Pomegranate Juice and Supplements Review Article

What Are the Benefits of Pomegranate Juice and Supplements? Find Out What Pomegranate Can and Cannot Do For Your Health.

Medically reviewed and edited by Tod Cooperman, M.D.

Last Updated : 02/01/2020 | Initially Posted: 12/19/2007

Pomegranate Juice Supplements Reviewed by ConsumerLab

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Table of Contents

What It Is:

Pomegranate (Punica granatum) is a shrub or small tree native to Iran and India, but now is also grown in the U.S. Traditionally, pomegranate bark, seeds, leaves and fruit extracts were used as remedies for wide range of conditions, such as bleeding and diarrhea. The name "pomegranate" is derived from the Latin pomum granatum (apple with many seeds).

Pomegranate Juice
Pomegranate fruit is about 80% water and 16% sugar. Pomegranate juice is a source of potassium, vitamin C, and small amounts of other nutrients. It is also rich in antioxidant polyphenols. Typically pomegranate juice contains 0.2% to 1.0% polyphenols — more than blueberry, cranberry, green tea or red wine. In fact, commercial pomegranate juice has three times the antioxidant activity of green tea or red wine. The polyphenols include a variety of compounds including anthocyanidins and tannins. There is particular interest in the biologic activity of the tannins, such as punicalagin, ellagic acid, and gallagic acid. Pomegranate juice made from the fruit kernels, although the fruit rind may also be used in making the juice and this results in juice with greater antioxidant activity than if made from the fruit kernels alone.

Commercial pomegranate juice made from the fruit kernels and fruit rind, has greater antioxidant activity than juice made from the fruit kernels alone.

Quality Concerns:

Although many compounds in pomegranate juice have been identified, the specific compounds (and amounts of those compounds) that represent a pomegranate product of high quality have not yet been defined. Currently, there is no way to definitively judge whether one product is more authentic than another — let alone more effective. However, researchers at UCLA tested commercial pomegranate extract supplements for levels of two polyphenols expected in pomegranate — punicalagins (which are responsible for 50% of the fruit's anti-oxidant activity) and ellagic acid. The findings demonstrated enormous variation among the products. Out of seven products (which were not identified by name), only three contained significant amounts of punicalagins. Two products had only trace amounts of punicalagins and two others had no detectable amount. Interestingly, all of the products contained ellagic acid — ranging from 4 to 90%. Finding ellagic acid without punicalagins suggests that the punicalagins may have been converted into other compounds during processing of the product or that the products may have been illicitly "spiked" with ellagic acid to make them meet label claims regarding total amounts of polyphenols. (Results reported in the book "Pomegranates: Ancient Roots to Modern Medicine" edited by Seeram, et al, 2006.)

What It Does:

Cardiovascular Health
Several small, preliminary clinical trials suggest drinking pomegranate juice may have modest cardiovascular benefits.

In one trial, drinking 240 mL (1 cup) of pomegranate juice every day for three months improved circulation in the heart muscle of people with coronary heart disease (CHD). However, it is not yet known whether pomegranate juice prevents heart attacks in people with CHD (Sumner, Am J Cardiol, 2005).

Daily consumption of pomegranate juice may modestly reduce blood pressure, possibly by inhibiting angiotensin converting enzyme (ACE) activity (Aviram, Atherosclerosis 2001). A review of eight placebo-controlled clinical trials in healthy adults as well as those with high blood pressure or cardiovascular disease lasting from two weeks to one year found that drinking between 1.6 ounces to 16 ounces pomegranate juice daily decreased average systolic blood pressure by 4.96 mm Hg (regardless of the amount of juice consumed or the length of the study), but there was no significant decrease in diastolic blood pressure (Sahebkar, Pharmacol Res 2017).

Daily consumption of 50 mL (about 3 tablespoons) of pomegranate juice concentrate for one year reduced arterial thickening in a study of people with atherosclerosis (Aviram, Clin Nutr, 2004).

