Understanding L-theanine and its relaxing effect
L-theanine is a non-protein amino acid primarily found in green and black tea leaves and some mushrooms. It is known for promoting relaxation without causing drowsiness and is a popular supplement. L-theanine crosses the blood-brain barrier and influences brain chemistry.
How L-theanine works in the brain
In the brain, L-theanine impacts neurotransmitters and brain wave activity, increasing GABA production for a calming effect, boosting alpha brain waves linked to relaxed alertness, and modulating stress-related neurotransmitters like dopamine and serotonin.
The relationship between L-theanine and blood pressure
Research suggests L-theanine's effect on blood pressure is mainly indirect, linked to its ability to reduce anxiety. It doesn't directly lower blood pressure but helps reduce the increase caused by stress. A study indicated that L-theanine supplementation significantly inhibited blood pressure increases during mental tasks in adults with high stress responses. This calming effect counteracts stress hormones that raise blood pressure. This effect appears strongest in those with high stress responses, while those with low or stable blood pressure may see little change. Animal studies on hypertensive rats also showed a dose-dependent reduction in blood pressure.
The L-theanine and caffeine interaction
L-theanine is naturally found with caffeine in tea, making their interaction relevant. While caffeine can temporarily increase blood pressure and heart rate, L-theanine seems to counteract these stimulant effects. Studies show L-theanine can blunt caffeine's blood-pressure-increasing and jitter-inducing effects while maintaining cognitive benefits when taken together. This synergy contributes to the smoother focus often experienced from tea.
Side effects, and contraindications
L-theanine is generally considered safe for short-term use with a good safety profile. However, certain precautions are necessary.
Comparison of effects in different populations
The impact of L-theanine varies significantly based on individual health status and other medications. For healthy individuals with low stress, the effect on blood pressure is minimal. Those with high stress may see reduced stress-induced spikes. However, individuals on antihypertensive drugs or with hypotension face a moderate to high risk of dangerously low blood pressure or a further drop. Medical supervision is essential for those on medication or with existing low blood pressure.
Safety
While no official recommendation exists, studies have safely used varying amounts for periods of time.
Contraindications and drug interactions
Combining L-theanine with blood pressure medication can cause blood pressure to drop too low and should be closely monitored by a healthcare provider. It may also reduce the effectiveness of stimulants. Individuals with low blood pressure should be cautious, as L-theanine could cause a further drop and lead to dizziness.
Natural sources and alternative strategies
Tea is the main natural source of L-theanine. Different teas have varying amounts: Green tea has 6.56 mg/g, white tea has 6.26 mg/g, Oolong tea has 6.09 mg/g, and black tea has 5.13 mg/g. A cup of green tea offers a mild amount. For a potentially stronger effect, supplements may be considered. Stress management techniques like mindfulness, exercise, and meditation are also beneficial for stress-related blood pressure issues.
Conclusion
L-theanine can impact blood pressure by reducing stress-induced spikes, promoting relaxation by increasing GABA and alpha brain wave activity. This effect is more pronounced in those with high stress reactivity. However, it is not a primary hypertension treatment and requires caution for individuals with low blood pressure or those taking antihypertensive medications. Consultation with a healthcare professional is vital for usage and safety. The interaction with caffeine in tea, where L-theanine smooths out stimulant effects, is another benefit. For more information, consult the National Institutes of Health research on the subject.
