthy adults. In this article, we will discover what science has to say about caffeine.
What does science say about caffeine?

There is a lot of public and scientific interest in the negative health benefits of regular consumption of caffeinated beverages. Find out what science has to say about caffeine!

The research has not been entirely conclusive. Only one cause-effect association related to the negative outcome of caffeine intake during pregnancy is known.

What science says about caffeine, especially through epidemiological studies, is that this drug has a beneficial effect in reducing the risk of chronic diseases.

To understand the effect caffeine has on health, however, one must first know where this active ingredient comes from.

Where does caffeine come from?

Caffeine is the most ingested stimulant in the world. The main sources are:

  • Cola nuts ( Cola acuminata )
  • Cocoa beans ( Theobroma cacao )
  • Yerba mate ( Ilex paraguariensis ), ingested in some South American countries.
  • Guarana ( Paullinia cupana )
  • Roasted coffee beans ( Arabica and Robusta ) and tea leaves ( Camellia sinensis ), the most common sources worldwide.

In addition to the sources above, you can find caffeine in some painkillers, carbonated drinks and energy drinks as well as supplements.

The concentration of caffeine varies considerably between the beverages that contain it. However, coffee is the drink with the highest concentration, as it contains 100 ml / cup. Mate comes in second place with 78 mg / 250 ml, followed by black tea with 55 mg / 250 ml.

Cup with black coffee
Coffee is the drink that contains the most caffeine. Food and black tea follow.

The science of caffeine: absorption and metabolism

When one ingests caffeine, it is quickly and immediately absorbed in the gastrointestinal tract (bioavailability is 100%). Furthermore, it is metabolized in the liver and creates three important metabolites:

  • 3,7-dimethylxanthine
  • 1,7-dimethylxanthine
  • 1,3-dimethylxanthine

What does the science say about caffeine when it is absorbed? This active substance exerts physiological effects on the body. Below we will describe them all.

The physiological mechanisms of caffeine

First , caffeine acts as an antagonist to the adenosine receptor in the brain. This is because caffeine has the ability to occupy the receptors (mainly A1 in the hippocampus and A2, which are located in dopamine-rich areas of the brain) since it has a similar molecular structure to adenosine.

By blocking the adenosine binding in the neurons (which includes sleep), it stimulates the central nervous system. In general, a low consumption of this drug (between 20 and 200 mg per day) causes positive effects for well-being, alertness and energy.

However, higher doses can cause anxiety and nervousness, especially in people who are not used to drinking caffeinated beverages.

What science says about caffeine and Parkinson’s disease

Parkinson’s disease manifests itself after the gradual reduction of dopaminergic neurons in the substantia nigra.

By improving the performance of the dopaminergic system, thanks to its antagonistic effect on the adenosine receptors, caffeine stimulates the release of dopamine, which reduces the deterioration of fine and gross motor skills.

Woman with Parkinson's disease
Caffeine intake promotes the production of dopamine, the neurotransmitter involved in Parkinson’s disease.

Caffeine intake for obesity and diabetes

What science has to say about caffeine and the effect it has on weight loss is very interesting. In this connection, the substance acts on the metabolic rate, energy consumption and thermogenic activities (especially the lipids).

Taking 300 ml of caffeine every day inhibits the AMP phosphodiesterase cycle to increase cyclic AMP and, by antagonizing the adenosine receptors, it increases the release of norepinephrine. These are effects that promote weight loss by increasing lipolysis.

In addition, a number of studies suggest an inverse relationship between coffee consumption and the risk of developing type 2 diabetes. Individuals who drink at least six cups of coffee each day have a 35% lower risk of developing the disease. At the same time, those who drink between four and six cups have a 28% lower risk of developing the disease.

The effect caffeine has on mineral absorption

When you drink a beverage that contains caffeine with your main meals, your body struggles to absorb important minerals such as iron and calcium.

Some cohort studies have reported that high doses of caffeine increase the excretion of calcium in the urine. Thus, they increase the risk of bone diseases. Experts therefore recommend moderating caffeine intake to either:

  • Four cups of black coffee
  • Three cups of cappuchino
  • Six cups of coffee

Note: You must compliment these recommendations with adequate calcium intake.

Caffeine during pregnancy and lactation

The reason that caffeine is contraindicated during pregnancy and breastfeeding is because it has the ability to get into the placenta and stimulate the fetal metabolic rate.

During pregnancy, high doses of caffeine are associated with the development of congenital anomalies, miscarriages, low birth weight and changes in the newborn’s behavior.

Similarly, caffeine is directly transferred through breast milk, causing irritability and sleep disturbances. Experts therefore recommend a maximum caffeine intake of 200 mg per day.

Pregnant woman at the doctor's - what does science have to say about caffeine?
Excessive caffeine intake during pregnancy and breastfeeding can harm the baby.

What science says about caffeine and its impact on health

In short, experts are familiar with the effect caffeine has on the body. Since the most ingested beverages in the world contain this substance, it is important to know the mechanisms and effects it exerts on the body, as well as the recommended doses to avoid changes and take full advantage of the benefits.

Most studies in humans suggest that a moderate intake (less than 400 mg / day) has effects on body weight as well as neurodegenerative and metabolic diseases.

However, it is important to note that this drug is contraindicated during pregnancy and lactation, and that it is convenient to control the diuretic effects.

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