On any given day, 159 million Americans enjoy a cup of tea.

And unlike soft drinks, AKA sugar water, tea is actually good for you, improving bone density, strengthening immunity, and reducing the risk of heart disease, stroke, and certain cancers.

What’s good for the body is good for the brain, too.

Consumed regularly, caffeinated tea is linked to clarity of mind, alertness and enhanced attention. But so far, the brain benefits of tea have mainly been tested in middle-aged people. Would tea also help seniors and the elderly? And what about differences between black tea and green tea? A research group in the United Kingdom decided to find out.

Dr. Edward Okello knows a thing or two about tea.

His first tea study was back in 2004 when he and fellow biologists at the University of Newcastle came up with a novel finding.

They discovered that both green and black tea inhibited two enzymes that are found in abnormally high levels in those with Alzheimer’s disease.

Another one of Dr. Okello’s studies showed both black and green tea alter brain waves to potentially reduce anxiety, and increase attention and concentration.

While much of the research has focused on green tea, 84 percent of all tea consumed in the U.S. is black tea, compared with 15 percent devoted to green tea.

For Dr. Okello’s latest study he focused on whether black tea has brain benefits in people over the age of 85. To that end he and his research team looked at data from a special study of the elderly that began in 2006.

Increased Attention, Accuracy and Speed

Dr. Okello and his team assessed the black tea drinking habits of 676 dementia-free men and women living in the north of England. They examined participant interviews and brain tests as well as data from a five-year health follow up.

Dr. Okello found those consuming the most black tea – more than five cups a day – had better focused and sustained attention. They also showed better psychomotor skills, which link brain and movement. In tests of cognition, the participants’ answers were more accurate and they also displayed faster reaction speeds.

All these benefits could help in any number of varied activities such as driving a car, sewing, or completing a puzzle.

Although the researchers took demographic factors and an extensive array of health variables into account that could influence their findings, Dr. Okello admitted that “the skills we see maintained in this group… may not only be due to the compounds present in tea but it may also be the rituals of making a pot or sharing a chat over a cup of tea which are just as important.”

He summed up by saying, “We now know that enjoying a cup of tea quenches your thirst and has benefits for the over 85s’ attention span. What better excuse do we need for enjoying a cup together?”

Previous studies on black tea and green tea conducted with a variety of different age groups have found similar results.

Reduces Risk of Cognitive Impairment and Decline

A population study from Singapore, involving 2,501 participants aged 55 or older, found tea was protective of brain and memory health.

Even after a wide range of factors that impact cognition were taken into account, when drinkers of tea were compared to non-drinkers their risk of cognitive impairment dropped from 44 percent for those drinking one to three cups a day, to 63 percent for those drinking seven cups a day or more. For cognitive decline, there was reduction of 26 percent and 43 percent respectively. The researchers found no such benefits for coffee drinkers.

The “tea” in this study included black tea (either Chinese or English), green tea, Ceylon tea and oolong tea. The researchers found that black tea and oolong tea provided the most protection against poor cognition.

These results were backed up by a randomized controlled trial, which found that 400ml (13½ fluid ounces) of black tea a day caused “rapid increases in alertness and information processing.” Even more interesting, this increase was not due to caffeine alone.

So if caffeine alone is not responsible, what is?

Tea Contains a Unique Amino Acid

All varieties of tea contain various polyphenols and catechins that have demonstrated positive effects on brain function in research studies.

Tea also contains L-theanine. The body does not produce this unique amino acid. Tea is almost the only place it’s found.

Research on L-theanine has uncovered that although it is not essential for health, it provides numerous positive brain benefits such as improved cognitive performance, elevated mood, improved relaxation, and enhanced sleep.

My Takeaway

While the research reported is certainly not an exhaustive review of black and green teas’ effects on cognition, it does appear that black tea edges out green tea for seniors’ memory and focus in the most recent research.

The result is a bit surprising. When it comes to cancer prevention and cardiovascular health, most studies suggest green tea has the edge. I’ll confess to a prejudice of my own: I much prefer black tea for flavor. I take mine with milk or half and half. I’ll drink green tea (milk not recommended), but as a taste experience it doesn’t do much for me.

The best move may be to switch it up from time to time and try both. The good news is that no matter which kind of tea you prefer, they all appear to have some positive impact on your brain, so drink up!


  1. https://pubmed.ncbi.nlm.nih.gov/15476306/
  2. http://www.teausa.com/teausa/images/Tea_Fact_2021.pdf
  3. https://academic.oup.com/ajcn/article/88/1/224/4648937 
  4. https://www.ncl.ac.uk/press/articles/latest/2020/12/cupofteabrightensthedayandthemind/ 
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7537102/