November 8, 2013
Weight Loss, Heart Health And More Linked To Drinking Tea
April Flowers for redOrbit.com - Your Universe Online
Tea is the second most consumed beverage in the world. Decades of research data reveals that tea might help prevent chronic illnesses, including heart disease, certain types of cancer and Type-2 diabetes. New research adds to the list of benefits, including promoting weight loss and maintaining a healthy weight, improving bone health and activating areas of the brain that bolster attention, problem solving and mood.
The American Journal of Clinical Nutrition will feature 12 new articles about the benefits of tea on human health. They are based on presentations from world-renowned scientists who participated in the Fifth International Scientific Symposium on Tea and Human Health, held in September. The following five papers highlight the compelling new data:
"Tea Leaf Polyphenols May Promote Weight Loss"
An increase in energy expenditure and fat oxidation, caused by the tea polyphenols and caffeine content in tea, provides benefits for achieving and maintaining an ideal body weight. One meta-analysis suggested that the increase in caloric expenditure equals approximately 100 calories over a 24-hour period (0.13 calories per mg catechins). Researchers in another review concluded that subjects consuming green tea and caffeine lost an average of 2.9 pounds within 12 weeks while adhering to their regular diet. Habitual tea drinkers were shown to have lower Body Mass Indexes (BMIs) and waist-to-hip ratios in population-based studies. They also had less body fat than non-tea drinkers. Green tea and caffeine were also shown to boost fat oxidation over 24 hours by an average of 16 percent, or 0.02 grams per mg catechins.
"Tea May Reduce Risk for Some Cancers"
Researchers found that green tea polyphenols might play a role in arresting the progression of certain cancers. In a double-blind, placebo-controlled study, the progression of prostate cancer was reduced with a supplementation of 600 mg/d green tea catechins. The study found that after a year, nine percent of men in the group being supplemented with green tea had progressed to prostate cancer, while thirty percent of men in the placebo group had progressed to prostate cancer.
"Tea Catechins are Cardioprotective"
Many studies have suggested that tea supports heart health and healthy blood pressure. It also appears to be associated with a reduced risk of cardiovascular disease, including stroke and heart attack.
Claudio Ferri, MD, from the University L'Aquila, found that black tea reduced blood pressure. His findings also showed that among hypertensive patients, tea helped counteract the negative effects of a high-fat meal on blood pressure and arterial blood flow.
Hypertensive participants were asked to drink a cup of tea after a meal that contained 0.45 grams fat/lb. body weight. The study findings indicate that tea prevented the reduction in flow-mediated dilation (FMD), the ability to increase arterial blood flow that occurs after a high-fat meal.
Ferri conducted a prior study showing that tea improved FMD from 7.8 to 10.3 percent, and reduced both systolic and diastolic blood pressure by -2.6 and -2.2 mmHg, respectively, in study participants.
"Our studies build on previous work to clearly show that drinking as little as one cup of tea per day supports healthy arterial function and blood pressure. These results suggest that on a population scale, drinking tea could help reduce significantly the incidence of stroke, heart attack and other cardiovascular diseases," concluded Dr. Ferri.
"Tea Flavonoids Improve Bone Strength and Quality"
Researchers say that osteoporosis is a major public health concern. New research, however, indicates that polyphenols in green tea might help improve bone quality and strength through many proposed mechanisms.
One study in particular found that drinking tea was associated with a 30 percent risk reduction in hip fractures for men and women over 50 years old. Another study recruited 150 postmenopausal women, finding that 500 mg green tea extract -- the equivalent of 4-6 cups of green tea daily -- alone or in combination with Tai Chi, improved markers for bone formation, reduced markers of inflammation and increased muscle strength in study participants.
Green tea flavanols have been shown in many studies to provide a restorative effect to bone remodeling to help maintain bone density and slow bone loss.
"Tea Improves Mood, Alertness and Problem Solving"
New studies have also found that drinking tea improves attention. Tea consumption also allows individuals to be more focused on the task at hand. The study, which was placebo-controlled, showed that subjects who drank tea produced more accurate results during an attention task.
They also felt more alert than subjects drinking a placebo. The researchers observed the effects for 2-3 cups of tea consumed within a time period of up to 90 minutes. Other studies have examined the role of tea in bolstering attention, mood and performance. The results so far have been promising. Researchers think that the amino acid theanine and caffeine, both present in tea, contribute to many of tea's psychological benefits.
The AJCN supplement was created by twelve internationally renowned scientists.
"The scientists who contributed their original research and insights are among the best in the world, and together, this body of research has significantly advanced the science of tea and human health," said compendium editor Jeffrey Blumberg, PhD, Professor, Friedman School of Nutrition Science and Policy and Director, Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston.
"These new peer-reviewed papers add to the previously-published body of evidence that shows that tea can improve human health—both physically and psychologically," added Blumberg. "Humans have been drinking tea for some 5,000 years, dating back to the Paleolithic period. Modern research is providing the proof that there are real health benefits to gain from enjoying this ancient beverage."