GMW: Your diet affects descendants' health

[Guest guest]

GMW: Your diet affects descendants' health

" GM WATCH " <info

Sat, 5 Nov 2005 15:03:01 GMT

 

 

 

GM WATCH daily

http://www.gmwatch.org

---

1.The Ghost in Your Genes

2.Grandad's diet affects descendants' health

 

The impact of the food experienced by a child could be passed on to

subsequent generations.

 

" ...the lives of your grandparents - the air they breathed, the food

they ate, even the things they saw – can directly affect you, decades

later, despite your never experiencing these things yourself. And... what

you do in your lifetime could in turn affect your grandchildren. "

 

" We are all guardians of our genome. " (item 1)

 

COMMENT - Claire Robinson, Weekly Watch editor

 

I hope some of our UK readers caught Thursday's BBC Horizon programme

about epigenetics. It showed a bunch of geneticists catching up with

what's been obvious to most of us all along: that environmental factors

(the programme mentioned severe emotional stress and smoking, though

mostly steered clear of the 'hot potato' of manmade environmental

pollutants) cause heritable effects in humans.

 

" The conventional view is that DNA carries all our heritable

information and that nothing an individual does in their lifetime will be

biologically passed to their children " . But epigenetics goes beyond DNA,

proposing that environmental factors can switch genes on or off and

that the

effects are passed down through generations.

 

Apparently, the news that what we take into our bodies affects our

progeny seems so " radical " to these geneticists that at least one of them

cannot sleep at night for thinking about the consequences. Could this be

the day Western science finally grows up?

---

1.The Ghost in Your Genes

http://www.bbc.co.uk/sn/tvradio/programmes/horizon/ghostgenes.shtml

 

Biology stands on the brink of a shift in the understanding of

inheritance. The discovery of epigenetics – hidden influences upon the

genes –

could affect every aspect of our lives.

 

At the heart of this new field is a simple but contentious idea – that

genes have a 'memory'. That the lives of your grandparents – the air

they breathed, the food they ate, even the things they saw – can directly

affect you, decades later, despite your never experiencing these things

yourself. And that what you do in your lifetime could in turn affect

your grandchildren.

 

The conventional view is that DNA carries all our heritable information

and that nothing an individual does in their lifetime will be

biologically passed to their children. To many scientists, epigenetics

amounts

to a heresy, calling into question the accepted view of the DNA sequence

– a cornerstone on which modern biology sits.

 

Epigenetics adds a whole new layer to genes beyond the DNA. It proposes

a control system of 'switches' that turn genes on or off – and suggests

that things people experience, like nutrition and stress, can control

these switches and cause heritable effects in humans.

 

In a remote town in northern Sweden there is evidence for this radical

idea. Lying in Overkalix's parish registries of births and deaths and

its detailed harvest records is a secret that confounds traditional

scientific thinking. Marcus Pembrey, a Professor of Clinical Genetics at

the Institute of Child Health in London, in collaboration with Swedish

researcher Lars Olov Bygren, has found evidence in these records of an

environmental effect being passed down the generations. They have shown

that a famine at critical times in the lives of the grandparents can

affect the life expectancy of the grandchildren. This is the first

evidence that an environmental effect can be inherited in humans.

 

In other independent groups around the world, the first hints that

there is more to inheritance than just the genes are coming to light. The

mechanism by which this extraordinary discovery can be explained is

starting to be revealed.

 

Professor Wolf Reik, at the Babraham Institute in Cambridge, has spent

years studying this hidden ghost world. He has found that merely

manipulating mice embryos is enough to set off 'switches' that turn

genes on

or off.

 

For mothers like Stephanie Mullins, who had her first child by in vitro

fertilisation, this has profound implications. It means it is possible

that the IVF procedure caused her son Ciaran to be born with

Beckwith-Wiedemann Syndrome – a rare disorder linked to abnormal gene

expression.

It has been shown that babies conceived by IVF have a three- to

four-fold increased chance of developing this condition.

 

And Reik's work has gone further, showing that these switches

themselves can be inherited. This means that a 'memory' of an event

could be

passed through generations. A simple environmental effect could switch

genes on or off – and this change could be inherited.

 

His research has demonstrated that genes and the environment are not

mutually exclusive but are inextricably intertwined, one affecting the

other.

 

The idea that inheritance is not just about which genes you inherit but

whether these are switched on or off is a whole new frontier in

biology. It raises questions with huge implications, and means the

search will

be on to find what sort of environmental effects can affect these

switches.

 

After the tragic events of September 11th 2001, Rachel Yehuda, a

psychologist at the Mount Sinai School of Medicine in New York,

studied the

effects of stress on a group of women who were inside or near the World

Trade Center and were pregnant at the time. Produced in conjunction

with Jonathan Seckl, an Edinburgh doctor, her results suggest that stress

effects can pass down generations. Meanwhile research at Washington

State University points to toxic effects – like exposure to fungicides or

pesticides – causing biological changes in rats that persist for at

least four generations.

 

This work is at the forefront of a paradigm shift in scientific

thinking. It will change the way the causes of disease are viewed, as

well as

the importance of lifestyles and family relationships. What people do

no longer just affects themselves, but can determine the health of their

children and grandchildren in decades to come. " We are, " as Marcus

Pembrey says, " all guardians of our genome. "

---

2.Grandad's diet affects descendants' health

New Scientist, 31 October 2002

http://www.newscientist.com/article.ns?id=dn2994

 

The amount of food a boy eats in the years before puberty influences

his grandchildren's risk of diabetes, a small Swedish study suggests.

 

Researchers looked at 303 people, born either in 1890, 1905 or 1920,

and the harvest data for the region where they lived. They found that

males in areas with a surfeit of food were four times more likely to have

grandchildren who died of diabetes mellitus than those who suffered

famine in childhood.

 

" Overeating in the 'slow-growth' period before puberty affects the

likelihood of the second generation having diabetes, " says lead

researcher

Gunnar Kaati at Umea University, Sweden. " But we don't know exactly

why. "

 

The researchers acknowledge that more research is needed to replicate

and explain their results. " But very little attention has been paid to

this kind of inheritance, and it is an important subject to look at, "

Kaati told New Scientist.

 

Similar effects have been shown in sons and daughters before, but if

confirmed, the study would be the first evidence of the effect in

grandchildren says geneticist Laurence Hurst at Bath University, UK.

 

Genetic imprint

 

Environmental factors can affect genes by altering the methylation of

DNA bases. This changes the expression of the genes concerned. The

impact of the nutritional conditions experienced by a child could be

passed

on to subsequent generations in this way.

 

In the study, only the paternal grandfather appeared to influence the

health of their descendants, although male and female grandchildren were

affected equally.

 

This suggests imprinted genes - whose expression is determined by which

parent they were inherited from - may be involved, says Marcus Pembrey

at the Institute of Child Health, London, UK. " For example, insulin

growth factor 2, which is involved in diabetes, is silenced when

transmitted by the mother and active when transmitted by the father, "

he told

New Scientist

 

Journal reference: European Journal of Human Genetics (DOI:

10.1038/sj.ejhg.5200859)

 

 

 

 

 

----------------------