Pomegranate juice does not seem to help with cholesterol levels. A review of 12 clinical trials lasting between two weeks and one year found no significant decrease in total or "bad" LDL cholesterol, or triglyceride levels in healthy adults who consumed pomegranate juice, nor in individuals who were overweight or who had high cholesterol, high triglycerides or other cardiovascular disease (Sahebkar, Phytomedicine 2016).

Blood sugar and diabetes
Pomegranate juice (but not pills) may reduce increases in blood sugar levels after eating. A small study of 16 healthy adults in England found that 6.7 ounces of pomegranate juice (Biona, Healthy Supplies Inc.) consumed with bread decreased the rise in blood sugar after eating by about 33% compared to eating bread without pomegranate juice. In the same study, however, taking one capsule of concentrated pomegranate extract (containing much more ellagic acid but lower amounts of punicalagin than the juice) did not reduce the rise in blood sugar levels after eating bread (Kerimi Am J Clin Nutr, 2017). In people with type 2 diabetes, a small study in Jordan found that fresh pomegranate juice (1.5 mL/kg — about 3.4 ounces for a 150 lb. individual) decreased fasting blood sugar levels three hours after consuming the juice, but in about 20% of the participants, pomegranate juice increased fasting blood sugar (Banihani, Nutr Res 2017).

Prostate Health
Laboratory research has suggested that pomegranate fruit extract may inhibit prostate tumor growth (Seeram, J Agric Food Chem, 2007). However, research in people has not demonstrated a clear benefit.

Drinking 8 ounces of pomegranate juice every day for up to two years slowed the time it took prostate-specific antigen (PSA) blood levels to double in men with prostate cancer after treatment with radiation or surgery. This study was financially supported by the owners of POM Wonderful Co., which also supplied the juice used in the study (Pantuck, Clin Cancer Res, 2006). Two subsequent studies had less favorable outcomes. One found that men taking pomegranate extract had similar PSA-doubling times (PSADT) as those in a placebo group (Pantuck, Prostate Cancer Prostatic Dis, 2015). The other showed that men taking either a low- or high-dose pomegranate extract supplement had significant, but similar, PSADT— a finding that led the researchers to question whether pomegranate compounds were actually responsible for the changes in PSADT (Paller, Prostate Cancer Prostatic Dis, 2013).

Cognitive function and memory
A 12-month study of 200 older adults (average age 60) found that 8 ounces of pomegranate juice helped slow declines in visual memory, but did not improve verbal recall or other measures of memory and cognition compared to placebo. The 8-oz serving of juice contained 368 mg punicalagins, 93 mg anthocyanins, 29 mg ellagic acid, and 98 mg other tannins. It was produced by The Wonderful Company, the makers of POM Wonderful (Siddarth, Am J Clin Nutr, 2019).

Exercise
A 2018 review of 11 studies concluded that pomegranate juice (6.7 to 16 ounces per day) or pomegranate extract (1,000 mg before exercise) may help improve endurance and strength exercise performance and recovery, especially when administered at least 1 hour before exertion. Pomegranate preparations that were highest in polyphenols were found to be most effective, purportedly because these plant compounds increase vasodilation and muscle blood flow (Ammar, Brit J Clin Nutr 2018).

ConsumerTips™:

