Phytonutrients, also called bioactives or phytochemicals, are plant compounds which are thought to have health-promoting qualities but are not technically considered “nutrients” (for instance, like vitamin C or potassium), which are essential to prevent classic nutrient deficiencies. Scientists are discovering that these plant-derived components are intimately involved in fighting cellular damage, a common initiation step in the pathways for cancer, aging, and a variety of diseases.
Fresh grapefruit and 100% grapefruit juice have an array of phytonutrients including flavonoids and carotenoids.
Grapefruit naturally includes many flavonoids, a class of plant compounds similar to those found in red wine (resveratrol), green tea (catechins) and chocolate (cocoa flavanols).
Naringenin is the most common flavonoid found in grapefruit, followed by hesperidin.1
Several flavonoids have been reported to have antioxidant, anti-inflammatory, and cardioprotective properties which may help protect against various diseases and conditions.2-7
Citrus variety, fruit maturity, post-harvest processing techniques, storage conditions, and the location within the fruit (e.g. peels are richer than pulp) can affect the levels of flavonoids in grapefruit juice. Thus, the amount of flavonoids in a food can vary widely. Citrus flavonoids are primarily concentrated in the peel of the fruit. Commercial processing of fresh grapefruit into grapefruit juice extracts flavonoids from the peel into the juice. For this reason the juice tends to have a higher flavonoid content than the whole fruit.
Carotenoids are yellow, orange and red pigments found in abundance in citrus. Grapefruit has many carotenoids, especially in pink/red grapefruit and grapefruit juices, but the most concentrated are beta-carotene, lycopene, lutein, and zeaxanthin.8
Pink/red grapefruit and 100% pink/red grapefruit juice have lycopene, the same carotenoid that makes tomatoes red. Test tube studies show lycopene has one of the highest antioxidant activities of the carotenoids.9 Although studies report mixed results, lycopene may have beneficial effects towards lowering the risk of some cancers, including prostate and lung cancer.9
Carotenoids behave as antioxidants, help our cells communicate with each other, support our immune system, and some studies show they contain properties that protect against certain types of cancer.10 Thousands of studies provide evidence of health benefits attributed to carotenoids including:
- reducing risk of illness10,11
- supporting eye health10,11
- protecting skin from sunburn12,13
- lessening premature aging of the skin14
- reducing risk of many cancers including breast and prostate cancer10,11
- supporting bone health15,16
- increasing breastmilk concentrations of carotenoids and vitamin A17,18
Within citrus are many carotenoids including beta-carotene, alpha-carotene, and beta-cryptoxanthin which can form vitamin A in the body. Vitamin A is necessary for normal eyesight, reproduction, growth and development, cell health, gene expression, and immune function.19
The amount of carotenoids in citrus can vary widely depending on citrus variety, growing conditions, fruit maturity, processing, storage, and multiple other factors. Only the pink/red varieties of grapefruit and grapefruit juice contribute to vitamin A intake. The amount of vitamin A delivered by carotenoids in 8 ounces of pink/red grapefruit juice or one-half of a medium pink/red grapefruit is approximately 2-4% of the recommended Daily Value.*
Learn more about the health benefits of fresh Florida Grapefruit and Florida Grapefruit Juice.
- Bhagwat, Haytowitz. USDA Database for the Flavonoid Content of Selected Foods Release 3.2. In. Beltsville, MD: Unites States Department of Agriculture; 2015.
- Rangel-Huerta et al. J Nutr. 2015;145(8):1808-1816.
- Milenkovic et al. PLoS One. 2011;6(11):e26669.
- Morand et al.Am J Clin Nutr. 2011;93:73–80.
- Rendeiro et al. Br J Nutr. 2017;116(12):1999-2010.
- Napoleone et al. Thrombosis Research. 2013;132(2):288-292.
- Gorinstein et al. J Agric Food Chem.2004;52(16):5215-5222.
- USDA FoodData Central.
- Linus Pauling Micronutrient Information Center. Oregon State University.
- Carotenoids, In: Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Institute of Medicine. The National Academies Press, Washington, DC. 2000.
- Linus Pauling Institute. Oregon State University.
- Lee et al. Proc Soc Exp Biol Med. 2000; 223:170-174.
- Stahl et al. Am J Clin Nutr. 2012; 96:1179-1184S.
- Terao et al. J Clin Biochem Nutr. 2011;48(1):57-62.
- Yamaguchi. J Health Sci. 2008; 54(4):356-369.
- Liang et al. 2012; 17:7093-7102.
- Turner et al. Am J Clin Nutr. 2013; 98:1200-8.
- Canfield et al. Eur J Nutr. 2001; 40:30-8.
- Vitamin A, In: Dietary Reference Intakes. Institute of Medicine. The National Academies Press, Washington, DC. 2006.