Is Green Tea a Fad or a Real Health Boost?

In continuation of my updates on Green tea

Green tea is a popular health trend, with many people sipping in hopes of deriving benefits from the brew.

There's nothing wrong with that, dietitians say -- green tea is a healthy drink loaded with antioxidants. But the jury's still out on many of its purported health benefits.

"Clinical trials related to green tea are still in their early stages," said Nancy Farrell Allen, a registered dietitian nutritionist in Fredericksburg, Va. "I say drink it, enjoy it. It's not going to hurt, and it might have worthy benefits to it. But nutrition is a science, and it takes time for our understanding to evolve."

Green tea's potential health benefits derive from catechins, which are powerful antioxidant compounds known as flavonoids, said Chelsey Schneider, clinical nutrition supervisor at Mount Sinai Beth Israel Cancer Center in New York City.

One catechin in particular, known as EGCG, is found at higher levels in green tea than in either white or black tea, she said.

"This compound can be even stronger than vitamin C and E, which are very, very strong antioxidants," Schneider said. Antioxidants help prevent damage to cells.

Green, black and white tea all come from the same plant, said Allen, who is a spokeswoman for the Academy of Dietetics and Nutrition.

Green tea is made from the leaves of the mature plant, while white tea is made of leaves plucked early in development. Black tea is made from green tea leaves that are laid out and covered with a damp cloth, she said.

"They dry and blacken and ferment a little, giving black tea that darker, richer flavor," Allen said. But this process also reduces levels of catechins in black tea.

Weight loss has been associated with green tea, with experts suggesting that its mixture of caffeine and catechins can enhance a person's metabolism and processing of fat, according to the University of California-Davis Department of Nutrition.

But it appears that folks have to drink a lot of green tea to get substantial weight loss benefits and carefully watch the rest of their diet, UC-Davis says.

Green tea also has been tied to heart health.

For example, green tea was shown to reduce "bad" LDL cholesterol in a 2018 study of more than 80,000 Chinese published in the Journal of the American Heart Association.

Evidence suggests catechins in green tea also could lower risk of heart attacks, help blood vessels relax and reduce inflammation, UC-Davis says.

Green tea even has been associated with a lower risk of some cancers.

The American Cancer Society says studies have linked green tea to a reduction in ovarian cancer risk. And UC-Davis said experimental models have shown that green tea might reduce risk of a variety of other cancers.

But a 2016 evidence review by the Cochrane Library concluded that there is "insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention."

Schneider said the research is limited. "Some small studies say green tea can maybe be preventative for certain cancers, like breast, ovarian, endometrial, pancreatic and oral cancers, but there aren't so many conclusive human trials that support that," she said.

Green tea also might help keep your brain younger. A 2014 study in the journal PLOS One found that Japanese who drank more green tea had significantly less decline in brain function, although researchers couldn't rule out the possibility that these folks might have other healthy habits that helped keep them mentally sharp.

One caveat with all of this research is that it tends to take place in Asian countries, where people drink much more green tea. There might be significant differences for Americans.

And the way you take your green tea could diminish any potential positive effects, Schneider added.

"A lot of people are adding processed white sugar to their green tea, which really makes something beautiful and healthy into something unhealthy," she said.

Adding milk or cream to your tea also might not be a good idea.

"There are some studies that say having milk in green tea can actually block the effects of you absorbing the antioxidant," Schneider said. "If it was me, I'd drink it straight up."

Coffee Might Be Your Go-to Brew for Weight Loss

In continuation of my update on coffee

Could America's favorite morning drink also help fight one of its biggest health issues, obesity?

That's the suggestion from a British study that finds coffee stimulates the human body's "brown fat," a heat-generating form of fat that literally burns calories in a process called thermogenesis.

"This is the first study in humans to show that something like a cup ofcoffeecan have a direct effect on our brown fat functions," said study leader Michael Symonds, of the University of Nottingham.

"The potential implications of our results are pretty big, as obesity is a major health concern for society and we also have a growing diabetes epidemic and brown fat could potentially be part of the solution in tackling them," he said in a university news release.

But one U.S. obesity and nutrition expert said it's just too early to label coffee a dieter's best friend.

