Tag Archives: green tea

Green tea and carrot compounds reverse Alzheimer’s symptoms in mice

Credit: Pixabay.

Billions have been spent on research that might lead to new drugs for treating Alzheimer’s, but while substantial progress has been made, there’s not much yet in the way of a cure. But one new study suggests that dieting may be an important factor for managing the neurodegenerative disease’s symptoms. According to the findings, chemical compounds typically found in green tea and carrots reversed Alzheimer’s-like symptoms in mice.

“You don’t have to wait 10 to 12 years for a designer drug to make it to market; you can make these dietary changes today,” said senior author Terrence Town, a professor of physiology and neuroscience at the University of Southern California. “I find that very encouraging.”

Town and colleagues focused on two compounds: EGCG ( epigallocatechin-3-gallate), one of the main ingredients of green tea, and FA (ferulic acid), commonly found in carrots, tomatoes, rice, wheat, and oats. The researchers randomly assigned 32 mice, which were genetically modified to have Alzheimer’s, to one of four groups, divided into an equal number of males and females. For three months, mice were given a combination of EGCG and FA, either EGCG or FA only, or a placebo — yes, rodents also have the placebo effect. Additionally, a group of healthy mice provided baseline performance for Alzheimer’s-free symptoms.

Before and after the three-month diet, the rodents were subjected to a barrage of tests that gauged their thinking and memory skills. One such test involves a Y-shape maze in order to assess a mouse’s spatial working memory, which is key to finding your way out of a building.

A healthy mouse will explore each arm of the Y maze in search of food or a way out. They will enter the three arms in sequence more often than by chance alone. But rodents with Alzheimer’s-like symptoms don’t do this as well because their spatial memory is impaired, making them more likely to explore the same arm twice.

“After three months, combination treatment completely restored spatial working memory and the Alzheimer’s mice performed just as well as the healthy comparison mice,” Town said.

Alzheimer’s disease is widely believed to be caused by the accumulation of beta-amyloid proteins which clump together to form plaques between neurons and disrupt cell function. Another physical characteristic of the Alzheimer’s diseased brain is the buildup of tau proteins, which tangle inside neurons, blocking their transport system. Town suspects that the compounds prevent bigger amyloid proteins from breaking up into smaller amyloid beta proteins that clog neurons. They may also reduce neuroinflammation and oxidative stress in the brain, both important aspects of Alzheimer’s pathology.

But while the study is exciting, its findings apply to mice and most such discoveries never translate into human treatments. Even so, green tea and carrots are harmless and there’s nothing to stop people from including them in their diet. In the future, Town wants to explore this combination treatment further.

The findings appeared in the Journal of Biological Chemistry.

How to brew the perfect black tea — according to science

So, you’ve gone through the basics. You’ve enjoyed a selection of herbal teas, the ubiquitous black tea, and who knows what other delicious wonders. But you want to do it right. Well, you’ve come to the right place. We’ll be looking at how to brew a tea properly, with advice from expert scientists, including the British Royal Society of Chemistry.

Tea brewing is as much an art as it is a science, and as George Orwell used to say, “the best manner of making it is the subject of violent disputes.” Needless to say, different teas require slightly different methods, and personal preference also plays an important role. However, there are some things which universally apply. We’ll have a look at how to brew the perfect tea, taking a black tea (Assam) as a sample, while keeping in mind that different teas require slightly different brewing times and temperatures.

The water

The water should be fresh and “soft” — hard water contains minerals that can create unwanted tea scum. This doesn’t really affect the taste, but it does create a rather unpleasant sight. For this reason, bottled mineral water is also a no-no. Having a nice soft water ensures that your tea will be smooth and uniform. It’s also good to use water that hasn’t been previously boiled. Tea loves oxygen, which allows it to spread its flavor generously, and pre-boiled water has lost some of that oxygen.

The cup

One should never drink tea from polystyrene cups, the Royal Society of Chemistry says. Not only does that make the tea too hot to drink straight away, but it also absorbs some of the flavors, and often adds in some of its own plastic or papery flavor. Tea should instead be enjoyed from a ceramic cup or a mug. Ideally, from your favorite mug, when it’s raining outside.

