Dr Michael Mosley, the health expert and creator of the Fast 800 and 5:2 diets, has said that changing to a 'green diet' can help 'ward off' dementia.

Green tea is a beverage or dietary supplement that may improve mental alertness, relieve digestive symptoms and headaches, and help with weight loss, but it apparently has other fantastic qualities.

Scientists have found that following a green diet appeared to slow the brain from shrinking - also known as brain atrophy that happens as people age, and can cause dementia - through eating antioxidant-rich foods.

Michael Mosley previously wrote about the effects of green tea for the Daily Mail, saying: "A recent study in Israel compared the impact of a low-fat diet, a Mediterranean diet (lots of veg, oily fish and olive oil) and a green Mediterranean diet.

"[This] is like the Mediterranean diet, but the participants also had to drink three cups of green tea and a green shake made of Mankai duckweed (a plant from Southeast Asia) that's packed with protein and other nutrients."

The health guru also discussed the key ingredient in the green 'super shake' that could be the main factor in warding off dementia.

He continued: "At the end of the 18-month study, both Mediterranean diets had improved the participants' brain volume, but it was the Greenies who came out on top.

"The researchers think this is because the green diet is especially rich in polyphenols, a type of antioxidant that can cross into the brain and encourage the production of new brain cells."

Professor Iris Shai, the lead author of the study Mosley quotes, added: "The beneficial association between the green Mediterranean diet and age-related neurodegeneration might be partially explained by the abundance of polyphenols in plant-based food sources which have antioxidant and anti-inflammatory metabolites.

"Polyphenols can cross the blood-brain barrier (BBB), reduce neuroinflammation, and induce cell proliferation and adult-onset neurogenesis in the hippocampus."

Fellow researcher, Doctor Alon Kaplan, explained that the study's findings could suggest a "simple, safe and promising" way to slow down age-related degeneration of the brain.