By Dr. Mercola
If you could have a cup of green tea and fight Alzheimer's disease in the process, how many cups would you have? The ancient beverage has been recognized for millennia as having a dramatic and positive impact on human health, but its potential for improving several aspects of your brain, as well as your heart, is becoming more clear thanks to ongoing research.
After all, nearly 50 million people worldwide — one of every nine people over the age of 651 — are wrestling with this devastating disease, described as a neurodegenerative condition evidenced by a progressively advancing mental decline that affects memory and behavior. Experts say that by 2050, that number could surpass 131.5 million.2
While scientists weren't yet clear on what mechanisms made the green tea-for-Alzheimer's link possible, new research, covered in the Journal of the American Chemical Society,3 has determined that antioxidant compounds called catechins are the facilitators (and to a lesser degree, theaflavin polyphenols in black tea).4
Lead study author Giuseppe Melacini, from the chemistry and chemical biology departments at McMaster University in Canada, asserts that the best remedy for Alzheimer's is early intervention. He also notes that using either green tea extracts or their derivatives — as far in advance as 15 to 25 years prior to symptoms appearing — is one method of early intervention.
What he's really suggesting is that anyone wanting to avoid the disease or lessen its effects should begin drinking green tea now rather than waiting until symptoms emerge — although there are a multitude of steps to reduce your Alzheimer's risk beyond drinking green tea.
What Causes Alzheimer's Disease?
It's important to remember how powerful antioxidants are and that polyphenols are some of the most prominent. Taking that a step further, one of the most potent polyphenols in green tea is a catechin known as epigallocatechin-3-gallate, or EGCG. The reason these findings are so important, Medical News Today reports, is because it:
"Disrupts the formation of toxic plaques that contribute to the disease. Researchers found that the green tea polyphenol epigallocatechin gallate (EGCG) stops the formation of beta-amyloid plaques — a hallmark of Alzheimer's disease — by interfering with the function of beta-amyloid oligomers."5
Beta-amyloid is a sticky protein that can clump together and form the plaques that cause the problems leading to Alzheimer's disease. Scientists used nuclear magnetic resonance to scrutinize the way EGCG made the difference in inhibiting plaque formation. Beta-amyloid monomers are tiny binding molecules. Think of it this way: A monomer is one, and a polymer is more than one. When beta-amyloid monomers form beta-amyloid oligomers, over time they can stick together and form toxic beta-amyloid plaques.
Melacini and his research team explained that EGCG in a sense "remodels" the oligomers by coating them, which keeps them from further development and eventually may be what halts the plaque-forming process. In fact, the study team discovered that it occurs at the molecular level by inhibiting the ability of toxic oligomers to grow and interact with healthy cells, Melacini explains.
Previous studies had determined this was the case, but the mechanism linking the prevention of plaque formation hadn't been connected. The bottom line is that drinking green tea could literally help prevent the development of Alzheimer's disease, and the sooner you start, the better. However, because it's difficult to deliver EGCG to the brain directly, further research is called for to discover ways to modify the compound in order to remedy this problem.
Other Ways Catechins Help Your Brain
According to Scholar Commons, examinations of post-mortem brains have shown that abnormalities from Alzheimer's include loss of synapses, inflammatory processes and "intraneuronal neurofibrillary tangles composed of hyperphosphorylated tau protein and extracellular 2 neuritic plaques comprised of aggregated amyloid-β (Aβ)."
Aβ is further described as an amphipathic peptide that originates from the proteolytic processing of the amyloid precursor protein (APP), a transmembrane glycoprotein that is concentrated in synapses and neurons. Animal studies show that Aβ plaques appear before the neurofibrillary tangles, implicating the accumulation of aggregated Aβ as the primary pathogenesis of Alzheimer's.
One study shows that the catechins in green tea cannot only protect your brain from developing Alzheimer's and other forms of dementia but also increase brain function, improve your memory and decrease damage done by heavy metal toxicity. The study adds that polyphenols' brain-penetrating, antioxidant and iron-chelating properties make them of special interest for future research into the "treatment of neurodegenerative diseases where oxidative stress has been implicated."6
Antioxidant Catechins: What Else Can They Do?
