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Research Spotlights: September 2021

Trends in Consumption of Ultraprocessed Foods Among US Youths Aged 2-19 Years, 1999-2018

The childhood obesity rate has been steadily rising among US youths during the past two decades. Ultraprocessed foods, which are foods that are manufactured with the addition of other ingredients (fats, starches, added sugars, hydrogenated fats), may be associated with this rise in childhood obesity. In a study funded by the NIMHD, investigators found that ultraprocessed food consumption has been rising in youth and now comprises two-thirds of calories in children and teen’s diet.

Investigators examined a serial cross-sectional analysis using information from a 24-hour dietary recall data from a nationally representative sample of US youths aged 2-19 years (n = 33 795) from the National Health and Nutrition Examination Survey (NHANES). To define ultraprocessed foods, they used the definition set forth by NOVA, a recognized food classification system that categorizes food according to the degree of food processing.

Researchers found that from 1999 to 2018, the estimated percentage of total energy from consumption of ultraprocessed foods increased from 61.4% to 67.0% (difference of 5.6%); symmetrically, the percentage of total energy from consumption of unprocessed or minimally processed foods decreased from 28.8% to 23.5% (difference of -5.3%). Among the subgroups of ultraprocessed foods, the estimated percentage of energy from consumption of Ready to Heat meals increased from 2.2% to 11.2% (difference of 8.9%) and from consumption of sweet snacks and sweets increased from 10.7% to 12.9% (difference of 2.3%). However, the estimated percentage of energy decreased for sugar-sweetened beverages from 10.8% to 5.3% (difference of -5.5%) and for processed fats and oils, condiments, and sauces from 7.1% to 4.0% (difference of -3.1%).

There was a significantly larger increase in the estimated percentage of energy from consumption of ultraprocessed foods among non-Hispanic Black youths (from 62.2% to 72.5%; difference of 10.3%) and Mexican American youths (from 55.8% to 63.5%; difference of 7.6%) compared to the increase among non-Hispanic White youths (from 63.4% to 68.6%; difference of 5.2%).

The researchers concluded, that based on these trends, the proportion of calories from consumption of ultraprocessed foods has increased among youths in the US, especially among non-Hispanic Black youth and Mexican American youth, and now comprises the majority of youths’ total calories.

Wang L, Martínez Steele E, Du M, et al. Trends in Consumption of Ultraprocessed Foods Among US Youths Aged 2-19 Years, 1999-2018. JAMA. 2021;326(6):519–530. doi:10.1001/jama.2021.10238

Social connections and maternal care in young wild hyenas modifies gene expression and stress resilience later in life

Laboratory animal research with rodents, primates, and humans have shown the impact of early life experiences on behavioral and physiological differences later in life through changes in DNA methylation. In a study partially funded by the NIEHS, researchers were the first to find an association in wild animals between early life social environments and subsequent impacts on molecular health markers and behavioral stress response later in life.

Wild hyenas offer an excellent model to measure the impact of maternal care and early life experiences on subsequent behavior, physiology, and molecular markers. Hyenas are devoted mothers, have a strict social hierarchy, and raise their cubs in a communal environment.

Researchers found that hyenas that were more socially connected during their adolescent years, but not necessarily early childhood years, had a lower baseline for stress hormone levels later in life as measured by fecal glucocorticoid metabolites. A lower baseline of stress hormone levels typically indicates a healthy stress response. As opposed to an acute increase in stress hormones, chronically high stress hormones can be detrimental one’s health.

To examine the mechanism by which early life social experiences may alter stress responses later in life, the investigators correlated an animal’s maternal care in early life with changes in DNA modifications later in life. Hyenas that received better maternal care in their first year of life and social connectedness during adolescent years had an increase in DNA methylation. Specifically, genes implicated in inflammation, immune response, and aging showed differential methylation, which may be the mechanism by which maternal care and stress phenotypes are linked.

Using wild animal populations, this study suggests that both maternal care during the first year of life and social connectedness during adolescent years influence DNA methylation and contribute to an animal’s stress response later in life.

Laubach ZM et al. 2021. Early-life social experience affects offspring DNA methylation and later life stress phenotype. Nature Communications 12:4398.

Examining unique substance-related risk profiles for neglectful behaviors among parents with and without clinical depression

Understanding interacting factors that occur with substance use disorder (SUD) and contribute to child neglect is essential to developing strategies to reduce child neglect. Intramural research funded by NIDA aimed to examine the relationship between neglect frequency, social support type, and parental clinical depression.

Child maltreatment in the form of child neglect contributes to 75.4% of child fatalities. Child neglect behaviors for parents include not providing basic medical needs, lack of medical or emotional care, and inadequate supervision which contributes to harmful outcomes in children. Parental SUD is a risk factor observed in cases of parental neglect.

Data from the National Survey of Child and Adolescent Well-Being, where children (ages 0-14 years of age) were identified as being at risk for child maltreatment as a result of experiencing a previous or ongoing child protective services (CPS) investigation but not necessarily receiving child welfare services (N= 3,545) from October 1999 to December 2000. Measures included past year neglect frequency, past year parental depression, past-year parental substance use, and past year social support type.

Both parental clinical depression and SUD was associated with high annual neglect frequency. Parents that showed presence of risky behaviors and met the SUD criteria also demonstrated higher neglect frequencies compared to parents with no past year substance use. Social supports were found to differ between parents that reported clinical depression compared to those without clinical depression. Specifically, presence of social companionship in parents that were clinically depressed increased neglect frequencies but decreased neglect frequencies in parents that were not clinically depressed.

Future directions should focus on risk behaviors of parental social networks and how the behaviors of their social networks may support or enable certain norms that can influence child experiences. Understanding parental profiles may be key to reducing neglect risk behaviors and can influence personalized services aimed to address parental behaviors.

Kepple, N.J. and Parker, A., 2021. Examining unique substance-related risk profiles for neglectful behaviors among parents with and without clinical depression. Children and Youth Services Review, 125, p.105987.