Eating junk food can affect the health of descendants for many generations.
Photo / Thinkstock
Eating junk food can affect the health of descendants for many generations.
Photo / Thinkstock
Eating junk food can affect the health of descendants for many generations.
What we eat and do today can have long-term consequences for the health of our descendants for generations to come, research shows.
Scientists have found that the ways our bodies adjust to changing environments, such as eating lots of fatty foods, can persist for many generations even if our descendants eat healthier food.
That means that the way our bodies respond to fatty foods today may reflect not just our own diet and lifestyle, but also our bodies' "metabolic memory" of the foods and lifestyle of our ancestors.
"Then you can turn that around, and the things that we are doing or not doing today in our lifestyles can have effects in our children's generation and in future generations," said Professor Joe Nadeau, an American diabetes researcher who is visiting Auckland University's Liggins Institute.
Eating junk food can affect the health of descendants for many generations according to research by US scientist Joe Nadeau.
"So we have an added responsibility because our lifestyle choices are not only affecting us, for good or bad, but potentially have an effect across generations."
His research is based on what he calls "one of the hottest topics in science today" - the realisation that changes in genes, or the structure of DNA molecules that have been regarded as determining the way our bodies develop and operate, actually explain only a small part of the natural variation we see within many living species. For example, about half of the variation in human susceptibility to diabetes is due to environmental factors such as exposure to fatty foods, and the other half to inherited differences. But differences in our genetic structure explain only about 10 per cent of the half that is due to inheritance, leaving the other 90 per cent to be explained by other kinds of inheritance that are still little understood.
Dr Nadeau's team has experimented with two groups of mice where one group has a small genetic sequence that is known to resist getting fat when they eat fatty food - a so-called "lean gene" - and the other group doesn't.
He cross-bred mice from the two groups for one generation, then separated them again to "breed out" the lean gene in one group.
Surprisingly, even the mice in later generations who didn't inherit the lean gene didn't get fat when they ate fatty foods.
"They didn't inherit the lean gene but they inherited the lean response to fatty food, a remarkable and unexpected result," Dr Nadeau said.
Other studies have shown that such non-genetic imprinting can persist for more than 100 generations.
It might even explain why we sometimes have a "deja vu" feeling that we have experienced something before, even though we can't have experienced it in our lifetimes.
Could we be responding to a "memory" of something an ancestor experienced?
"It's possible, but there is no evidence, at least in humans," Dr Nadeau said.
Non-genetic inheritance
What is non-genetic inheritance? Characteristics that are passed down through generations without changing the DNA molecules in our body cells that form our genetic structure.
How does it work? We don't know yet. Scientists believe it may happen through chemical changes to elements in our DNA molecules, and/or through other cell molecules such as proteins through which our genes are expressed.
What are the implications? Unlike genetic changes, non-genetic inheritance is reversible - it's usually a short-term response to environmental changes. So if we can understand it better, then we may be able to improve human health by reversing any undesirable traits.