Personally, I like large mugs, because aside from allowing you to drink more tea, they retain heat better than smaller cups. Smaller cups (especially those with a large surface) tend to cool down faster. To accelerate cooling, you can leave a teaspoon inside the mug, where the metal will act like a radiator.

The tea

Loose tea is often more flavorful, but teabags can work just as well.

Tea bags are, of course, very convenient, but they do have a few downsides. Producers often bag lower-quality tea, though that is not always the case. Even if the tea is high quality, the bag itself slows down the infusion. In the case of black tea, not only do they slow down infusion, but they also favor the spread of tannins, which is less desirable due to their strong and unpleasant taste. Therefore, we recommend using leaves or other loose tea.

You don’t need a lot of tea per cup. A teaspoon (2 grams) is almost always sufficient and will ensure that the flavor spreads properly.

Of course, make sure that your tea is high quality. Good tea is not necessarily expensive — you can find cheap, high-quality. Make sure that the production area is written clearly on the label, and make sure it’s a type of tea you enjoy. Avoid artificial flavorings. Opting for fairtrade tea is always a good choice since it ensures that the people who worked to grow and harvest the tea get paid properly. But no matter what kind of tea you opt for, make sure it’s good.

The brewing

For green and black tea, infusion needs to be done at the highest possible temperature. However, as mentioned before, you don’t want to over-boil the water because that will make it lose oxygen. So as soon as it starts to boil, take it out of the kettle (or stop the fire) and start the infusion process.

For the perfect tea, you don’t want to put the hot water into a cold pot, so either pre-heat the pot (maybe in a microwave) or pre-fill it at least a quarter with boiling water, and then drain it.

Brew for 3-4 minutes. Again, this is often a matter of preference and depends from tea to tea, but 3-4 minutes is generally a good reference. The more you brew it, the more tannins and antioxidants are released into the brew. You want some of those because they’re good for you, but too many will leave behind a nasty aftertaste, which you want to avoid.

Image credits: Patrick George.

Milk and sugar

Milk and sugar are optional. Traditionally, milk was added to tea to preserve the delicate and very expensive Bone China cups, and the taste has remained popular, especially in the UK. If you do add milk, make sure to pour it first, before the tea, to ensure a nice spread of color. You can, of course, also add it after the tea — just be sure to mix it well to obtain a uniform color. If you’re lactose intolerant, you can substitute in other options, such as soy or almond milk. Just keep in mind that anything you add will change the taste of the tea.

There were some studies which claimed that adding milk to tea neutralizes the beneficial effect of its antioxidants, but more recent research has found that that is not really the case. It’s not clear why different studies obtained different results.

Sugar is also optional. White sugar is the most common option, but dark sugar and honey can also be used. A bit of sweetness works great with tea, as it moderates the tea’s natural astringency. Of course, too much sugar isn’t good for you, and it will also mask the flavor of the tea. Honey is another great choice — it’s not as sweet, it adds a bit of secondary flavor, and it’s more healthy than sugar. Just make sure to not pour it into boiling water, because that will destroy its beneficial properties; add it after the tea cools down a bit.

Drinking tea

Typical color of black tea with milk.

So, you’ve got the right water, the right pot, the right cup, the right tea, and you’ve poured some milk (or not); now you’re waiting for the brew to cool down a bit. After 3-4 minutes, take the tea out (or pour it into your cup). Let it cool down to 60°C and 65°C, which is usually obtained around 1 minute after the brewing time. If it’s hotter than that, you won’t be able to drink it — and no one likes a slurper. If it cools down more , its taste starts to change. Of course, no one’s going to measure the temperature. As a rule of thumb, it should have cooled down enough to be comfortably drunk, but still hot.

… and most importantly

Sit down and relax. Drinking tea is as much a feeling as it is an actual activity. Focus on the brew ahead of you, smell it before you drink it, and enjoy it thoroughly. Experiment with different teas and different brewing processes. Find what you like and tweak things according to your own taste. Good company makes for better tea, but tea also works perfectly with “me moments.”