Lower your risk of developing dementia
Keep your blood pressure at a healthy level
Improve your eye health
Put your body in fat-burning mode to help you lose weight7
Improve both your bone structure and strength
Lower your risk of certain cancers8
Help relax your mind
Boost your energy
Enhance glucose tolerance for diabetics9
Catechins have the potential to deliver several more very potent perks, noted in the featured video. Multiple studies have noted that green tea has positive effects on nearly every part of your body. The Journal of the American College of Nutrition lists a number of them and further supports the above studies:
"Recent human studies suggest that green tea may contribute to a reduction in the risk of cardiovascular disease and some forms of cancer, as well as to the promotion of oral health and other physiological functions such as anti-hypertensive effect, body weight control, antibacterial and antivirasic activity, solar ultraviolet protection, bone mineral density increase, anti-fibrotic properties, and neuroprotective power."10
How Do Catechins in Green Tea Help Your Heart?
EGCG may also reduce oxidative stress because it combats cell damage that can be unleashed by free radicals.11 In a search to find more ways drinking green tea can improve your health, clinical studies have shown that it also helps optimize your cholesterol and triglycerides.12 EGCG in particular can also help prevent the buildup of plaque in the arteries, known as atherosclerosis.
One comprehensive review in Japan, citing research on 90,000 participants, linked green tea consumption with a lower risk of death due to heart disease, as well as from stroke or a heart attack.13 Another Japanese study (where green tea may be considered the most widely consumed beverage), involving more than 40,000 people, noted that the practice coincided with lowering the risk of death from heart disease by 22 percent in men and 31 percent in women.14
Interestingly, green tea catechins also have antibacterial effects, with low concentrations of the compounds inhibiting the growth of bacterial spores, including those that are generally resistant to disinfectants.17 Research published in the journal Cardiovascular & Hematological Disorders Drug Targets further noted, "[C]atechins may be effective against cardiovascular problems through modulating blood lipid metabolism, protecting vascular endothelial and decreasing blood pressure."15
Everyday Health quotes Erin Palinski-Wade, registered dietitian and author of "Belly Fat for Dummies:" "EGCG can [also] help boost metabolism, helping to make it easier to achieve and maintain a healthy weight. In addition, green tea helps improve the function of endothelial cells in blood vessels."16
The Results Are In: Green Tea Is Heart and Brain Protective
While green tea does contain caffeine, which is a stimulant, it imparts a calming effect on the jittery feeling you can get when you get too much. This is due to a high concentration of an amino acid called L-theanine, which boosts alpha wave activity in your brain and produces a state that one meta-study referred to as a state of "relaxed concentration." As a bonus, it also helps decrease blood pressure.18
Huffington Post19 notes that the best way to prepare your green tea in order to release the most powerful effects of the polyphenolic EGCGs is to use a high-quality loose-leaf green tea and steep it for three to five minutes.
You don't even need to drink very much: According to The Spruce,20 you should drink four of five cups daily for the maximum benefit — and that would be a true cup, equaling 16 tablespoons — although you could drink more with no problem. Healthy Eating21 maintains that two cups will provide a healthy amount of polyphenols. It's really up to you.
It's clear that, besides the anecdotal narratives passed down from ancient cultures throughout Asia, Europe and the rest of the world, and the many clinical studies that have confirmed its beneficial attributes, green tea is something you should be making part of your routine. Not only could it help you live longer, it may also improve your quality of life.
When selecting tea, opt for organic (to avoid pesticides) and grown in a pristine environment (to avoid fluoride, heavy metals and other toxins from contaminated soil and water). If you're consuming Matcha green tea (which contains the entire ground tea leaf), it's especially important that it comes from Japan instead of China, where excessive industrial pollution may lead to soil with substantial amounts of lead. A clean growing environment is essential to producing a pure, high-quality tea.