Green Tea in Non-Alcoholic Fatty Liver Disease; A Double Blind Randomized Clinical Trial

2Baqiyatallah Research Center for Gastroenterology and Liver Diseases (BRCGL), Baqiyatallah University of Medical Sciences, Tehran, IR Iran; Middle East Liver Diseases

(MELD) Center, Tehran, Iran

3Mental Health Research Center, Iran University of Medical Sciences

4Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

5Cellular and Molecular Research Center (CMRC), Iran University of Medical Sciences, Tehran, Iran

6Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran

*Corresponding author: Mohammad Reza Vafa, PhD, MSPH, Professor of Nutritional Sciences, School of Public Health, Iran University of Medical Sciences. Tel: +98-2186704743,

Fax: +98-2188622707, E-mail: vafa.m@iums.ac.ir

Received 2017 June 11; Accepted 2017 August 28.

Abstract

Objectives: Antioxidant treatment with Iron chelating agents is one of the suggested treatments for fatty liver disease, which has

become an important health problem in the recent decades. In this study the authors evaluated the general antioxidant, iron chelat-

ing, and sugar and fat absorption characteristics of green tea.

Methods: Patients with non-alcoholic fatty liver disease were randomly assigned to 2 groups for a double blind clinical trial. Patients

in the intervention group received 550 milligrams of green tea tablets daily as well as nutritional education for 3 months. The control

group received the same protocol with green tea replaced with placebo tablets.

Results: After 3 months, 45 participants (21 in the intervention and 24 in the placebo group) completed the follow-up. The change

in body mass index (BMI), aspartate aminotransferase (AST), and fasting blood sugar (FBS) was significantly different between the 2

groups, while the change in total iron binding capacity (TIBC), ferritin, alanine transaminase (ALT), HOMA, and weight did not show

a significant difference.

Conclusions: The difference between the 2 groups was mainly observed in anthropometrics, liver enzyme, and metabolic indi-

cators, although the difference might not have been highlighted due to the effectiveness of routine treatments, that both groups

received.

Keywords: Green Tea, NAFLD, Iron

1. Background

Non-communicable diseases have become a major

challenge for health systems worldwide and are respon-

sible for an increasing number of premature deaths and

preventable morbidity and disability (1). Globalization,

change in life style, reduced physical activity, and un-

healthy diet are among the causing factors for the increase

in the prevalence and burden of non-communicable dis-

eases (2).

Nonalcoholic fatty liver disease (NAFLD) is a common

non-communicable disease affecting 20% to 30% of adult

populations in developed countries (3). Furthermore,

NAFLD is generally associated with obesity, sedentary life

style, and metabolic syndrome (4). It includes a wide range

of liver pathology from mild steatosis to severe hepatic fi-

brosis and cirrhosis (5). Thus, diagnosis of NAFLD could

at times be problematic (6). Even when the diagnosis

is achieved, treatment is not easily established, as there

are no approved drugs for treatment. Several treatment

protocols are suggested and applied by clinicians and re-

searchers, yet there is no consensus among experts and

clinicians on medical treatment (7). Generally, a combi-

nation of modified diet and exercise is recommended for

treatment (8).

Some researchers have shown that a high antioxidants

and anti-inflammatory diet could be effective in NAFLD

treatment (9). Food bioactive compounds are among the

suggested therapeutic approaches for NAFLD (10). In fact,

some anti-oxidants, anti-inflammatory, and insulin sensi-

tizer dietary supplements are believed to modulate the

activation of genes involved in lipogenesis, fibrogenesis,

lipid peroxidation, and inflammation (9).

Iron chelating agents, such as green tea extracts, are

suggested by some researchers to have beneficial effects in

animal and human studies (11). These effects are observed

on obesity, total and visceral body fat, insulin resistance,

Copyright � 2017, Hepatitis Monthly. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International

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Tabatabaee SM et al.

serum cholesterol, and different degrees of liver steato-

sis. Steatosis is reduced by decreased lipids and carbohy-

drates absorption and inhibited adipose tissue turn over

in both hepatic and adipose tissues. Antioxidant and anti-

inflammatory characteristics of the active agents result in

inhibited steatohepatitis (12).

