10 Evidence-Based Benefits of Green Tea
By Kris Gunnars
Green tea is touted to be one of the healthiest beverages on the planet.
It's loaded with antioxidants that have many health benefits, which may include:
There may be even more potential health benefits.
This article looks at the evidence behind 10 possible health benefits of green tea.
1. Green Tea Contains Healthy Bioactive Compounds
Green tea is more than just a hydrating beverage.
The green tea plant contains a range of healthy compounds that make it into the final drink.
Tea is rich in polyphenols, which are natural compounds that have health benefits, such as reducing inflammation and helping to fight cancer.
Green tea contains a catechin called EGCG (epigallocatechin-3-gallate). Catechins are natural antioxidants that help prevent cell damage and provide other benefits.
These substances can reduce the formation of free radicals in the body, protecting cells and molecules from damage. These free radicals play a role in aging and many types of diseases.
EGCG is one of the most powerful compounds in green tea. Research has tested its ability to help treat various diseases. It appears to be one of the main compounds that gives green tea its medicinal properties.
Green tea also has small amounts of minerals that can benefit your health.
Try to choose a higher quality brand of green tea, because some of the lower quality brands can contain excessive amounts of fluoride.
That being said, even if you choose a lower quality brand, the benefits still outweigh any risk.
Green tea is loaded with polyphenol antioxidants, including a catechin called EGCG. These antioxidants can have various beneficial effects on health.
2. Green Tea Can Improve Brain Function
Green tea does more than just keep you alert, it might also help boost brain function.
The key active ingredient is caffeine, which is a known stimulant.
It doesn't contain as much as coffee, but enough to produce a response without causing the "jittery" effects associated with taking in too much caffeine.
Caffeine affects the brain by blocking an inhibitory neurotransmitter called adenosine. This way, it actually increases the firing of neurons and the concentration of neurotransmitters like dopamine and norepinephrine.
Research has consistently shown that caffeine can improve various aspects of brain function, including mood, vigilance, reaction time, and memory.
Studies show that caffeine and L-theanine can have synergistic effects. This means that the combination of the two can have particularly powerful effects in improving brain function.
Because of the L-theanine and the small dose of caffeine, green tea might give you a much milder and different kind of "buzz" than coffee.
Many people report having more stable energy and being much more productive when they drink green tea compared to coffee.
Green tea contains less caffeine than coffee, but enough to produce an effect. It also contains the amino acid L-theanine, which can work synergistically with caffeine to improve brain function.
3. Green Tea Increases Fat Burning
If you look at the ingredients list for any fat burning supplement, chances are, green tea will be on there.
In one study involving 10 healthy men, taking green tea extract increased energy expenditure by 4%. In another involving 12 healthy men, green tea extract increased fat oxidation by 17% compared to those taking a placebo.
However, some studies on green tea don't show any increase in metabolism, so the effects may depend on the individual and how the study was set up.
Caffeine may also improve physical performance by mobilizing fatty acids from fat tissue and making them available for use as energy.
Two separate review studies reported that caffeine may increase physical performance by approximately 11–12%.
Green tea may boost metabolic rate and increase fat burning in the short term, although not all studies agree.
4. Green Tea Antioxidants May Lower the Risk of Some Cancers
Cancer is caused by uncontrolled growth of cells. It's one of the world's leading causes of death.
Research has shown that oxidative damage can lead to chronic inflammation, which can lead to chronic diseases, including cancers. Antioxidants can help protect against oxidative damage.
Green tea is an excellent source of powerful antioxidants.
Research has linked green tea compounds with a reduced risk of cancer, including the following studies:
- Breast cancer: A comprehensive review of observational studies found that women who drank the most green tea had an approximately 20–30% lower risk of developing breast cancer, one of the most common cancers in females.
- Prostate cancer: One study found that men drinking green tea had a lower risk of advanced prostate cancer.
- Colorectal cancer: An analysis of 29 studies showed that those drinking green tea were around 42% less likely to develop colorectal cancer.
Many observational studies have shown that green tea drinkers are less likely to develop several types of cancer, but more high-quality research is needed to confirm these effects.
To get the most health benefits, avoid adding milk to your tea. Some studies suggest it can reduce the antioxidant value in some teas.
Green tea has powerful antioxidants that may protect against cancer. Multiple studies show that green tea drinkers have a lower risk for various types of cancer.
5. Green Tea May Protect the Brain From Aging
Not only can green tea improve brain function in the short term, it may also protect your brain as you age.
Alzheimer's disease is a common neurodegenerative disease and the most common cause of dementia in older adults.
Parkinson's disease is another common neurodegenerative disease and involves the death of dopamine-producing neurons in the brain.
Several studies show that the catechin compounds in green tea can have various protective effects on neurons in test tubes and animal models, possibly lowering the risk for dementia.
Bioactive compounds in green tea can have various protective effects on the brain. They may reduce the risk of dementia, a common neurodegenerative disorder in older adults.
6. Green Tea Can Reduce Bad Breath
The catechins in green tea also have benefits for oral health.
Test tube studies suggest that catechins can suppress the growth of bacteria, potentially lowering the risk for infections.