"Usually thermogenic properties are too minimal and insignificant" to help someone go from overweight to normal weight, explained registered dietitian Sharon Zarabi. She directs the bariatrics program at Lenox Hill Hospital in New York City.

As Symonds' team explained, thermogenic brown fat was long thought to only exist in either human babies or hibernating animals, such as bears.

But in recent years it's been discovered in adult people. It's distinct from white fat cells, which is where the body stores excess calories.

"Brown fat works in a different way to other fat in your body and produces heat by burning sugar and fat, often in response to cold," Symonds explained. So, "increasing its activity improves blood sugar control as well as improving blood lipid [cholesterol] levels, and the extra calories burnt help with weight loss."

But can brown fat be stimulated into calorie-burning activity by something you eat or drink?

To find out, the British team used stem cell-based studies to first see if caffeine might do the trick. It did, at a certain dose.

The next step was to use high-tech imaging to track changes in brown fat stored in people's necks.

"We were able to image someone straight after they had a drink [of coffee] to see if the brown fat got hotter," said Symonds.

"The results were positive," he said, so the next step is to figure out which component of coffee -- perhaps the caffeine -- is activating brown fat.

His team is also "looking atcaffeinesupplements to test whether the effect is similar," Symonds said. "Once we have confirmed which component is responsible for this, it could potentially be used as part of a weight management regime or as part of [a] glucose regulation program to help prevent diabetes."

But Zarabi said dieters shouldn't view coffee as any magic potion for weight loss.

"I'd still recommend a cup o' joe at some point in the morning for a mental boost and pep in the day, but definitely not to help you lose weight -- unless you're using that caffeine for stimulation of a heart-pounding workout," she said.

That's because exercise remains the best and most efficient way to burn calories, Zarabi said.

But if you do choose to try coffee to lose weight, drink it black, she advised.

"This shouldn't give anyone the pass to drink unlimited amounts of coffee," Zarabi said. "And many drink coffee 'light and sweet,' which defeats the whole purpose of burning energy, because you're taking it all back in with the condiments."

Coffee May Have Another Perk for Kidney Patients

In continuation of my update on coffee

The benefit remained "even after considering other important factors such as age, gender, race, smoking, other diseases and diet," according to one of the study's lead authors, Miguel Bigotte Vieira, of North Lisbon Hospital Center in Portugal.

In the study, Vieira's team tracked data on 4,863 U.S. chronic kidney disease patients monitored from 1999 to 2010.

Although the study couldn't prove cause-and-effect, it found that greater caffeine intake was tied to greater life expectancy for people with chronic kidney disease.

Compared to those who consumed very little caffeine per day, people with caffeine intake in the high range had about a 25 percent lower risk of death over an average follow-up of five years.

People who consumed the most caffeine tended to be white and male, with more education and higher incomes. They were also more likely to be current or former smokers and heavier drinkers than those who drank only small amounts of caffeine.

The findings were published Sept. 12 in Nephrology Dialysis Transplantation.

According to the researchers, chronic kidney disease affects 14 percent of American adults, leading to higher health care costs and a greater risk of death.

So, simply drinking more coffee or other caffeine-laden beverages "would represent a simple, clinically beneficial and inexpensive option, though this benefit should ideally be confirmed in a randomized clinical trial," Vieira said in a journal news release.

One U.S. endocrinologist who wasn't connected to the study said there could be physiologic reasons behind the benefit.

"Coffee has had a bad reputation, but this study showed that people who drink coffee did better," said Dr. Robert Courgi, of Southside Hospital in Bay Shore, N.Y."Perhaps it is because coffee may help the blood vessels function better through nitric oxide," he said. Nitric oxide is a key player in healthy blood vessel function.

Ref: https://medlineplus.gov/caffeine.html

Four cups of coffee a day shown to protect heart muscle

In continuation of my update on coffee

A new study has shown that drinking four cups of coffee a day can protect against heart muscle damage through the effect of caffeine on a protein called p27

Caffeine intake has been associated with a lower risk of several chronic metabolic diseases such as cardiovascular disease (stroke and ischemic heart disease), and type II diabetes.

The current study, which was carried out at Heinrich-Heine-University and the IUF-Leibniz Research Institute for Environmental Medicine in Duesseldorf, Germany, shows that caffeine, at a concentration equivalent to that in four cups of coffee, works to enhance the mitochondrial entry of a protein called p27.