Despite the findings of a few studies evaluating the

effect of green tea, there are controversies regarding the

effects of green tea extract on NAFLD. More studies are

needed to provide enough evidence on the probable effect

of green tea on preventing the development and/or pro-

gression of NAFLD (9).

In this study, the authors evaluated the effect of green

tea extract as a general antioxidant and iron chelating

agent on liver function, anthropometric measures, and

Iron markers in a randomized double blind controlled trial

on patients with NAFLD.

2. Methods

The study protocol of this double-blind randomized

controlled trial was approved by the ethical committee of

Iran University of Medical Sciences. The study was also reg-

istered on the Iranian registry of clinical trials (IRCT), as

IRCT201404132365N8.

The researchers evaluated 108 known cases of NAFLD

for inclusion and exclusion criteria, from which 67 cases

entered the study. The inclusion criteria were confirmed

NAFLD diagnosis by a gastroenterologist with ultrasonog-

raphy, liver biopsy or liver Fibroscan, age of 18 or older, and

willingness to participate in the study. The exclusion crite-

ria were Iron deficiency anemia, allergy of green tea, his-

tory of alcohol consumption (more than 20 grams daily),

other liver disorders (viral hepatitis, auto immune hepati-

tis, celiac, Wilson, and Alpha 1-antitrypsin deficiency), preg-

nancy, and lactation. Participants were also supposed to be

excluded during the study if they showed allergy or other

side effects, became pregnant, and consumed less than 80%

of the supplements they received or did not wish to con-

tinue the study.

The participants were randomly assigned to 2 groups

based on a list already generated using a random number

sequence. Only the main researcher had access to this list

and could detect if a certain participant was receiving sup-

plements or placebo.

Patients in the intervention group received 550 mil-

ligrams of green tea tablets daily in divided doses, as well

as nutritional education and consultation for weight loss

with low calorie diet and life style change recommenda-

tion (minimum 2 to 3 sessions of 30 to 60 minutes of aer-

obic exercise weekly) for 3 months. The control group

received the same protocol with green tea replaced with

identical placebo capsules with starch composition.

Anthropometric evaluation, body composition, food

intake for energy, nutritional agents and Iron, liver en-

zymes, fasting blood sugar, insulin, hemoglobin, TIBC, fer-

ritin, transferrin, serum Iron, transferrin saturation, to-

tal antioxidant capacity, and malondialdehyde were eval-

uated at the beginning and end of the study. Biologic sam-

ple was acquired for mRNA extraction and cDNA synthesis

using reverse transcriptase.

Statistical analysis was performed using SPSS version

19. Mean, Standard Deviation (SD), and percentage were

used for describing the data. Normality of the data was

evaluated by Shapiro-Wilk’s Test. T test and Mann-Whitney

U test were used for comparing the groups.

3. Results

After primary evaluation, 67 participants in the 2

groups (33 in the intervention and 34 in the control group)

were studied. Mean age of participants in the intervention

and control group was 41 and 39.5, respectively (P value of

0.61). There were 18 female participants in the intervention

and 22 in the control group. (P value of 0.85). In each group,

7 people had diabetes (P value: 0.73). There were no statis-

tical differences in other baseline characteristics (Table 1).

Each participant was followed for 3 months and fi-

nally 45 participants (21 in the intervention and 24 in the

placebo group) completed the follow-up. Two of the con-

trol group and 3 of the intervention group participants dis-

continued due to assumed side effects. The reasons for dis-

continuation were immigration, other medical problems,

side effects, and losing their interest in the study. Details

are presented in the participant’s flow diagram (Figure 1).

Table 2 shows the mean change of the study variables

after 3 months in each group. The difference in the mean

change of the 2 groups was statistically significant for BMI,

AST, and FBS, in contrast to MCV, MCHC, TIBC, Hb, Ferritin,

ALT, HOMA, and weight.

