Pom?lo

Related Terms

Antioxidizers, bergamottin, bergapten, bergaptol, blond grapefruits, citricidal, Citrus decumana, Citrus maxima, Citrus paradisi, Citrus paradisi Macf., Citrus paradisi Macfayden, Citrus x paradisi, citrus seed, citrus seed extract, flavonoids, Fresca?, furanocoumarins, geranylcoumarin, grapefruit juice, grapefruit pectin, grapefruit seed, grapefruit seed extract, naringenin, naringin, nootkatone, organic grapefruit juice, paradisapfel, ParaMicrocidin?, pomelo, pummelo grapefruit, red grapefruit, Red Mexican grapefruit, Rio Red Grapefruit, rutacea, sesquiterpen, shaddock oil, Sun Drop?, toronja, vitamin C, white grapefruit.

Background

The grapefruit was first described in the 1750s as the "forbidden fruit" of Barbados. It was introduced to Florida in the 1820s. Most grapefruit in the United States is still grown in Florida. Grapefruit juice has been used in folk medicine for the treatment of diabetes as well as to strengthen the immune system. Grapefruit is also added to cosmetics and hair care products as a fragrance.
Grapefruit has been suggested as a treatment for several conditions, but there is currently insufficient scientific evidence to support the use of grapefruit for any medical disorder. The use of supplemental grapefruit pectin in the prevention of cardiovascular disease and the use of grapefruit seed extract in atopic eczema warrants further scientific investigation before a strong recommendation can be made. There is conflicting research regarding the use of grapefruit for kidney stones.
Grapefruit juice alters the way some drugs are broken down in the liver. Grapefruit may increase the effects of calcium channel blockers, benzodiazepines, immunosuppressants, and HMG-CoA reductase inhibitors.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


There is early, but inconclusive evidence to support the use of grapefruit seed extract in the treatment of atopic eczema. Additional study is needed to confirm these findings.

 C


There is early, but inconclusive evidence to support the use of grapefruit seed extract in the treatment of atopic eczema. Additional study is needed to confirm these findings.

 C


Early studies suggest grapefruit may have some benefit in the management of metabolic syndrome. More studies are needed to understand this relationship.

 C


Early studies suggest grapefruit may have some benefit in the management of metabolic syndrome. More studies are needed to understand this relationship.

 C


Grapefruit pectin supplementation may inhibit high cholesterol. There is promising but inconclusive human evidence to support the use of grapefruit pectin in the prevention of heart disease. Additional study is needed in this area.

 C


Grapefruit pectin supplementation may inhibit high cholesterol. There is promising but inconclusive human evidence to support the use of grapefruit pectin in the prevention of heart disease. Additional study is needed in this area.

 C


There is limited and mixed research regarding the use of grapefruit for kidney stones. Further research is needed to clarify these results.

 C


There is limited and mixed research regarding the use of grapefruit for kidney stones. Further research is needed to clarify these results.

 C
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Dosing

Adults (over 18 years old)
There is no proven effective dose for grapefruit. Grapefruit is typically taken as a fruit, seed extract, or pectin by mouth. It has also been applied on the skin as a disinfectant for skin wounds. For atopic eczema, 150 milligrams of grapefruit seed extract has been taken by mouth three times daily for one month. For heart disease, 15 grams of grapefruit pectin in divided doses with meals for 16 weeks has been used. For metabolic syndrome, grapefruit capsules, fresh grapefruit, or 8 oz. of grapefruit juice three times daily before each meal has been studied for 12 weeks.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Interactions

Interactions with Drugs
Grapefruit juice may interfere with the way the body breaks down certain drugs in the liver. As a result, the levels of some drugs may be increased in the blood, and may cause increased effects or potentially serious adverse reactions. Patients using medications such as amitriptyline, clomipramine, clozapine, cyclobenzaprine, haloperidol, naproxen, ondansetron, propranolol, theophylline, and verapamil should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.
Grapefruit juice may also interact with nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g., diclofenac, ibuprofen, meloxicam, piroxicam), oral antidiabetic agents (tolbutamide, glipizide), and angiotensin II blockers (e.g., losartan).
Caution is advised when mixing grapefruit juice with proton pump inhibitors (e.g., lansoprazole, omeprazole, pantoprazole), anti-epileptics (e.g., diazepam, phenytoin), carisoprodol, citalopram, and nelfinavir.
Grapefruit juice may increase drug levels and the risk of adverse effects when taken with macrolide antibiotics (e.g., erythromycin, clarithromycin), anti-arrhythmics (e.g., quinidine), benzodiazepines (e.g., alprazolam, midazolam, diazepam, triazolam), immune modulators (e.g., cyclosporine, tacrolimus), protease inhibitors (e.g., ritonavir, saquinavir), prokinetic agents (e.g., cisapride), antihistamines (e.g., terfenadine), calcium channel blockers (e.g., amlodipine, felodipine, diltiazem), HMG-CoA reductase inhibitors (e.g., atorvastatin, lovastatin), alfuzosin, etc.
Although not well studied in humans, numerous other potential interactions with grapefruit juice may occur with acebutolol, alfentanil, alprazolam, amlodipine, amprenavir, anthelmintics (e.g., praziqauntel), antiarrhythmics (e.g., amiodarone, propafenone, quinidine), anticonvulsants (e.g., carbamazepine), antifungal agents (e.g., itraconazole), antimalarial agents (e.g., halofantrine, artemether, quinine), antineoplastic agents, aripiprazole, atorvastatin, beta-blocking agents, benzodiazepines, budesonide, celiprolol, digoxin, eplerenone, etoposide, felodipine, fentanyl, hormone replacement, imatinib, indinavir, lovastatin, levothyroxine, oral contraceptives (e.g., estradiol, progesterone), methylprednisolone, mifepristone, nifedipine, nimodipine, nitrendipine, opioids, pranidipine, ranolazine, scopolamine, selective serotonin reuptake inhibitors (e.g., sertraline), simvastatin, sufentanilbuspirone, sunitinib, talinolol, tolterodine, trazadone, triazolam, and zolpidem. Check with a qualified healthcare professional, including a pharmacist, for any interactions.
Grapefruit may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin?) or heparin, anti-platelet drugs such as clopidogrel (Plavix?), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin?, Advil?) or naproxen (Naprosyn?, Aleve?).
Grapefruit has been shown to modestly increase the absorption of sildenafil, an erectile dysfunction agent. Theoretically, grapefruit may have similar effects if used with other erectile dysfunction agents, such as tadalafi or vardenafil.
Clinical studies show that the ingestion of grapefruit juice should not cause any pharmacokinetic or pharmacodynamic interactions when coadministered with caffeine.
Grapefruit may reduce the effectiveness of antihistamines such as fexofenadine.
Theoretically, grapefruit juice may inhibit the hepatic metabolism of oxybutynin leading to increased drug levels and associated adverse events.
Grapefruit juice was found to have no significant effect on the metabolism of prednisone or prednisolone in one study of kidney transplant patients.
Based on laboratory study, grapefruit may inhibit the absorption of vinblastine or alter the permeation of vincristine across the blood-brain barrier.

Attribution

This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

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