Nutrition Facts with Dr. Greger The Health Benefits of Black and Green Teas
Mar 26, 2026
A dive into what makes Camellia sinensis special and why one plant yields both black and green teas. Exploration of theanine and how tea shifts brain waves toward relaxed alertness. Research on using green tea as a mouthwash for plaque and bad breath is discussed. Studies linking tea drinking to longer life and tea’s antiviral immune-boosting effects are highlighted.
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Tea L-theanine Produces Meditative Alertness
- The tea plant Camellia sinensis contains L-theanine, a compound concentrated almost nowhere else in nature.
- L-theanine increases alpha brain waves, producing relaxed alertness similar to long meditation after just a cup of tea.
Try Green Tea Mouthwash For Oral Health
- Use green tea as an oral-care adjunct because it can match or approach chlorhexidine for reducing plaque and has far fewer side effects.
- Randomized trials show a green tea mouthwash twice daily for a month reduced halitosis compounds ~40% versus ~10% with placebo.
Three Cups Of Tea Associated With Longer Life
- Epidemiological data link tea drinking to lower premature death, cardiovascular disease, stroke, and type 2 diabetes.
- A three-cup per day increase associates with a 24% lower risk of premature death, roughly adding two years of life.
