Hate Your Hair? Blame Your Mother's
Diet By
Maggie Fox Health and Science
Correspondent 8-2-3
- WASHINGTON (Reuters) - In
a study that shows more than ever you are what you eat, U.S. scientists
said on Friday they had changed the coat colors of baby mice simply by
altering their mothers' diets.
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- The study shows that common nutrients can influence
which genes turn on and off in a developing fetus, and help explain some
of the factors that decide which genes "express" and which remain
silent.
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- Writing in Friday's issue of the journal Molecular and
Cellular Biology, the scientists at Duke University Medical Center said
they changed the color of baby mouse fur by feeding pregnant mice four
supplements -- vitamin B12, folic acid, choline and betaine.
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- Mice given the four supplements gave birth to babies
predominantly with brown coats. Pregnant mice not fed the supplements
gave birth mostly to babies with yellow coats.
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- Careful study showed the extra nutrients turned down
_expression_ of a gene called Agouti, which affects fur color.
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- "We have long known that maternal nutrition profoundly
impacts disease susceptibility in their offspring, but we never
understood the cause-and-effect link," said Randy Jirtle, a professor of
radiation oncology at Duke who directed the study.
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- "For the first time ever, we have shown precisely how
nutritional supplementation to the mother can permanently alter gene
_expression_ in her offspring without altering the genes themselves," he
said in a statement.
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- The findings have not been shown in humans, but the
researchers said there is much support for the idea that nutrition can
affect gene _expression_ in people.
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- Several studies have shown, for instance, that women
who eat a poor diet while pregnant have children who grow up with a
tendency to diabetes and heart disease.
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- OBESITY, DIABETES LINK
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- This study could help explain that. The Agouti gene
not only affects coat color, but also metabolic factors involved in
diabetes and heart disease.
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- Mice with overactive Agouti genes tend to be obese and
susceptible to diabetes because the protein controlled by the gene
affects one brain signal involved in appetite.
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- "Diet, nutritional supplements and other seemingly
innocuous compounds can alter the development in utero to such an extent
that it changes the offspring's characteristics for life, and
potentially that of future generations," said researcher Rob Waterland,
who worked on the study.
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- Nutrition is likely to be one of the "environmental
factors" that decides which genes turn on and which stay silent.
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- Everyone inherits two copies of each gene -- one from
each parent. For most functions, only one gene expresses while the other
is silent.
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- This idea, first explained by 19th century genetic
pioneer Gregor Mendel with his experiments on green and yellow peas, can
explain why two brown-eyed parents can have a blue-eyed child -- who may
be expressing a grandparents' gene that was silent in the parent.
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- "Our study demonstrates how early environmental
factors can alter gene _expression_ without mutating the gene itself,"
said Waterland said.
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