Green tea reduces cholesterol risk

by Deborah Braconnier report
Green tea. Credit: Wikimedia Commons

(Medical Xpress) -- In a recent study published in the American Journal of Clinical Nutrition, Xin-Xin Zheng reports that green tea reduces LDL and total cholesterol. This could explain the reasoning behind green tea’s apparent reduction to the risk of heart disease.

Xin-Xin Zheng and his colleagues from Peking Union Medical College pooled the results of 14 previous trials that looked at the consumption of green tea. The researchers divided participants up into one group that had either consumed green tea or taken green tea supplements for up to at least three months and another group which had been given placebos.

In looking at the results, participants who had consumed green tea saw an average reduction in total levels of 7.2mg/dL when compared to the control group. LDL cholesterol showed an average reduction of 2.2mg/dL. There was no change reported in the levels of HDL, or good cholesterol.

Green tea contains catechin which is a flavonoid with antioxidant properties. Researchers believe it is these catechins that decrease the absorption of cholesterol in the body and help reduce cholesterol levels.

These catechins have also been shown in previous studies to demonstrate other heart-healthy benefits. They seem to work as a natural blood thinner and anticoagulant as well as reducing inflammation in the blood vessels.

While the reduction of cholesterol in green tea has been shown, it is only a small reduction and researcher’s stress that green tea should not be used in place of standard cholesterol-reducing treatments. may however be a useful addition to a traditional heart-healthy diet.

More information: Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials, Xin-Xin Zheng, Yan-Lu Xu, Shao-Hua Li, Xu-Xia Liu, Rutai Hui, and Xiao-Hong Huang, Am J Clin Nutr. First published June 29, 2011, doi: 10.3945/​ajcn.110.010926

Abstract

Background: The effect of green tea beverage and green tea extract on lipid changes is controversial.

Objective: We aimed to identify and quantify the effect of green tea and its extract on total cholesterol (TC), LDL cholesterol, and HDL cholesterol.

Design: We performed a comprehensive literature search to identify relevant trials of green tea beverages and extracts on lipid profiles in adults. Weighted mean differences were calculated for net changes in lipid concentrations by using fixed-effects or random-effects models. Study quality was assessed by using the Jadad score, and a meta-analysis was conducted.

Results: Fourteen eligible randomized controlled trials with 1136 subjects were enrolled in our current meta-analysis. Green tea consumption significantly lowered the TC concentration by 7.20 mg/dL (95% CI: −8.19, −6.21 mg/dL; P < 0.001) and significantly lowered the LDL-cholesterol concentration by 2.19 mg/dL (95% CI: −3.16, −1.21 mg/dL; P < 0.001). The mean change in blood HDL-cholesterol concentration was not significant. Subgroup and sensitivity analyses showed that these changes were not influenced by the type of intervention, treatment dose of green tea catechins, study duration, individual health status, or quality of the study. Overall, no significant heterogeneity was detected for TC, LDL cholesterol, and HDL cholesterol; and results were reported on the basis of fixed-effects models.

Conclusion: The analysis of eligible studies showed that the administration of green tea beverages or extracts resulted in significant reductions in serum TC and LDL-cholesterol concentrations, but no effect on HDL cholesterol was observed.

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User comments

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Tachyon
not rated yet Jul 08, 2011
Well its true...but is can also give you osteoporosis, induce fractures, increase the risk of developing rheumatoid arthritis, raise blood cholesterol and obviously anxiety and reduction in the ability to sleep.
sstritt
not rated yet Jul 08, 2011
Well its true...but is can also give you osteoporosis, induce fractures, increase the risk of developing rheumatoid arthritis, raise blood cholesterol and obviously anxiety and reduction in the ability to sleep.

References please.
Tachyon
5 / 5 (1) Jul 08, 2011
Well its true...but is can also give you osteoporosis, induce fractures, increase the risk of developing rheumatoid arthritis, raise blood cholesterol and obviously anxiety and reduction in the ability to sleep.

References please.


Here you go,

Bonner, James R. Drug Allergy in Cecil Textbook of Medicine. Goldman, Lee and Claude J. Bennett, eds. Philadelphia: W.B. Saunders, 2000.

McManamy, M.C., Schube, P.G. Caffeine intoxication: report of a case the symptoms of which amounted to a psychosis. N Engl J Med, 215 (1936): 616-620.