The short version

For those who can’t be bothered to read the whole thing, here’s the short version:

  • Soft water, no mineral water and no hard water. No pre-boiled water.
  • Ceramic mug or cup.
  • Try loose tea or high-quality teabags.
  • Boil water, start brewing.
  • Brew for 3-4 minutes.
  • Milk and sugar (or honey) are optional.
  • Drink at 60°C – 65°C degrees.
  • Enjoy!

Green tea and iron don’t go well together

Rightfully touted for its many health benefits as an antioxidant, green tea doesn’t really play well with iron. A lab study on mice found that consuming an iron-rich diet can greatly reduce the tea’s benefits, as well as the iron’s.

Photo by Wild Bindy.

The main component in green tea is called epigallocatechin gallate (EGCG), a substance still under investigation for its potential to affect human health and disease. EGCG is used in many dietary supplements, but we still don’t know exactly how or why it works. Howeveer, we do know it potently inhibits myeloperoxidase, a pro-inflammatory enzyme released by white blood cells during inflammation. But when EGCG and iron are consumed together, they bind to each other, with EGCG losing its ability to inhibit myeloperoxidase.

“If you drink green tea after an iron-rich meal, the main compound in the tea will bind to the iron,” said Matam Vijay-Kumar, assistant professor of nutritional sciences, Penn State. “When that occurs, the green tea loses its potential as an antioxidant. In order to get the benefits of green tea, it may be best to not consume it with iron-rich foods.” Iron-rich foods include red meat and dark leafy greens, such as kale and spinach. According to Vijay-Kumar, the same results also apply to iron supplements.

The research can be especially useful for inflammatory bowel syndrome (IBD) patients. EGCG is especially helpful for this condition, as is iron. Dietary supplements containing both substances are often prescribed, which according to the study, is especially counterproductive as it cancels both their effects.

“It is important that IBD patients who take both iron supplements and green tea know how one nutrient affects the other,” Vijay-Kumar said. “The information from the study could be helpful for both people who enjoy green tea and drink it for its general benefits, as well as people who use it specifically to treat illnesses and conditions.”

“The benefit of green tea depends on the bioavailability of its active components,” said Beng San Yeoh, graduate student in immunology and infectious diseases and first author of the study. “It is not only a matter of what we eat, but also when we eat and what else we eat with it.”

It should be noted that the results haven’t been validated for humans.

Scientists think they’ve figured out why green tea helps you lose weight

Green tea is one of those things that’s really healthy for you, but its health benefits have been greatly exaggerated; one of the things which has been consistently reported about green tea is that it helps you lose weight, but scientists didn’t know how (or if) this happens. Now, a team from Poland believe they’ve zeroed in on this mystery: it’s all about the starch.

Image via University of Florida.

Jaroslaw Walkowiak of Poznan University of Medical Sciences, Poland, found that a single dose of green tea extract made people digest less starch and eliminate more of it. He gave people the equivalent of drinking a few cups of green tea every day after they had breakfast.

“Green tea is known worldwide for its beneficial effects on human health,” the researchers write in the journal Scientific Reports. “However, objective data evaluating this influence in humans is scarce.”

Indeed, green tea is given credit for many health benefits – it’s supposed to help against cancer, but despite suggestive evidence, there is no conclusive evidence that green tea helps to prevent or treat cancer. It’s supposed to level glycemic control but again, evidence is inconclusive, and it’s supposed to help with losing weight. It’s safe to say that green tea is quite controversial, but hopefully, studies like this one will shed some light on what the substance actually does.

“In most subjects (78.6%), the decreased starch digestion and absorption due to GTE was rapid and the aforesaid effect persisted until the last measure.”

They continue making a case for using the substance instead of other weight-loss substances.

“Our data suggest that the use of GTE is a viable alternative to pharmaceutical inhibitors of glucoside hydrolase enzymes. This plant extract is widely available, inexpensive, and well tolerated, so it has potential utility for weight control and the treatment of diabetes. Our study supports the concept that pure GTE inhibits starch digestion and absorption. However, the clinical significance of each green tea catechin and the exact mechanism responsible for this action in humans remain to be determined.”

The debate around green tea won’t end anytime soon, but regarding weight loss, the evidence seems to be piling up: a few cups of green tea per day might actually help you lose weight.

