type 2 diabetes is the most prevalent metabolic disease in the world , estimated to reach over 300 million cases by the year 2030 ( 1 ) . as in other developing countries , the prevalence of diabetes is increasing in iran , and it is estimated that more than 8% of iranian people currently suffer from this disease ( 2 ) . diabetes is a disorder with multiple etiologies , such as chronic hyperglycemia with disturbances of carbohydrate , fat , and protein metabolism that result from defects in insulin secretion , insulin action , or both , which characterizes type 2 diabetes ( 3 ) . inflammation plays a major role in the processes of obesity , cardiovascular disease , type 2 diabetes , and other disorders ( 4 ) . inflammatory cytokines are important markers , and among them , il-6 and tnf- are often used to describe the degree of inflammation in patients with type 2 diabetes ( 5 ) . also , it has been indicated that diabetes increases oxidative stress and inflammation , and it decreases circulating adiponectin ( 6 ) . hypoglycemic drugs can lead to unpleasant side effects , such as lactic acidosis , peripheral edema , severe hypoglycemia , and abdominal discomfort ( 7 ) . it is well - documented that some natural antioxidants , such as polyphenols , have acute beneficial effects on endothelial function ( 8) . studies have shown that polyphenols may improve glucose and lipid disorders , and it is also established that they have anti - inflammatory effects ( 9 ) . as demonstrated by in vivo and in vitro research , pomegranate and its juice have therapeutic hypoglycemic effects , including increased insulin sensitivity , inhibition of -glucosidase , impact on the function of glucose transporter type 4 , decreased total cholesterol ( tc ) , and improved blood lipid profiles . in addition , anti - inflammatory action is exerted through modulation of the peroxisome proliferator - activated receptor pathway ( 11 - 14 ) . concentrated pomegranate juice ( cpj ) , called  robe annar  , is used in iran as a traditional additive . several studies have suggested that reduced cholesterol biosynthesis in the liver might be due to the antioxidant activity of flavonoids . some limited studies have investigated the effects of cpj consumption on blood glucose and lipid concentrations in diabetic patients ( 15 , 16 ) . however , no previous study has assessed the effects of cpj on inflammatory factors . as studies on the effect of cpj on type 2 diabetes are limited , the present study was performed to assess the effects of cpj on fasting blood sugar ( fbs ) , lipid profiles , and inflammatory biomarkers , including high - sensitivity c - reactive protein ( hs - crp ) , interleukin-6 ( il-6 ) , tumor necrosis factor- ( tnf- ) , serum adiponectin , and total antioxidant capacity ( tac ) in patients with type 2 diabetes . this quasi - experimental study was performed on 40 subjects aged 25 - 60 years with type 2 diabetes , who were recruited from the diabetes clinic at golestan hospital , ahvaz jundishapur university of medical sciences , ahvaz , iran . participants had a mean systolic blood pressure of 124.25  2.87 mmhg and a mean diastolic blood pressure of 83.02  1.74 mmhg at baseline . the sample size , using ncss software and a power of 90% , based on the results of an article on pj with inflammation factors and significant il-6 , was calculated to be 31 subjects , assuming an estimated 30% dropout rate ( 13 ) . the exclusion criteria were as follows : the use of insulin , pregnancy or nursing , impaired renal function , active liver disease , and other chronic diseases . oral hypoglycemic agents were taken by all of the patients except two , who controlled their diabetes with diet . the cpj was made from natural pomegranate juice with no added sugar , sweeteners , or preservatives ; it was purchased from a local market in mashhad , iran . the total polyphenol concentration , determined spectrophotometrically , was 6.3 mg/100 g. the study protocol was approved by the ethics committee at ahvaz jundishapur university of medical sciences , ahvaz , iran ( no : rec.1392.148.b-9214 ) . the study was registered at the iranian registry of clinical trials under registration number irct2013091614680n1 . height was measured to the nearest 0.1 cm and body weight was measured to the nearest 0.05 kg using a digital scale ( seca clara 803 , hamburg , germany ) . bmi was calculated as weight in kilograms