4. Discussion

The current study evaluated the effect of green tea ex-

tract on various aspects of NAFLD pathology and treat-

ment. The researchers evaluated liver function tests and

observed better AST results in the intervention group com-

pared to controls. The change in ALT was similar in direc-

tion, yet not statistically significant. In a similar study on

a group of Iranian patients, significant changes were ob-

served in ALT and AST (13). The study of Sakato et al. also

Hepat Mon. In Press(In Press):e14993.

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Tabatabaee SM et al.

Table 1. Comparison of Study Variables Between the Intervention and Control Group at the Beginning of the Study

Variables

Control

Intervention

P Value

Mean

TAC

6.88

2.47

7.18

2.50

0.655

Hemoglobin

14.26

1.28

14.61

1.36

0.345

Iron

68.74

29.60

83.43

33.64

0.115

TIBC

346.16

39.43

333.57

27.28

0.223

Ferritin

91.12

96.76

136.68

135.16

0.159

Transferrin

260.87

56.76

261.21

50.75

0.984

FBS

110.88

47.22

113.55

44.40

0.835

Ins

16.49

10.23

18.75

12.97

0.512

Cholesterol

193.31

36.87

194.45

39.63

0.914

132.75

66.37

152.23

65.30

0.291

HDL

47.88

8.20

44.68

7.43

0.150

LDL

112.44

33.56

112.45

23.56

0.998

ALT

31.16

21.33

32.41

29.43

0.857

AST

23.72

12.52

25.36

16.83

0.682

HOMA

10.02

9.03

13.33

12.03

0.244

Weight

129.64

32.93

116.75

30.83

0.151

BMI

44.31

6.68

43.06

7.37

0.540

Fat Mass

55.90

14.34

51.83

15.11

0.344

MDA

58.27

54.98

89.73

84.32

0.150

Iron intake

10.9

3.69

9.7

3.57

0.31

showed significant changes in ALT but not AST (14). Con-

sidering the high prevalence of obesity in the current sam-

ple and the majority of grade 2 and 3 fatty liver, more pro-

longed interventions may be needed to determine signifi-

cant changes in both liver function tests.

Among anthropometric parameters evaluated in this

study, the changes in BMI was more pronounced in green

tea consumers than the control group, who received rou-

tine treatment. Changes in other anthropometric parame-

ters, such as body weight, fat mass, and fat proportion did

not present significant differences. Nagao et al. showed

similar effects of green tea on different anthropometric pa-

rameters (15). Other researchers have also observed similar

results with longer follow up durations (14, 16). Sakata et al.

showed a three-fold increase in weight loss in patients with

NAFLD, although it was not statistically significant (14). The

current study showed a significant reduction in green tea

group compared to the control group although the quan-

tity was less.

Hemoglobin, Iron, Transferrin, and Ferritin were mea-

sured as markers of iron level. At the end of the study,

the change was more dominant in the intervention group

than the controls, while the difference was not statistically

significant. The iron chelating activity of green tea was

widely discussed in other studies (17) and researchers have

highlighted positive effects (18).

The researchers did not observe statistically signifi-

cant differences in antioxidant markers in this study, while

some other researchers have documented such effects in

animal (19) and human studies (20, 21). The study of Basu et

al. showed change in MDA in 35 fat patients with metabolic

syndrome with average BMI equal to 35. Also, the adminis-

tered dose is higher in their study, compared to the current

work. The fact that the current patients had much higher

BMI average (44) might be the reason for the changes ob-

served in the current study sample (20).

The difference in metabolic marker change between

the 2 groups were present yet not statistically significant,

except for FBS. Researchers have shown the positive effect

of green tea in reducing insulin resistance, yet we could

not document such change in the current study (22).

While the iron chelating activity of green tea has been

Hepat Mon. In Press(In Press):e14993.

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Tabatabaee SM et al.

