Fresh grapefruit, grapefruit juice and grapefruit-pommelo hybrid fruit and juices have been shown in clinical studies to:
White and pink/red grapefruit have similar nutrition profiles; however, pink/red grapefruit contain more caroteniods, like lycopene, that give them their color.
Vitamins, minerals, and phytonutrients found in fresh grapefruit and 100% grapefruit juice may play a role in heart health:
Vitamin C has been shown to reduce monocyte adhesion to vascular tissue, improve nitric oxide production and vasodilation, and reduce vascular smooth muscle cell death, factors which support cardiovascular health.14 Fresh grapefruit and 100% grapefruit juice are excellent sources of vitamin C providing at least 50% of the recommended Daily Value (DV) in ½ medium grapefruit or an 8-ounce glass of 100% grapefruit juice.*
Potassium is an electrolyte that helps maintain fluid balance which affects blood pressure. It is also needed for heart function and nerve transmission. Diets containing foods that are a good source of potassium and low in sodium may reduce the risk of high blood pressure and stroke.15 People suffering from kidney disease should consult their doctor on how much potassium is right for their diet. One 8-ounce serving of 100% grapefruit juice delivers 6% and ½ medium grapefruit offers 4% of the DV for potassium.*
Folate and Vitamin B6 may help regulate homocysteine. While research has not shown definitive results, some studies show folate and vitamin B6 may help protect against heart disease by lowering homocysteine levels in the blood,16 an amino acid believed to cause damage to the arteries and increase the risk of blood clots when elevated. One 8-ounce glass of grapefruit juice offers 8% of the DV for folate and 6% of the DV for vitamin B6, while ½ medium grapefruit has 2% of the DV for folate and 4% of the DV for vitamin B6.*
Phytonutrients found in grapefruit and grapefruit juice, such as carotenoids and the polyphenol, naringin, may help support heart health. Grapefruit contains flavonoids, a class of plant compound similar to those found in red wine (resveratrol), green tea (catechins), and chocolate (flavanols). Naringin is the most common flavonoid found in grapefruit and naringin as been reported to have antioxidant, anti-inflammatory, and cardioprotective properties.11,17,18 Carotenoids, which contribute to the colors of fruits and vegetables, also have antioxidant traits that may help protect against certain diseases, like cardiovascular disease.19
Epidemiological data suggest consuming fruits and vegetables, including citrus and citrus juices, may be beneficial to the cardiovascular system as they have been associated with reduced risks of cardiovascular disease and stroke.20-25 A meta-analysis found 100% citrus juice consumption related to a lower risk of cardiovascular disease and ischemic stroke.25
Many heart benefits may be partially attributable to plant compounds such as flavonoids. In several prospective cohort studies, higher intakes of the flavonoids found in citrus, including naringenin and/or hesperidin, were associated with:
In a prospective cohort study that included over 34,000 post-menopausal women, grapefruit intake was associated with a 15 percent reduced risk for coronary heart disease mortality when adjusting for a number of confounding factors including age, energy intake, blood pressure, diabetes, BMI, and smoking.13
Fresh grapefruit and grapefruit juice may have beneficial effects on blood pressure. In an acute study with 40 normotensive and hypertensive adults age 30-45 years, consumption of 250mL fresh-squeezed grapefruit juice significantly decreased diastolic blood pressure (DBP) and systolic blood pressure (SBP) compared to a control beverage.3 In a longer-term study, participants who consumed ½ of a Rio-Red grapefruit daily with each of 3 meals for 6 weeks had significantly lower SBP (−3.21 ± 10.13mmHg, P=0.03) compared with baseline.4 However, the changes were not different than with a control beverage but suggested that grapefruit should be further evaluated for its blood-lowering potential.
A double-blind cross-over study sought to isolate the potential effects of grapefruit flavanones from sweetie juice (a grapefruit-pummelo hybrid) on blood-pressure lowering potential in people with stage 1 hypertension. Twelve participants consumed 500mL/day of either high- or low-flavonoid sweetie juice for 5 weeks. The low-flavonoid juice contained only 25% of the naringin and 30% of the narirutin of the high-flavonoid juice. SBP decreased in both groups with no difference between low- and high-flavonoid juice. DBP decreased in both groups, but more so with the high-flavonoid juice, suggesting that the flavonoids may be an active ingredient.2
In a systematic review and meta-analysis the pooled the results of three randomized controlled trials, grapefruit consumption was associated with a small but significant reduction in SBP (-2.43 mmHg), although this association was attenuated depending on study randomization procedures and whether fresh grapefruit or grapefruit juice was used in the study.5 The authors cite the lack of studies and the need for larger studies of longer duration.
An analysis of National Health and Nutrition Examination Survey (NHANES) 2003-2008 data reported that consumption of any amount of grapefruit (100% grapefruit juice or fresh, canned, or frozen) by adults was associated with significantly lower triglycerides and higher HDL cholesterol compared to non-consumers.12 Likewise, in a randomized controlled trial with 85 obese adults, HDL-cholesterol levels increased significantly for those consuming grapefruit or grapefruit juice for 12 weeks before meals compared to those consuming water.9 However, there was no effect on total or LDL cholesterol or triglycerides.
The consumption of one fresh red or white grapefruit each day for 30 days by 57 hyperlipidemic adults was associated with a significant reduction in LDL cholesterol, with additionally a significant reduction in total cholesterol and triglycerides with red grapefruit only.7 In a cross-over study with 28 healthy volunteers, consumption of 250 mL grapefruit juice daily for 3 weeks (with a 3-week washout between intervention beverages) resulted in a 6% reduction in LDL cholesterol although this was not significantly different when compared with control beverages.8 Likewise, in a cross-over study, overweight adults who consumed ½ of a Rio-Red grapefruit daily with each of 3 meals for 6 weeks had reductions in total (-11.7 mg/dL) and LDL (-18.7 mg/dL) cholesterol compared with baseline values.4 However, these changes were not significantly different than the control diet.
Grapefruit juice may be beneficial toward arterial health. In a double-blind, randomized, controlled, crossover trial 48 healthy postmenopausal women aged 50–65 years consumed 340 mL grapefruit juice daily or a matched control drink without flavanones for 6 months, with a 2-month washout in between beverage intervention periods. Mean carotid-femoral pulse wave velocity, which reflects central aortic stiffness, was significantly lower after consumption of grapefruit juice compared to control (P=0.019).11 The effects seen in this study were thought to be primarily due to naringin, the primary flavanone found in grapefruit and grapefruit juice. Arterial stiffness increases with aging and has been associated with an increased risk of cardiovascular disease, including heart attack and stroke.*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.