Journal Reference: Klaudia Lochocka, Joanna Bajerska, Aleksandra Glapa, Ewa Fidler-Witon, Jan K. Nowak, Tomasz Szczapa, Philip Grebowiec, Aleksandra Lisowska & Jaroslaw Walkowiak. Green tea extract decreases starch digestion and absorption from a test meal in humans: a randomized, placebo-controlled crossover study. doi:10.1038/srep12015

Green tea ingredient may target protein to kill oral cancer cells

A component found in green tea may be very effective at destroying oral cancer cells, while leaving healthy cells alone. The research from Penn State could become very useful in fighting oral cancer, as well as other types of cancer.

Image via Real Buzz.

Green tea originated in China, but it has since become a very popular beverage throughout the world. Many claims have been made for the beneficial health effects of green tea, but only a few of them have actually been backed by scientific investigations. Green tea contains a myriad of enzymes, amino acids, carbohydrates, lipids, sterols, related compounds, phytochemicals, and dietary minerals which show great promise in fighting against cancer, cardiovascular diseases and glycemic control, but not many peer reviewed studies actually showed that green tea is effective against a specific type of cancer.

There have been previous studies which showed that epigallocatechin-3-gallate — EGCG — a compound found in green tea, killed oral cancer cells without harming normal cells, but the reason and mechanism through which this is done has not been understood. Joshua Lambert, associate professor of food science and co-director of Penn State’s Center for Plant and Mushroom Foods for Health believes he has found the answer to that mystery.

“EGCG is doing something to damage the mitochondria and that mitochondrial damage sets up a cycle causing more damage and it spirals out, until the cell undergoes programmed cell death,” said Lambert. “It looks like EGCG causes the formation of reactive oxygen species in cancer cells, which damages the mitochondria, and the mitochondria responds by making more reactive oxygen species.”

Mitochondria are membrane bound organelles found in most eukaryotic cells often referred to as the powerhouses of the cells. They generate the energy that our cells need to do their jobs. In a way, they generate the chemical energy for our body to function. If you destroy the mitochondria, you basically destroy the cell. EGCG basically does just that – but only in cancerous cells – it leaves healthy cells unscathed.

Researchers grew the normal and cancer cells on petri dishes and then exposed them to EGCG, the major polyphenol found in green tea, at concentrations typically found in the saliva after consuming green tea. They found that a specific protein, SIRT3, is critical to the process.

“It plays an important role in mitochondrial function and in anti-oxidant response in lots of tissues in the body, so the idea that EGCG might selectively affect the activity of sirtuin 3 in cancer cells — to turn it off — and in normal cells — to turn it on — is probably applicable in multiple kinds of cancers,” Lambert said.

The next step is to test the substance on animals, and ultimately, in human trials. In the meantime, just like many previous studies, this shows a lot of promise – green tea may be a valuable tool against cancer.

“The problem with a lot of chemotherapy drugs — especially early chemotherapy drugs — is that they really just target rapidly dividing cells, so cancer divides rapidly, but so do cells in your hair follicles and cells in your intestines, so you have a lot of side effects,” said Lambert. “But you don’t see these sorts of side effects with green tea consumption.”



Tea flavors changing with shifting rainfall patterns

Climate change has many unexpected consequences – as a research has shown yet again. This time, a team of Montana scientists have shown that the tea flavors are changing, mainly as a result of shifting rainfall patterns. This variability can jeopardize the livelihood of tea growers and has significant effects on the end product we drink.

People working on tea plantations. Image via China Tour.

Tea is the most consumed beverage in the world – after water, of course. Its consumption equals all other manufactured drinks in the world – including coffee, chocolate, soft drinks, and alcohol – put together. The total consumption is estimated 3.21 million tonnes annually and in the United States, tea purchases have increased for 20 consecutive years and annual sales have surpassed $2.2 billion, with 160 million Americans drinking tea every single day. So naturally, any changes that affect tea affect a huge number of people.

“Climate change is impacting agro-ecosystems, crops, and farmer livelihoods in communities worldwide. While it is well understood that more frequent and intense climate events in many areas are resulting in a decline in crop yields, the impact on crop quality is less acknowledged, yet it is critical for food systems that benefit both farmers and consumers through high-quality products”, the study reads.

