Bone Health and Florida Grapefruit

Nutrients in Florida Grapefruit and 100% Grapefruit Juice Support Bone Health

A healthy diet is important to support strong bones and healthy cartilage. Featuring nutrients such as vitamin C, potassium, magnesium, and calcium in fortified varieties, these compounds in fresh grapefruit and 100% grapefruit juice can help support healthy bones and connective tissues.

Healthy Bone Nutrients

  • Vitamin C: Vitamin C supports collagen production needed for bones and cartilage to form.1-4
  • Calcium (fortified grapefruit juice): Calcium is an essential mineral in the structure of bones and is essential for growing kids to develop strong bones, and for adults to maintain bone health.5 
  • Potassium: Potassium, often found with citrate in fruits and vegetables, may play a role in acid-base balance which influences bone mineral density.6
  • Magnesium: Magnesium is an important mineral in the structure of bones.7
  • Phytonutrients: Many plant compounds, such as carotenoids and flavonoids, may be involved in processes that affect bone structure and formation.8-16

Pink text reading "Did You Know" with a pink question mark

An 8-ounce glass of fortified grapefruit juice has similar amounts of calcium as an 8-ounce glass of milk.17*


Detailed Nutritional Information

Vitamin C

Vitamin C is essential in collagen production, which is important for maintaining healthy cartilage, bones and other connective tissues.1-4 Citrus juices are reported to be one of the largest contributors of vitamin C in the diet.18 An 8-ounce serving of grapefruit juice provides 60% of the Daily Value for vitamin C.*

Calcium

Many factors affect bone health, including physical activity. Adequate calcium and vitamin D, as part of a well-balanced diet, may help reduce the risk of osteoporosis.19

Calcium is a critical nutrient necessary for bone health.5 Drinking calcium-fortified grapefruit juice may help improve calcium blood levels. Studies suggest that citrus juices fortified with calcium and vitamin D can be beneficial toward vitamin D status20,21 and bone health.22,23 

An 8-ounce glass of fortified grapefruit juice is a rich source of calcium supplying 25% of the Daily Value.*

Potassium and Citrate

Research suggests higher intake of dietary potassium may be linked to improvements in bone mineral density and lowered risk of osteoporosis.24 Potassium is often found with citrate (as well as other minerals) in fruits and vegetables, including fresh grapefruit and 100% grapefruit juice, which may be one of the reasons for the link between potassium and bone health.6 Citrate is converted in the body to bicarbonate, and consequently may support acid-base balance.6

The body must keep the amount of acids and bases balanced to keep pH within a safe range. If excess acids are generated, such as when sulfur-containing amino acids in high protein foods are consumed, the body uses buffers like bicarbonate to restore balance.6 Calcium can be lost from the bone when too little bicarbonate is available because bone will demineralize to release buffers for pH neutralization.6

Disturbance in pH, low intake of potassium from fruits and vegetables, and high sodium intake may lead to a loss of calcium from the bones.6, 24-26 These, as well as other factors, can increase risk for osteoporosis.6,19

An 8-ounce glass of 100% grapefruit juice delivers 6% of the recommended Daily Value for potassium, while one-half of a medium fresh grapefruit contributes 4% of the Daily Value.*

Magnesium

About 50 to 60 percent of the body’s magnesium is stored in the bones. Magnesium plays an important role in bone health mainly by contributing to the structural development of bone (modifies the crystalline size via changes in solubility of hydroxyapatite), but also by affecting the number of osteoblasts, or bone cells that build bones.6 Deficiency experiments in animals have caused negative changes to bone structure and function, including decreased bone mass, reduced osteoblast numbers, and increased inflammation.6

An 8-ounce glass of 100% grapefruit juice delivers 6% of the recommended Daily Value for magnesium.*

Phytonutrients

Other components of citrus, like carotenoids and flavonoids, may be involved in supporting bone health through their actions on bone healing and formation.7,8