Pomegranate juice is generally sold as a bottled juice, a juice concentrate, or as an extract (typically a pill). A cup of juice provides about 480 mg to 2,400 mg of polyphenols. About three tablespoons of a concentrate (to be mixed with water) should be equivalent to a cup of juice. Pills made from extracts tend to offer about 250 to 1,000 mg of polyphenols in a one or two pill serving. The juices and concentrates can offer the full spectrum of plant compounds found in the fruit. However, as they are not fresh, some of the compounds may have degraded and lost antioxidant strength. With an extract you may be getting a higher amount of specific compounds, but generally not with the full spectrum of compounds found in pomegranate juice or concentrate. An important advantage with an extract, however, is that you can avoid the 150 or so calories normally found in a cup of juice or serving of concentrate. When comparing products, keep in mind that 1 fluid ounce of liquid equals 2 tablespoons or 30 mL, and that 8 fluid ounces of liquid equal 1 cup or 240 mL. Some products list the amount of polyphenols in a serving. Some list specific polyphenols, such as punicalagins or ellagic acid. Others, particularly juices and some concentrates, may not list any information about these compounds. It is advisable to look for products that list amounts of total or specific polyphenols. A concern remains, as noted earlier, as to whether products live up to these claims and whether the polyphenols are truly from pomegranate or have been introduced from an unrelated source. If you are counting calories or watching sugar intake, be aware that pomegranate juice, like other juices, contributes calories and sugar to your diet. One cup of pomegranate juice provides about 140 to 170 calories — the vast majority of which is from sugar.

Concerns and Cautions:

Gastrointestinal symptoms such as such as diarrhea, stomach pain and vomiting have been reported in a small number of participants in clinical trials using pomegranate extract (i.e., POM Wonderful, POMx) (Forest, Int J Impot Res 2007; Paller, Prostate Cancer Prostatic Dis 2013).

As indicated in the What It Does section, pomegranate may lower blood pressure to a moderate degree and therefore has the potential to have an additive blood pressure-lowering effect when taken with blood pressure lowering medicines. Check with your doctor or pharmacist before using pomegranate juice along with blood pressure-lowering drugs.

There are several case reports of priapism (prolonged or painful erection) associated with the consumption of pomegranate juice and sildenafil (Senthilkumaran, Urol Ann 2012).

Pomegranate fruit is generally considered to be safe as a food. However, allergic reactions to pomegranate fruit and seeds have been reported — even among people who had previously eaten pomegranates for years without problems. If you experience swelling of the tongue or face while eating pomegranates, stop immediately and seek medical advice. Pomegranates have also been reported to cause contact allergic reactions. Itching and/or swelling of skin, runny nose, red itchy eyes are indications of a contact allergic reaction (Petersen, Clin Transl Allergy 2011).

A case of rapid muscle breakdown was reported in a person taking the statin drug Crestor (rosuvastatin) who started drinking pomegranate juice twice weekly for three weeks. It is unclear what role, if any, the pomegranate juice played in the events of the case, but, as a result, people taking statin drugs to lower cholesterol should use pomegranate juice with some caution (Sorokin, Am J Cardiol, 2006). More research is needed to clarify to what degree, if any, pomegranate juice interferes with prescription drug treatment.

Excessive amounts of pomegranate bark extract (not fruit juice) can cause vomiting, diarrhea, dilated pupils, reduced vision, muscle weakness and paralysis.

Conclusion:

Current usage of pomegranate juice does not reflect its traditional usage and is driven predominantly by preliminary research findings. Human research suggests potential health benefits such as improved blood flow from pomegranate juice and fruit peel extract. However, additional well-designed human studies are needed to substantiate preliminary findings. Until more is known, it seems generally safe to use pomegranate juice (other than potential allergic reaction), but its benefits remain largely unproven. The composition of pomegranate products on the market may vary significantly due to a lack of standards, and an optimal dosage has not been established.

Information on this site is provided for informational purposes only. It is not an endorsement of any product nor is it meant to substitute for the advice provided by physicians or other healthcare professionals. The information contained herein should not be used for diagnosing or treating a health problem or disease. Consumers should inform their healthcare providers of the dietary supplements they take.

Latest Clinical Research Updates for Pomegranate Juice and Supplements

Pomegranate for Memory?

2/01/2020

Pomegranate juice and supplements have been promoted for improving cardiovascular health, controlling blood sugar, and inhibiting prostate cancer. Most recently pomegranate juice was tested in a year-long study for its effects on memory. Find out if it helped, and see if it works for other touted uses, in the What It Does section of the Pomegranate Juice and Supplements Review Article.