Gener lagrar kosthållning
genom flera generationsled

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."

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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. ¹

Våra gener lagrar vår livsstil och för den vidare till våra efterkommande. Därför är det så viktigt för våra efterkommande generationer att vi lever friskt och sunt.

A mother's diet can change the behaviour of a specific gene for at least two subsequent generations, a new study demonstrates for the first time.

Feeding mice an enriched diet during pregnancy silenced a gene for light fur in their pups. And even though these pups ate a standard, un-enriched diet, the gene remained less active in their subsequent offspring.

The findings could help explain the curious results from recent studies of human populations – including one showing that the grandchildren of well-fed Swedes had a greater risk of diabetes.

The new mouse experiment lends support to the idea that we inherit not only our genes from our parents, but also a set of instructions that tell the genes when to become active. These instructions appear to be passed on through "epigenetic" changes to DNA – genes can be activated or silenced according to the chemical groups that are added onto them.

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"The results make it clear that a nutritional status can affect not only that individual, but that individual's children as well," says study member Kenneth Beckman. ²