Studies have not established the effect of grapefruit on breast cancer

Grapefruit has been found to have antioxidant, antiseptic, detoxicant, antinitrosaminic, cardiotonic, hypocholesterolemic, and sedative actions. Although components of grapefruit peel have been found to reduce blood pressure by decreasing coronary vascular resistance and mean arterial pressure, pink grapefruit juice appears to have proarrhythmic actions which might be of concern for some heart patients. Pink grapefruit is a good source of the phytochemicals naringenin, limonene, beta-carotene and lycopene, and also contains quercetin and hesperidin. Naringenin has been shown to have cytotoxic activity against leukemia, stomach, colon, liver, pancreas, cervix, and breast cancer cells. D-limonene has been used clinically to dissolve cholesterol-containing gallstones and for the relief of heartburn and gastroesophageal reflux disease. In addition, D-limonene has been shown to inhibit the proliferation of human colon cancer cells. Lycopene, a cartenoid responsible for the red color in pink and red grapefruit, has been found to inhibit the proliferation of rat prostate cancer cells in a dose-dependent manner.

Breast cancer-related effects of eating grapefruit

Naringenin has been shown to inhibit the proliferation of hormone receptor positive MCF-7 breast cancer cells by impairing glucose uptake.

A major epidemiological study published in 2009 found no evidence of an association between grapefruit intake and the risk of breast cancer. However, there is evidence to suggest that grapefruit components may play a role in estrogen metabolism (in much the same way that drug interactions occur with grapefruit) and thereby increase circulating estrogen and breast cancer risk. Accordingly, another major population study published in 2007 found that grapefruit consumption was associated with increased risk of breast cancer among postmenopausal women. Overall, the results of both the population-based and laboratory studies concerning grapefruit are contradictory.

Additional comments

Grapefruit should not be consumed during chemotherapy. Grapefruit juice can affect the metabolism of many drugs, in some cases increasing their effect and in other cases blocking their intended action. The effect can vary considerably from person to person, so that the extent of the impact of consuming grapefruit juice on drug metabolism is not predictable. Drug interactions have been observed between grapefruit and albendazole, amiodarone, atorvastatin, buspirone, carbamazepine, cisapride, cyclosporine, diltiazem, etoposide, felodipine, lovastatin, midazolam, nitrendipine, nimodipine, nisoldipine, quinidine, sertraline, simvastatin, terfenidine, and triazolam, to name only some of the drugs affected. It has not been clearly determined which components of grapefruit are responsible for these drug interactions.

Below are links to recent studies concerning this food. For a more complete list of studies, please click on grapefruit.

Tags: carotenoid, D-limonene, grapefruit, hesperetin, lycopene, naringenin, proliferation

Selected breast cancer studies

Hesperetin induces apoptosis in breast carcinoma by triggering accumulation of ROS and activation of ASK1/JNK pathway Plasma Carotenoids and Retinol and Overall and Breast Cancer Risk: A Nested Case-Control Study Tangeretin, a citrus pentamethoxyflavone, exerts cytostatic effect via p53/p21 upregulation and suppresses metastasis in 7, 12 - dimethylbenz(α)anthracene induced rat mammary carcinoma Hesperidin protects against cyclophosphamide-induced hepatotoxicity by upregulation of PPARγ and abrogation of oxidative stress and inflammation Phytoestrogens induce differential effects on both normal and malignant human breast cells in vitro Quercetin-3-O-glucuronide inhibits noradrenaline-promoted invasion of MDA-MB-231 human breast cancer cells by blocking β2-adrenergic signaling A naringenin-tamoxifen combination impairs cell proliferation and survival of MCF-7 breast cancer cells Specific carotenoid intake is inversely associated with the risk of breast cancer among Chinese women Anti-proliferative and apoptosis-inducing activity of lycopene against three subtypes of human breast cancer cell lines The Effect of Grapefruit Intake on Endogenous Serum Estrogen Levels in Postmenopausal Women Vitamin C intake and breast cancer mortality in a cohort of Swedish women Naringin inhibits growth potential of human triple-negative breast cancer cells by targeting β-catenin signaling pathway Modulating effects of hesperidin on key carbohydrate-metabolizing enzymes, lipid profile, and membrane-bound adenosine triphosphatases against 7,12-dimethylbenz(a)anthracene-induced breast carcinogenesis Quercetin and epigallocatechin gallate inhibit glucose uptake and metabolism by breast cancer cells by an estrogen receptor-independent mechanism Citrus Fruit Intake and Breast Cancer Risk: A Quantitative Systematic Review Lycopene-derived bioactive retinoic acid receptors/retinoid-X receptors-activating metabolites may be relevant for lycopene's anti-cancer potential Circulating Carotenoids and Risk of Breast Cancer: Pooled Analysis of Eight Prospective Studies d-limonene modulates T lymphocyte activity and viability Hesperidin Inhibits Cyclophosphamide-Induced Tumor Growth Delay in Mice Dietary compared with blood concentrations of carotenoids and breast cancer risk: a systematic review and meta-analysis of prospective studies The naringenin-induced proapoptotic effect in breast cancer cell lines holds out against a high bisphenol a background Selective Inhibition of Cell Proliferation by Lycopene in MCF-7 Breast Cancer Cells In vitro: A Proteomic Analysis Degreening and postharvest storage influences ‘Star Ruby’ grapefruit (Citrus paradisi Macf.) bioactive compounds Combinatorial Antitumor Effect of Naringenin and Curcumin Elicit Angioinhibitory Activities In Vivo Modulation of angiogenesis by dietary phytoconstituents in the prevention and intervention of breast cancer

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