Figure 1. Sample Template for the CONSORT Diagram Showing the Flow of Participants Through Each Stage of a Randomized Trial

Assessed for eligibility

(n = 108)

Excluded (n = 41)

Not meeting inclusion criteria

(n = 28)

Refused to participate

(n = 11)

Other reasons (n = 2)

Randomized (n = 67)

Allocated to intervention

(n = 33)

Received allocated

intervention (n = 28)

Did not receive allocated

intervention (n = 5)

(give reasons)

Allo

tio

Enrollment

Allocated to intervention

(n = 34)

Received allocated

intervention (n = 33)

Did not receive allocated

intervention (n = 1)

(give reasons)

ollow Up

Lost to follow up

(n = 4) (give reasons)

Discontinued intervention

(n = 3) (give reasons)

Lost to follow up

(n = 7) (give reasons)

Discontinued intervention

(n = 2) (give reasons)

lysis

Analyzed (n = 21)

Excluded from analysis

(n = 0) (give reasons)

Analyzed (n = 24)

Excluded from analysis

(n = 0) (give reasons)

The text boxes could be modified by clicking on them.

widely discussed, (17) the researchers did not observe dif-

ferences in iron markers. It seems that the therapeutic

effects of green tea are generally explained through anti-

oxidant features (23). These features are being studied in a

variety of disease, such as Parkinson’s and Alzheimer’s dis-

ease (24) and other neurodegenerative disorders (17), car-

diovascular disease, and malignancies among others.

Although there is supporting literature on health pro-

moting effects of green tea in vitro and in animal studies

(25, 26), the researchers need more evidence from human

Hepat Mon. In Press(In Press):e14993.

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Tabatabaee SM et al.

Table 2. Comparison of Study Variables Between the Intervention and Control Group After 3 Months of Follow-Up

Variables

Control

Intervention

P Value

Mean

Std. Deviation

Mean

Std. Deviation

TAC

2.95

1.87

2.58

2.43

0.597

0.09

0.90

-0.13

0.75

0.431

Iron

7.12

39.01

-8.87

33.62

0.218

TIBC

-11.00

58.95

2.50

43.27

0.193a

Ferritin

2.11

24.76

-28.46

74.89

0.496a

Transfer

-10.73

43.66

-12.47

37.39

0.914

FBS

6.35

27.32

-0.89

34.80

0.019a

Ins

0.62

9.37

-0.58

8.78

0.708

Cholesterol

1.42

31.43

-12.67

43.17

0.262

4.58

44.72

-18.89

56.08

0.167

HDL

-3.37

6.28

-2.39

9.33

0.709

LDL

-3.84

29.14

-6.50

25.88

0.771

Alt

-3.50

21.85

-12.17

19.17

0.079a

AST

-0.22

14.63

-6.78

13.42

0.037a

HOMA

-3.17

9.20

-3.43

9.42

0.802a

Weight

-1.83

5.15

-5.27

6.45

0.143a

BMI

-0.25

2.02

-1.88

1.86

0.037

Fat Mass

-2.90

3.19

-4.28

4.51

0.713a

MDA f

21.98

60.97

-0.89

67.09

0.278

aMann-Whitney U test.

research before it could be considered as a widely accepted

therapeutic agent (27). Also, the researchers need to gain a

detailed understanding of its mechanisms at the molecu-

lar level and the pathways through which it affects fat ac-

cumulation, oxidative stress, and inflammation (10).

The researchers observed positive effects from green

tea mainly in anthropometrics, liver enzyme, and

metabolic indicators. This could be due to the short

duration of the study or the limited sample size. Also, the

green tea extract dose was higher in most of the other stud-

ies. The difference between the intervention and control

group might not be highlighted due to the effectiveness

of routine treatments that both groups received.

References

1. Maher D, Harries AD, Zachariah R, Enarson D. A global frame-

work for action to improve the primary care response to chronic

non-communicable diseases: a solution to a neglected problem.

BMC Public Health. 2009;9:355. doi: 10.1186/1471-2458-9-355. [PubMed:

19772598].

2. Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT, et al.

Effect of physical inactivity on major non-communicable diseases

worldwide: an analysis of burden of disease and life expectancy.

Lancet. 2012;380(9838):219–29. doi: 10.1016/S0140-6736(12)61031-9.

[PubMed: 22818936].

3. Pournik O, Dorri S, Zabolinezhad H, Alavian SM, Eslami S. A diagnos-

tic model for cirrhosis in patients with non-alcoholic fatty liver dis-

ease: an artificial neural network approach. Med J Islam Repub Iran.

2014;28:116. [PubMed: 25678995].