divided by height in meters squared ( m ) . waist circumference was measured at the minimal waist circumference between the last rib and the iliac crests ( 17 ) . blood pressure was measured on the left arm in a seated position after a 10-minute rest . the subjects were asked to consume 50 g of cpj daily for 4 weeks . to ensure that the cpj was taken regularly , the subjects were also asked to carefully record their diet and physical activity , and to not change their usual diet , drug regimen , and physical activity during the study period . dietary intake was assessed using 3-day food records at the beginning and end of the intervention period . the 3-day record was checked and completed by the dietician using color pictures of food . the total daily energy and nutrient consumption was estimated with nutrition 4 software ( diet analysis module version 3.5.2 , usa ) . the subjects mean physical activity level was assessed by using a standard physical activity questionnaire based on the metabolic equivalents of all activities during the previous week , including at work , during leisure time , and at rest or sleep ( 18 ) . at the beginning of the experiment , venous blood samples ( 10 ml ) were taken from all patients between 8:00 and 9:30 am after 12 - 14 hours of overnight fasting ; this was repeated after the 4-week intervention period . the blood samples were centrifuged at  1000 g for 10 minutes and stored at -70c for further analysis . fasting serum glucose was measured using glucose - oxidize ( pars azmoon co. , tehran , iran ) . a commercially available enzyme - linked immunosorbent assay ( elisa ) kit ( orgenium laboratories business unit , vantaa , finland ) was used for the measurements of tnf- , il-6 , and adiponectin . labor diagnostic nord was used for hs - crp according to the manufacture s specifications . the inter - assay coefficients of variation were 8.6% for il-6 , 4% for tnf- , and 12% for adiponectin . sensitivity was 7 pg / ml for il-6 and tnf- , 10 ng / ml for hs - crp , and 185 ng / ml for adiponectin . statistical analyses were performed using spss for windows ( version 17 ; spss , chicago , il , usa ) . this quasi - experimental study was performed on 40 subjects aged 25 - 60 years with type 2 diabetes , who were recruited from the diabetes clinic at golestan hospital , ahvaz jundishapur university of medical sciences , ahvaz , iran . participants had a mean systolic blood pressure of 124.25  2.87 mmhg and a mean diastolic blood pressure of 83.02  1.74 mmhg at baseline . the sample size , using ncss software and a power of 90% , based on the results of an article on pj with inflammation factors and significant il-6 , was calculated to be 31 subjects , assuming an estimated 30% dropout rate ( 13 ) . the exclusion criteria were as follows : the use of insulin , pregnancy or nursing , impaired renal function , active liver disease , and other chronic diseases . oral hypoglycemic agents were taken by all of the patients except two , who controlled their diabetes with diet . the cpj was made from natural pomegranate juice with no added sugar , sweeteners , or preservatives ; it was purchased from a local market in mashhad , iran . the total polyphenol concentration , determined spectrophotometrically , was 6.3 mg/100 g. the study protocol was approved by the ethics committee at ahvaz jundishapur university of medical sciences , ahvaz , iran ( no : rec.1392.148.b-9214 ) . the study was registered at the iranian registry of clinical trials under registration number irct2013091614680n1 . height was measured to the nearest 0.1 cm and body weight was measured to the nearest 0.05 kg using a digital scale ( seca clara 803 , hamburg , germany ) . bmi was calculated as weight in kilograms divided by height in meters squared ( m ) . waist circumference was measured at the minimal waist circumference between the last rib and the iliac crests ( 17 ) . blood pressure was measured on the left arm in a seated position after a 10-minute rest . the subjects were asked to consume 50 g of cpj daily for 4 weeks . to ensure that the cpj was taken regularly , the subjects were also asked to carefully record their diet and physical activity , and to not change their usual diet , drug regimen , and physical activity during the study period . dietary intake was assessed using 3-day food records at the beginning and end of the intervention period . the 3-day record