Naringenin is a natural compound (a flavonoid) found in fruits such as grapefruit, oranges, and tomatoes. It has antioxidant and anti-inflammatory effects. Naringenin based supplements are being promoted on the internet and elsewhere for a wide variety of uses including "curing" obesity, preventing or treating metabolic syndrome, reducing oxidative damage to DNA, and more.
I discussed naringenin's effects with Tieraona Low Dog, M.D., an internationally recognized expert in the fields of integrative medicine, dietary supplements and women's health, and a leading authority on botanical medicine. She notes that naringenin does have some ability to prevent carbohydrate absorption from the intestines, possibly reducing rapid rises in blood sugar and insulin after eating. This could have some beneficial effect on weight management and metabolic syndrome (a combination of risk factors for obesity, type- 2 diabetes, and heart disease that include insulin resistance, high blood pressure, low HDL cholesterol, high serum triglycerides and excess abdominal fat).
Dr. Low Dog also tells me that some research suggests that naringenin may have the ability to protect the liver. I'm aware of one study from Harvard that showed it may help curb the spread of the hepatitis C virus by interfering with the secretion of the virus from infected cells. However, the researchers described these results as preliminary and noted that since naringenin isn't very well absorbed, if it proved to be useful for treating hepatitis C, it probably would have to be given intravenously. The study was published in the journal Hepatology in May 2008.
Keep in mind that naringenin in grapefruit juice can interact with a number of pharmaceutical drugs, altering and influencing their blood levels. These include:
- statins used for cholesterol control
- calcium channel blockers used to treat high blood pressure
- non-sedating antihistamines such as Hismanal (astemizole)
- anti-anxiety drugs like Valium (diazepam), Xanax (alprazolam), Halcion (triazolam), and others
- immunosuppressive drugs used to prevent rejection of transplanted tissues organs
- antiviral agents used to treat HIV/AIDS
If you take any of these medications, be sure to talk to your physician or pharmacist before taking a naringenin supplement or even before you increase the amount of grapefruit or grapefruit juice you eat or drink on a regular basis.
Andrew Weil, M.D.