4. Malekzadeh R, Mohamadnejad M, Merat S, Pourshams A, Etemadi

A. Obesity pandemic: an Iranian perspective. Arch Iranian Med.

2005;8(11):1–7.

5. Sohrabpour A, Rezvan H, Amini-Kafiabad S, Dayhim M, Merat S, Pour-

shams A. Prevalence of Nonalcoholic Steatohepatitis in Iran: A Pop-

ulation based Study. Middle East J Dig Dis. 2010;2(1):14–9. [PubMed:

25197507].

6. Pournik O, Alavian SM, Ghalichi L, Seifizarei B, Mehrnoush L, Aslani

A, et al. Inter-observer and Intra-observer Agreement in Pathologi-

cal Evaluation of Non-alcoholic Fatty Liver Disease Suspected Liver

Biopsies. Hepat Mon. 2014;14(1):e15167. doi: 10.5812/hepatmon.15167.

[PubMed: 24497882].

7. Cho J, Koh Y, Han J, Kim D, Kim T, Kang H. Adiponectin mediates

the additive effects of combining daily exercise with caloric restric-

tion for treatment of non-alcoholic fatty liver. Int J Obes (Lond).

2016;40(11):1760–7. doi: 10.1038/ijo.2016.104. [PubMed: 27216820].

8. Rahimlou M, Yari Z, Hekmatdoost A, Alavian SM, Keshavarz SA. Gin-

ger Supplementation in Nonalcoholic Fatty Liver Disease: A Ran-

domized, Double-Blind, Placebo-Controlled Pilot Study. Hepat Mon.

2016;16(1):e34897. doi: 10.5812/hepatmon.34897. [PubMed: 27110262].

Hepat Mon. In Press(In Press):e14993.

Uncorrected Proof

Page 7

Tabatabaee SM et al.

9. Eslamparast T, Eghtesad S, Poustchi H, Hekmatdoost A. Re-

cent advances in dietary supplementation, in treating non-

alcoholic fatty liver disease. World J Hepatol.

2015;7(2):204–12.

doi: 10.4254/wjh.v7.i2.204. [PubMed: 25729475].

10. Dongiovanni P, Lanti C, Riso P, Valenti L. Nutritional therapy for

nonalcoholic fatty liver disease. J Nutr Biochem. 2016;29:1–11. doi:

10.1016/j.jnutbio.2015.08.024. [PubMed: 26895659].

11. Bose M, Lambert JD, Ju J, Reuhl KR, Shapses SA, Yang CS. The major

green tea polyphenol, (-)-epigallocatechin-3-gallate, inhibits obesity,

metabolic syndrome, and fatty liver disease in high-fat-fed mice. J

Nutr. 2008;138(9):1677–83. [PubMed: 18716169].

12. Xiao J, Ho CT, Liong EC, Nanji AA, Leung TM, Lau TY, et al. Epigallocat-

echin gallate attenuates fibrosis, oxidative stress, and inflammation

in non-alcoholic fatty liver disease rat model through TGF/SMAD, PI3

K/Akt/FoxO1, and NF-kappa B pathways. Eur J Nutr. 2014;53(1):187–99.

doi: 10.1007/s00394-013-0516-8. [PubMed: 23515587].

13. Pezeshki A, Safi S, Feizi A, Askari G, Karami F. The Effect of Green Tea

Extract Supplementation on Liver Enzymes in Patients with Nonalco-

holic Fatty Liver Disease. Int J Prev Med. 2016;7:28. doi: 10.4103/2008-

7802.173051. [PubMed: 26955458].

14. Sakata R, Nakamura T, Torimura T, Ueno T, Sata M. Green tea with

high-density catechins improves liver function and fat infiltration

in non-alcoholic fatty liver disease (NAFLD) patients: a double-

blind placebo-controlled study. Int J Mol Med. 2013;32(5):989–94. doi:

10.3892/ijmm.2013.1503. [PubMed: 24065295].

15. Nagao T, Hase T, Tokimitsu I. A green tea extract high in catechins

reduces body fat and cardiovascular risks in humans. Obesity (Sil-

ver Spring). 2007;15(6):1473–83. doi: 10.1038/oby.2007.176. [PubMed:

17557985].

