Grapefruit juice is extracted from the grapefruit, a large orange-like citrus fruit, which can range from 4 to 6 inches in diameter. It grows in clusters and has a bitter taste. The color of the flesh of this fruit may be white, pink or ruby. The grapefruit and its juice have many health benefits due to the amounts of nutrients, including vitamin C and several other antioxidants, which are found in this fruit.
Lycopene
Grapefruit juice is rich in lycopene, an antioxidant, which, according a March 2010 article in "Oncology," has been linked with a reduced risk of prostate cancer. Lycopene is the strongest antioxidant among the carotenoids and is also found in tomatoes and green tea. Antioxidants protect the body from damage caused by free radicals, which have been implicated in cardiovascular disease and the various degenerative processes associated with aging.
Limonoids
Grapefruit juice contains phytonutrients called limonoids, which inhibit tumor formation by enhancing the production of glutathione-S-transferase, a detoxifying enzyme. This enzyme solubilizes toxic compounds in the body, thus making it easier for the body to excrete them. According to an October 2007 article in the "Journal of Agricultural and Food Chemistry," citrus limonoids have anti-cancer, cholesterol-lowering and antiviral properties.
Cholesterol
Grapefruit and to a lesser extent grapefruit juice, contain pectin, a soluble form of fiber which can slow down the progression of atherosclerosis. According to the March 2006 issue of the "Journal of Agricultural Food Chemistry," this is believed to occur through reduction in triglyceride levels and LDL, or bad, cholesterol. In a study on pigs supplemented with grapefruit pectin, reported in the "Transactions of the American Clinical and Climatological Association," it was found that after a year, grapefruit pectin lowered plasma cholesterol by nearly 30 percent and reduced plaque formation by 85 percent.
Naringenin and Prostate Cancer
The risk of prostate cancer increases with age, because there is a greater chance of a DNA mutation occurring. According to a March 2006 article in "Toxicology in Vitro," naringenin found in grapefruit juice helps repair damaged DNA in human prostate cancer cells. Naringenin is a flavonoid having antioxidant and anti-inflammatory properties. The mechanism by which naringenin helps in DNA repair is by induction of two DNA-repairing enzymes during the replication phase: 8-oxoguanine-DNA glycosylase 1 and DNA polymerase beta. Prostate cancer progresses slowly and is often undetectable for a long time. Including grapefruit and grapefruit juice in the diet may help to prevent its progression by enhancing the DNA repair mechanism of prostate cells.
Drug Interactions
Certain pharmaceutical drugs combined with grapefruit juice become more potent, because compounds in grapefruit juice, such as naringenin, slow the normal metabolism and elimination of the drug in the intestines and liver. According to J.L. Straughan in the "Cardiovascular Journal of South Africa," drugs known to be affected include calcium channel blockers, statins, antihistamines and the hormone estradiol. It is thus advised that individuals on medications should check with their health care providers as to whether if it is safe to consume grapefruit juice.
References
- PubMed.gov: Lycopene; Cassileth B; March 2010
- PubMed.gov: Citrus limonoids: analysis, bioactivity, and biomedical prospects; Manners GD; October 2007
- PubMed.gov: Red Grapefruit Positively Influences Serum Triglyceride Level in Patients Suffering from Coronary Atherosclerosis: Studies in Vitro and in Humans; Gorinstein S et al.; March 2006
- PubMed.gov: The role of grapefruit pectin in health and disease; Cerda JJ; 1988
- PubMed.gov: Dietary flavonoids: effects on xenobiotic and carcinogen metabolism; Moon YJ et al.; March 2006
- "Cardiovascular Journal of South Africa"; Grapefruit-drug interactions; Straughan JL; February 2007
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