Carotenoids

Carotenoids, including beta-carotene, lycopene, lutein and zeaxanthin provide the beautiful colors in fresh grapefruit and grapefruit juice. Beta-carotene also forms vitamin A in the body. In three separate clinical trials, participants consuming citrus juices rich in the carotenoid beta-cryptoxanthin had positive changes in markers of bone activity.9 Additional clinical trials observed lower markers of bone turnover and less oxidation of protein and lipids in postmenopausal women fed lycopene-rich foods or capsules.12 In elderly men and postmenopausal women, intake and serum levels lycopene were associated with lower hip fracture risk, lower markers of bone turnover and lower protein oxidation.10,11 Additionally, total carotenoids and specific carotenoids (beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin) were positively associated with lower hip fractures in older Chinese adults (55 to 80 years old).27 Various animal studies investigating the carotenoids lycopene and beta-cryptoxanthin have shown positive benefits to bone health, including increased bone formation, bone mineralization and increased bone strength, gene expression of osteoblast growth factors, and inhibition of bone resorption.9,13  Lycopene intake or status has been positively associated with bone mass and bone turnover and may protect bone mass during ageing by attenuating bone resorption.9

Flavonoids

While many flavonoids can be found in grapefruit and grapefruit juice, naringenin is found in highest amounts.28 Flavonoids in citrus can have two forms: the glycone (has glucose attached) and aglycone (no glucose attached) forms. Naringin is the glycone form and naringenin is the aglycone form. In an in vitro study, naringin had positive effects on bone-forming activities.29 In a rat study, naringin was able to inhibit adverse changes in the microstructure and physical properties of bone that may occur with diabetes, possibly through its antioxidant action and enhancement of osteoblastogenesis.30 In animal studies, a combination of hesperidin with naringenin increased bone mineral density.16 A number of preclinical studies support a pro-osteogenic role for naringin which may be beneficial in the treatment of bone disorders like osteoporosis or osteoarthritis.31 A systematic review and meta-analysis of the effects of naringin on ovariectomized rats found that naringin may help promote bone formation.32

In the United Kingdom Adult Twin Registry study, researchers found higher intakes of flavanones, a subclass of flavonoids found primarily in citrus, were positively associated with hip bone and mineral density.15 Flavonoid intakes have been associated with higher bone mineral density and lower risk of bone fractures.33

* Daily Value: Based on a 2000 calorie diet. FDA rounding rules applied when calculating percent DV based upon 2018 rules. Information is not intended for labeling food in packaged form. Nutrient values may vary based on brand or product types.


References

  1. Vitamin C. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, D.C.: National Academy Press; 2000:95-185.
  2. Vitamin C. Linus Pauling Institute Micronutrient Information Center. Oregon State University.
  3. Lykkesfeldt et al. Adv Nutr 2014;5:16-18.
  4. Vitamin C. Health Professionals Fact Sheet. Office of Dietary Supplements. National Institutes of Health.
  5. Dietary Reference Intakes for Calcium and Vitamin D. Food and Nutrition Board. Institute of Medicine; Washington, DC: National Academies Press, 2010.
  6. Potassium. In: Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Institute of Medicine. Washington, DC: The National Academies Press. 2005.
  7. deBaaij et al. Physiol Rev. 2015;95(1):1-46.
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  14. Liang et al. Molecules. 2012; 17:7093-7102.
  15. Welch et al. J Bone Miner Res. 2012;27(9):1872-1878.
  16. Habauzit et al. Proc An Meeting Am Society Bone Miner Res. San Diego, CA; Sept 16-29, 2011.
  17. USDA FoodData Central.
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  19. A Food Labeling Guide; Guidance for Industry. FDA Center for Food Safety and Applied Nutrition. January 2013.
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  22. Lee et al. J Medicinal Food. 2014;17(10):1142-1150.
  23. Neyestani et al. J Human Nutr Diet. 2014;27:606-616.
  24. Potassium. Linus Pauling Institute Micronutrient Information Center. Oregon State University.
  25. Siener. Urolithiasis. 2016;44:51-56.
  26. Prezioso et al. Archivo Italiano di Urologia e Andrologia. 2015;87(2):105-120.
  27. Cao et al. Bone. 2018;111:116-122.
  28. Bhagwat S, Haytowitz D. USDA Database for the Flavonoid Content of Selected Foods Release 3.2. Beltsville, MD: United States Department of Agriculture; 2015.
  29. Wong et al. J Orthop Res. 2006;24(11):2045-2050.
  30. Rivoira et al. Arch Biochem Biophys. 2018;637:56-63.
  31. Lavrador et al. Drug Discov Today. 2018;23(6):1293-1304.
  32. Zhu et al. Evid Based Complement Alternat Med. 2021; Feb 10:6016874.
  33. Del Bo et al. Nutrients. 2019;11(6):1355.