P27 is protein that promotes effective mitochondrial function. It protects the cells of the heart and blood vessels against damage. The study was recently published in the open access journal PLOS Biology.

Prior research by the same scientists revealed that caffeine improves the function of endothelial cells that line the cardiovascular system. This was seen to occur at normal, safe doses and was related to mitochondria.

Following the study, the scientists focused on the p27 protein, known better as a cell cycle inhibitor, and found that it was present within the mitochondria of all major cell-types in the heart.

The p27 protein prevents cell death in cardiac muscle cells, encourages endothelial cells to migrate, and promotes the maturation of fibroblasts into contractile cells. These processes are vital components of cardiac muscle repair following a heart attack.

Caffeine promotes this repair by facilitating the first step, namely, the entry of p27 protein into the mitochondria, at physiologic levels. This protective effect against heart damage is present in elderly, obese and prediabetic mice.

Our results indicate a new mode of action for caffeine, one that promotes protection and repair of heart muscle through the action of mitochondrial p27. These results should lead to better strategies for protecting heart muscle from damage, including consideration of coffee consumption or caffeine as an additional dietary factor in the elderly population.”

Dr. Judith Haendeler, Heinrich-Heine-University

Ref : https://www.eurekalert.org/pub_releases/2018-06/p-cff061418.php

Coffee helps teams work together, study suggests

In continuation of my update on coffee

Good teamwork begins with a cup of coffee for everyone, a new study suggests.

Researchers found that people gave more positive reviews for their group's performance on a task—and their own contribution—if they drank caffeinated coffee beforehand.

A second study showed that people talked more in a group setting under the influence of caffeinated coffee—but they also were more on-topic than those who drank decaf.

Coffee seems to work its magic in teams by making people more alert, said Amit Singh, co-author of the study and a doctoral student in marketing at The Ohio State University's Fisher College of Business.

"We found that increased alertness was what led to the positive results for team performance," Singh said.

"Not surprisingly, people who drank caffeinated coffee tended to be more alert."

Singh conducted the study with Vasu Unnava and H. Rao Unnava, both formerly at Ohio State and now with the Graduate School of Management at the University of California, Davis. The study appears online in the Journal of Psychopharmacology.

While many studies have looked at how caffeine affects individual performance, this is the first to examine the impact it has on teams, Singh said.

The first study involved 72 undergraduate students who said they were coffee drinkers. They were instructed not to drink coffee before the experiment.

Half of them first participated in what they were told was a coffee-tasting task. They were split into groups of five. After drinking a cup of coffee and rating its flavor, they were given 30 minutes of filler tasks to give the caffeine a chance to kick in. The other half of the participants did the coffee tasting at the end of the experiment.

Each group then read about and were asked to discuss a controversial topic—the Occupy movement, a liberal movement that highlighted social and economic inequality. After a 15-minute discussion, group members evaluated themselves and the other group members.

Results showed that those who drank the coffee before the discussion rated themselves and their fellow team members more positively than did those who drank coffee after the discussion, Singh said.

The second study was similar, except that 61 students all drank coffee at the beginning of the study. However, half drank decaf and the others drank caffeinated brew.

http://journals.sagepub.com/loi/jop

What Does the Research Say About Coffee and Your Health?

In continuation of my update on coffee...

Coffee-Cup of joe. Java. No matter what you call it, millions of people worldwide wake up and fuel their day with it. And though consumers might be jittery about the recent court battle in California over cancer warnings, experts say most of the science actually indicates coffee could have health benefits.

"The overall picture is quite clear," said Dr. Frank Hu, chair of nutrition at Harvard University's T.H. Chan School of Public Health. "There is no long-term increased risk of major chronic disease, including diabetes, cardiovascular disease or even cancer."

The java confusion stems over an eight-year court case. A Los Angeles-based judge's preliminary decision last month requires cancer warning labels because of concerns about acrylamide, a chemical produced during the roasting process. Acrylamide also is present in some fried or roasted starchy foods, including french fries, potato chips, breakfast cereals and toast. It's also found in cigarette smoke. The judge gave the coffee industry a few weeks to file appeals and could issue a final ruling late this month.

