Intake of polyphenol-rich pomegranate pure juice influences urinary glucocorticoids, blood pressure and homeostasis model assessment of insulin resistance in human volunteers.
J Nutr Sci 2012;
1:e9. [PMID:
25191556 PMCID:
PMC4153032 DOI:
10.1017/jns.2012.10]
[Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 06/14/2012] [Accepted: 07/04/2012] [Indexed: 02/05/2023] Open
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.
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