Our traumas can be passed down through multiple generations

The hypothesis that an individual’s experience might alter the cells and behavior of their children and grandchildren has become widely accepted. In animals, exposure to stress, cold, or high-fat diets has been shown to trigger metabolic changes in later generations. And small studies in humans exposed to traumatic conditions – among them the children of Holocaust survivors – suggest subtle biological and health changes in their children.

The implications are profound. If our experiences can have consequences that reverberate to our children or our children’s children, that’s a powerful argument against everything from smoking to immigration policies that split families. “This is really scary stuff. If what your grandmother and grandfather were exposed to is going to change your disease risk, the things we’re doing today that we thought were erased are affecting our great-great-grandchildren,” says Michael Skinner, a biologist at Washington State University in Pullman.

Skinner’s own research in animals suggests changes to the epigenome, a swirl of biological factors that affect how genes are expressed, can be passed down through multiple generations. If trauma can trigger such epigenetic changes in people, the alterations could serve as biomarkers to identify individuals at greater risk for mental illness or other health problems – and as targets for interventions that might reverse that legacy.

Epidemiological studies of people have revealed similar patterns. One of the best-known cases is the Dutch hunger winter, a famine that gripped the Netherlands in the closing months of World War II. The children of women pregnant during the food shortages died earlier than peers born just before, and had higher rates of obesity, diabetes, and schizophrenia. Studies of other groups suggested the children of parents who had starved early in life – even in the womb – had more heart disease. And a look last year at historical records showed the sons of Civil War soldiers who had spent time as prisoners of war were more likely to die early than the sons of their fellow veterans.

Source: Science Mag