What We Already Belived...

[Guest guest]

Hi, new member, here. I had to post this piece from, The NY Times,

because it shows how science knows that what we believe

in " alternative medicine " is correct. Here's a quote from

the 3rd paragraph of the piece to illustrate my point, " Scientists

have long known that what pregnant mothers eat — whether they are

mice,fruit flies or humans — can profoundly affect the

susceptibility of their offspring to disease. "

If scientists have long known this why haven't doctors propagated it?

Wouldn't this be vital info for us to help future generations be

healthier with less expenditures on treatment drugs for so may

illnesses? If you talk about the nutritional basis of illness to

the " medical cartel " they " poo-poo " it. I know I'm preaching to the

choir here, but I had to vent.

 

 

October 7, 2003 NY Times

A Pregnant Mother's Diet May Turn the Genes Around

By SANDRA BLAKESLEE

 

With the help of some fat yellow mice, scientists have discovered

exactly how a mother's diet can permanently alter the functioning of

genes in her offspring without changing the genes themselves.

 

The unusual strain of mouse carries a kind of trigger near the gene

that determines not only the color of its coat but also its

predisposition to obesity, diabetes and cancer. When pregnant mice

were fed extra vitamins and supplements, the supplements interacted

with the trigger in the fetal mice and shut down the gene. As a

result, obese yellow mothers gave birth to standard brown baby mice

that grew up lean and healthy.

 

Scientists have long known that what pregnant mothers eat —

whether

they are mice, fruit flies or humans — can profoundly affect the

susceptibility of their offspring to disease. But until now they have

not understood why, said Dr. Randy Jirtle, a professor of radiation

oncology at Duke and senior investigator of the study, which was

reported in the Aug. 1 issue of Molecular and Cellular Biology.

 

The research is a milestone in the relatively new science of

epigenetics, the study of how environmental factors like diet, stress

and maternal nutrition can change gene function without altering the

DNA sequence in any way.

 

Such factors have been shown to play a role in cancer, stroke,

diabetes, schizophrenia, manic depression and other diseases as well

as in shaping behavioral traits in offspring.

 

Most geneticists are focusing on sequences of genes in trying to

understand which gene goes with which illness or behavior, said Dr.

Thomas Insel, director of the National Institute of Mental

Health. " But these epigenetic effects could turn out to be much more

important. The field is revolutionary, " he said, " and humbling. "

 

Epigenetics may indeed hold answers to many mysteries that classical

genetic approaches have been unable to solve, said Dr. Arturas

Petronis, an associate professor of psychiatry at the Center for

Addiction and Mental Health at the University of Toronto.

 

For example, why does one identical twin develop schizophrenia and

not the other? Why do certain disease genes seem to affect

or " penetrate " some people more than others? Why do complex diseases

like autism turn up in more boys than girls?

 

For answers, epigeneticists are looking at biological mechanisms

other than mutation that affect how genes function. One, called

methylation, acts like a gas pedal or brake. It can turn gene

expression up or down, on or off, depending on how much of it is

around and what part of the genetic machinery it affects.

 

During methylation, a quartet of atoms called a methyl group attaches

to a gene at a specific point and induces changes in the way the gene

is expressed.

 

The process often inactivates genes not needed by a cell. The genes

on one of the two X chromosomes in each female cell are silenced by

methylation.

 

Methyl groups and other small molecules may sometimes attach to

certain spots on chromosomes, helping to relax tightly coiled strands

of DNA so that genes can be expressed.

 

Sometimes the coils are made tighter so that active genes are

inactivated.

 

Methyl groups also inactivate remnants of past viral infections,

called transposons. Forty percent of the human genome is made up of

parasitic transposons.

 

Finally, methyl groups play a critical role in controlling genes

involved in prenatal and postnatal development, including some 80

genes inherited from only one parent. Because these so-called

imprinted genes must be methylated to function, they are vulnerable

to diet and other environmental factors.

 

When a sperm and egg meet to form an embryo, each has a different

pattern of methylated genes. The patterns are not passed on as genes

are, but in a chemical battle of the sexes some of the egg and sperm

patterns do seem to be inherited. In general, the egg seems to have

the upper hand.

 

" We're compounds, mosaics of epigenetic patterns and gene sequences, "

said Dr. Arthur Beaudet, chairman of the molecular and human genetics

department at Baylor College of Medicine in Houston. While DNA

sequences are commonly compared to a text of written letters, he

said, epigenetics is like the formatting in a word processing

program.

 

Though the primary letters do not vary, the font can be large or

small, Times Roman or Arial, italicized, bold, upper case, lower

case, underlined or shadowed. They can be any color of the rainbow.

