Whew. And here you were worried too many pizzas would influence the risk of obesity.
The downside to epigenetics studies is that they run the risk of turning legitimate aspects of biology into the DNA equivalent of evolutionary psychology by making bizarre correlation-causation claims.
The researchers measured epigenetic changes in 300 children (samples first taken after birth, using umbilical cord tissue DNA) and ages six and nine and found correlation which they say predicted the degree of obesity - the children varied in how fat they are but their measurement of the epigenetic change at birth allowed the researchers to predict 25 percent of this variation, basically by mapping data to the topology they had and achieving results which would be the the placebo effect in a medical study but let's move on and come back to that part.
What it means, if this is true, is that your body type is not determined by lifestyle and genetics, it is also impacted by your mother's nutrition in the womb. If you are obese, you don't have to blame Ben&Jerry's, you can blame your mom. Of course, every study ever done on obesity has shown that people who consume fewer calories lose weight, but the culture war ramifications are substantial. For example, a number of people want law sin tax laws placed on some food businesses because they 'cause' obesity. Well, those businesses are off the hook if it's epigenetics, they are not causing obesity any more than the spoon industry is. And other people think that the future health care burden will be onerous due to fat people, who have a much higher risk of various diseases, so they should pay more for health care, or be told what to eat, but the counter-argument would now be 'I was born this way, just like gay people. Are you taxing gay people and making them pay more for health insurance?' and they would be legally correct in their protest.
Obviously some motherly behavior while pregnant can cause problems for the child - we've all seen what crack babies look like - but the idea that some calories modify a child's DNA, even after being processed, and some do not (look for claims from the high-fructose corn syrup folks, since sugar may be toxic to babies in the womb) and then, worse, the researchers speculate it is a socio-economic issue also beyond the mother's control, well, no one will ever have to control themselves again.
An epigenetic study which says a mother who eats at Burger King can alter the function of the child's DNA without changing the actual inherited DNA sequence and changes the future ability to respond to lifestyle factors such like diet or exercise, has to be treated with some skepticism. If it means more government money spent foolishly on awareness programs or, worse, the medical community being forced to factor in parental diet into diagnoses, that's a true negative.
And that is what it means - more people telling other people what to eat. In the press release for the study, Mark Hanson, research team member and Director of the University of Southampton's Human Development and Health Unit is quoted as saying, "This study provides compelling evidence that epigenetic changes, at least in part, explain the link between a poor start to life and later disease risk. It strengthens the case for all women of reproductive age having greater access to nutritional, education and lifestyle support to improve the health of the next generation, and to reduce the risk of the conditions such as diabetes and heart disease which often follow obesity."
Back to the statistics. With a 95% confidence interval (physicists makes goat noises at 99.7% so you can imagine what hard science thinks about 95%) the study can't be cause for alarm. It certainly makes sense to encourage all people, not just pregnant women, to have a healthy diet.
Citation: Keith M. Godfrey, Allan Sheppard, Peter D. Gluckman, Karen A. Lillycrop, Graham C. Burdge, Cameron McLean, Joanne Rodford, Joanne L. Slater-Jefferies, Emma Garratt, Sarah R. Crozier, B. Starling Emerald, Catharine R. Gale, Hazel M. Inskip, Cyrus Cooper, and Mark A. Hanson, 'Epigenetic Gene Promoter Methylation at Birth Is Associated With Child’s Later Adiposity', Diabetes April 6, 2011 doi: 10.2337/db10-0979
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