Is it worth to consume caffeine while pregnant or during lactation?

Introduction

A cup of coffee remains the most socially accepted way to get a rush of caffeine, the drug of happiness, in our bodies.

From the very beginning through the Literary Cafés, where, thanks to this new drink, ideas flowed faster and people felt more alive and alert, coffee has gained its reputation as the invigorating drink par excellence both in Europe and in the United States.

The caffeine present in coffee and many other drinks is viewed with suspicion by many pregnant women who are regular coffee consumers.

But not all coffees are the same! American coffee, espresso coffee, and Turkish coffee can vary a lot in their caffeine content [1].

Let’s find out how much caffeine the different types of coffee in the world contain and the amount of coffee that pregnant women around the world can drink with pleasure avoiding risks for themselves and their babies.

What’s caffeine?

Caffeine is a xanthine alkaloid and protects several parts of the coffee plant from being eaten or attacked by insects or animals. Basically, it acts as a natural pesticide.

Over the course of their evolution and in order not to be eaten, plants controlled the behaviour of animals—and, indirectly, us by producing caffeine [2].

As regards the human body, the stimulant effects of caffeine are primarily due to its ability to resemble adenosine, a neurotransmitter that promotes sleep and relaxation. Caffeine is structurally similar to adenosine and can occupy the same receptors. By blocking adenosine receptors, caffeine prevents the calming effects associated with adenosine binding [3].

This leads to increased neuronal activity and the release of neurotransmitters like dopamine and norepinephrine. Dopamine is associated with pleasure and reward, while norepinephrine is involved in the body’s “fight or flight” response. The level of alertness increases and the perception of fatigue is temporarily reduced [4].

That’s why caffeine is so beloved.

Variables affecting the percentage of caffeine in coffee

The quantity of caffeine present in a coffee depends on various factors ranging from the variety of coffee to the type of extraction [1]. Among these, the type of extraction is the element that most influences the final caffeine content, as the latter is soluble in water.

The longer the water is in contact with the coffee, the higher the caffeine content of the resulting drink will be. But let’s go into more detail and see how the various ways of preparing coffee influence the final caffeine content of the product.

The habits of coffee drinking vary across cultures, for example, Italy is known for its expresso while Nord European countries prefer long coffee such as Filter Kaffee in Germany or lightly roasted coffee in Finland. The American coffee is once again different from the styles mentioned above, as well as the Turkish coffee.

Additionally, variations in extraction methods, such as French press versus pour-over, contribute to the diversity of caffeine levels in the final cup. Finally, the brewing method significantly impacts caffeine content.

The landscape of coffee consumption is complicated and even more so during pregnancy.

Accordingly, it becomes essential to consider not only the cultural differences in coffee preferences but also the inherent variations in caffeine content. Understanding that a shot of espresso may differ significantly from a standard brewed cup is crucial when adhering to recommended guidelines for safe caffeine intake during this particular moment of a woman’s life.

Table 1: Factors influencing caffeine content in coffee brews [1]

Factors	Possible Impact on Caffeine Content
Species	Robusta coffee has genetically more caffeine than Arabica
Brewing time	Not a decisive factor
Temperature of water	Caffeine is most soluble at 100 °C. A lower temperature reduces caffeine extraction
Water pressure	Not a decisive factor. Higher water pressure does not increase caffeine extraction
Roasting beans	Possible increase in caffeine loss during roasting, but the evidence is inconclusive
Grinding degree	The evidence is not conclusive, whereas the degree of grinding is closely related to the brewing method. It affects the aroma and taste of coffee, which is probably more important from the point of view of the consumer
Type of water	Probably does not affect caffeine extraction, but may affect the flavour and aroma of coffee
Coffee/water ratio	Probably has the greatest influence on caffeine content in the brew
Volume of coffee drink	Different brewing methods have a different volume, which affects caffeine content in the brew
Origin of coffee beans	The origin is related to climatic and environmental factors that may have an influence
Light exposure	The shade can have a positive effect on caffeine content in the coffee beans, but it is probably species dependent
Height above sea level	Possible positive effect on caffeine in Arabica beans. No data available on Robusta
Method of growing	The use of nitrogen fertilizers can increase the amount of caffeine
Storage of coffee beans	Not-significant influence of caffeine beans processing methods

 

Which aspects have a major influence on the amount of caffeine?

The temperature of water used for brewing and the brewing techniques significantly impact the caffeine content in coffee.

Using hotter water in the brewing process extracts more caffeine from the coffee grinds. Brewing methods that fully submerge the coffee grinds result in coffee with increased caffeine levels compared to pour-over methods.

There are several brewing methods according to the different world cultures and traditions in coffee consumption, this makes it even worse to evaluate the amount of coffee a pregnant woman can drink per day respecting the indications of the World Health Organization.

Let’s consider the most common types of brewing methods and their caffeine content.

Infographic 1: Extraction methods of coffee around the world

In the study conducted by Crema Coffee Garage and the University of Newcastle the caffeine content of the espresso, stovetop espresso, pour-over (filter brew), cold brew, and French press (plunger) was measured not only according to the aspects influencing the brewing method but it was also reported to the serving size [21].

