Featured Research

from universities, journals, and other organizations

Grapefruit's bitter taste holds a sweet promise for diabetes therapy

Date:
August 27, 2010
Source:
Public Library of Science
Summary:
A new study demonstrates the mechanism by which a single grapefruit compound controls fat and glucose metabolism, replacing multiple drugs.

Naringenin, an antioxidant derived from the bitter flavor of grapefruits and other citrus fruits, may cause the liver to break down fat while increasing insulin sensitivity, a process that naturally occurs during long periods of fasting.
Credit: iStockphoto

Naringenin, an antioxidant derived from the bitter flavor of grapefruits and other citrus fruits, may cause the liver to break down fat while increasing insulin sensitivity, a process that naturally occurs during long periods of fasting.

Related Articles


A team of researchers from the Hebrew University of Jerusalem and Massachusetts General Hospital (MGH) report that naringenin activates a family of small proteins, called nuclear receptors, causing the liver to break down fatty acids. In fact, the compound seems to mimic the actions of other drugs, such as the lipid-lowering Fenofibrate and the anti-diabetic Rosiglitazone, offering the advantages of both. If the results of this study extend to human patients, this dietary supplement could become a staple in the treatment of hyperlipidemia, type-2 diabetes, and perhaps metabolic syndrome. The report appears in this week issue of the online journal PLoS ONE.

"It is a fascinating find," says Yaakov Nahmias, PhD, of the Hebrew University of Jerusalem the paper's senior author. "We show the mechanism by which naringenin increases two important pharmaceutical targets, PPARα and PPARγ, while blocking a third, LXRα. The results are similar to those induced by long periods of fasting."

The liver is the main organ responsible for the regulation of carbohydrate and lipid levels in the blood. Following a meal, the blood is flushed with sugars, which activate LXRα, causing the liver to create fatty acids for long-term storage. During fasting, the process is reversed; fatty acids are released by fat cells, activate PPARα in the liver, and are broken down to ketones. A similar process, involving PPARγ, increases sensitivity to insulin.

"It is a process which is similar to the Atkins diet, without many of the side effects," says Martin L. Yarmush, MD, PhD, director of the MGH Center for Engineering in Medicine and one of the paper's authors.

"The liver behaves as if fasting, breaking down fatty acids instead of carbohydrates." Yarmush is the Helen Andrus Benedict Professor of Surgery and Bioengineering at Harvard Medical School.

"Dual PPARα and PPARγ agonists, like naringenin, were long sought after by the pharmaceutical industry," says Nahmias, "but their development was plagued by safety concerns. Remarkably, naringenin is a dietary supplement with a clear safety record. Evidence suggests it might actually protect the liver from damage."

Grapefruit's bitter taste is caused the presence of the flavonoid naringin, which is broken down in the gut into naringenin. Earlier evidence has shown the compound has cholesterol lowering properties and may ameliorate some of the symptoms associated with diabetes. The researchers demonstrated that the compound activates PPARα and PPARγ by dramatically increasing the levels of a co-activator peptide of both, called PGC1α. At the same time, naringenin bound directly to LXRα, blocking its activation. These effects culminated with increased fatty acid oxidation and the inhibition of vLDL ('bad cholesterol') production.

Additional co-authors of the PLoS ONE paper are Jonathan Goldwasser, PhD, Eric Yang, PhD, MGH; Pazit Cohen, PhD, Hebrew University; and Patrick Balaguer, PhD, INSERM Univ. Montpellier France. The work was supported by grants from the National Institutes of Health (NIH) and European Research Council (ERC).

This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases (K01DK080241), a European Research Council starting grant (TMIHCV 242699), and the Harvard Clinical Nutrition Research Center (P30-DK040561). Resources were provided by the BioMEMS Resource Center (P41 EB-002503), Shriners Burns Hospital, and the Alexander Silberman Institute of Life Sciences.


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Goldwasser J, Cohen PY, Yang E, Balaguer P, Yarmush ML, et al. Transcriptional Regulation of Human and Rat Hepatic Lipid Metabolism by the Grapefruit Flavonoid Naringenin: Role of PPARa, PPARc and LXRa. PLoS ONE, 5(8): e12399 DOI: 10.1371/journal.pone.0012399

Cite This Page:

Public Library of Science. "Grapefruit's bitter taste holds a sweet promise for diabetes therapy." ScienceDaily. ScienceDaily, 27 August 2010. <www.sciencedaily.com/releases/2010/08/100825174110.htm>.
Public Library of Science. (2010, August 27). Grapefruit's bitter taste holds a sweet promise for diabetes therapy. ScienceDaily. Retrieved January 31, 2015 from www.sciencedaily.com/releases/2010/08/100825174110.htm
Public Library of Science. "Grapefruit's bitter taste holds a sweet promise for diabetes therapy." ScienceDaily. www.sciencedaily.com/releases/2010/08/100825174110.htm (accessed January 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, January 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC: Get Vaccinated for Measles

CDC: Get Vaccinated for Measles

Reuters - US Online Video (Jan. 30, 2015) The CDC is urging people to get vaccinated for measles amid an outbreak that began at Disneyland and has now infected more than 90 people. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Obama To Outline New Plan For Personalized Medicine

Obama To Outline New Plan For Personalized Medicine

Newsy (Jan. 30, 2015) President Obama is expected to speak with drugmakers Friday about his Precision Medicine Initiative first introduced last week. Video provided by Newsy
Powered by NewsLook.com
NFL Concussions Down; Still on Parents' Minds

NFL Concussions Down; Still on Parents' Minds

AP (Jan. 30, 2015) The NFL announced this week that the number of game concussions dropped by a quarter over last season. Still, the dangers of the sport still weigh on players, and parents&apos; minds. (Jan. 30) Video provided by AP
Powered by NewsLook.com
U.S. Wants to Analyze DNA from 1 Million People

U.S. Wants to Analyze DNA from 1 Million People

Reuters - US Online Video (Jan. 30, 2015) The U.S. has proposed analyzing genetic information from more than 1 million American volunteers to learn how genetic variants affect health and disease. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins