Grapefruit: Top Benefits & Side Effects

by Meenakshi Nagdeve last updated - Medically reviewed by Vanessa Voltolina (MS, RD)

The powerful benefits of grapefruit might include its ability to aid in weight loss, improve insulin sensitivity, help manage diabetes, and reduce the risk of cardiovascular diseases. It might be a rich source of vitamins C and A, that can make it a strong immune booster. However, care must be taken while having this particular citrus fruit or its juice regularly as they may be associated with medical drug interactions, which in some cases might have proven fatal. Let us learn more about this interesting citrus fruit.

What is Grapefruit?

Grapefruit (Citrus x paradisi) is a hybrid citrus fruit that originated in Barbados as an accidental cross between a pomelo and a sweet orange. The fruit is known to have been first described by Revered Griffth Hughes in 1750 in his book ‘The Natural History of Barbados’ as the forbidden fruit. The fruit is round or oblate with a thick pale lemon rind. The rind may have a pink blush sometimes and has a bitter white spongy layer inside. The pulp may have different colors depending on the variety, such as pale yellow, white, pink, or deep red color. The juicy flesh has a bitter to bitter-sweet acidic taste when fully ripe. [1]

A closeup view of whole and sliced grapefruit

Grapefruits can be rich in vitamins A and C. Photo Credit: Shutterstock

For more health information on grapefruit products and helpful tips on how to eat the fruit, you can head over to:

Nutrition Facts

Grapefruit, raw, pink and red, all areas
Serving Size :
Water [g]88.06
Energy 42
Energy [kJ]176
Protein [g]0.77
Total lipid (fat) [g]0.14
Ash [g]0.36
Carbohydrate, by difference [g]10.66
Fiber, total dietary [g]1.6
Sugars, total including NLEA [g]6.89
Sucrose [g]3.51
Glucose (dextrose) [g]1.61
Fructose [g]1.77
Calcium, Ca [mg]22
Iron, Fe [mg]0.08
Magnesium, Mg [mg]9
Phosphorus, P [mg]18
Potassium, K [mg]135
Zinc, Zn [mg]0.07
Copper, Cu [mg]0.03
Manganese, Mn [mg]0.02
Selenium, Se [µg]0.1
Vitamin C, total ascorbic acid [mg]31.2
Thiamin [mg]0.04
Riboflavin [mg]0.03
Niacin [mg]0.2
Pantothenic acid [mg]0.26
Vitamin B-6 [mg]0.05
Folate, total [µg]13
Folate, food [µg]13
Folate, DFE [µg]13
Choline, total [mg]7.7
Betaine [mg]0.1
Vitamin A, RAE [µg]58
Carotene, beta [µg]686
Carotene, alpha [µg]3
Cryptoxanthin, beta [µg]6
Vitamin A, IU [IU]1150
Lycopene [µg]1419
Lutein + zeaxanthin [µg]5
Vitamin E (alpha-tocopherol) [mg]0.13
Tocotrienol, alpha [mg]0.02
Fatty acids, total saturated [g]0.02
16:0 [g]0.02
18:0 [g]0
Fatty acids, total monounsaturated [g]0.02
16:1 [g]0
18:1 [g]0.02
Fatty acids, total polyunsaturated [g]0.04
18:2 [g]0.03
18:3 [g]0.01
Tryptophan [g]0.01
Threonine [g]0.01
Isoleucine [g]0.01
Leucine [g]0.02
Lysine [g]0.02
Methionine [g]0.01
Cystine [g]0.01
Phenylalanine [g]0.01
Tyrosine [g]0.01
Valine [g]0.02
Arginine [g]0.09
Histidine [g]0.01
Alanine [g]0.02
Aspartic acid [g]0.14
Glutamic acid [g]0.2
Glycine [g]0.02
Proline [g]0.06
Serine [g]0.03
Sources include : USDA [2]

Grapefruit Nutrition

Grapefruit might be one of the most nutrient-dense fruits per calorie, with high amounts of vitamins A and C. According to the USDA, one serving or half a grapefruit (123g) contains 52 calories and 13 grams of carbohydrates. It might be rich in dietary fiber, calcium, potassium, and folate. [3] [4]

Also, the fruit might have bioflavonoids and phytonutrients such as lycopene and beta-carotene.

Health Benefits of Grapefruits

Let us take a look at the most important grapefruit benefits in detail.

Natural Appetite Suppressant

Grapefruit and grapefruit juice might have long been considered a natural appetite suppressant, which led to the evolution of the ‘grapefruit diet’ in the 1970s. There might have been several studies that have linked it to weight loss. For instance, a 2011 study published in the Nutrition & Metabolism journal concluded that adding half a grapefruit, half a cup of 100 percent grapefruit juice, or half a cup of water before breakfast, lunch, and dinner might have helped obese people lose weight. The participants saw a dip in overall weight, an increase in their HDL or good cholesterol levels, and reported a significant decrease in appetite. [5] [6]

Aids In Weight Loss

Grapefruit and grapefruit products like the juice and oil may also help improve insulin resistance and regulate blood sugar levels, which can help keep you feel fuller longer. This is one of the important reasons why they might be included in many weight management programs. A randomized controlled trial to study the effects of the fruit on body weight and metabolic syndrome revealed that eating half a grapefruit before a meal might have been associated with significant weight loss due to an improvement in insulin resistance. Another research revealed that nootkatone, an aromatic compound in the fruit, may significantly reduce weight gain and belly fat accumulation in obese individuals. [7] [8] [9]

Moreover, researchers have found that including grapefruit as one of the fruit servings as per dietary recommendations can help maximize nutrient intake. Eating it regularly may be associated with higher intakes of vitamin C, magnesium, potassium, and dietary fiber. [10]

For more information on the grapefruit diet for weight loss, you can read our article on the Best Grapefruit Diet Plan.