Selena Ahmed, lead author of the study, found that major antioxidant compounds that determine tea properties – including epigallocatechin, epigallocatechin gallate, epicatechin gallate, gallocatechin gallate, catechin, and gallic acid – can rise and fall by up to 50 percent! The change is big enough to not only affect the taste, but also the nutritive properties of the beverage. Ahmed, from Montana State University, conducted the research in an area of southwest China, where the changes are most likely representative.

Researchers collected samples during two extreme (opposite) weather events – a severe drought and a very powerful monsoon. They conducted chemical samples and also asked experienced tea growers about the quality of the tea they grew during these events. The interviews revealed that the vast majority of people considered tea grown during the monsoon period to be inferior to the one grown outside of that period. The chemical analysis confirmed this – antioxidant levels were observed to be lower during the monsoon period. More tea was grown, but the quality was lower.

“The increase in precipitation that occurs with the seasonal transition from the spring drought to the monsoon tea harvests results in an increase in tea yields and a decrease in functional quality”, Selena further writes.

Green Tea is a significant source of antioxidants and has a myriad of positive effects on the body. Image Source.

This has significant impact not only on the farmers’ livelihoods, but also on the end consumers, which get significant quantities of antioxidants from tea.

“Extrapolating findings from this study with climate scenarios suggests that tea farmers will face increased variability in their livelihoods with the increased prevalence and intensity of extreme droughts and heavy rains associated with climate change,” Ahmed explained. “The study has compelling implications not only for tea, but also for all other food and medicinal plants for which changes in weather patterns can alter flavor and nutritional and medicinal properties.”

It is well known that tea (especially green tea) contains antioxidants such as polyphenols in green tea can help prevent cardiovascular disease, burn calories and even ward off some types of cancer. Furthermore, green tea in general (as well as many other types of tea) is associated with a healthier lifestyle and can help regulate body temperature and blood sugar, encourage digestion and even sooth the mind.

Journal Reference: Selena Ahmed, John Richard Stepp, Colin Orians, Timothy Griffin, Corene Matyas, Albert Robbat, Sean Cash, Dayuan Xue, Chunlin Long, Uchenna Unachukwu, Sarabeth Buckley, David Small, Edward Kennelly. Effects of Extreme Climate Events on Tea (Camellia sinensis) Functional Quality Validate Indigenous Farmer Knowledge and Sensory Preferences in Tropical China. DOI: 10.1371/journal.pone.0109126

Green tea not only good for preventing cancer – but also for slowing it down

Green tea has some absolutely remarkable properties: it has a swarm of antioxidants, it is good for preventing a huge number of diseases (including some cancers), it boosts the immune system and it also helps you lose weight. But now, researchers have found that it can also help regulate and slow down the evolution of already present cancer.

Susanne M. Henning, PhD, RD, adjunct professor at the David Geffen School of Medicine at the University of California, Los Angeles presented her discoveries at the American Association for Cancer Research meeting on cancer prevention.

”We were able to show the green tea polyphenols (antioxidants) reached the prostate tissue and they did modify inflammation of the prostate,” she says. Polyphenols are antioxidants that protect against cell damage.

Hanning’s team analyzed 79 men with prostate cancer to drink either six cups of brewed green tea or water daily – they were all scheduled for surgery, and had to drink these before the operation. The bad thing is that only 67 men actually completed the study, but out of them, those who had drank green tea showed remarkably lower levels of PSA (prostate-specific antigen, a protein which may reflect the status of the prostate cancer). An indicator of inflammation and cancer growth, called nuclear factor-kappaB, was also reduced in those who drank green tea compared to those who didn’t. Still, it’s not all rosy.

“We were not able to inhibit tumor growth,” she says. But the study length may not have been long enough to show that; a longer-term study is needed, she says.

Prostate cancer is typically a slow developing cancer, so dietary measures to slow it down even more are often a way of action. If green tea indeed inhibits the growth of the cancer, and not just some related proteins, then it might be a true weapon in the cancer-fighting arsenal. But there’s still a long way to go.