Grandpa's diet hits
descendants
Effects of nutrition could be
carried down generations.
1 November 2002
HELEN PEARSON
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| Hungry parents seem to leave
healthier offspring. |
| © GettyImages |
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Grandfathers who overeat might ruin their grandchildren's
health, say Swedish researchers. The study suggests that diet,
which does not change genes, can nevertheless influence future
generations.
Gunnar Kaati and his team at the University of Umeε collected
health histories of 300 Swedes born between 1890 and 1920. Crop
records showed how much they were eating just before puberty.
Grandchildren of well-fed grandfathers were four times as
likely to die from diabetes, they found. Kids of men who
suffered famine were less likely to die from heart disease1.
"It's a big leap" to say that such effects are passed on to
future generations, says Eugene Albrecht, who studies fetal
growth at the University of Maryland in Baltimore. "But I have a
gut feeling [Kaati's] right."
Blast from the past
The idea that diet could have heritable effects smacks of
lamarckism, a long-rubbished evolutionary theory dating from the
nineteenth century. Jean-Baptiste Lamarck suggested that, for
example, an animal that sprouts thick hair to survive winter
would have hairier offspring. This is thought impossible,
because only genetic changes are inherited.
Nevertheless, "we have to take this seriously", argues
geneticist Marcus Pembrey of the Institute of Child Health,
London, UK. A father's nutrition could change the activity of
genes in sperm, rather than the genetic code itself, he
suggests.
Chemical stamps on DNA switch genes on and off. Some of these
switches are thrown when sperm begin forming in puberty. Bodies
might sense the food supply, says Pembrey, and set up sperm
genes to give children the best chance of survival.
If, for example, the grandfather's generation has ample food,
sperm would carry a particular set of switches into the
offspring. Next generation, food might be sparse, and a father's
sperm would re-program their genes to deal with an erratic food
supply.
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We have to take this seriously
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Marcus Pembrey
Institute of Child Health, London
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When the father reproduces, such a stamp might decrease the
total number of children, but boost each baby's growth, so that
each would be more likely to survive lean times. This process
could influence subsequent disease rates, speculates Pembrey.
Non-genetic factors might affect a child's health in other
ways. A mother's stress and diet during pregnancy are thought to
shape her baby's risk of developing conditions such as high
blood pressure. This is also thought to occur by altering gene
activity.
Another possibility is that malnutrition killed off certain
children and only those with particular genes - that later
predisposed them to diabetes - survived. But Kaati found no
evidence that more babies died during food shortages. |
