Featured Research

from universities, journals, and other organizations

Findings bolster fiber's role in colon health

Date:
January 16, 2014
Source:
Medical College of Georgia at Georgia Regents University
Summary:
Scientists have more reasons for you to eat fiber and not abuse antibiotics. They've shown that a receptor doctors already activate with mega-doses of niacin to protect patients' cardiovascular systems also plays a key role in preventing colon inflammation and cancer.

This shows Dr. Vadivel Ganapathy, Chairman of the Department of Biochemistry and Molecular Biology at the Medical College of Georgia at Georgia Regents University; Dr. Nagendra Singh, MCG immunologist, member of the Cancer Immunology, Inflammation and Tolerance Program at the GRU Cancer Center, both corresponding study authors.
Credit: Phil Jones

Scientists have more reasons for you to eat fiber and not abuse antibiotics. They've shown that a receptor doctors already activate with mega-doses of niacin to protect patients' cardiovascular systems also plays a key role in preventing colon inflammation and cancer, according to a study featured on the cover of the journal Immunity.

The finding helps explain why a high-fiber diet reduces the risk of colon problems and indicates that when fiber is lacking, niacin, or vitamin B3, just may help keep the colon healthy as well, said Dr. Vadivel Ganapathy, Chairman of the Department of Biochemistry and Molecular Biology at the Medical College of Georgia at Georgia Regents University and a corresponding study author.

The study found that mice lacking the receptor, Gpr109a, were prone to inflammation and cancer of the colon, said Dr. Nagendra Singh, MCG immunologist, member of the Cancer Immunology, Inflammation and Tolerance Program at the GRU Cancer Center, and a corresponding study author.

And, when they gave niacin to mice whose healthy colonic bacteria had been wiped out by antibiotics – a frequent occurrence in chronic antibiotic use – it helped steer immune cells in the colon into a safe, anti-inflammatory mode.

Good bacteria in the colon thrive on fiber and its digestion produces butyrate, a short-chain fatty acid, which Ganapathy discovered years before naturally activates Gpr109a. However this relationship appears limited to the colon, where butyrate levels can soar in the face of a high-fiber diet.

Research teams at GlaxoSmithKline and the University of Heidelberg, Germany showed in 2003 that Gpr109a receptors on the surface of fat cells mediate the protective cardiovascular effect of niacin, including increasing good cholesterol, or HDL, while decreasing levels of disease-producing LDL. Their search for other activators identified butyrate, which led Ganapathy to find that not only is the Gpr109a receptor expressed on the surface of colon cells, but that with sufficient fiber intake, butyrate levels in the colon can activate it.

Now, he and Singh have shown activation of Gpr109a in the colon by butyrate prompts immune cells, which are in ample supply in that region, to suppress rather than promote inflammation, a factor in a number of painful conditions such as ulcerative colitis, Crohn's disease, and colorectal cancer.

Once butyrate activates the Gpr109a receptor on dendritic cells and macrophages in the colon, these immune cells start producing anti-inflammatory molecules and sending messages to the T cells, key orchestrators of immunity, to do the same, Singh said. Butyrate also prompts epithelial cells that line the colon to produce cytokines, which aid wound-healing, a critical step for resolving the intestinal inflammation that occurs in ulcerative colitis and Crohn's.

"To protect your colon, you need this receptor, as well as the fiber and butyrate which activate it," Ganapathy said. For people who won't or can't eat high-fiber diets, mega-doses of niacin, may help protect the colon, the way it's already protecting hearts, the scientists suggest.

"We think mega-doses of niacin may be useful in the treatment and/or prevention of ulcerative colitis, Crohn's disease, and colorectal cancer as well as familial adenomatous polyposis, or FAP, a genetic condition that causes polyps to develop throughout the gastrointestinal tract," Singh said. In fact, they've already shown that fiber depletion increases and mega-niacin doses decrease development of polyps in mice with FAP.

The colon and intestines are constantly exposed to foreign bacteria that enter the body primarily through the mouth. The good bacteria, which are essential to digestion and colon health, regularly communicate to immune cells that they are not the enemy and butyrate appears to be a key signal there as well, said Ganapathy, who also leads the Signaling and Angiogenesis Program at the GRU Cancer Center.

Next steps include pursuing clinical trials of niacin supplements in colon health and, potentially, epidemiological studies that examine intestinal inflammation and colon cancer rates in patients already taking niacin for cardiovascular health. The research was funded by the National Institutes of Health.


Story Source:

The above story is based on materials provided by Medical College of Georgia at Georgia Regents University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nagendra Singh, Ashish Gurav, Sathish Sivaprakasam, Evan Brady, Ravi Padia, Huidong Shi, Muthusamy Thangaraju, PutturD. Prasad, Santhakumar Manicassamy, DavidH. Munn, JeffreyR. Lee, Stefan Offermanns, Vadivel Ganapathy. Activation of Gpr109a, Receptor for Niacin and the Commensal Metabolite Butyrate, Suppresses Colonic Inflammation and Carcinogenesis. Immunity, 2014; DOI: 10.1016/j.immuni.2013.12.007

Cite This Page:

Medical College of Georgia at Georgia Regents University. "Findings bolster fiber's role in colon health." ScienceDaily. ScienceDaily, 16 January 2014. <www.sciencedaily.com/releases/2014/01/140116113510.htm>.
Medical College of Georgia at Georgia Regents University. (2014, January 16). Findings bolster fiber's role in colon health. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2014/01/140116113510.htm
Medical College of Georgia at Georgia Regents University. "Findings bolster fiber's role in colon health." ScienceDaily. www.sciencedaily.com/releases/2014/01/140116113510.htm (accessed July 22, 2014).

Share This




More Health & Medicine News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Powered by NewsLook.com
Contaminated Water Kills 3 Babies in South African Town

Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP
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:
from the past week

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