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Pomegranate and Hypertension

 

    Cardiovascular disorders are a leading cause of global death and disability. Hypertension, a major risk factor for various diseases, has a high prevalence and is expected to reach 30% by 2025. Studies show that a 5 mmHg decrease in diastolic blood pressure (DBP) is linked to 15% and 40% reductions in cardiovascular disease and stroke risks. Despite various anti-hypertensive drugs, uncontrolled hypertension remains a common medical issue (1).

 

    Pomegranate is a popular fruit with applications in traditional medicine. Scientific evidence highlights its therapeutic efficacy against various disorders. Pomegranate is rich in active compounds like flavonoids, polyphenols, ellagitannins, and antioxidants, known for their anti-inflammatory properties and inhibition of angiotensin-converting enzymes. These qualities make pomegranate potentially beneficial for treating hypertension and improving endothelial function. Several clinical studies have demonstrated its hypotensive and cardioprotective effects (1).

 

    One study examined how drinking pomegranate juice immediately affects blood pressure and endothelial function markers. Thirteen hypertensive men, aged 39-68, were part of this single-arm study. They were given natural pomegranate juice (150 ml/day) after a 12-hour fast. Measurements of systolic blood pressure (SBP), diastolic blood pressure (DBP), and other biomarkers were taken at baseline and 4-6 hours after drinking pomegranate juice (1).

 

    Comparing before and after values, there was a significant reduction in both systolic blood pressure (125.38 ± 11.80 to 116.15 ± 7.94 mmHg, -7%; p = 0.013) and diastolic blood pressure (82.69 ± 5.25 to 78.08 ± 3.25 mmHg, -6%; p=0.010). Changes in other biomarkers did not reach statistical significance. This study provided valuable clinical evidence on the immediate blood pressure-lowering and vascular effects of pomegranate juice (1).

 

    A 2-week supplementation with 50 ml/day of pomegranate juice in 10 hypertensive patients led to a significant 5% decrease in systolic blood pressure (155 ± 7 to 147 ± 10 mmHg), along with a 36% reduction in serum angiotensin-converting enzyme (ACE) activity. Angiotensin-converting enzyme (ACE) is a central component of the renin–angiotensin system, which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstrictor angiotensin II. Therefore, ACE indirectly increases blood pressure by causing blood vessels to constrict. ACE inhibitors are widely used as pharmaceutical drugs for the treatment of cardiovascular diseases. This study showed that 2-week of pomegranate juice consumption could reduce ACE activity and lower blood pressure (2).

 

    The impact of chronic pomegranate juice supplementation (50 ml/day) was examined in atherosclerotic patients with carotid artery stenosis. Ten patients took pomegranate juice for 1 year, with five continuing for up to 3 years. A notable reduction in systolic blood pressure starting from 1 month and generally increasing up to month 12 (12% reduction). However, no further reduction was observed when supplementation continued for another 2 years (3).

 

    Supplementing diets with polyphenolic antioxidants has been linked to inhibiting LDL oxidation, reducing macrophage foam cell formation, and slowing down the development of atherosclerosis. In the control group without pomegranate juice, carotid intima-media thickness (IMT) increased by 9% in a year. While pomegranate juice consumption led to a significant IMT reduction of up to 30% after 1 year. After 12 months of pomegranate juice consumption, patients showed an 83% increase in serum paraoxonase 1 (PON 1) activity. Paraoxonase1 (PON1) is an enzyme connected to high-density lipoproteins (HDL) particles and plays an important role in protecting arteries against atherosclerosis. Serum LDL basal oxidative state and LDL susceptibility to copper ion-induced oxidation were significantly reduced by 90% and 59%, respectively. Antibodies against oxidized LDL decreased by 19%, and serum total antioxidant status (TAS) increased by 130% after 1 year of pomegranate juice consumption (3).

 

    The study results suggested that pomegranate juice consumption by carotid artery stenosis patients could reduce carotid IMT and systolic blood pressure, likely due to the potent antioxidant properties of pomegranate juice polyphenols. Continued pomegranate juice consumption for up to 3 years showed no additional benefits on IMT and serum PON1 activity but further reduced serum lipid peroxidation by up to 16% (3).

 

    Another study by Lynn et al. indicated significant reductions in systolic and diastolic blood pressure following pomegranate juice consumption. They conducted a randomized placebo-controlled parallel study to examine the effect of pomegranate juice on pulse wave velocity, blood pressure, and plasma antioxidant status (ferric reducing power; FRAP) in 51 healthy adults (30-50 years). Participants consumed 330 ml/day of pomegranate juice or a control drink for four weeks. Measurements were made at baseline and four weeks. There was no effect of the intervention on pulse wave velocity and plasma FRAP. However, there was a significant fall in systolic blood pressure (-3.14 mmHg, p < 0.001), diastolic blood pressure (-2.33 mmHg p < 0.001), and mean arterial pressure (-2.60 mmHg, p < 0.001). Weight change was similar in the two groups over the intervention period. The study concluded that pomegranate juice supplementation has benefits for BP in the short term (4).

