14 DAY TRIAL // Grapefruits contain naringenin, which is an antioxidant derived from their bitter flavor, as well as from other citrus fruits, that causes the liver to break down fat and increase insulin sensitivity.
Research carried out by a team from the Hebrew University of Jerusalem and Massachusetts General Hospital (MGH), found that naringenin activates a family of small proteins – nuclear receptors, that cause the liver to break down fatty acids, thing that usually happens during fasting.
Actually naringenin does exactly what two other drugs, the lipid-lowering Fenofibrate and the anti-diabetic Rosiglitazone do, with the advantages of both.
This report appearing in the online journal PloS ONE, says that if the results were the same for humans, this dietary supplement could be the new treatment of type 2 diabetes, hyperlipidemia and maybe metabolic syndrome.
Yaakov Nahmias, PhD, of the Hebrew University of Jerusalem the paper's senior author, says that these findings are rather interesting as they show the mechanism by which this compound increases two pharmaceutical targets that are very important - PPARα and PPARγ, and blocks a third one – LXRα.
“The results are similar to those induced by long periods of fasting,” he adds.
In the human body, the liver regulates the levels of carbohydrate and lipids within the blood, so after a meal, the blood is flushed with sugars, that activate LXRα, that triggers the liver to create fatty acids and store them.
When fasting, the process is reversed, as fatty acids are released by fat cells, they activate PPARα in the liver and are broken down to ketones.
The process that increases sensitivity to insulin is quite similar except it involves PPARγ.
Martin L. Yarmush, MD, PhD, director of the MGH Center for Engineering in Medicine, the Helen Andrus Benedict Professor of Surgery and Bioengineering at Harvard Medical School and one of the paper's authors, says that “It is a process which is similar to the Atkins diet, without many of the side effects: the liver behaves as if fasting, breaking down fatty acids instead of carbohydrates.”
Many researches were carried out by the pharmaceutical industry on dual PPARα and PPARγ agonists, but because of safety concerns, their development was compromised.
Naringenin, on the other hand has absolutely no record of side effects and as Nahmias says, “it might actually protect the liver from damage.”
If you ever wandered why grapefruit is bitter, know that it is because of the presence of the flavonoid naringin, that the intestines break down into naringenin.
The compound lowers cholesterol and it could improve some diabetes-associated symptoms.
It also activates PPARα and PPARγ by dramatically increasing the levels of a co-activator peptide of both, called PGC1α, and at the same time, naringenin blocks the activation of the LXRα.
All these processes lead to an increase in fatty acid oxidation and the inhibition of the 'bad cholesterol' production.