Groene thee tegen overgewicht en osteoporose*
Uit een Chinese studie blijkt dat het regelmatig drinken van groene thee goed kan werken tegen
overgewicht. In de studie kregen deelnemers gedurende 3 maanden verschillende hoeveelheden groene thee met ook verschillende hoeveelheden
catechinen, de bioactieve stoffen in groene thee. Na 3 maanden bleken zij met de meeste
thee en catechinen duidelijk afgevallen te zijn en minder buikvet meer te hebben. Uit een andere Chinese laboratoriumstudie blijkt dat dezelfde catechinen uit groene thee zorgen voor een gezonde
botopbouw. Er vindt in het lichaam voortdurend ombouw plaats van bot. Cellen met de naam osteoclasten breken bot af, de osteoblasten bouwen bot op. Catechinen uit groene thee activeren nu de osteoblasten en remmen de osteoclasten.
Green Tea Promotes Weight Loss, New Research Finds
New research from China has found that regular consumption of green tea - which is rich in naturally-occurring tea actives called catechins - can significantly and positively effect body composition in moderately overweight
individuals.
The 90-day trial, conducted at Fudan University, in Shanghai, China, and funded by the Lipton Institute of Tea, supports existing evidence that green tea has a significant beneficial effect on body composition in Asian populations.
This new investigation monitored the effects of green tea consumption on body weight, body fat mass, as well as the distribution of fat. 182 moderately overweight Chinese subjects, aged between 18 and 55, were divided into four groups, with each group allocated a regular dose of green tea containing a different quantity of catechins. Amounts consumed ranged from 30mg to almost 900mg; an average cup of green tea contains between 50 to 100mg of catechins.
Participants in the study drank their designated tea divided in two daily doses. On days zero, 30, 60 and 90, measurements of body composition were taken to assess the effects that the prescribed tea had on body mass and fat.
The results showed that, relative to the control group consuming no green tea catechins, body weight, waist circumference, intra-abdominal fat and the total lean mass all decreased after 90 days in the group that drank the tea with the highest concentration of catechins. The authors concluded that regular consumption of green tea with very high catechin content can, over a 90-day period, significantly reduce body weight, body fat mass and waist size in moderately overweight Chinese individuals.
Dr Niels Boon, the research scientist at the Lipton Institute of Tea who led the research programme, explained: "This latest research demonstrates that commercially available green tea can have a very real - and positive - effect on weight loss and body shape. During the investigation, participants drank green tea that contained as many catechins as found in between six to ten regular cups of green tea.
"Using state-of-the-art measurement techniques, we analysed the effect of the green tea consumption on body fatness and the distribution of fat across the body. We observed significant decreases in body weight and fat mass. These effects were more pronounced in the group consuming the highest amount of catechins and the results also indicate that the effects are particularly strong on fat located in the abdominal region. In addition, they did not consume any other beverages containing catechins or caffeine during the intervention period - so we can be confident that the effects seen are a consequence of the green tea intervention."
Dr Paul Quinlan, Research Director at the Lipton Institute of Tea, added: "Our work on tea continues to reveal new and compelling health benefits associated with drinking tea. The effects of green tea on body shape and composition in Asian populations is well documented, although more research is needed to determine whether the same effects occur in other
populations.
"We are proud to be able to put the Lipton Institute of Tea's name to this piece of break-through research and look forward to furthering our knowledge of tea's other as yet uncharted health
benefits."
The original research paper, Effects of catechin enriched green tea on body composition, has just been published in
Obesity.
New Evidence That Green Tea May Help Improve Bone Health
Researchers in Hong Kong are reporting new evidence that green tea - one of the most popular beverages consumed worldwide and now available as a dietary supplement - may help improve bone health. They found that the tea contains a group of chemicals that can stimulate bone formation and help slow its breakdown. Their findings are in ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication. The beverage has the potential to help in the prevention and treatment of osteoporosis and other bone diseases that affect million worldwide, the researchers
suggest.
In the new study, Ping Chung Leung and colleagues note that many scientific studies have linked tea to beneficial effects in preventing cancer, heart disease, and other conditions. Recent studies in humans and cell cultures suggest that tea may also benefit bone health. But few scientific studies have explored the exact chemicals in tea that might be responsible for this effect.
The scientists exposed a group of cultured bone-forming cells (osteoblasts) to three major green tea components - epigallocatechin (EGC), gallocatechin (GC), and gallocatechin gallate (GCG) - for several days. They found that one in particular, EGC, boosted the activity of a key enzyme that promotes bone growth by up to 79 percent. EGC also significantly boosted levels of bone mineralization in the cells, which strengthens bones. The scientists also showed that high concentrations of ECG blocked the activity of a type of cell (osteoclast) that breaks down or weakens bones. The green tea components did not cause any toxic effects to the bone cells, they note.
ARTICLE: "Effects of Tea
Catechins, Epigallocatechin, Gallocatechin, and Gallocatechin Gallate, on Bone
Metabolism"
Source:
Michael Woods
American Chemical Society (Oktober
2009)
