Moving beyond the overly simplistic unhealthy lifestyle paradigm, researchers are slowly uncovering the genetic and epigenetic mechanisms behind obesity.
Recent research by Ludmer Centre researcher Dr Patricia P Silveira at McGill and the Douglas Institute and her colleagues has shown that altered dopamine signaling may increase a preference for more palatable high-sugar foods leading to a risk for obesity among children born at low birth weights. Specifically, intrauterine growth restriction (IUGR), where a fetus fails to grow at a normal rate inside the womb, leads to altered behavioral responses to variations in dopamine signaling capacity, increasing a child’s preference for palatable foods (those higher in sugar).
The researchers developed a ‘multilocus genetic score’ to determine if and how dopamine signaling associates with spontaneous palatable food intake in children based on their fetal growth status. They found that variations in the genetic score, reflecting dopamine signaling associated with differences in sugar intake, occurred only in IUGR children. This suggests that dopamine function is involved in this behavioral feature, especially in IUGR children. It further suggests that this behavioral profile is linked to both the function of the genes associated with dopamine signaling capacity and the environmental adversities that led to IUGR and the low birth weight. Thus, fetal growth interacted with the multilocus genetic score, reflecting dopamine signaling capacity, to predict spontaneous sugar intake in children.This study builds on a previous study in IUGR rodents that also found altered striatal dopamine signaling associates with a preference for palatable foods.
These findings could have important implications for obesity prevention – as well as relate metabolic disturbances and consequences on cognition and mental health – in IUGR individuals.
Why this research is important
IUGR affects between 3% and 7% of the population1 and can lead to health issues such as obesity, diabetes, hypertension, and neurodevelopment problems. Over six million Canadians, 1 in 4 adults and 1 in 10 children, have clinical obesity, 2 a leading cause of type 2 diabetes, high blood pressure, heart disease, stroke, arthritis and cancer.3 These types of studies are helping us to understand the mechanisms underlying the rise in obesity and the link to poor physical and mental-health outcomes.
The research also adds to our understanding of the neurotransmitter dopamine, the dysfunction of which is associated with a number of neurological and mental disorders including central nervous system diseases such as Parkinson’s and mental illnesses such as schizophrenia.
Read the article: PP Silveira, I Pokhvisneva, H Gaudreau, L Atkinson, AS Fleming, MB Sokolowski, M Steiner, JL Kennedy, L Dubé, RD Levitan, MJ Meaney, MAVAN team. Fetal growth interacts with multilocus genetic score reflecting dopamine signaling capacity to predict spontaneous sugar intake in children. Appetite, Volume 120, 1 January 2018, Pages 596-601
Listen to a PowerPoint presentation of the research by Dr PP Silveira
Research powered by a collaboration of Ryerson University, McMaster University, University of Toronto, the Centre for Addiction and Mental Health, Douglas Mental Health University Institute, and McGill University
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