Navigation Links
Genetic variants associated with vitamin B12
Date:9/8/2008

Boston, MA - Researchers at the Harvard School of Public Health (HSPH) and their collaborators at Tufts University and the National Cancer Institute (NCI) have identified a common genetic influence on B12 vitamin levels in the blood, suggesting a new way to approach the biological connections between an important biochemical variable and deficiency-related diseases.

"The news here is the discovery of a robust genetic predictor of vitamin B12 levels," said David Hunter, the Vincent L. Gregory Professor of Cancer Prevention and director of the Program in Molecular and Genetic Epidemiology at HSPH and senior author of the study. "This is an example of the way we're going to understand more about how levels of vitamins and other nutrients in the body are partially determined by genetic factors as well as by what we eat."

Other studies have found rare gene mutations with dramatic effects on people's ability to digest, absorb, and use vitamin B12. This paper found more common variations of a gene that has a much smaller effect by itself, but it may belong to an important biological pathway whose careful study may lead to clinically useful strategies and therapeutic intervention.

The researchers first found the gene, called FUT2, in a genome-wide scan of 1,658 women of European ancestry who participated in the Cancer Genetic Markers of Susceptibility (CGEMS) project. They replicated the findings in another 1,059 women from the Nurses' Health Study.

"This provides a framework for further nutrigenomics studies and for exploring gene-diet interactions with cancer and other diseases," said Aditi Hazra, HSPH instructor and lead author of the study. The paper was published in the Sept. 7 advance online Nature Genetics.

Other studies have linked B12 deficiency with pernicious anemia, cardiovascular disease, cancer, and neurodegenerative disorders. Lower B12 levels have been associated with cognitive impairment. A key player in the B-vitamin pathway, B12 helps maintain healthy nerve cells, form red blood cells, and synthesize DNA.

In the diet, B12 comes from meat, fish, dairy, other animal products, and fortified breakfast cereals. As many as one-quarter of the elderly may have mild B12 deficiency. Strict vegetarians, who avoid meat, and vegans, who avoid all animal products, are also at risk of B12 deficiency.

"This is an unexpected finding. We thought we had already learned everything about the absorption of vitamin B12," said co-author Jacob Selhub, director of the Vitamin Metabolism Laboratory at the USDA Human Nutrition Research Center on Aging at Tufts University. He has conducted many of the studies linking B12 status in the elderly with cognitive impairment, anemia, and bone marrow density and osteoporosis.

Anything in the stomach that affects the normal acidity and digestive processes, ranging from infections to acid reflux medicine to aging, may also interfere with B12 absorption, studies suggest. B12 is first separated from food by stomach acid and then escorted from there by a protein called intrinsic factor to the small intestine, where the complex is absorbed and B12 is released into the blood.

Until further studies are conducted, the most plausible explanation is the potential preventive effect of the gene variant on factors known to cause B12 malabsorption, such as H. pylori infection, the researchers say.

Hazra and her colleagues had been investigating the genetic and epigenetic links between colorectal cancer and adenoma and the B-vitamin pathway, also known as the one-carbon metabolism pathway, including folate, vitamins B6 and B12, and homocysteine. Ultimately, she hopes to identify different gene variants that work together and create a nutrigenomics predictor score to assist in future individual cancer prevention strategies.

Evaluating more than 528,000 genetic variants, the strongest signals came from variants in FUT2. The gene variant associated with the highest B12 levels has previously been determined to protect the stomach from infection by the Norwalk virus and ulcer-causing H. pylori bacterium.

In the study, the FUT2 genetic variant accounted for about three percent of the variation in B12 plasma levels, Hazra said. The researchers do not have direct evidence that people who carry the gene variant suffer from any cognitive or other adverse affects of low B12 levels.


'/>"/>

Contact: Christina Roache
croache@hsph.harvard.edu
617-432-6052
Harvard School of Public Health
Source:Eurekalert

Related medicine news :

1. Many Parents Share Genetic Test Findings With Kids
2. Genetic predisposition increases childhood asthma risk
3. New Alzheimers findings: High stress and genetic risk factor lead to increased memory decline
4. Test Spots Genetic Damage Done by Smoking
5. Scientists demonstate link between genetic variant and effectiveness of smoking cessation meds
6. Scientists highlight benefits of genetic research in sport, but warn of ethical concerns
7. Genetics Hold Promise, Challenges for Cancer Care
8. Researchers genetically engineer micro-organisms into tiny factories
9. Study Questions Genetic Screening for Treatable Diseases
10. Researchers provide genetic associations from a genome-wide scan for cardiovascular disease traits
11. Genetic variation affects smoking cessation treatment
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/23/2017)... ... February 23, 2017 , ... The American Cleft Palate-Craniofacial Association (ACPA) ... Meeting. KLS is a longtime supporter of the event. , "We are pleased ... Sponsor," said Dr. Bob Havlik, 2017 ACPA President. "KLS Martin has a long track ...
(Date:2/23/2017)... ... February 23, 2017 , ... EBSCO ... the National Institute for Health and Care Excellence (NICE) framework. The ... National Health Service (NHS) to search, order and purchase medical and healthcare-related content ...
(Date:2/23/2017)... ... February 23, 2017 , ... ERT, a global ... announced that Premier Research, a leading clinical development service provider, has selected ERT’s ... increasingly complex, due in part to an array of circumstances including the use ...
(Date:2/23/2017)... VA – , ... ... coming. It’s the perfect opportunity for the nation to come ... a college basketball bracket – with its favorite fruit – ... is encouraging apple lovers to join the “Apple Madness” bracket ...
(Date:2/23/2017)... ... 2017 , ... HealthPostures, the desk for standing designer headquartered in Prior Lake, ... the Minneapolis Home and Garden Show which is being held February 24 through 26 ... is the Minneapolis Convention Center. , From its broad line of sit stand ...
Breaking Medicine News(10 mins):
(Date:2/24/2017)... Feb 24, 2017 Research and Markets has ... and Strategies - 2016" report to their offering. ... The latest research Urinary ... data and benchmarks in the global Urinary Incontinence market. The ... are the key drugs marketed for Urinary Incontinence and their clinical ...
(Date:2/23/2017)... 2017 LG Innotek hat heute die weltweit ... beträgt das 1,5-fache des 45-mW-Moduls der Konkurrenz. ... 200 und 280 nm und eignet sich damit für Sterilisationsaufgaben. ... DNA zerstört. Das Produkt von LG Innotek erzeugt UV-Strahlung ... ...
(Date:2/23/2017)... Research and Markets has announced the addition of the "Menopause ... ... Drugs Price Analysis and Strategies - 2016, provides drug pricing data and ... questions: What are the key drugs marketed ... Global Menopause market? What are the unit prices and ...
Breaking Medicine Technology: