NEW YORK (GenomeWeb) – Results from a new gene-environment analysis suggest parents may be prone to give more food to children who are genetically predisposed to weigh less than usual, while kids who have genetic profiles coinciding with a higher body mass index (BMI) appear to get parental pressure to eat less.
"We found that parents whose children were genetically predisposed to have a lower weight were more pressuring of them to eat, and those parents whose children were genetically predisposed to have a higher weight were more restrictive over how much and what they were allowed to eat," first and co-corresponding author Saskia Selzam, a psychiatry, psychology, and neuroscience researcher at King's College London, said in a statement.
Selzam and her colleagues looked at a genome-wide polygenic risk score for body mass index (BMI) — gleaned from BMI-related variants identified through an independent genome-wide meta-analysis — in 10,346 identical or non-identical twins enrolled through the Twins Early Development Study, alongside child feeding questionnaires completed by parents when the children were around 10 years old, on average.
As the team reported online today in PLOS Genetics, the polygenic score for twins genotyped with Affymetrix or Illumina SNP arrays corresponded with BMI standard deviation scores in the twin participants, at times differing from their non-identical siblings despite a shared environment and family circumstances.
Similarly, food restrictions reported by parents seemed to rise alongside genetic propensity for weight gain, while parents were more apt to push food on children with low weight-associated genome-wide polygenic risk scores.
Based on their quantitative analyses of the children's genotype and parental feeding patterns, the researchers estimated that genotype accounts for more than half of feeding pressure by parents, whereas roughly 43 percent of food restriction by parents could be explained by the child's genetics.
The results dispute the notion that food restriction by parents alone eventually prompts weight gains in children. Rather, the findings hint that "parents develop their feeding practices in response to their child's natural tendency towards a higher or lower weight," Selzam said. "The way a parent feeds their child may also influence their child's weight to some extent, but our results challenge the prevailing view that parental behavior is the major influence on childhood weight."
Even so, the researchers cautioned that parents' own genetic susceptibility to higher- or lower-than-usual weight — which would be reflected, in part, in BMI-related genetic patterns present in their children — could also contribute to the restrictive feeding or food-pushing patterns documented in parental questionnaires.
In a statement, senior and co-corresponding author Clare Llewellyn, a behavioral science and health researcher at the University College London, noted that "[l]arge-scale randomized controlled trials which follow children from early life to later childhood are needed to test if a parent's feeding practices can influence their child's eating behavior and weight."