"American Journal of Physiology"; Effects of Caffeine on Energy Metabolism, Heart Rate, and Methylxanthine Metabolism in Lean and Obese Women; D. Bracco, et al.; October 1995

Effect of caffeine consumption on efficacy of methotrexate in rheumatoid arthritis. Nesher G, Mates M, Zevin S. Shaare-Zedek Medical Center, Jerusalem, Israel. 2006 Jul;33(7):1275-81.

Cooper C, Atkinson EJ, Wahner HW, O'Fallon WM, Riggs BL, Judd HL, et al. Is ca
Tachyon
5 / 5 (1) Jul 08, 2011
Here you go,

Bonner, James R. Drug Allergy in Cecil Textbook of Medicine. Goldman, Lee and Claude J. Bennett, eds. Philadelphia: W.B. Saunders, 2000.

McManamy, M.C., Schube, P.G. Caffeine intoxication: report of a case the symptoms of which amounted to a psychosis. N Engl J Med, 215 (1936): 616-620.

"American Journal of Physiology"; Effects of Caffeine on Energy Metabolism, Heart Rate, and Methylxanthine Metabolism in Lean and Obese Women; D. Bracco, et al.; October 1995

Effect of caffeine consumption on efficacy of methotrexate in rheumatoid arthritis. Nesher G, Mates M, Zevin S. Shaare-Zedek Medical Center, Jerusalem, Israel. 2006 Jul;33(7):1275-81.

Cooper C, Atkinson EJ, Wahner HW, O'Fallon WM, Riggs BL, Judd HL, et al. Is caffeine consumption a risk factor for osteoporosis? J Bone Miner Res 1992; 7 (4): 465-471.

Bauer DC, Browner WS, Cauley JA, Orwoll ES, Scott JC, Black
DM, et al. Factors associated with appendicular bone mass. Ann Intern Med 1993;118 (9): 657-665
Mr_Ittha
5 / 5 (2) Jul 08, 2011
Tachyon,
The titles of those studies seem to indicate a problem with caffeine. The study here states "Green tea contains catechin which is a flavonoid with antioxidant properties" as the likely cause of the cholesterol reduction. Since catechin and caffeine are not the same, and green tea tends to have far less caffeine than other beverages (such as coffee, or black tea), your comment doesn't really make sense.
Tachyon
1 / 5 (1) Jul 08, 2011
Well, yes and no. You know that people will always look for excuses to keep doing things they normally like to do, and I dont have any problem with that, is not my body but the facts are still there... I know catechin and caffeine are not the same, and green tea tends to have far less caffeine than other beverages, but less doesn't mean none or free of it. Doing stuff we like (even though we know it's bad for us), instead of doing the things that really bring wellness and better health to us is the real thing that doesn't make sense here.
HealthAdvocate
5 / 5 (1) Jul 08, 2011
I'm sorry Tachyon, but you're far afield on this one. Not only are the studies you're quoting not relevant, but the evidence is quite to the contrary. First, Americans don't drink that much green tea relative to the rest of the world, and that's something I'm trying to change. Catechin is a favorable substance and antioxidant that's about as far away from caffeine as I can imagine. There is caffeine in green tea, but it's so low you'd have to drink about six cups to get the same amount of caffeine in a one cup of coffee. Green tea has been shown to lower cholesterol. Green tea decreases anxiety because it stimulates the release of dopamine in the brain - a hormone that controls one's sense of well-being. Finally, green tea either improves or prevents many health conditions including acne, Alzheimer's disease, prostate cancer, breast cancer, tooth decay, diabetes and prediabetes, blood pressure, cardiovascular disease, obesity, and more.
HealthAdvocate
Jul 08, 2011
This comment has been removed by a moderator.
Tachyon
1 / 5 (1) Jul 08, 2011
Not so fast my friend, as I said before everyone will look for excuses...if you like green tea go ahead, you will find a lot of benefits of it. If you want to know all the risks, go ahead, you will find them too. The best thing we can do is be objective about both positions, not only defend one of them just to keep going with the stream, or ignore wrong health habits. Read first the "irrelevant" references and then make your own conclusion. I'm not saying you are wrong, but remember that everything has its pros and cons...