By Mark Waghorn via SWNS
The beverages are rich in antioxidant flavonols - plant chemicals that boost blood flow to the brain, say scientists.
Older people who consumed most had better memory skills. The antioxidants are also found in fruit and vegetables.
"It's exciting our study shows making specific diet choices may lead to a slower rate of cognitive decline," said lead author Dr. Thomas Holland, of Rush University.
Flavonols are pigments. Drinking and eating a "rainbow of colors" ensures you get all the different ones.
Holland and colleagues tracked 961 Americans in their 70s and 80s for an average of seven years.
Cognitive scores of those who had the highest intake - about a black of cup tea a day - fell 40 percent slower per decade than peers with the least.
Flavonols were broken down into five different types - kaempferol, isorhamnetin, myricetin, quercetin and isorhamnetin.
Kaempferol, abundant in leafy green vegetables, kale and tea had the biggest benefit followed by myricetin - which is found in red wine.
Then came quercetin - also in tea and kale as well as tomatoes and apples. Isorhamnetin which is in olive oil had no effect.
The results stood after taking into account other factors such as age, sex and smoking history.
Holland believes the phenomenon is due to the "inherent antioxidant and anti-inflammatory properties of flavonols."
"Something as simple as eating more fruits and vegetables and drinking more tea is an easy way for people to take an active role in maintaining their brain health," he said.
The number of dementia cases worldwide is expected to tripled to more than 150 million by 2050.
With no cure in sight protective lifestyle behaviors, such as eating healthily and getting plenty of exercise, are currently seen as the best bet.
Participants completed annual cognitive and memory tests such as remembering words and numbers and filled out food questionnaires.
They were also asked about their level of education and how much time they spent doing exercise and mentally engaging activities like reading and playing games.
The volunteers were divided into five groups based on the amount of flavonols in their diet - the lowest about 5 mg per day and the highest 15 mg.
Rates of memory decline were worked out using an overall global score summarizing 19 cognitive tests.
Alzheimer's and other forms of dementia affects more than 920,000 Britons - a figure that will rise to two million within the next three decades. The study is in Neurology.
Stories and infographics by ‘Talker Research’ are available to download & ready to use. Stories and videos by ‘Talker News’ are managed by SWNS. To license content for editorial or commercial use and to see the full scope of SWNS content, please email email@example.com or submit an inquiry via our contact form.
World’s first solar-electric car in production
Featuring 5sqm of curved solar arrays, the Lightyear 0 charges wherever there is daylight, whether parked up or on the...
Stunned onlookers watch as fleet of robots line up at crosswalk
"I even heard one of them ask a lady passing to press the button for them."
Woman creates new device to help women recovering from a mastectomy
"With other prosthetics, like legs, the primary concern isn't that it looks like a real leg, it's that it's functional...
Noisy neighbors scientifically proven to be more annoying than other sounds
The team believe their research is pressing as populations are becoming increasingly dense and working from home is more and...
New study shows sharks ‘walking’ on sea floor
“This work illustrates the immense behavioral adaptability of coastal shark species."
- Quizzes4 days ago
Take a swipe at our online dating quiz
- Holidays5 days ago
Stunning photos show 100,000 colorful poinsettias ready for Christmas
- Outer Space6 days ago
NASA grants 3D printing company $57.2 million to build towns on lunar surface
- Holidays4 days ago
Should the holiday season last longer?
- Dating & Relationships4 days ago
What do people lie about on their online dating profiles?
- News5 days ago
Manor once owned by ‘Sherlock Holmes’ author Sir Arthur Conan Doyle on sale
- Home6 days ago
What are the keys to a good relationship with your landlord?
- Cars6 days ago
Aston Martin designed home lets owners park cars near dining table