Coffee and Asthma

Introduction

What is Asthma? 

Asthma is one of the most common long term health issues that affect the lungs. People diagnosed with asthma have inflamed airways that become narrow with high mucous production leading to breathing difficulties such as coughing, wheezing and breathlessness. ^(1,2)

These symptoms can suddenly get worse momentarily, which is known as an asthma attack. Asthma affects over 8 million people (around 12% of the population) in the UK, and worldwide it affects around 300 million people.^(1,2) 

What is coffee (caffeine)?

Coffee is one of the most commonly consumed drinks which comes from roasted and brewed coffee beans (seed of coffea plant). 

Coffee’s most prevalent compound is caffeine (depending on the type of coffee beans used, the beans can consist of between 0.8-4% of caffeine). 

Caffeine is the most widely consumed central nervous system stimulant worldwide, with a dose of 5.7 mg/kg of body weight recommended for safe consumption.^(3,4)

What are the physiological effects of caffeine?

Caffeine has several modes of action, and with its interaction with various receptors it can lead to different physiological effects, including the following: 

• Caffeine exerts its main effect by blocking the effect of adenosine on its receptors in the heart, hence preventing drowsiness normally caused by adenosine. Via the same receptors, caffeine causes (through a complicated series of interactions) a raise in systole blood pressure (about 5-10 mmHg).⁽³⁾

• Caffeine is also a stimulant of gut motility, which leads to increased contraction of muscle that forces the contents of the gastrointestinal (GI) tract through the gut, leading to loose stool and diarrhoea.^(3,5)

Can Coffee be beneficial for asthmatics?

Caffeine is a weak bronchodilator and also capable of reducing respiratory muscle fatigue, which could potentially help with symptoms of asthma. Caffeine also appears to improve lung function for up to four hours after consumption, shown in studies that used low doses of caffeine at less than 5mg/kg body weight (because of this coffee should be avoided before lung tests such as spirometry).⁽⁶⁾  

Risks of drinking coffee as an asthmatic

If asthmatic patients are taking theophylline for the treatment of asthma, consumption of coffee can actually increase the risk of side effects associated with caffeine and theophylline, which include anxiety, heart palpitations, and diarrhea.^(6,7) 

Another main side effect of coffee is its impact on the stomach, as it is slightly acidic in nature. It can aggravate acid reflux in people who suffer from gastro-oesophageal reflux disease (GORD).

In GORD, the acid in the stomach tends to leak into the oesophagus (food pipe). GORD can trigger asthma symptoms, therefore if someone is suffering from GORD and coffee aggravates their asthma, it might be better for them to avoid coffee.⁽⁸⁾ 

Can coffee be used as an alternative for asthma treatment? 

Coffee is not recommended as an alternative treatment for asthma for the following reasons: 

1. The amount of caffeine in different brands and brewed cups can vary hugely, for example, beans from different regions can contain various degrees of caffeine, the temperature at which the ground coffee has been brewed, degree of roast of beans, and brewing time all impact on caffeine concentration. This makes it difficult to accurately dose it (if trying to use coffee as a treatment).⁽⁹⁾
2. Even though caffeine is effective to some extent, it cannot replace or be as effective as the current treatments for asthma attacks, such as salbumol (ventolin) inhaler. Furthermore, Theophylline, a member of the xanthine family (similar structure as caffeine), is used as a treatment of chronic and severe acute asthma.⁽⁶⁾ 
3. Caffeine cannot also compete with the fast onset of salbutamol inhaler (within 5 minutes) to relieve asthma attacks, and for prophylaxis of asthma theophylline is superior.^(6,10)   
4. Drinking 1-2 cups of coffee per day can have protective effects against asthma. 
5. It is important to note caffeine is used medically, for example, it is used for neonatal apnoea (pause in breathing in infants), and it is used at a low dose alongside paracetamol, ibuprofen, and codeine for pain relief. However, its efficacy for treatment of asthma and chronic asthma is poor, while better and more effective treatments are available.⁽¹¹⁾ 

Summary

Research suggests that coffee can alleviate some asthmatic symptoms. However, some effects of caffeine can be beneficial to lung functions for asthmatics. Considering the discrepancy in the usage of coffee for asthmatics, it is best to consult your doctor if you are thinking to use coffee to manage your asthma.