 

    One study examined the effects of a 2-week intake of fresh pomegranate juice on blood pressure, flow-mediated dilatation, serum lipid profile, and concentrations of inflammatory and endothelial function biomarkers in 21 hypertensive patients (aged 30-67 years). They were assigned to receive either pomegranate juice (150 ml/day on a single occasion between lunch and dinner; n = 11) or the same amount of water (n = 10) for 2 weeks. Systolic and diastolic blood pressures and various biomarkers were measured at baseline and the end of the trial. Pomegranate juice consumption was associated with significant reductions in systolic blood pressure (130.91 ± 13.00 to 124.55 ± 15.72 mmHg, - 5%, p = 0.002) and diastolic blood pressure (80.00 ± 8.94 to 76.36 ± 6.74, -4.5%, p = 0.038). The results showed that consuming pomegranate juice for 2 weeks had effective hypotensive effects and suggested that pomegranate juice was a beneficial cardioprotective supplement for hypertensive subjects (5).

 

    In a double-blind 2 x 2 crossover study, 30 individuals with metabolic syndrome received a daily dose of 500 mL pomegranate juice for one week. After one week of the washout period, they received a placebo for one week. Lipid profile, blood glucose control indices including fasting blood glucose, fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), systolic and diastolic blood pressure, and high sensitivity C-reactive protein (hs-CRP, is a marker of inflammation that predicts incident myocardial infarction, stroke, peripheral arterial disease, and sudden cardiac death among healthy individuals with no history of cardiovascular disease, and recurrent events and death in patients with acute or stable coronary syndromes) were measured at the beginning and end of the study (6).

 

    The results indicated that in comparison to the placebo, pomegranate juice was more effective in reducing systolic and diastolic blood pressure (-7.7 ± 1.41 and -4.9 ± 0.91 mmHg, respectively, p = 0.00) and hs-CRP (p = 0.018). The level of triglyceride (p = 0.030) and very low-density lipoproteins cholesterol (VLDL-C) (p = 0.014) were increased after the consumption of pomegranate juice, as opposed to the baseline condition. The rest of the lipid profile, fasting blood glucose, insulin, and HOMA-IR did not show any significant difference. Natural pomegranate juice supplementation lowered the systolic and diastolic blood pressures in patients with metabolic syndrome as well as their blood hs-CRP. However, it also increased their triglyceride and VLDL-cholesterol (6).

 

    Pomegranate has remarkable antioxidant activity due to its high content of polyphenols and flavonoids, with bioactive compounds known for their antioxidant, anti-inflammatory, and heart-protective effects. In addition to the glucose-lowering effect of pomegranates that was discussed in a previous blog Pomegranates and Blood Glucose Control, the few studies mentioned in this blog pointed out the potential benefits of a broader use of pomegranate in the therapy of vascular diseases, such as lessens hypertension and attenuates atherosclerosis in humans.

 

 

References:

 

  1. Asgary S, Keshvari M, Sahebkar A, Hashemi M, Rafieian-Kopaei M. Clinical investigation of the acute effects of pomegranate juice on blood pressure and endothelial function in hypertensive individuals. ARYA Atheroscler. 2013 Nov;9(6):326-31. PMID: 24575134; PMCID: PMC3933059.

  2. Aviram M, Dornfeld L. Pomegranate juice consumption inhibits serum angiotensin converting enzyme activity and reduces systolic blood pressure. Atherosclerosis. 2001 Sep;158(1):195-8. doi: 10.1016/s0021-9150(01)00412-9. PMID: 11500191.

  3. Aviram M, Rosenblat M, Gaitini D, Nitecki S, Hoffman A, Dornfeld L, Volkova N, Presser D, Attias J, Liker H, Hayek T. Pomegranate juice consumption for 3 years by patients with carotid artery stenosis reduces common carotid intima-media thickness, blood pressure and LDL oxidation. Clin Nutr. 2004 Jun;23(3):423-33. doi: 10.1016/j.clnu.2003.10.002. Erratum in: Clin Nutr. 2008 Aug;27(4):671. PMID: 15158307.

  4. Lynn A, Hamadeh H, Leung WC, Russell JM, Barker ME. Effects of pomegranate juice supplementation on pulse wave velocity and blood pressure in healthy young and middle-aged men and women. Plant Foods Hum Nutr. 2012 Sep;67(3):309-14. doi: 10.1007/s11130-012-0295-z. PMID: 22648092.

  5. Asgary S, Sahebkar A, Afshani MR, Keshvari M, Haghjooyjavanmard S, Rafieian-Kopaei M. Clinical evaluation of blood pressure lowering, endothelial function improving, hypolipidemic and anti-inflammatory effects of pomegranate juice in hypertensive subjects. Phytother Res. 2014 Feb;28(2):193-9. doi: 10.1002/ptr.4977. Epub 2013 Mar 21. PMID: 23519910.

  6. Moazzen H, Alizadeh M. Effects of Pomegranate Juice on Cardiovascular Risk Factors in Patients with Metabolic Syndrome: a Double-Blinded, Randomized Crossover Controlled Trial. Plant Foods Hum Nutr. 2017 Jun;72(2):126-133. doi: 10.1007/s11130-017-0605-6. PMID: 28303364.

 

Photo by Arjun Kapoor on Unsplash

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