Tea vs Alzheimer’s Disease
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- Long’jing 龍井, a flat-roasted tea, is by far the most famous green tea of China. This one from Meijiawu, Hangzhou 杭州梅家塢 20528 | 8768
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- Huangshan Maofeng 黄山毛峰, original style, premium quality. This is perhaps the most famous baked green tea. Notice that it is more yellow than some other green tea.
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- Uji Gyokuro 宇治玉露 of a very fine quality “Purple Cloud” grade, a classic representation of premium Japanese steamed green tea.
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- Shiguping Wulong 石古坪烏龍, a rare Phoenix oolong made from a local wulong cultivar
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- Wenshan Paochong, or Wenshan Baozhong 文山包種, classic traditional Taiwan oolong
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- Wuyi Aijiao Wulong 武夷矮腳烏龍, an oolong made from a special local wulong cultivar. 20053, 2007 | 8981
Theanine — protective effects on the nervous system
These scientists have found out that theanine helps the neuron cells stay alive against the bad effects of Aß. This substance that is unique in tea also neutralises the enzymes and free radicals that turns protein bad, thereby reducing the plaque density and lessening its killing power — fortifying the base and weakening the enemy.
In fact, in various cognitive and memory tests, the mouse could avoid a minimum average of over 22% of the adverse effects when fed with a dosage of 2mg/kg of theanine a day, and as much as 86% when the dosage is double. In another word, the protective effect of theanine against the damage of Alzheimer’s Disease is dose dependent.
Caffeine, the substance that can contribute to good health
We all know caffeine for its stimulating effects on the nervous system and the side effects of its overdosage. It is lesser known, however, that moderate consumption of this common substance can reduce or reverse symptoms caused by Alzheimer’s Disease 1. Aß plaques in the brain are reduced 2.
Scientists have observed that it may be working in another direction supplementing that of theanine.
As we age, the production of our cerebrospinal fluid (CSF), the clear liquid that protects our brain in between it and the skull, reduces. However, it can go as dramatically severe as 50% lower in Alzheimer’s patients 3. Lesser CSF means reduced blood flow and weakened immune in the brain, ideal for proteins to become bad. In several studies, consistent moderate intake of caffeine has led to an increase in CSF production, thereby replenished blood flow volume and immunity to the brain, which in turn helped to reduce Aß plaques 4.
Most studies, however, have focused in EGCG and other flavonoids that fight free radicals in our systems that cause various oxidative stresses that makes such originally good substances as proteins or oils to become bad. Anti-oxidative properties, as this defensive mechanism is called, are possessed by many of the tea substances, including theanine and caffeine, but most noticeably in EGCG.
EGCG, more than an anti-oxidant
A great number of studies have pointed out that EGCG — the most potent flavonoid found uniquely in tea — not only enhances our cognitive functioning 5, but also protects various types of neurons in different parts of the whole nervous system both from the toxicity of Aß or other metabolic mutants, and from reverting the conditions where these pathogens can be formed 6. It is therefore a most researched substance as a natural drug.
Neuron cells in Gyrus Dentatus, an important structure in hippocampus, which is widely believed to be responsible for how we perceive incidents and the environment. In a study where scientists focus in the action of EGCG in this part of the mammalian brain, they found that the tea substance not only protect these particular neutron cells from harmful oxidative damages, but also maintain their active functions 7
Scientists in UK, having examined yet more reports, proposed that we should actually look at the neuro-protective functions of EGCG and other flavonoids a bit more precisely. They observed that as EGCG is ingested, it interacts with our digestive system to have transformed in nature to become available in our blood stream into various parts of the body, including the brain. There it integrates into the daily neuron activities to encourage the making of good enzymes and discourage the forming of bad ones. Some of the latter, if let free, can cause the formation of bad protein such as the tangling of tau protein and Aß plaques as mentioned earlier. Good enzymes help to repair endangered cells and to maintain the balance of our physiological functions. A bit of substance can do a lot.
More than that. Potent flavonoids, such as EGCG, the scientists concluded, regulates blood flow to the brain so as to maintain its normal health. They are also powerful immunological substances that inhibit a wide range of pathological processes that may take place in the brain 8. In a recent and more dramatic study, scientists actually observed how EGCG protects the neuron cells in the crucial hippocampus part of the brain and maintains their active functions.