was checked and completed by the dietician using color pictures of food . the total daily energy and nutrient consumption was estimated with nutrition 4 software ( diet analysis module version 3.5.2 , usa ) . the subjects mean physical activity level was assessed by using a standard physical activity questionnaire based on the metabolic equivalents of all activities during the previous week , including at work , during leisure time , and at rest or sleep ( 18 ) . at the beginning of the experiment , venous blood samples ( 10 ml ) were taken from all patients between 8:00 and 9:30 am after 12 - 14 hours of overnight fasting ; this was repeated after the 4-week intervention period . the blood samples were centrifuged at  1000 g for 10 minutes and stored at -70c for further analysis . fasting serum glucose was measured using glucose - oxidize ( pars azmoon co. , tehran , iran ) . a commercially available enzyme - linked immunosorbent assay ( elisa ) kit ( orgenium laboratories business unit , vantaa , finland ) was used for the measurements of tnf- , il-6 , and adiponectin . labor diagnostic nord was used for hs - crp according to the manufacture s specifications . the inter - assay coefficients of variation were 8.6% for il-6 , 4% for tnf- , and 12% for adiponectin . sensitivity was 7 pg / ml for il-6 and tnf- , 10 ng / ml for hs - crp , and 185 ng / ml for adiponectin . statistical analyses were performed using spss for windows ( version 17 ; spss , chicago , il , usa ) . nine patients were excluded from the study due to inadequate consumption of cpj or gastrointestinal problems , and 31 subjects ( 15 males , 16 females ) completed the study . the age of the participants was 46  8.3 years and the duration of diabetes was 4 - 10 years . the mean bmi of the participants was 29.53  0.69 m. the comparison of anthropometric indices , metabolic factors , and inflammatory factors before and after of consumption of cpj is presented in table 1 . bmi , weight , and waist circumference did not change after consumption of the cpj . the intake of cpj produced a significant increase in both tc and hdl - c from baseline . however , changes observed in serum triglyceride ( tg ) , ldl - c , fbs , and blood pressure were not statistically significant . administration of cpj for 4 weeks caused a significant reduction in serum il-6 , but tnf- and hs - crp remained unchanged . compared to baseline , serum adiponectin levels were significantly decreased . the mean value of serum tac was substantially increased ( ~ 75% ) , from 381.88  114.4 at baseline to 1501  817 after 4 weeks of cpj consumption . energy , nutrient intake , and physical activity at baseline and after the 4-week intervention are presented in table 2 . the 3-day food records showed no significant changes in energy or nutrient intakes before and after the study . abbreviations : met , kcal / hour.day ; mufa , monounsaturated fatty acid ; pufa , polyunsaturated fatty acid ; sfa , saturated fatty acid . values were derived from 3-day food records completed at baseline and the final week of the intervention . we found that one advantage of cpj intake on inflammatory factors in patients with type 2 diabetes was a significant decrease in plasma levels of il-6 . the daily consumption of 50 g of cpj for 4 weeks had no effects on fasting serum glucose of diabetic patients . this finding is in agreement with most clinical trials that have examined the effects of pj or cpj on glycemic parameters in diabetic subjects ( 13 , 16 , 19 , 20 ) . in a similar study by rashidi et al . ( 15 ) neither fbs nor hba1c changed after a 3-month administration of 45 g of cpj per day in patients with type 2 diabetes . however , in another trial of diabetic patients , the consumption of 200 ml pj for 6 weeks was associated with a significant reduction in fbs ( 21 ) . we could not detect any significant correlations between cpj and fbs , due to the different study duration or type of intervention in comparison to previous studies ( 21 ) . it has been suggested that polyphenols , as the main component of pomegranate , might have hypoglycemic effects on different mechanisms , including increased glucose uptake by peripheral tissues , inhibition of glucose absorption in the gut , increased insulin release , or inhibition of gluconeogenesis ( 22 ) . thus , the overall results suggest that in diabetic patients , who usually avoid sugar - containing fruit , the intake of pj or cpj does not aggravate glycemic parameters . this study indicated that 4 weeks of cpj consumption increased tc and hdl - c levels in diabetic patients , but had no effects on serum tg . these results are in line with most previous studies showing that pj did not alter serum tg levels in diabetic patients ( 13 , 15 , 23 , 24 ) . however , significant reductions of tc and ldl - c in diabetic patients with hyperlipidemia were reported after 6 weeks of 200 ml of pj , and 8 weeks of 40 g cpj , in diabetic patients with hyperlipidemia ( 20 , 21 ) . regarding these differences , it seems that the hypocholesterolemic effects of pj might be attributed to the higher baseline levels of tc and ldl - c of these patients , or to the duration of intervention in those studies . in the present study , serum concentrations of tc since this increase coincided with the significant increase in hdl - c levels , it can be concluded that the increased tc observed in our study was due to increased concentration of hdl - c . in line with this result , the hdl - raising effect of pj has been reported in patients with non - alcoholic fatty liver disease ( 23 ) . however , no changes in serum hdl - c were reported in other similar studies ( 4 ) . it has been shown that polyphenols , via antioxidant activity , could protect hdl particles from oxidation and catabolism ( 25 , 26 ) . varying results have been reported regarding the effects of pj or cpj on blood pressure . in the present study , blood pressure did not show any significant reduction after intervention with cpj , which is consistent with the results of a similar study that investigated the effect of 40 g of cpj in type 2 diabetic patients with hyperlipidemia ( 16 , 20 ) . however , this finding is in contrast with the results of a clinical trial in which a significant reduction in blood pressure was reported after 2 weeks of pj consumption in diabetic patients ( 27 ) . similarly , beneficial effects of pj on blood pressure and serum angiotensin - converting enzyme  ace ) activity in hypertensive patients have been reported in other studies ( 12 , 24 , 25 , 28 ) . the concentration of circulatory cytokines , such as il-6 , crp , and tnf- , increased due to low - grade inflammation in diabetic patients ( 29 ) . in the present study , a 33% reduction of serum il-6 this result is in agreement with a recent clinical trial that showed a 30% decline in serum il-6 due to daily intake of 250 ml of pj in diabetic subjects ( 30 ) . also , a significant constant decrease in il-6 one month after drinking 240 ml / day of pj was reported in adolescents with metabolic syndrome ( 31 ) . furthermore , a significant reduction of il-6 levels was reported after one year of intake of pj in hemodialysis patients ( 32 ) . another study showed a significant reduction in il-6 after consumption of punica granatum extract in patients undergoing periodontal treatment ( 33 ) . however , it has been suggested that pj inhibits the enzymes related to inflammation , such as peroxisome proliferator active receptors ( ppars ) , nuclear transcription factor kappa b ( nf-b ) , and nsaid activated gene-1 ( nag-1 ) , which reduces pro - inflammatory cytokine secretion through the inhibition of map kinases ( 34 ) . in this study consistent with these findings , consumption of pj for 4 weeks in patients with metabolic syndrome ( 13 ) , and for 2 weeks in hypertensive patients , had no significant impact on hs - crp ( 28 ) . another iranian study of type 2 diabetes patients reported that pj  240 cc for 8 weeks ) did not decrease hs - crp values compared to baseline ( 35 ) . however , 12 weeks of pj intake showed a significant reduction of serum hs - crp in diabetic patients ( 36 ) . these conflicting results could be due to the study duration of 4 weeks not being long enough to detect significant changes in this marker . there was no significant effect of cpj on serum tnf- in the present study , which differs from the results of a study by shema - didi et al . that showed a significant reduction in tnf- after one year of pj intake by hemodialysis patients ( 32 ) . pj might suppress tnf--induced expression of cyclooxygenase , an enzyme that catalyzes the synthesis of prostaglandins , which are involved in pain and swelling during the inflammatory response ( 4 ) . this discrepancy between the two studies could be attributed to differences between the pathological