The warm drink fights memory loss, inflammation and heart disease

Green tea could help fight memory loss and improve learning caused by a high-fat, high-sugar Western diet, a recent study suggests. The drink, rich in a chemical that has antioxidant, anti-inflammatory and heart-protective properties, also protects against diabetes and obesity.

Green tea has been used for centuries in traditional Chinese medicine to treat everything from headaches to depression. The popular drink is also richer in antioxidants than other teas, thanks to the way it’s steamed rather than fermented.

It contains B vitamins, folic acid, manganese, potassium, magnesium, caffeine and other antioxidants, especially catechins. Previous studies suggested that green tea boosted weight loss, lowered cholesterol, fought cardiovascular disease, and prevented cancer and Alzheimer’s disease.

But its impact on the cognitive decline triggered in the brain by a Western diet remained unclear. Researcher Dr Xuebo Liu from the College of Food Science and Engineering, Northwest A&F University, Yangling, China, said: “Obesity, which is caused by an energy imbalance between calorie intake and consumption, has become a major health burden in international level.

“Obesity increases the risk of insulin resistance and age-related cognitive decline accompanied by peripheral inflammation. Epigallocatechin-3-gallate (EGCG), the main polyphenol in green tea, possesses antioxidant, anti-inflammatory and cardioprotective activities.

“However, few reports have focused on its potential effect on cognitive impairment.” The study gave three-month-old mice either a control diet, a high-fat, high-sugar diet, or a high-fat, high-sugar diet and two grams of EGCG per liter of drinking water.

They were monitored for 16 weeks, and those fed the “Western diet” had a higher final body weight than control mice and a significantly higher final body weight than mice fed the Western diet and polyphenol. Their memory loss was measured using a Morris water maze test.

The study found that polyphenol prevented memory impairment and neuronal loss caused by the Western diet. It was found that mice on the Western diet took longer to find the platform compared to mice in the control group.

Mice deprived of polyphenols were better at finding their way, and food sources suggest the chemical improved memory. It also reduced a high-fat, fructose-induced diet and significantly ameliorated insulin resistance and cognitive impairment by upregulating insulin receptors.

Long-term high-fat, high-fructose diet triggered neuroinflammation was also restored by inhibiting harmful pathways as well as expression of inflammatory mediators. Dr Liu added: “To our knowledge, this study is the first to provide compelling evidence that the nutritional compound EGCG has the potential to ameliorate learning and memory loss caused by a high-fat, high-fructose diet.

“Green tea is the second most consumed beverage in the world, after water, and is grown in at least 30 countries. “The ancient habit of drinking green tea may be a more acceptable alternative to medicine when it comes to fighting obesity, insulin resistance, and memory disorders.”

The study was published in The FASEB Journal. Dr. Thoru Pederson, its editor-in-chief, said: “Many reports, anecdotal and to some extent research-based, are now greatly strengthened by this more penetrating study.”