16. Fukuzawa Y, Kapoor MP, Yamasaki K, Okubo T, Hotta Y, Juneja LR. Ef-

fects of green tea catechins on nonalcoholic steatohepatitis (NASH)

patients. J Funct Foods. 2014;9:48–59. doi: 10.1016/j.jff.2014.04.010.

17. Mandel S, Amit T, Reznichenko L, Weinreb O, Youdim MB. Green tea

catechins as brain-permeable, natural iron chelators-antioxidants

for the treatment of neurodegenerative disorders. Mol Nutr Food

Res.

2006;50(2):229–34. doi: 10.1002/mnfr.200500156. [PubMed:

16470637].

18. Imai K, Nakachi K. Cross sectional study of effects of drinking green

tea on cardiovascular and liver diseases. BMJ. 1995;310(6981):693–6.

doi: 10.1136/bmj.310.6981.693. [PubMed: 7711535].

19. Skrzydlewska E, Ostrowska J, Farbiszewski R, Michalak K. Protec-

tive effect of green tea against lipid peroxidation in the rat liver,

blood serum and the brain. Phytomedicine. 2002;9(3):232–8. doi:

10.1078/0944-7113-00119. [PubMed: 12046864].

20. Basu A, Sanchez K, Leyva MJ, Wu M, Betts NM, Aston CE, et al.

Green tea supplementation affects body weight, lipids, and lipid

peroxidation in obese subjects with metabolic syndrome. J Am Coll

Nutr. 2010;29(1):31–40. doi: 10.1080/07315724.2010.10719814. [PubMed:

20595643].

21. Coimbra S, Castro E, Rocha-Pereira P, Rebelo I, Rocha S, Santos-Silva A.

The effect of green tea in oxidative stress. Clin Nutr. 2006;25(5):790–6.

doi: 10.1016/j.clnu.2006.01.022. [PubMed: 16698148].

22. Fargion S, Dongiovanni P, Guzzo A, Colombo S, Valenti L, Fracanzani

AL. Iron and insulin resistance.Aliment Pharmacol Ther. 2005;22 Suppl

2:61–3. doi: 10.1111/j.1365-2036.2005.02599.x. [PubMed: 16225476].

23. Babu PV, Sabitha KE, Shyamaladevi CS. Therapeutic effect of green

tea extract on oxidative stress in aorta and heart of streptozo-

tocin diabetic rats. Chem Biol Interact.

2006;162(2):114–20. doi:

10.1016/j.cbi.2006.04.009. [PubMed: 16860299].

24. Weinreb O, Mandel S, Amit T, Youdim MB. Neurological mechanisms

of green tea polyphenols in Alzheimer’s and Parkinson’s diseases. J

Nutr Biochem. 2004;15(9):506–16. doi: 10.1016/j.jnutbio.2004.05.002.

[PubMed: 15350981].

25. Thangapazham RL, Singh AK, Sharma A, Warren J, Gaddipati JP,

Maheshwari RK. Green tea polyphenols and its constituent epi-

gallocatechin gallate inhibits proliferation of human breast can-

cer cells in vitro and in vivo. Cancer Lett. 2007;245(1-2):232–41. doi:

10.1016/j.canlet.2006.01.027. [PubMed: 16519995].

26. Ortiz-Lopez L, Marquez-Valadez B, Gomez-Sanchez A, Silva-Lucero

MD, Torres-Perez M, Tellez-Ballesteros RI, et al. Green tea compound

epigallo-catechin-3-gallate (EGCG) increases neuronal survival in

adult hippocampal neurogenesis in vivo and in vitro. Neuroscience.

2016;322:208–20. doi: 10.1016/j.neuroscience.2016.02.040. [PubMed:

26917271].

27. Zaveri NT. Green tea and its polyphenolic catechins: medicinal uses

in cancer and noncancer applications. Life Sci. 2006;78(18):2073–80.

doi: 10.1016/j.lfs.2005.12.006. [PubMed: 16445946].

Hepat Mon. In Press(In Press):e14993.

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