Intake of polyphenol-rich pomegranate pure juice influences urinary glucocorticoids, blood pressure and homeostasis model assessment of insulin resistance in human volunteers

Abstract

Pomegranate juice (PJ; also known as pomegreat pure juice) provides a rich and varied source of polyphenolic compounds that may offer cardioprotective, anti-atherogenic and antihypertensive effects. The aim of this study was to investigate the effect of PJ consumption on glucocorticoids levels, blood pressure (BP) and insulin resistance in volunteers at high CVD risk. Subjects (twelve males and sixteen females) participated in a randomised, placebo-controlled cross-over study (BMI: 26·77 (sd 3·36) kg/m2; mean age: 50·4 (sd 6·1) years). Volunteers were assessed at baseline, and at weeks 2 and 4 for anthropometry, BP and pulse wave velocity. Cortisol and cortisone levels in urine and saliva were determined by specific ELISA methods, and the cortisol/cortisone ratio was calculated. Fasting blood samples were obtained to assess plasma lipids, glucose, insulin and insulin resistance (homeostasis model assessment of insulin resistance). Volunteers consumed 500 ml of PJ or 500 ml of a placebo drink containing a similar amount of energy. Cortisol urinary output was reduced but not significant. However, cortisol/cortisone ratios in urine (P = 0·009) and saliva (P = 0·024) were significantly decreased. Systolic BP decreased from 136·4 (sd 6·3) to 128·9 (sd 5·1) mmHg (P = 0·034), and diastolic BP from 80·3 (sd 4·29) to 75·5 (sd 5·17) mmHg (P = 0·031) after 4 weeks of fruit juice consumption. Pulse wave velocity decreased from 7·5 (sd 0·86) to 7·44 (sd 0·94) m/s (P = 0·035). There was also a significant reduction in fasting plasma insulin from 9·36 (sd 5·8) to 7·53 (sd 4·12) mIU/l (P = 0·025) and of homeostasis model assessment of insulin resistance (from 2·216 (sd 1·43) to 1·82 (sd 1·12), P = 0·028). No significant changes were seen in the placebo arm of the study. These results suggest that PJ consumption can alleviate key cardiovascular risk factors in overweight and obese subjects that might be due to a reduction in both systolic and diastolic BP, possibly through the inhibition of 11β-hydroxysteroid dehydrogenase type 1 enzyme activity as evidenced by the reduction in the cortisol/cortisone ratio. The reduction in insulin resistance might have therapeutic benefits for patients with non-insulin-dependent diabetes, obesity and the metabolic syndrome.

Does pomegranate consumption affect weight and body composition? A systematic review and meta‐analysis of randomized controlled clinical trials

“…After removing duplicates, 786 studies remained that were screened by reading both titles and abstracts, and from these, 734 articles did not meet the inclusion criteria. Eventually, of 52 potential relevant publications, a number of studies were excluded because of following reasons: 32 articles evaluated the effect of pomegranate consumption on other outcomes, 6 articles were not randomized controlled clinical trial (Al‐Dujaili, Stockton, Davidson, & Drummond, ; Heber et al, ; Lansky & Newman, ; Sahebkar, Gurban, Serban, Andrica, & Serban, ; Tsang et al, ; Turrini, Ferruzzi, & Fimognari, ), one study could not provide data on the pure effect of pomegranate or its products, and one study conducted on a blend of pomegranate juice and other juices without an appropriate control group (Díaz‐Rubio, Pérez‐Jiménez, Martínez‐Bartolomé, Álvarez, & Saura‐Calixto, ). Finally, 13 eligible RCTs were eligible to be included in the present systematic review and meta‐analysis.…”

“…Limited studies, however, have evaluated the effect of pomegranate consumption on weight in humans, with mixed results. Although some trials have shown that pomegranate has a weight reduction effect (González‐Ortiz, Martínez‐Abundis, Espinel‐Bermúdez, & Pérez‐Rubio, ), other studies found no significant effect (Ekhlasi, Shidfar, Agah, Merat, & Hosseini, ; Park et al, ; Sohrab et al, ; Tsang, Smail, Almoosawi, Davidson, & Al‐Dujaili, ).…”

Potential Hypoglycemic Effect of Pomegranate Juice and Its Mechanism of Action: A Systematic Review

“…Most of PJ studies in humans were randomized studies, placebo and double and triple blind 17,[21][22][23][24][25][26][27][28] ; as well as quasiexperimental studies. 29,30 One did not report the trial design in the article.…”

“…The studies have evaluated the effect of PJ on parameters related to metabolic alterations in healthy, 17,24,28 obese, 23 and diabetic people, 21,26,27,29,30 with metabolic syndrome 25 and arterial pathologies, 27,31 and in women with polycystic ovarian syndrome. 22 In most studies, patients were excluded if they were taking any hypoglycemic drug, due to possible interaction with PJ compounds.…”

Effects of natural polyphenol-rich pomegranate juice on the acute and delayed response of Homocysteine and steroidal hormones following weightlifting exercises: a double-blind, placebo-controlled trial

“…Additionally, it has been shown that POM supplementation is an effective inhibitor of some cellular inflammation transcripts such as tumor necrosis factor α, nuclear factor -κB and cyclooxygenase-2 [14,15]. Similarly, POM supplementation has been shown to regulate expression of androgen-synthesizing genes in human prostate cancer cells [16] and to modulate hormonal profile by reducing cortisol [C] urinary output and fasting plasma insulin in volunteers at high CVD risk [17] and increasing testosterone [T] levels in testis torsion Wistar rats [18] and healthy humans [19].…”