conditions of the participants and the duration of the interventions . in the present study , a significant reduction of serum adiponectin since there has been no clinical trial investigating the effect of pomegranate on serum adiponectin , a comparison to our result is difficult . several phenol compounds , such as anthocyanins , punicalagins , ellagic acids , and hydrolysable tannins found in pj ( 37 ) , are well known for their effects on scavenging free radicals and preventing lipid oxidation ( 38 ) . our data revealed that ingestion of cpj resulted in a significant rise in plasma tac , nearly fourfold compared to baseline . consistent daily intake of 100 g of fresh pomegranate fruit for 10 days among healthy subjects and daily intake of 100 ml of pj for 2 weeks in adolescents , as well as 4 weeks of pj administration in elderly subjects , led to significantly increased serum tac ( 23 , 39 , 40 ) . furthermore , a significant increase in tac and a decrease in serum malondialdehyde  mda ) , as a biomarker of oxidative stress , were also observed after 2 weeks of administration of 240 ml of pj in healthy young men ( 41 ) . the total polyphenol level in the cpj in this study was 6.3 mg/100 g. as the dietary intake of our patients did not significantly change during the study period , it can be concluded that the increased plasma antioxidant capacity may be attributed to the polyphenols in pj . as oxidative stress and lipid peroxidation in diabetic patients are high , antioxidant supplements such as polyphenols have been suggested to be useful . the antioxidant properties of pj and its scavenging effects on free radicals have also been reported ( 41 ) . we did not measure changes in plasma mda or lipid peroxidation in the present study . however , previous studies have shown that daily intake of pomegranate polyphenols significantly decreased mda and lipid peroxidation in patients with type 2 diabetes ( 39 ) . these results indicate that cpj administration in diabetic patients substantially improves their serum oxidative status . to the best of our knowledge , this is the first study to investigate the effects of cpj on inflammatory markers in diabetic patients , and which was well - controlled by frequent contact with the participants . nevertheless , the one - group study design , without blinding of participants or a placebo group , was a limitation . in conclusion , a 4-week intervention of 50 g of cpj per day appeared to have favorable effects on certain markers of subclinical inflammation , and increased the plasma concentrations of antioxidants in diabetic patients . however , further research is necessary to better investigate the impact of cpj on biomarkers of oxidative stress and inflammation .
backgroundthe health benefits of pomegranate juice have been reported in several studies . however , limited clinical trials have examined the effects of concentrated pomegranate juice ( cpj ) on inflammatory factors.objectivesthis study aimed to investigate the effects of cpj on metabolic risk factors , including inflammatory biomarkers , in patients with type 2 diabetes mellitus.patients and methodsin a quasi - experiment trial , 40 type 2 diabetic patients were asked to consume 50 g of cpj daily for 4 weeks . 
 anthropometric indices , dietary intake , blood pressure measurements , and fasting blood samples were conducted at baseline and 4 weeks after the intervention.resultsthe intake of cpj produced a significant increase in both total and high - density lipoprotein cholesterol ( hdl - c ) ( 4.7% and 3.9% , respectively ) from baseline ( p < 0.05 ) . 
 however , changes that were observed in serum triglyceride ( tg ) , low - density lipoprotein cholesterol ( ldl - c ) , fasting blood glucose , and blood pressure were not statistically significant . 
 administration of cpj caused significant reduction in serum interleukin-6 ( il-6 ) ( p < 0.05 ) , but tumor necrosis factor- ( tnf- ) and high - sensitivity c - reactive protein ( hs - crp ) remained unchanged during the study . the mean value of serum total antioxidant capacity ( tac ) was substantially increased ( ~ 75% ) from 381.88  114.4 at baseline to 1501  817 after 4 weeks of cpj consumption.conclusionsconsumption of cpj ( 50 g / day ) appears to have favorable effects on some markers of subclinical inflammation , and to increase plasma concentrations of antioxidants in patients with type 2 diabetes .