Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nutritional friend or foe? Vitamin E sends mixed messages

06.03.2006


One of the most powerful antioxidants is truly a double-edged sword, say researchers at Ohio State University who studied how two forms of vitamin E act once they are inside animal cells.



In the past couple of decades, a slough of studies has looked at the benefits of vitamin E and other antioxidants. While a considerable amount of this research touts the advantages of consuming antioxidants, some of the studies have found that in certain cases, antioxidants, including vitamin E, may actually increase the potential for developing heart disease, cancer and a host of other health problems.

This study provides clues as to why this could happen, say Jiyan Ma, an assistant professor of molecular and cellular biochemistry, and his colleague David Cornwell, an emeritus professor of molecular and cellular biochemistry, both at Ohio State.


The two men led a study that compared how the two most common forms of vitamin E –– one is found primarily in plants like corn and soybeans, while the other is found in olive oil, almonds, sunflower seeds and mustard greens – affect the health of animal cells. The main difference between the two forms is a slight variation in their chemical structures.

In laboratory experiments, the kind of vitamin E found in corn and soybean oil, gamma-tocopherol, ultimately destroyed animal cells. But the other form of vitamin E, alpha-tocopherol, did not. (Tocopherol is the scientific name for vitamin E.)

“In the United States we tend to eat a diet rich in corn and soybean oil, so we consume much greater amounts of gamma-tocopherol than alpha-tocopherol,” Cornwell said. “But most of the vitamin E coursing through out veins is alpha-tocopherol – the body selects for this version. We want to know why that is, and whether the selection of the alpha-tocopherol confers an evolutionary benefit in animal cells.”

Cornwell and Ma explain their findings in this week’s Early Edition of the Proceedings of the National Academy of Sciences. They conducted the study with several colleagues from the departments of molecular and cellular biochemistry and chemistry at Ohio State.

The researchers conducted laboratory experiments on cells taken from the brains of mice. They treated some of the cells with metabolic end products, called quinones, of alpha- and gamma-tocopherol.

When the body breaks down vitamin E, these end products are what enter and act on our cells. However, Ma said that our bodies get rid of most gamma-tocopherol before it ever has a chance to reach its quinone stage.

Still, some nutritional supplement companies make and sell gamma-tocopherol supplements, promoting this version of vitamin E as a good antioxidant source. In theory, taking a vitamin supplement – a concentrated form of the vitamin - increases the amount of that substance in the body.

Using laboratory techniques that allowed them to detect the activity of the quinones inside the cells, the researchers found that the gamma-tocopherol quinone formed a compound which destroyed that cell. It did so by preventing proper protein folding in the cells, which causes a cellular response that is involved in a variety of human diseases, including diabetes and Parkinson’s disease.

However, the alpha-tocopherol quinone did not kill cells, nor did it interfere with protein folding. The researchers repeated their experiments on kidney cells cultured from monkeys and on skin cells cultured from mice and found similar results.

“We think that gamma-tocopherol may have this kind of damaging effect on nearly every type of cell in the body,” Ma said.

While the study doesn’t get into the possible effects on health, the researchers raise the point that there is still a great deal that isn’t known about how antioxidants act in the body. In order to get to that point, scientists must study how antioxidants and cells interact on their most fundamental levels.

This work was funded through grants from the National Science Foundation Environmental Molecular Science Institute and the Large Interdisciplinary Grants Program in the Office of Research at Ohio State.

Jiyan Ma | EurekAlert!
Further information:
http://www.osu.edu

More articles from Health and Medicine:

nachricht Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Foods of the future
15.08.2018 | Georg-August-Universität Göttingen

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Interactive software tool makes complex mold design simple

16.08.2018 | Information Technology

Study tracks inner workings of the brain with new biosensor

16.08.2018 | Health and Medicine

Fraunhofer HHI develops next-generation quantum communications technology in the UNIQORN project

16.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>