But there's little evidence acrylamide levels in food cause cancer in humans. Studies have found no consistent evidence acrylamide exposure in food is associated with cancer risk, according to the U.S. National Cancer Institute. The World Health Organization's International Agency for Research on Cancer reviewed more than 1,000 human and animal studies and issued a statement in 2016 that "found no conclusive evidence for a carcinogenic effect of drinking coffee."

"The California judge's decision to label coffee as a cancer risk is really inconsistent with the scientific literature," Hu said. "It's very misleading and has already caused a huge amount of confusion in the general public. The health outcomes have been remarkably consistent."

Hu was senior author of a 2015 study in the journal Circulation that concluded people who regularly drink moderate amounts of coffee daily -- fewer than five cups -- experienced a lower risk of death from heart and neurological diseases.

About four years ago, the U.S. government gave coffee its OK, too. The Department of Agriculture's dietary guidelines for all Americans, published every five years as a go-to source for nutrition advice, said three to five cups a day, which can be up to 400 milligrams a day of caffeine, can be part of a healthy diet. The American Heart Association suggests that people who have an arrhythmia, an abnormal heart rhythm, talk to their health care provider about caffeine intake.

"This guidance on coffee is informed by strong and consistent evidence showing that, in healthy adults, moderate coffee consumption is not associated with an increased risk of major chronic diseases (e.g., cancer) or premature death, especially from cardiovascular disease," the federal guidelines say. "However, individuals who do not consume caffeinated coffee or other caffeinated beverages are not encouraged to incorporate them into their eating pattern."

More recently, a review of more than 200 studies published last fall in the BMJ concluded three to four cups a day may be "more likely to benefit health than harm." It found a lower risk of liver disease and some cancers in coffee drinkers, and a lower risk of dying from stroke.

All of that should be good news to the people around the world who drink more than 1.1 billion cups of coffee each day.

But it's still easy to be confused. A quick search for coffee and health online yields hundreds, even thousands, of results.

Studies abound -- some funded by the coffee industry. For example, a European Journal of Nutritionstudy investigated the effects of coffee and its antioxidant properties and found no effect. Researchers took blood samples of 160 volunteers who drank up to three to five cups of coffee or water each day for eight weeks.

"Up to five cups of coffee per day had no detectable effect, either beneficial or harmful, on human health," that study concluded. It was funded by Kraft Foods, which makes Maxwell House coffees.

Of course, "no one is talking about coffee as a magic bullet," Hu said. He and other experts say it's important to keep track of the bigger picture, with the focus on moderation and dietary patterns.

"You can't pin anything on any one specific lifestyle behavior, particularly with diet," said Alice Lichtenstein, a senior scientist and director of the Cardiovascular Nutrition Laboratory at Tufts University in Boston.

"When we talk about diet, it should really be about the whole package, not single items. Right now, the majority of the evidence suggests there may be a health benefit from drinking coffee and there doesn't seem to be any disadvantage. Of course, with a caveat that you don't want to add a lot of cream and sugar, or to use it as an excuse to have a few cookies or a pastry. Then, there is a downside," said Lichtenstein, a professor of nutrition science and policy who also was an advisor on the federal dietary guidelines.

"We have a tendency to focus on one or two specific foods or beverages, and that's when the whole floor falls out from under us."

Caffeine consumption may help kidney disease patients live longer

In continuation of my update on caffeine..

Caffeine consumption may prolong the lives in patients with chronic kidney disease (CKD), according to a study that will be presented at ASN Kidney Week 2017 October 31-November 5 at the Ernest N. Morial Convention Center in New Orleans, LA.  

Coffee consumption has been linked to a longer life in the general population. To see if this holds true for individuals with CKD, Miguel Bigotte Vieira, MD (Centro Hospitalar Lisboa Norte, in Portugal), and his colleagues examined the association of caffeine consumption with mortality among 2328 patients with CKD in a prospective US cohort, using the continuous National Health and Nutrition Examination Survey(NHANES) 1999-2010.

The team found a dose-dependent inverse association between caffeine and all-cause mortality. Compared with those in the lowest quartile of caffeine consumption, those in the second, third, and highest quartiles had 12%, 22%, and 24% lower risks of dying.

"Our study showed a dose-dependent protective effect of caffeine consumption on mortality among patients with CKD. This association was independent of potential confounders including age, gender, race, annual family income, education level, estimated GFR, albumin/creatinine ratio, hypertension, smoking status, dyslipidemia, body mass index, previous cardiovascular events and diet: consumption of alcohol, carbohydrates, polyunsaturated fatty acids, and fibers," said Dr. Bigotte Vieira. 

"These results suggest that advising patients with CKD to drink more caffeine may reduce their mortality. This would represent a simple, clinically beneficial, and inexpensive option, though this benefit should ideally be confirmed in a randomized clinical trial." Dr. Bigotte Vieira stressed that this observational study cannot prove thatcaffeine reduces the risk of death in patients with CKD, but onlysuggests the possibility of such a protective effect.

Caffeine consumption may help kidney disease patients live longer

Moderate coffee consumption may offer protection against age-related cognitive decline

A new report from the Institute for Scientific Information on Coffee (ISIC), a not-for-profit organisation devoted to the study and disclosure of science related to coffee and health, highlights the potential role of coffee consumption in reducing the risk of cognitive decline. The report concludes that a moderate intake of coffee (3-5 cups per day) may provide protection against age-related cognitive decline and other neurodegenerative diseases such as Alzheimer's and Parkinson's.

The report provides a summary of the research presented at ISIC's symposium, titled 'Nutrition, Coffee and Age-Related Cognitive Decline', held during the European Union Geriatric Medicine Society's 2016 Congress in Lisbon, Portugal. The findings are particularly relevant given Europe's ageing population: the number of people aged 60 years or over is projected to rise to 217.2 million by 2030, therefore understanding and communicating diet and lifestyle factors that may limit age-related cognitive decline will help to improve the quality of life for this growing demographic.

The symposium speakers whose insights and research contributed to ISIC's report were:

• Professor Lisette de Groot, Professor of Nutrition and Ageing, Division of Human Nutrition at Wageningen University (The Netherlands)
• Professor Rodrigo A. Cunha, Professor at the Faculty of Medicine of the University of Coimbra and Principal Investigator at the Centre for Neuroscience and Cell Biology of the University of Coimbra (CNC) (Portugal)
• Dr Elisabet Rothenberg, Associate Professor of Nutrition at Kristianstad University (Sweden)

Key highlights about coffee from the report include:

• Research published in 2016 suggests that moderate coffee consumption can reduce the risk of developing Alzheimer's by up to 27%. Research has suggested that it is regular, long-term coffee drinking that is key to helping to reduce the risk of Alzheimer's Disease.
• The association between coffee consumption and cognitive decline is illustrated by a 'U-shaped' pattern in recent meta-analyses, with the greatest protection seen at an intake of approximately 3-5 cups of coffee per day.
• Although the precise mechanisms of action behind the suggested association between coffee and age-related cognitive decline are unknown, caffeine is likely to be involved. There are many other compounds in coffee, such as antioxidants and anti-inflammatory agents, which may also play a role. Caffeic acid, for example, is a polyphenol (antioxidant) found in coffee, and research suggests that these may be associated with improved cognitive function.

Professor Rodrigo A. Cunha, Professor at the Faculty of Medicine of the University of Coimbra and Principal Investigator at the Centre for Neuroscience and Cell Biology of the University of Coimbra (CNC), Portugal, commented:

"Healthcare professionals have an important part to play in providing patients with accurate research-based information, to help them to follow a healthy diet and lifestyle, and in turn, reduce their risk of age-related cognitive decline. Moderate coffee consumption could play a significant role in reducing cognitive decline which would impact health outcomes and healthcare spending across Europe."

In its Scientific Opinion on the safety of caffeine, the European Food Safety Authority (EFSA) concluded that intakes of up to 400mg of caffeine (the equivalent of up to 5 cups of coffee per day), from all sources, do not raise any concerns for healthy adults. One cup of coffee provides approximately 75-100mg caffeine.

Seeds of tropical shrub guarana contain ten times more amount of catechins than green tea

 

In continuation of my update on catechins. 

The millions of people who consume green tea all over the world benefit from the catechins it contains. Catechins are a class of chemical compounds with anti-oxidant and anti-inflammatory properties, among other healthy ingredients. Researchers at the University of São Paulo's Public Health School (FSP-USP) have discovered that guarana (Paullinia cupana) is a worthy competitor, at least as far as catechins are concerned: the seeds of the tropical shrub, used in fizzy drinks that are among the most popular in Brazil, as well as in over-the-counter supplements, contain more than ten times the amount of catechins found in green tea.

 Catechins

A clinical trial with healthy human volunteers has demonstrated that guarana is a rich source of catechins, which, when properly absorbed, reduce the oxidative stress associated with the development of neurodegenerative and cardiovascular disorders, as well as diabetes, cancer, inflammation and premature aging due to cell death, among other conditions harmful to health and wellbeing.

"Guarana has always been seen above all as a stimulant, especially by the international scientific community, because of its high caffeine content. We also found few Brazilian scientific studies that seek to identify other biological effects of guarana," said Lina Yonekura, the principal investigator for this research and currently an assistant professor at Kagawa University's School of Agriculture in Japan. "This pioneering assessment of the absorption and biological effects of its catechins in human volunteers should foster interest in guarana as a functional food on the part of scientists, the market, and society in general."

The paper with the results of the study is featured on the cover of the latest issue ofFood & Function, published by the Royal Society of Chemistry in the United Kingdom as one of the "Hot Articles in Food & Function 2016.

The month-long study was conducted in two stages. After selecting volunteers who were healthy but slightly overweight and with a moderately elevated risk of cardiovascular disease, the researchers measured baseline parameters on the first day and evaluated the same items again on day 15 after a the implementation of a controlled diet.

The participants were then asked to take guarana at home every morning before breakfast for the next fortnight. They were given bottles containing guarana seed powder and instructed to prepare a daily drink with the contents of one bottle (3 g of guarana powder) in 300 mL of water.

This procedure ensured that each participant acted as his or her own control. The researchers compared the same volunteers' blood tests at different times to avoid the influence of variability between individuals. The acute effect of guarana was measured one hour after the participants drank the solution on day 1 and day 15. The prolonged effect was assessed after overnight fasting on the same days.

The researchers assessed the extent to which guarana affected oxidative stress markers during the two-week intervention period. They also performed a detailed study to evaluate the subjects' absorption of catechins and their metabolites, as they had found no information in the scientific literature on the bioavailability of these compounds in guarana.

The oxidative stress markers included oxidation of low-density lipoprotein (LDL), popularly known as bad cholesterol. LDL is essential to an organism's proper functioning because it is the main particle that carries cholesterol to cells. Cholesterol is a structural component of all cell membranes and is used to manufacture steroid hormones (estrogen and testosterone). When oxidized, however, LDL causes atherosclerosis and increases the risk of cardiovascular disease. The tests performed by Yonekura's team showed an increase in oxidation resistance of the LDL in the blood samples taken from the volunteers after they drank guarana.

They also performed a comet assay, also called single cell gel electrophoresis (SCGE), a technique for quantifying and analyzing DNA damage in individual cells due to various factors, including oxidative stress. In this case, lymphocyte DNA in blood samples taken one hour after guarana intake was less damaged than expected when submitted to an oxidizing environment, indicating the presence of anti-oxidant substances or enhanced performance of the lymphocytes' enzymatic anti-oxidant system.

"All these markers depend on the presence of catechins in the bloodstream," Yonekura said. "The improvement in the parameters we assessed was associated with a rise in the concentration of plasma catechins after guarana intake, showing that guarana was indeed responsible for this effect."

Moreover, she went on, the guarana catechins strengthened the cells' native anti-oxidant enzymes, especially glutathione peroxidase, catalase, and superoxide dismutase, which combine to convert superoxide into peroxide and finally into water, protecting cells from the oxidative damage caused by their own metabolism of outside factors.

The tests showed increased glutathione peroxidase and catalase activity both shortly after guarana ingestion and on the following day.

"These results are exciting, suggesting that the bioavailability of guarana catechins is equal to or greater than that of green tea, cocoa and chocolate catechins," Yonekura said. "In fact, their bioavailability was sufficient to have a positive effect on plasma anti-oxidant activity, protect erythrocyte DNA, reduce plasma lipid oxidation, and increase anti-oxidant enzyme activity. We hope the results lead to heightened interest in guarana as the species is native to the Amazon, and Brazil is practically the only country that produces it on a commercial scale."