Streptococcus mutans is a common bacterium in the mouth. It causes plaque formation and is a leading contributor to cavities and tooth decay.
Studies indicate that the catechins in green tea can inhibit the growth of oral bacteria in the lab, but no evidence shows that drinking green tea has similar effects.
However, there's some evidence that green tea can reduce bad breath.
The catechins in green tea may inhibit the growth of bacteria in the mouth, reducing the risk for bad breath.
7. Green Tea May Help Prevent Type 2 Diabetes
The rates of type 2 diabetes are increasing in recent decades. The condition now affects about 1 in 10 Americans.
Type 2 diabetes involves having elevated blood sugar levels, which may be caused by insulin resistance or an inability to produce insulin.
Studies show that green tea can improve insulin sensitivity and reduce blood sugar levels.
One study in Japanese individuals found that those who drank the most green tea had an approximately 42% lower risk of developing type 2 diabetes.
According to a review of 7 studies with a total of 286,701 individuals, tea drinkers had an 18% lower risk of developing diabetes.
Controlled trials show that green tea can cause mild reductions in blood sugar levels. It may also lower the risk of developing type 2 diabetes.
8. Green Tea May Help Prevent Cardiovascular Disease
Cardiovascular diseases, including heart disease and stroke, are the leading causes of death worldwide.
Studies show that green tea can improve some of the main risk factors for these diseases, which includes improving total cholesterol and LDL (bad) cholesterol levels.
Green tea also increases the antioxidant capacity of the blood, which protects the LDL particles from oxidation, which is one part of the pathway toward heart disease.
Given the beneficial effects on risk factors, it may not be surprising that people who drink green tea have up to a 31% lower risk of dying from a cardiovascular disease.
Green tea may lower total and LDL cholesterol, as well as protect the LDL particles from oxidation. Studies show that people who drink green tea have a lower risk of cardiovascular disease.
9. Green Tea May Help You Lose Weight
Given that green tea can boost the metabolic rate in the short term, it makes sense that it could help you lose weight.
Several studies show that green tea can help reduce body fat, especially in the abdominal area.
One of these studies was a 12-week randomized controlled trial involving 240 people with obesity.
In this study, those in the green tea group had significant decreases in body fat percentage, body weight, waist circumference, and belly fat compared with those in the control group.
However, some studies don't show a statistically significant increase in weight loss with green tea, so researchers need to perform further studies to confirm this effect.
Some studies show that green tea leads to increased weight loss. It may be particularly effective at reducing the dangerous abdominal fat.
10. Green Tea May Help You Live Longer
Given that some compounds in green tea may help protect against cancer and heart disease, it makes sense that it could help you live longer.
In one study, researchers studied 40,530 Japanese adults over 11 years. Those who drank the most green tea — 5 or more cups per day — were significantly less likely to die during the study period:
- Death of all causes: 23% lower in women, 12% lower in men.
- Death from heart disease: 31% lower in women, 22% lower in men.
- Death from stroke: 42% lower in women, 35% lower in men.
Another study involving 14,001 older Japanese individuals found that those who drank the most green tea were 76% less likely to die during the 6-year study period.
Studies show that people who drink green tea may live longer than those who don't.
11. The Bottom Line
Green tea has a range of possible health benefits.
To help you feel better, lose weight, and lower your risk for chronic diseases, you might want to consider making green tea a regular part of your life.
If you'd like to try it, there's a wide variety of green tea products available online.
Reposted with permission from Healthline.
For detailed source information, see original story at Healthline.
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By Tara Lohan
Warming temperatures on land and in the water are already forcing many species to seek out more hospitable environments. Atlantic mackerel are swimming farther north; mountain-dwelling pikas are moving upslope; some migratory birds are altering the timing of their flights.
Numerous studies have tracked these shifting ranges, looked at the importance of wildlife corridors to protect these migrations, and identified climate refugia where some species may find a safer climatic haven.
"There's a huge amount of scientific literature about where species will have to move as the climate warms," says U.C. Berkeley biogeographer Matthew Kling. "But there hasn't been much work in terms of actually thinking about how they're going to get there — at least not when it comes to wind-dispersed plants."
Kling and David Ackerly, professor and dean of the College of Natural Resources at U.C. Berkeley, have taken a stab at filling this knowledge gap. Their recent study, published in Nature Climate Change, looks at the vulnerability of wind-dispersed species to climate change.
It's an important field of research, because while a fish can more easily swim toward colder waters, a tree may find its wind-blown seeds landing in places and conditions where they're not adapted to grow.
Kling is careful to point out that the researchers weren't asking how climate change was going to change wind; other research suggests there likely won't be big shifts in global wind patterns.
Instead the study involved exploring those wind patterns — including direction, speed and variability — across the globe. The wind data was then integrated with data on climate variation to build models trying to predict vulnerability patterns showing where wind may either help or hinder biodiversity from responding to climate change.
One of the study's findings was that wind-dispersed or wind-pollinated trees in the tropics and on the windward sides of mountain ranges are more likely to be vulnerable, since the wind isn't likely to move those dispersers in the right direction for a climate-friendly environment.