The defense is yet to build, or it maybe in your own hands
On the subject of how tea substances or other related naturally occurring “nutraceuticals” can be contributive to the fight against the dreadful disease of Alzheimer’s, research efforts will continue to show new findings, albeit with great varieties and focuses.
The bad news is, nothing concrete as an immunity shot or a proven drug seems to happen soon. Not likely to be sooner than before the baby-boomers turn 65
The good news is, we know from these scientific findings ( and a lot more that we have not quoted here ) that natural occurring substances such as the theanine, caffeine and EGCG in tea “may have a greater potential for therapeutic success than drugs…”, because drugs, such as the one that was recently given up for tests by Pfizer and Johnson & Johnson, have “only one mechanism of action” 9.
As the world becomes more linked by such modern amenities as the internet and international air parcels, it really is not that difficult to treat oneself ( or one’s maturing parents ) daily with a few cups of fine tea, if not only for the taste, at least for the more potent and complex protection mechanism this may provide. At least there can be one less regret.
Mom in her favourite dress — cheung-sham
- X. Chen et al, Caffeine protects against disruptions of the blood-brain barrier in animal models of Alzheimer’s and Parkinson’s diseases, Journal of Alzheimer’s Disease, 2010, 20, supplement 1, 127–141
G.W. Arendash et al, Caffeine protects Alzheimer’s mice against cognitive impairment and reduces brain β-amyloid production, Neuroscience, 2006, 142-4, 941–952 ↩ - R. Zeitlin et al, Caffeine induces beneficial changes in PKA signaling and JNK and ERK activities in the striatum and cortex of Alzheimer’s transgenic mice, Brain Research, 1417, 12 October 2011, 127–136
H. Qosa et al, Enhanced Brain Amyloid-β Clearance by Rifampicin and Caffeine as a Possible Protective Mechanism Against Alzheimer’s Disease, Journal of Alzheimer’s Disease, 31-1, 2012, 151-165 ↩ - G.D. Silverberg et al, The cerebrospinal fluid production rate is reduced in dementia of the Alzheimer’s type, Neurology, 57-10, 2001, 1763–1766 ↩
- P. Wostyn et al, Increased Cerebrospinal Fluid Production as a Possible Mechanism Underlying Caffeine’s Protective Effect against Alzheimer’s Disease, International Journal of Alzheimer’s Disease, doi:10.4061/2011/617420 ↩
- A. Schmidt et al, Green tea extract enhances parieto-frontal connectivity during working memory processing, Psychopharmacology (2014) 231:3879–3888 ↩
- R. Shytle et al, Green Tea Epigallocatechin-3-Gallate (EGCG) and Other Flavonoids Reduce Alzheimer’s Amyloid-Induced Mitochondrial Dysfunction, Journal of Alzheimer’s Disease: 2011-101629
K.Rezai-Zadeh et al, Green Tea Epigallocatechin-3-Gallate (EGCG) Modulates Amyloid Precursor Protein Cleavage and Reduces Cerebral Amyloidosis in Alzheimer Transgenic Mice, The Journal of Neuroscience, September 21, 2005, 25(38):8807– 8814 ↩ - K.J. Seong et al, Epigallocatechin-3-gallate rescues LpS-impaired adult hippocampal neurogenesis through suppressing the TLR4-NF-kB signaling pathway in mice, Korean Journal of Physiological Pharmacology 2016; 20(1):41-51 ↩
- R.J. Williams et al, Flavonoids, cognition, and dementia: Actions, mechanisms, and potential therapeutic utility for Alzheimer disease, Free Radical Biology & Medicine, 2012, 52, 35–45 ↩
- NA Kelsey, Nutraceutical Antioxidants as Novel Neuroprotective Agents, Molecules, 2010, 15, 7792-7814 ↩
Thank you @Scott. We’d wanted to be even more specific in the writing referencing citations in the named reports, yet we have to balance it with the need for a broader audience. This goes for all our articles in the tea health category, except for the TCM sub-category, which reference canonical classic literature and common sense in better TCM practice.
Well done. Glad to see the references–so many people like to make claims without backing it up with references. I am a biomedical engineer, writer, and tea merchant. Thanks for sharing.