Effect of Green Tea Consumption on Alzheimer’s disease

The intake of tea, which contains caffeine and tea polyphenols, may be important. High caffeine intake may reduce the risk for dementia. Particularly in Alzheimer’s disease, the green tea catechin polyphenols have been reported to have neuro-protective effects such as anti-oxidative stress, anti-inflammation, inhibition of amyloid-beta aggregation, and anti-apoptosis.

Alzheimer’s disease is one of the most common neurodegenerative disorders worldwide. Its incidence is gradually increasing because of an aging demographic. Therefore, Alzheimer’s disease prevention and modification is important to improve the health status of older adults. Oxidative stress is a component of the pathological mechanisms underlying Alzheimer’s disease.

Alzheimer’s disease is the second leading health concern among adults following cancer, being the sixth leading cause of death, and also the only disease among the top 10 that cannot be prevented, cured, or treated.

Catechins, which are bioactive components of tea, have antioxidative and anti-inflammatory effects. Catechins may contribute to protection from neuro-degeneration. Beverages containing plant polyphenols have been recommended as a natural complementary therapy for alleviating the symptoms of A Alzheimer’s disease. Specifically, one study reported that language and verbal memory were positively associated with the intake of green tea catechins and black tea theaflavins.

Bioactive green tea components reportedly have antioxidant and anti-inflammatory activities, induce protein kinase C activation, inhibit acetylcholine esterase activity, and modulate other neurotransmission systems (e.g., GABAergic, glutamatergic, dopaminergic, and serotonergic neurotransmission).

Data from several cross-sectional studies consistently showed that tea drinking is associated with better performance on cognitive tests. Tea consumption is considered to be one simple lifestyle adjustment that may either prevent or treat the cognitive declines associated with neurodegenerative Alzheimer’s disease.

Effect of Green Tea Consumption on Alzheimer’s disease  

Antioxidant in green tea

Green tea is made from leaves of camellia sinensis that have undergone minimal oxidation during processing. The chemical composition of green tea varies with genetic strain, climatic conditions, soil properties, plucking season, position of the leaf, processing and storage.

The chemical composition of tea leaves has been well documented. The main constituents of tea leaves are polyphenols. Polyphenols constitute the most interesting group of green tea leaf components and in consequence green tea can be considered as an important dietary source of polyphenols, particularly flavanoids. Especially, catechins, the main component of polyphenols, are well known for their antioxidant properties, which have led to their evaluation in many diseases associated with free radicals, including cancer, cardiovascular and neurodegenerative diseases.

Generally, the major catechins of tea leaves are (+)-catechin (C), (−)-epicatechin (EC), (+)-gallocatechin (GC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECg), (−)-epigallocatechin gallate (EGCg), and (+)-gallocatechin gallate (GCg).

The antioxidant activity of green tea polyphenols is primarily attributed to the combination of aromatic rings and hydroxyl groups that assemble their chemical structure and consequently binding and neutralization of lipid free radicals by these hydroxyl groups. Catechins also exhibit antioxidant activity via chelating redox active transition-metal ions. Polyphenolic compounds, possess hydroxyl and carboxyl groups, are able to bind particularly iron and copper.

A wide variety of other components exists, including, flavones, phenolic acids and depsides, carbohydrates, alkaloids, minerals, vitamins and enzymes. Green tea also contains carotenoids, tocopherols, ascorbic acid (vitamin C), minerals such as Cr, Mn, Se or Zn, and certain phytochemical compounds.
Antioxidant in green tea