Navigation Links
Genetic variants associated with vitamin B12

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
Harvard School of Public Health

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:
(Date:11/29/2015)... ... November 29, 2015 , ... ProStatic Analog Distortion ... tool designed specially for Final Cut Pro X. FCPX users can ... easy-to-use modification controls. Destoying and creating chaotic distortion is now quick and simple, ...
(Date:11/28/2015)... , ... November 28, 2015 , ... Safe storage for ... of two inventors, one from Lakewood, New Jersey and the other from Bradley Beach, ... patent-pending PROTECTOR to save the expense of having to replace NuvaRings more often than ...
(Date:11/27/2015)... Canada (PRWEB) , ... November 28, 2015 , ... There ... do we outperform our billings from last year? , This question has not been ... organizations are coming to the retirement age and the younger workforce don’t share the ...
(Date:11/27/2015)... ... November 27, 2015 , ... The rapid speed ... As people age, more care is needed, especially with Alzheimer’s, dementia and other ... are being overworked. The forgotten part of this equation: 80 percent of medical ...
(Date:11/27/2015)... ... November 27, 2015 , ... Lizzie’s Lice Pickers just announced ... offering customers 10% off of their purchase of lice treatment product. In addition, customers ... According to a company spokesperson. “Finding lice is a sure way to ruin the ...
Breaking Medicine News(10 mins):
(Date:11/29/2015)... , Nov. 29, 2015 CIVCO Medical ... technology at the Radiological Society of ... Chicago November 29 – December ... designed to offer customers unrivaled versatility, enhanced user ... --> ...
(Date:11/27/2015)... -- --> --> ... potential to save costs, improve treatment quality and accelerate ... exploited as yet. Here, particular emphasis is placed on ... tablet or directly at the patients, bedside. ... -->      (Photo: ) ...
(Date:11/27/2015)... 2015 Research and Markets ( ) ... Devices Market 2015-2019" report to their offering. ... this report, the author the present scenario and growth ... To calculate the market size, the report considers revenue ... Hormonal IUDs and copper IUDs. The report forecasts the ...
Breaking Medicine Technology: