BBC Radio 4, Tuesday 30 August 2011
The immediate impact of environmental factors like diet, smoking and stress on health are well understood. But less is known about how your lifestyle can directly affect the health of your unborn children and grandchildren.
Dr Porter's previous programme discussed how the first 1000 days of a child's life play a crucial role in determining that child's health as an adult. But what do we know about how the environment affects the health of future generations? In his latest programme, Dr Porter discusses the latest developments in epigenetics and the transgenerational impact of our actions today.
The debate about which traits are affected by gene and the environment has continued for many years, explained Anne Ferguson-Smith, Professor of Developmental Genetics at the University of Cambridge. The extent to which these two factors contribute and interact has, until recently, been less clear.
Professor Ferguson-Smith suggested the environment 'talks' to DNA and the nature of this relationship influences how our genetic make-up functions. This complicates the idea of nature versus nurture. Researchers now believe your genes influence your environment, the programme claimed. This, in turn, affects how you behave in your environment and how your environment influences your genes.
But how does this communication happen? Professor Ferguson-Smith explained this occurs via molecular flags, known as epigenetic markers, found along the DNA. These signal which genes are to be switched on/off - so-called gene expression.
Environmental changes, such as malnutrition, and their effects on gene expression were discussed by David Barker, Professor of Epidemiology at the University of Southampton. In the first programme, we heard about the 'Barker Theory', which suggests the risk of developing conditions like diabetes in adulthood is linked to nutrition in the womb. Low birth-weight babies are at higher risk.
'It is the nutrients which come from the mother which turn on the genes or not', Professor Barker said. He argued poor nutrition potentially hinders gene expression and leads to increased disease susceptibility. This vulnerability could be passed onto future generations and years of good nutrition would be needed to reverse the effect.
A more direct inheritable influence on your health is 'the egg that made you', Dr Porter claimed. This is the idea that your life began when your mother was growing in her mother's womb.
Unlike men, who constantly generate sperm after they reach puberty, girls are born with their lifetime supply of eggs. The egg that created you was formed inside your mother's fetus while she was inside your grandmother's womb. Environmental influences on your mother at this time could be passed onto you.
I was left with food for thought, as with the previous episode of Dr Porter's programme. Could the lifestyle of young women today be writing the map of Britain in 100 years' time? To what extent do transgenerational consequences affect our children and grandchildren?
When embarking on an improved diet or healthier lifestyle, many people primarily consider the personal benefits - reduced stress, weight loss or generally feeling fitter. Dr Porter ended his programme with the claim that these positive changes also improve the lives of peoples' future families.