 

Methylation is nature's way of allowing environmental factors to

tweak gene expression without making permanent mutations, Dr. Jirtle

said.

 

Fleeting exposure to anything that influences methylation patterns

during development can change the animal or person for a lifetime.

Methyl groups are entirely derived from the foods people eat. And the

effect may be good or bad. Maternal diet during pregnancy is

consequently very important, but in ways that are not yet fully

understood.

 

For his experiment, Dr. Jirtle chose a mouse that happens to have a

transposon right next to the gene that codes for coat color. The

transposon induces the gene to overproduce a protein that turns the

mice pure yellow or mottled yellow and brown. The protein also blocks

a feeding control center in the brain. Yellow mice therefore overeat

and tend to develop diabetes and cancer.

 

To see if extra methylation would affect the mice, the researchers

fed the animals a rich supply of methyl groups in supplements of

vitamin B12, folic acid, choline and betaine from sugar beets just

before they got pregnant and through the time of weaning their pups.

The methyl groups silenced the transposon, Dr. Jirtle said, which in

turn affected the adjacent coat color gene. The babies, born a normal

brownish color, had an inherited predisposition to obesity, diabetes

and cancer negated by maternal diet.

 

Unfortunately the scientists do not know which nutrient or

combination of nutrients silence the genes, but noted that it did not

take much. The animals were fed only three times as much of the

supplements as found in a normal diet.

 

" If you looked at the mouse as a black box, you could say that adding

these methyl-rich supplements to our diets might reduce our risk of

obesity and cancer, " Dr. Jirtle said. But, he added, there is strong

reason for caution.

 

The positions of transposons in the human genome are completely

different from the mouse pattern. Good maps of transposons in the

human genome need to be made, he said. For that reason, it may be

time to reassess the way the American diet is fortified with

supplements, said Dr. Rob Waterland, a research fellow in Dr.

Jirtle's lab and an expert on nutrition and epigenetics.

 

More than a decade ago, for example, epidemiological studies showed

that some women who ate diets low in folic acid ran a higher risk of

having babies with abnormalities in the spinal cord and brain, called

neural tube defects.

 

To reduce this risk, folic acid was added to grains eaten by all

Americans, and the incidence of neural tube defects fell

substantially. But while there is no evidence that extra folic acid

is harmful to the millions of people who eat fortified grains

regularly, Dr. Waterland said, there is also no evidence that it is

innocuous.

 

The worry is that excess folic acid may play a role in disorders like

obesity or autism, which are on the rise, he said. Researchers are

just beginning to study the question.

 

Epidemiological evidence shows that undernutrition and overnutrition

in critical stages of development can lead to health problems in

second and third generations, Dr. Waterland said.

 

A Dutch famine near the end of World War II led to an increased

incidence of schizophrenia in adults who had been food-deprived

during the first trimester of their mothers' pregnancy.

Malnourishment among pregnant women in the South during the Civil War

and the Depression has been proposed as an explanation for the high

incidence of stroke among subsequent generations.

 

And the modern American diet, so full of fats and sugars, could be

exerting epigenetic effects on future generations, positive or

negative. Abnormal methylation patterns are a hallmark of most

cancers, including colon, lung, prostate and breast cancer, said Dr.

Peter Laird, an associate professor of biochemistry and molecular

biology at the University of Southern California School of Medicine.

 

The anticancer properties attributed to many foods can be linked to

nutrients, he said, as well as to the distinct methylation patterns

of people who eat those foods. A number of drugs that inhibit

methylation are now being tested as cancer treatments. Psychiatrists

are also getting interested in the role of epigenetic factors in

diseases like schizophrenia, Dr. Petronis said.

 

Methylation that occurs after birth may also shape such behavioral

traits as fearfulness and confidence, said Dr. Michael Meaney, a

professor of medicine and the director of the program for the study

of behavior, genes and environment at McGill University in Montreal.

 

For reasons that are not well understood, methylation patterns are

absent from very specific regions of the rat genome before birth.

Twelve hours after rats are born, a new methylation pattern is

formed. The mother rat then starts licking her pups. The first week

is a critical period, Dr. Meaney said. Pups that are licked show

decreased methylation patterns in an area of the brain that helps

them handle stress. Faced with challenges later in life, they tend to

be more confident and less fearful.

 

" We think licking affects a methylation enzyme that is ready and

waiting for mother to start licking, " Dr. Meaney said. In perilous

times, mothers may be able to set the stress reactivity of their

offspring by licking less. When there are fewer dangers around, the

mothers may lick more.