The results were pretty interesting, when compared milliliter to milliliter (mL) with other brew methods, espresso contains the biggest amount of caffeine, as shown in the table below.

Table 2: Coffee Types and Caffeine Content (mg/L) [21]

However, the amount of caffeine per serve depends on serving size, which is not equal for all methods as each brew is served differently.

The open question about caffeine is the correspondence between the amount suggested by the World Health Organization, that is 300 mg for pregnant women, and the serving size according to the differences existing all over the world.

According to the measurements of the mentioned study, a pregnant woman can drink 60 mL or 2-oz of Espresso, 100 mL of Stovetop Espresso, 90 mL of Cold Brew, 300 mL of French Press, 250 mL or 8-oz of Filter Coffee (Filter Kaffee in Germany).

Table 3: Caffeine content according to Mug Size [21]

According to the study, a pregnant woman can drink a cup of expresso (60 mL) per day, or 300 mL of French Press Coffee and the amount of caffeine will remain pretty similar but the amount of liquid is 5 times more.

So, the brewing method makes a great difference in the amount of coffee and the serving size that we can drink.

For the ones who like to drink coffee even when pregnant, a solution could be to make a change from expresso to French Press or Pour-over.

Let’s analyze some alternatives like decaffeinated, instant, and moka coffees.

Decaffeinated brewed

Even if during decaffeination, about 97% of caffeine is removed, a typical cup of decaf coffee still has about 2 mg of caffeine. It is not a lot, compared to a typical cup of regular coffee, but it is not completely absent [22].

Instant coffee

Instant coffee usually contains less caffeine than freshly brewed coffee. A typical 8-oz cup of regular instant coffee contains about 62 mg of caffeine [23].

Moka Pot

A study conducted by the College of Newcastle outlines that a Moka pot-brewed 100 ml (around 3.4 ounces) of coffee contains generally 219 mg of caffeine, implying a considerable caffeine substance. In comparison, the French press yields almost 74 mg of caffeine in a comparable volume of brew, making it around three times less caffeinated [24].

Be that as it may, there’s a caveat to this comparison. French presses by and large create a bigger volume of coffee per serving. The commonplace service cup of French press coffee is around 100 ml (3.4 oz), whereas a service cup of Moka pot coffee is approximately 30 ml (1 oz). Thus, when considering a single serving of coffee for each strategy, the caffeine substance per cup remains moderately reliable.

Mechanisms of action: how it overcomes the fetal barrier, which substances can increase caffeine absorption.

Do you know what passive diffusion is?

Passive diffusion is the classic mechanism through which molecules pass from a solution of higher concentration to a solution of lower concentration. In this case, the solution with the highest concentration is the maternal blood while the placenta is the part with the lowest concentration.

Thanks to this mechanism, the baby receives oxygen and nutrients but unfortunately also medicines, drugs, or potentially toxic substances taken by the mother during pregnancy [7].

Caffeine is a water-soluble and rather small molecule. It is, therefore, able to pass from the maternal bloodstream to the placenta without any difficulty. Caffeine is then metabolized in the liver [11].

However, a child’s liver is not able to metabolize caffeine in the same way as an adult’s liver. The time it takes for the amount of a drug in the body to decrease by 50% during elimination is called the half-life (T/2) [5].

The half-life of caffeine in the child is longer than in the mother. The caffeine that enters the circulation, therefore, remains much longer in the child’s body than in the mother’s body [5].

The child has a limited ability to metabolize and eliminate substances; therefore, caffeine can accumulate in the tissues of the embryo in higher doses than in the maternal tissues [5,8].

The consequences involve an increased risk of preterm birth and low birth weight. The choice to eliminate or significantly reduce the doses of caffeine by the future mother is, therefore, desirable to minimize the risks due to the accumulation of caffeine in the embryo [9,10].

What are the risks during pregnancy?

Major risks associated with caffeine consumption during pregnancy include stunted baby growth and an elevated risk of miscarriage. As always, it’s essential to consider the dose as the determining factor [7].

Caffeine exerts adverse effects on successful pregnancy development, necessitating limitation of its use. Specifically, heightened caffeine intake during pregnancy can elevate fetal catecholamine levels, leading to increased fetal heart rate, placental vasoconstriction, and compromised fetal oxygenation. Therefore, immediate treatment is imperative for cases of caffeine intoxication in pregnant women [1,11].

Subsequently, we will explore the permissible milligrams of caffeine to avert the aforementioned risks and the corresponding amounts in various types of coffee.

Out of the 1,063 pregnant women interviewed, 172 experienced miscarriages. The investigation revealed an escalated risk of miscarriage with higher caffeine levels, showing an adjusted hazard ratio of 2.23 (95% confidence interval [CI] 1.34–3.69) for an intake of 200 mg per day or more [4, 5].

In addressing coffee during pregnancy, the World Health Organization recommends limiting caffeine intake to 300 mg daily. In Italy, this is reduced to 200 mg based on the Ministry of Health’s guidelines [6].

However, caution is necessary, as caffeine is present not only in coffee but also in other beverages and foods containing nerve-stimulating substances such as tea, chocolate, and energy drinks.

Equally important is vigilance in tea consumption due to the presence of theine and catechins, which can interfere with folic acid absorption. This substance is crucial for preventing fetal malformations, particularly in the case of black tea [2].

Doses allowed during lactation

The elimination time of caffeine during the latter stages of pregnancy is significantly prolonged compared to nonpregnant women [12]. Nevertheless, maternal caffeine half-life normalizes within the initial week after childbirth. Caffeine manifests in breast milk, typically reaching its peak about an hour after maternal consumption [13]. Its presence in breast milk occurs swiftly following ingestion. Unfortunately, there is a lack of sufficient high-quality data to formulate evidence-based recommendations regarding safe maternal caffeine intake.

Infants born to mothers with exceptionally high caffeine consumption, equivalent to around 10 or more cups of coffee daily, have exhibited signs of fussiness, jitteriness, and disrupted sleep patterns [14]. Conversely, studies involving mothers consuming 5 cups of coffee daily showed no discernible stimulation in breastfed infants aged 3 weeks and older [15,16].

Other sources of caffeine, including cola, energy drinks, yerba mate, or guarana, are likely to induce similar dose-dependent effects on breastfed infants [17]. Notably, a daily coffee intake exceeding 450 mL may lead to decreased iron concentrations in breast milk, potentially resulting in mild iron deficiency anaemia in some breastfed infants [18].

The consequences involve an increased risk of preterm birth and low birth weight. The choice to eliminate or significantly reduce the doses of caffeine by the future mother is, therefore, desirable to minimize the risks due to the accumulation of caffeine in the embryo [19,20].

Caffeine intake during breastfeeding, in accordance with the statements from the European Food Safety Authority (EFSA), is considered safe under specific conditions.

According to the EFSA, single doses of caffeine up to 200 mg and habitual caffeine consumption at doses of 200 mg per day by lactating women in the general population do not raise safety concerns for the breastfed infant. At these caffeine doses, the daily caffeine intake for the breastfed infant would not exceed 0.3 mg/kg body weight, which is 10 times below the lowest dose of 3 mg/kg body weight tested in a dose-finding study where no adverse effects were observed in the majority of infants.

However, it is essential to note that there is insufficient data to characterize the risk of single doses of caffeine consumed by lactating women, and information on habitual caffeine consumption in this population subgroup is limited. Therefore, it is advisable for breastfeeding women to adhere to the EFSA recommendations, limiting caffeine intake within the specified limits to ensure the safety of the breastfeeding infant.

Conclusion

Caffeine, a widely consumed stimulant found in various sources, including coffee, exhibits convergent evolution in plants and has an established role in human physiology [2]. Its mechanisms of action involve passive diffusion, allowing it to cross the fetal barrier and potentially impact the developing embryo [3]. Maternal caffeine consumption during pregnancy has been associated with an increased risk of adverse outcomes, including miscarriage and fetal growth restriction [4,5].

The risks extend into lactation, with caffeine passing into breast milk and potentially affecting the breastfed child [6,7]. While the evidence regarding the effects on breastfed infants is nuanced, very high maternal caffeine intakes have been linked to fussiness, jitteriness, and disrupted sleep patterns in infants [5].

Considering the potential risks, it becomes imperative to delineate safe doses during lactation. Various studies have explored the transfer of caffeine into breast milk and the subsequent effects on infants [14,15]. Striking a balance between maternal caffeine intake and minimizing risks to the infant is crucial.

In light of the available evidence, the question arises: Is it worth consuming caffeine while pregnant or during lactation? The answer depends on individual circumstances, but caution is advised. The potential risks associated with caffeine intake during these critical periods suggest that moderation and informed decision-making are key. Pregnant and breastfeeding individuals should at least respect the indications of the WHO of 300 mg daily.

References

1. Olechno E, Puścion-Jakubik A, Zujko ME, Socha K. Influence of Various Factors on Caffeine Content in Coffee Brews. Foods. 2021 May 27;10(6):1208. doi: 10.3390/foods10061208. PMID: 34071879; PMCID: PMC8228209. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8228209/
2. Huang R, O’Donnell AJ, Barboline JJ, Barkman TJ. Convergent evolution of caffeine in plants by co-option of exapted ancestral enzymes. Proc Natl Acad Sci U S A. 2016 Sep 20;113(38):10613-8. doi: 10.1073/pnas.1602575113. PMID: 27638206; PMCID: PMC5035902. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5035902/#:~:text=The%20well%2Dknown%20stimulant%20caffeine,in%20plant%20defense%20and%20pollination
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The information contained here is not intended to replace professional medical advice, diagnosis, or treatment. Before making any changes to your dietary, exercise, or treatment regimen, always consult your doctor or a qualified healthcare professional.

The provided explanations are based on general knowledge and may not be suitable for your specific situation. Never make any health decisions solely based on information provided in this article.

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