The grapefruit (Citrus paradisi Macfad) is a large orange-like fruit that belongs to the citrus family. Fruit grows in varieties of pink/red, yellow, white or ruby color. The pink or red varieties are higher in vitamin content.
Fresh squeezed grapefruit juice contains vitamin C. Vitamin-C is a potent antioxidant and helps the body develop resistance against infectious agents and scavenge harmful free radicals. The fruit contains very good levels of vitamin-A, and flavonoid antioxidants such as naringenin, and naringin. Vitamin A intake supports your immune system, helps maintain healthy retinas and acts as an antioxidant in body. Grapefruit is a good source of potassium. Potassium, is one of several electrolytes that sustain fluid levels and electrical activity in your body. Insufficient potassium can result in an irregular heartbeat, known as arrhythmia. Potassium is an important component of cell and body fluids, helps controlling heart rate and blood pressure through countering sodium effects.
The vitamin C and the antioxidant properties protect the skin from environmental hazards. It also stimulates the production of skin collagen that brings smoothness and elasticity to the skin. “Grapefruit is loaded with vitamin C, a mild acid, which helps fade spots by reducing excess production of skin pigment,” says Jessica Wu, MD, a Los Angeles–based dermatologist.
Grapefruit is a source of fiber. This fruit contains high level of pectin which acts as a bulk laxative and helps to protect the colon mucous membrane by decreasing exposure to toxic substance in the colon. Fiber is necessary to promote regular bowel movements and to prevent constipation.
Grapefruit juice helps increase your urinary pH value, which significantly lowers risk of calcium oxalate stones forming in the kidney. A study reported in the “British Journal of Nutrition” demonstrated that drinking 2-4 cups daily of grapefruit or orange juice reduced the risk of developing kidney stones.
Red varieties of grapefruits are particularly rich in the most strong flavonoid antioxidant, lycopene. This carotenoid is believed to have potent antioxidant effects with some studies showing a reduced risk of cancer, cardiovascular disease and macular degeneration. The optimum dosage for lycopene has not been established, but the amount found useful in studies usually fell in the range of 4 to 8 mg daily. In a study reported in the March 2005 edition of International Journal of Cancer, scientists found that prostate cancer risk declined with increased consumption of lycopene. Lycopene has shown promise for leukoplakia. In a clinical trials, 58 participants with oral leukoplakia received either 8 mg oral lycopene daily, 4 mg daily, or placebo capsules for 3 months. Subjects were then followed for an additional two months. The results showed that lycopene in either dose was more effective than placebo for reducing signs and symptoms of leukoplakia, and that 8 mg daily was more effective than 4 mg.
Naringenin, a flavonoid concentrated in grapefruit, helps repair damaged DNA in human prostate cancer cells. A study that was reported in the “Journal of Nutritional Biochemistry” shows that grapefruits help repair damaged DNA in human prostate cancer cells. A group of phytonutrients in grapefruits called limonoids help prevent tumors by promoting an enzyme that causes the liver to expel more toxins from the body. In animal-based studies and lab tests with human cells, limonoids have been shown to help fight cancers of the mouth, skin, lung, breast, stomach and colon. Limonoids help control the activity of genes in cancer cells, activating genes that promote cancer cell death, according to a research reported in the Journal of Biological Chemistry in 2011. Research indicate that drinking grapefruit juice everyday helps reduce the activities of enzymes that can activate cancer triggering chemicals found in cigarette smoke. In humans, drinking three 6-ounce glasses of grapefruit juice a day was shown to reduce the activity of an enzyme that activates cancer-causing chemicals found in tobacco smoke.