The researchers also looked specifically at lodgepole pines, a species that's both wind-dispersed and wind-pollinated.
They found that populations of lodgepole pines that already grow along the warmer and drier edges of the species' current range could very well be under threat due to rising temperatures and related climate alterations.
"As temperature increases, we need to think about how the genes that are evolved to tolerate drought and heat are going to get to the portions of the species' range that are going to be getting drier and hotter," says Kling. "So that's what we were able to take a stab at predicting and estimating with these wind models — which populations are mostly likely to receive those beneficial genes in the future."
That's important, he says, because wind-dispersed species like pines, willows and poplars are often keystone species whole ecosystems depend upon — especially in temperate and boreal forests.
And there are even more plants that rely on pollen dispersal by wind.
"That's going to be important for moving genes from the warmer parts of a species' range to the cooler parts of the species' range," he says. "This is not just about species' ranges shifting, but also genetic changes within species."
Kling says this line of research is just beginning, and much more needs to be done to test these models in the field. But there could be important conservation-related benefits to that work.
"All these species and genes need to migrate long distances and we can be thinking more about habitat connectivity and the vulnerability of these systems," he says.
The more we learn, the more we may be able to do to help species adapt.
"The idea is that there will be some landscapes where the wind is likely to help these systems naturally adapt to climate change without much intervention, and other places where land managers might really need to intervene," he says. "That could involve using assisted migration or assisted gene flow to actually get in there, moving seeds or planting trees to help them keep up with rapid climate change."
Tara Lohan is deputy editor of The Revelator and has worked for more than a decade as a digital editor and environmental journalist focused on the intersections of energy, water and climate. Her work has been published by The Nation, American Prospect, High Country News, Grist, Pacific Standard and others. She is the editor of two books on the global water crisis. http://twitter.com/TaraLohan
Reposted with permission from The Revelator.
The last Ice Age eliminated some giant mammals, like the woolly rhino. Conventional thinking initially attributed their extinction to hunting. While overhunting may have contributed, a new study pinpointed a different reason for the woolly rhinos' extinction: climate change.
The last of the woolly rhinos went extinct in Siberia nearly 14,000 years ago, just when the Earth's climate began changing from its frozen conditions to something warmer, wetter and less favorable to the large land mammal. DNA tests conducted by scientists on 14 well-preserved rhinos point to rapid warming as the culprit, CNN reported.
"Humans are well known to alter their environment and so the assumption is that if it was a large animal it would have been useful to people as food and that must have caused its demise," says Edana Lord, a graduate student at the Center for Paleogenetics in Stockholm, Sweden, and co-first author of the paper, Smithsonian Magazine reported. "But our findings highlight the role of rapid climate change in the woolly rhino's extinction."
The study, published in Current Biology, notes that the rhino population stayed fairly consistent for tens of thousands of years until 18,500 years ago. That means that people and rhinos lived together in Northern Siberia for roughly 13,000 years before rhinos went extinct, Science News reported.
The findings are an ominous harbinger for large species during the current climate crisis. As EcoWatch reported, nearly 1,000 species are expected to go extinct within the next 100 years due to their inability to adapt to a rapidly changing climate. Tigers, eagles and rhinos are especially vulnerable.
The difference between now and the phenomenon 14,000 years ago is that human activity is directly responsible for the current climate crisis.
To figure out the cause of the woolly rhinos' extinction, scientists examined DNA from different rhinos across Siberia. The tissue, bone and hair samples allowed them to deduce the population size and diversity for tens of thousands of years prior to extinction, CNN reported.
Researchers spent years exploring the Siberian permafrost to find enough samples. Then they had to look for pristine genetic material, Smithsonian Magazine reported.
It turns out the wooly rhinos actually thrived as they lived alongside humans.
"It was initially thought that humans appeared in northeastern Siberia fourteen or fifteen thousand years ago, around when the woolly rhinoceros went extinct. But recently, there have been several discoveries of much older human occupation sites, the most famous of which is around thirty thousand years old," senior author Love Dalén, a professor of evolutionary genetics at the Center for Paleogenetics, said in a press release.
"This paper shows that woolly rhino coexisted with people for millennia without any significant impact on their population," Grant Zazula, a paleontologist for Canada's Yukon territory and Simon Fraser University who was not involved in the research, told Smithsonian Magazine. "Then all of a sudden the climate changed and they went extinct."
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For example, she says that locally owned businesses can lead the local clean energy economy and create new jobs in underserved communities.
"We really need to think about … connecting climate and energy with other issues that people wake up every day really worried about," she says, "whether it be jobs, housing, transportation, health and well-being."
To maximize that potential, she says the energy sector must have more women and people of color in positions of influence. Research shows that leadership in the solar industry, for example, is currently dominated by white men.
"I think that a more inclusive, diverse leadership is essential to be able to effectively make these connections," Stephens says. "Diversity is not just about who people are and their identity, but the ideas and the priorities and the approaches and the lens that they bring to the world."
So she says by elevating diverse voices, organizations can better connect the climate benefits of clean energy with social and economic transformation.
Reposted with permission from Yale Climate Connections.