Eating any kind of grapefruit can have a positive impact on cholesterol according to a study at Israel’s Hebrew University, but only red grapefruit makes a significant difference. Using in vitro assays, researchers established that red grapefruit has higher amounts of bioactive compounds and higher antioxidant potential than white grapefruit.

The study gathered 57 volunteers aged 39 to 72 who had already had coronary bypass surgery and who suffered from high blood cholesterol. A third of the volunteers ate one red grapefruit every day for a month, another third ate an equal-weight white one, and the control group ate just the standard anti-atherosclerosis diet. The promising results: Cholesterol levels dropped in both grapefruit groups, but red grapefruit outpaced white in all three measures. It was twice as effective in lowering total cholesterol, just under twice as effective at reducing LDL (bad) cholesterol, and three times more effective on triglycerides.
—James Keough