The Composition of Pomegranates
Pomegranate contains the phenol ellagic acid, which in recent research has been associated with protective effects against cancer. The fruit is a good source of vitamin C, tannins, and flavonoids. Major anthocyanidins include delphinidin, cyanidin, and pelargonidin, which contribute to the pomegranate's antioxidant activity.1 An examination of the pomegranate fermented juice and seed oil's antioxidant properties found activity similar to that of green tea, red wine, and and may even act as a preservative.2 Flavonoids extracted from the juice and seed oil demonstrated an ability to inhibit lipoxygenase — an enzyme that converts favorable unsaturated fatty acids to damaging peroxides.
Punicalagin, an ellagitannin contained in pomegranate, has been identified as a major source of the fruit's antioxidant activity.3 A trial in which 14 healthy participants consumed pomegranate juice daily for 15 days found a decrease in plasma malondialdehyde (MDA, a marker of oxidative stress), and an increase in red blood cell levels of the antioxidant glutathione.4 Some of the benefits of pomegranate juice persisted a week after discontinuing the beverage.
While pomegranate seeds and their fleshy covering known as aryls are the parts of the fruit normally consumed, significant free radical scavenging ability has been found in the peel as well.5 For example, a trial of humans with ulcerative colitis found that the peel improved symptoms in comparison with a placebo after four weeks.6
Pomegranates Have Cardiovascular BenefitsIn a trial of patients with high cholesterol levels, the addition of pomegranate to the drug simvastatin lowered low density lipoprotein (LDL) cholesterol levels more than simvastatin alone and improved oxidative stress levels in addition to other benefits.7 In another human study, pomegranate juice decreased susceptibility of LDL to aggregation and retention, and increased serum paraoxonase activity, which helps protect against lipid oxidation.8 In other research, pomegranate juice given daily for two weeks lowered systolic blood pressure by 5% and serum angiotensin converting enzyme (ACE, which controls blood pressure by regulating fluid volume) by 36% in a trial of hypertensive individuals.9
When consumed for up to three years by carotid artery stenosis patients, pomegranate juice was associated with a significant decrease in carotid intima media thickness (a measure of atherosclerosis) and systolic blood pressure.10
Pomegranates Have Antimicrobial EffectsA study involving extracts of pomegranate aril and peel found antimicrobial activity against Staphyloccus aureus and Escherichia coli, two common pathogens that are frequently implicated in foodborne illnesses.11 In laboratory studies, pomegranate peel extract as well as some of the fruit's individual polyphenols have demonstrated activity against Mycobacterium tuberculosis and Klebsiella pneumoniae.12Another study found antimicrobial activity for pomegranate extractagainst Clostridium difficile.13
Pomegranates Have Anticancer EffectsA review of pomegranate polyphenols in cancer prevention and treatment noted that "Pomegranate evokes antiproliferative, anti-invasive, and antimetastatic effects, induces apoptosis […]. Furthermore, pomegranate blocks the activation of inflammatory pathways including, but not limited to, the NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) pathway."14
In estrogen-dependent and independent human breast cancer cells, fermented pomegranate juice polyphenols exhibited an antiproliferative effect that was approximately double that of fresh juice polyphenols.15 Additionally, pomegranate seed oil was effective at inhibiting proliferation and invasion in estrogen-receptor positive cells and inducing apoptosis in estrogen receptor negative metastatic cells.
A review of the pomegranate's effects against breast cancer notes that "Punica (pomegranate) extracts and its components, individually or in combination, can modulate and target key proteins and genes involved in breast cancer" and that other mechanisms attributed to pomegranate act "at various steps of carcinogenesis including proliferation, invasion, migration, metastasis, angiogenesis, and inflammation." 16
In a trial involving men with prostate cancer and rising prostate-specific antigen (PSA) levels, participants who received pomegranate extract experienced a six month or greater increase in PSA doubling time, which indicates slowing of disease.17
Superfruit, Not SuperstarSo why aren't pomegranates more popular? While appearing with greater frequency in the produce section of supermarkets since achieving "superfruit" status, they aren't a top seller.
Combined with their unfamiliarity to some individuals and the absence of year-round availability is the lack of ease of consumption. Pomegranates must be cut open and the juicy, messy aryls removed and consumed raw. Not exactly like biting into an apple.
Fortunately, concentrated pomegranate juice and pomegranate extract capsules are available for those individuals who find whole pomegranate fruit too messy or time-consuming to eat on a regular basis. For those watching their sugar intake, consider the capsules as an alternative to the juice, which contains sugar.
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- Schubert SY et al. J Ethnopharmacol. 1999 Jul;66(1):11-7.
- Cerdá B et al. Eur J Nutr. 2003 Jan;42(1):18-28.
- Matthaiou CM et al. Food Chem Toxicol. 2014 Nov;73:1-6.
- Singh RP et al. J Agric Food Chem. 2002 Jan 2;50(1):81-6.
- Kamali M et al. Complement Ther Clin Pract. 2015 Aug;21(3):141-6.
- Hamoud S et al. Atherosclerosis. 2014 Jan;232(1):204-10.
- Aviram M et al. Am J Clin Nutr. 2000 May;71(5):1062-76.
- Aviram M et al. Atherosclerosis. 2001 Sep;158(1):195-8.
- Aviram M et al. Clin Nutr. 2004 Jun;23(3):423-33.
- Pagliarulo C et al. Food Chem. 2016 Jan 1;190:824-31.
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- Finegold SM et al. Nutrition. 2014 Oct;30(10):1210-2.
- Turrini E et al. Oxid Med Cell Longev. 2015;2015:938475.
- Kim ND et al. Breast Cancer Res Treat. 2002 Feb;71(3):203-17.
- Vini R et al. Biofactors. 2015 Mar-Apr;41(2):78-89.
- Paller CJ et al. Prostate Cancer Prostatic Dis. 2013 Mar;16(1):50-5.
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