Kombucha is a fizzy, fermented tea beverage made by combining sweetened tea with a symbiotic culture of bacteria and yeast (SCOBY). Heart palpitations refer to the sensation that your heart is skipping a beat, fluttering, or beating too rapidly or intensely. While generally safe, some individuals report experiencing these changes in heart rhythm after drinking kombucha. The potential for kombucha to trigger these cardiac sensations relates directly to several naturally occurring chemical components that influence the body’s cardiovascular and nervous systems.
Identifying the Culprits
The possibility of experiencing palpitations from kombucha is due to the synergistic effect of several compounds resulting from fermentation, not a single ingredient. The most likely components responsible for cardiac stimulation are residual caffeine from the tea base and the high sugar content found in many commercial varieties. Additionally, the highly acidic nature of the drink and the presence of trace amounts of alcohol contribute secondary effects that can affect sensitive individuals.
Caffeine’s Stimulant Effect
Kombucha is traditionally brewed using black or green tea, meaning it naturally contains caffeine, a potent central nervous system stimulant. Caffeine acts as an adenosine receptor antagonist, blocking the chemical that promotes relaxation. This action increases the release of stimulating neurotransmitters like norepinephrine and dopamine. This biochemical change directly leads to an increase in heart rate (tachycardia) and greater force of heart muscle contraction, which is perceived as a palpitation.
The exact amount of caffeine in a serving of kombucha can vary widely, ranging from 4 milligrams (mg) to over 60 mg in some high-caffeine “masterbrew” products. For comparison, an average cup of coffee contains about 95 mg of caffeine. Even lower doses can trigger a response in individuals highly sensitive to stimulants or those with pre-existing cardiac conditions.
The final caffeine concentration depends heavily on the type of tea used and the length of the brewing cycle. Black tea kombucha generally retains more caffeine than green tea varieties. The total amount consumed is directly linked to the likelihood and severity of a stimulating effect.
Metabolic and Acidity Effects
Sugar and Adrenaline Response
Beyond caffeine, the sugar content in kombucha provides a separate pathway for inducing heart palpitations. Many commercially flavored kombuchas contain significant amounts of added sugar that the yeast did not fully consume. A rapid influx of sugar can cause a spike in blood glucose, triggering the body’s sympathetic nervous system (the “fight-or-flight” response). This response releases stress hormones like adrenaline, which naturally increases heart rate and can be felt as a sudden, intense palpitation.
Acidity and Electrolyte Balance
The highly acidic nature of the beverage is primarily due to acetic acid, the same compound found in vinegar, giving kombucha a pH typically between 2.5 and 3.5. While the body maintains a stable pH, consuming highly acidic substances in large volumes could, in rare cases, contribute to metabolic changes. Furthermore, a highly acidic load can potentially interfere with the precise balance of electrolytes, such as potassium and magnesium, which are necessary for the stable electrical signaling that governs a normal heart rhythm.
Trace Alcohol
Trace amounts of alcohol are a natural byproduct of the yeast’s metabolic process during fermentation, typically less than 0.5% by volume. Alcohol is a known vasodilator and can act as a slight stimulant in sensitive individuals. This small amount of ethanol can contribute to an elevated heart rate and flushing, which may be felt as a palpitation.
Risk Factors and Medical Advice
Certain individuals are more susceptible to experiencing heart palpitations after consuming kombucha. People with diagnosed or undiagnosed heart conditions, such as arrhythmias, should approach this beverage with caution, as the stimulating ingredients could exacerbate their symptoms. Those who are generally sensitive to caffeine, or who metabolize it slowly, are also at an increased risk of feeling the effects more intensely. Pregnant women are often advised to limit or avoid kombucha due to the combined presence of caffeine and trace alcohol.
The quantity consumed is a major factor, as large servings increase the total dose of caffeine, sugar, and organic acids. New consumers should start with a small, four-ounce serving to assess their individual tolerance. While most palpitations are harmless and resolve quickly, any instance accompanied by more severe symptoms warrants immediate medical attention. Warning signs include chest pain, significant shortness of breath, profound dizziness, or fainting, as these may indicate a more serious underlying cardiac event.