By Teresa Johnson, MSPH, RD
Robert Waterland, PhD, an associate professor at Baylor College of Medicine, described nutritional influences on human developmental epigenetics. Waterland defined epigenetics as “mitotically heritable stable alterations in gene expression potential that are not caused by changes in DNA sequence.” Multiple factors likely contribute to epigenetic changes, including cytosine methylation, histone modification, auto-regulatory transcription factors, and non-coding RNAs, Waterland pointed out, and they tend to work in a synergistic fashion to influence gene transcription. Waterland said he is particularly interested in DNA methylation because methylation requires dietary donors and cofactors, which is influenced by nutritional factors. He presented data demonstrating that periconceptual maternal nutrition status predicts hypomethylation in a mother’s infant. These changes are stable and maintained over a lifetime, Waterland said, and may point to evidence of metabolic imprinting as an adaptive response to early nutrition.
“We live in a microbial world,” said Dingding An, PhD, a researcher at Boston Children’s Hospital. An elaborated on the role of early life gut microflora in immune system development, and explained that microbial exposure begins at birth and influences our risk for chronic diseases such as inflammatory bowel disease, asthma, arthritis, and autism later in life. Many early-life factors impact the makeup of the gut microbial population in particular, such as nutrition, hygiene, and antibiotic use. An presented data indicating that some gut microbes enhance immune cell maturation and immune response. But the timing of microbial exposure is critical, An added, because later exposure diminishes the response, indicating that key windows of regulation have been missed.
Deborah Sloboda, PhD, an associate professor at McMaster University, provided insights into the impacts of fructose consumption during pregnancy. Fructose is a monosaccharide present in honey, maple syrup, and fruit sugar, and is widely available in processed foods. Fructose consumption differs by sex and age, Sloboda said, with highest consumption reported among lower socioeconomic status females during their reproductive years. This is important, Sloboda said, because “the early-life environment plays a very big role in determining health and disease risk later in life.” Her data from animal models indicate that high fructose intake during pregnancy induces changes in the offspring’s metabolic response. Taurine supplementation reversed fructose-induced adverse metabolic programming, Sloboda said, but not in the presence of a high fat diet, emphasizing the importance of correctly identifying the population in need of intervention.
Growing up in the now well-studied Swedish village Överkalix strongly influenced the research of Lars Bygren, MD, PhD, a professor at University of Umea. Bygren, who addressed the topic of transgenerational outcomes associated with paternal nutrition, explained that human responses to early-life exposures, especially in males, have the potential to impact development for multiple generations. In particular, exposure to high food availability during slow-growth periods negatively affects the health of subsequent generations, and could explain the present day prevalence of many chronic diseases. Byrgen said data from other studies, including the Taiwan betel nut study and the ALSCAP study, lend support to these conclusions.