Might have Antioxidant Properties

Research published in Comprehensive Natural Products 2010 says that the bitter properties arising from an essence called ‘naringin‘ in grapefruits might tone up the system and the digestive process. It is thought that it may be a valuable remedy for influenza since it helps minimize acidity in the system. Naringin might also be considered a flavonoid, which is a powerful antioxidant. Antioxidants have antifungal, antibacterial, and anti-inflammatory qualities, which can make them one of the most important lines of defense in the immune system, protecting against influenza as well as many other serious conditions. [11] [12]

May Improve Immunity

Most of the fruit’s immune-boosting benefits come from the high content of vitamin C present in it. A medium-sized grapefruit has nearly 39 milligrams of the vitamin, which is about half a day’s recommended supply. Vitamin C is vital in supporting a healthy immune system and may reduce the duration as well as the severity of cold symptoms. In Nicaragua, its juice was even used as a folklore remedy to reduce fever due to its high nutrient content. As mentioned above, the fruit also contains vitamin A, zinc, and copper – all of which work to strengthen the immune system and reduce the chances of infection in the body. [13] [14] [15] [16] [17]

Might Help Manage Diabetes

Eating grapefruit might have been associated with decreased fasting blood glucose and insulin levels. According to a report published in the Journal of Medicinal Food, consuming it can likely to help control one’s insulin levels and consequently can lessen the chances of becoming insulin resistant. Researchers found that this can be mainly due to the major flavanones present in the fruit – naringin and hesperidin. Additionally, a combined treatment with naringin and vitamin C might have helped manage streptozotocin-induced diabetes in rats. However, studies are required in humans to understand how the fruit can be used in diabetes management programs. [18] [19] [20]

May Reduce Risk Of Cardiovascular Diseases

Citrus flavonoids present in grapefruit may decrease the risk of coronary heart diseases by improving coronary vasodilatation, decreasing the ability of the platelets to clot, and preventing oxidation of LDL cholesterol. The Journal of Agricultural and Food Chemistry shows that consumption of the fruit can help reduce LDL cholesterol (bad cholesterol), as well as hazardous triglycerides. Furthermore, its high potassium content might works as a vasodilator, meaning that blood vessels and arteries relax, thereby reducing blood pressure and lessening the risk of heart attack and stroke. [21] [22] [23] [24]

Other health benefits:

  • Might Improve digestion: The high fiber and water content in the fruit may help add bulk to the bowels and regulates excretion. Grapefruit extract might also be used in modern medicine for these same reasons. [25]
  • Might Reduce the risk of stroke: Studies are ongoing to show that the dietary intake of citrus flavonoids, like in grapefruit, may be associated with a reduced risk of ischemic stroke and cardiovascular disease. [26]
Health benefits of grapefruit infographic

Grapefruit might be an excellent appetite suppressant.

Side Effects: Grapefruit-Drug Interactions

Despite all of these health benefits, you must exercise caution while taking medicines and consuming grapefruit juice at the same time. A lot of attention might have been given to the grapefruit-drug interactions by research papers. Some call grapefruit juice a cardiovascular drug prescriber’s nightmare. A 2009 case report in the Lancet described a 42-year-old woman who developed venous thrombosis after taking the fruit for three days while on a low-dose combined oral contraceptive containing drospirenone and Ethinylestradiol. [27] [28]

Certain chemicals in the fruit, like naringin, and other less common compounds can negatively interact with various drugs and might cause damage to your organ systems. Be sure to consult your doctor in terms of drug interactions with grapefruit juice in your diet before beginning any new treatment. According to the USFDA, medications that grapefruit could interact with include: [29] [30]

  • Certain statin drugs to lower cholesterol
  • Drugs that treat high blood pressure
  • Anti-anxiety drugs such as buspirone
  • Certain corticosteroids that treat Crohn’s disease or ulcerative colitis
  • Some organ-transplant rejection drugs
  • Drugs that treat abnormal heart rhythms
  • Some antihistamines, such as Allegra (fexofenadine)

Also, people with kidney infections who are on a potassium-restricted diet need to check with their doctor about the amount of grapefruit juice to include in their diet as it might be high in potassium. [31] Protection Status
About the Author

Meenakshi Nagdeve, Co-Founder, Organic Facts is a health and wellness enthusiast and is responsible for managing it. She has completed the Nutrition And Healthy Living Cornell Certificate Program, Cornell University, US. She holds a Post Graduate Diploma in Management from IIM Bangalore and B. Tech in Metallurgical Engineering and Materials Science from IIT Bombay. Prior to this, she worked for a few years in IT and Financial services. An ardent follower of naturopathy, she believes in healing with foods. In her free time, she loves to travel and taste different types of teas.

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