Caffeine and MG: Energy boost or symptom trigger?

The effects of caffeine on myasthenia gravis (MG) can vary substantially depending on a number of factors. Patients must work with their healthcare providers to determine if, and how much, caffeine is safe for them.

Mistaken immune attacks on proteins involved in nerve-muscle communication cause MG. This leads to MG symptoms of fatigue and muscle weakness.

Because caffeine acts as a central nervous system stimulant, enjoying a cup of coffee or tea could help ease this fatigue in certain situations. However, long-term caffeine use may also exacerbate symptoms for some individuals.

Ultimately, patients should pay close attention to how caffeine and MG interact in their own bodies, and work with their doctors to determine personal intake limits.

Does caffeine affect myasthenia gravis?

No evidence shows that caffeine directly affects the course or progression of MG. However, caffeine can alter the function of various systems in the body, which may interact with MG symptoms for some people. Specifically, caffeine can affect:

• energy levels
• muscle function and nerve-muscle signaling
• immune function

Caffeine blocks brain cells from responding to signals that normally induce sleepiness, helping to ease fatigue and promote wakefulness. It could therefore help counteract daytime fatigue in MG, although the relationship appears complex and the opposite may be true for some people.

Studies show that caffeine can improve muscle contractions and boost strength. Most often, MG is caused by self-reactive antibodies that target acetylcholine receptors, which help muscles receive signals from nerve cells via a molecule called acetylcholine. Caffeine can slow the breakdown of acetylcholine and boost its levels, which is similar to how some MG treatments work.

However, limited data are available about caffeine and neuromuscular function in MG specifically, and caffeine may not affect acetylcholine signaling enough to have a therapeutic effect in the long-term.

While data show that caffeine may alter immune function, the potential benefits of this immune-altering activity are not established for people with MG.

Possible effects in people with MG

How caffeine affects MG symptoms varies greatly from person to person. Weighing the pros and cons of caffeine consumption depends on an individual’s clinical situation and caffeine tolerance.

Caffeine and muscle weakness

While MG-specific data are lacking, caffeine’s effects on acetylcholine and other aspects of muscle function could, in theory, help ease muscle weakness. Conversely, caffeine side effects like jitteriness and muscle twitches may worsen MG-related movement problems.

Some data suggest that prolonged, high-dose caffeine use is detrimental to muscle health, although the long-term effects of stimulants on muscle weakness in people with MG are not established.

Caffeine and fatigue

Caffeine can help with MG fatigue management for some people, temporarily improving alertness and decreasing daytime sleepiness.

However, the relationship between fatigue relief and coffee or other caffeinated foods and drinks is complex. In the long run, some people find that caffeine makes them more tired, ultimately worsening fatigue.

This happens partly because caffeine, especially when consumed at night, can alter sleep patterns and increase daytime fatigue. Ultimately, the negative effects of poor sleep on MG symptoms may sometimes outweigh the benefits of caffeine.

Other considerations

People with MG may also want to consider the following factors when making decisions about caffeine use:

• Gastrointestinal effects: Both caffeine and certain MG medications can cause gastrointestinal side effects; their combined use may exacerbate these effects.
• Temperature sensitivity: Hot beverages can trigger MG symptoms for some people, so avoiding hot coffee or tea may be helpful.
• Cholinergic crisis: Some MG medications that boost acetylcholine levels can increase the risk of a rare but serious event called a cholinergic crisis. Caffeine could worsen an ongoing cholinergic crisis.

Fatigue vs. muscle weakness

Differentiating MG fatigue from weakness can be difficult, as can separating the effects of caffeine on these symptoms.

Muscle weakness is a decrease in the force that muscles can exert, while fatigue is a subjective feeling of tiredness and low energy. Both issues can make it more difficult to use muscles for extended periods.

While caffeine may temporarily reduce fatigue — making it easier to use muscles for longer — this boost doesn’t necessarily mean the muscles are stronger or that MG has improved overall.

How much caffeine is reasonable?

The U.S. Food and Drug Administration recommends that most adults consume no more than 400 mg of caffeine each day, which is about two to three 12-ounce cups of coffee. However, caffeine limits vary depending on medications, overall health, age, and other factors, such as pregnancy.

Individual variability in tolerance also affects caffeine limits in MG. Every person will need to find their own balance by paying attention to how their body responds. Doctors may be able to provide tailored recommendations.

Some things that can help maximize the benefits of caffeine and minimize side effects for people living with MG include:

• starting with a low caffeine intake, and working up slowly if tolerated
• avoiding hot coffee or tea if heat is a trigger
• staying hydrated
• avoiding caffeine before bedtime
• moderating intake to avoid challenging side effects
• asking doctors about any concerns, particularly in relation to MG medications

Being aware of the caffeine content in foods and drinks is also helpful, since some processed foods may unexpectedly contain added caffeine. If using energy drinks with MG, checking the caffeine content, which varies broadly between brands, can help avoid overconsumption.