How does early life diet affect a child's mental health and personality?

By Dr. Priyom Bose, Ph.D.Jan 10 2023Reviewed by Danielle Ellis, B.Sc.

In a child's life, the period from conception until two years old is crucial for growth and development. In addition to the development of vital organs and regulatory systems, this phase also determines a child's personality, mental health, and socio-emotional growth. Hence, optimal nourishment must be provided during pregnancy and the first years of a child's life.

Background

The key factors influencing the early phase of life are nutrition and nurture. Initially, nutrition is provided through formula or breastmilk and later via nutritious foods, which impacts a child's physiological development. Iron, iodine, and long-chain fatty acids are identified to be essential for normal brain development. Therefore, deficiency of these components in the aforementioned critical phase may lead to irreversible harm to cognitive and neural motor development. 

Feeding a child is considered to be an important interactive event that has been associated with a child's socio-emotional development. Typically, a child mimics the caregiver and family and acquires skills that are important for their entire life.

Similar to any non-communicable disease, a child may develop depression and anxiety at an early age. Often these mental health conditions are found in children as young as 5 to 9 years of age. It has been observed that early-life nutritional deficiencies make a child susceptible to mental health conditions. Maternal diet has also been linked with mental health conditions (e.g., Attention Deficit Hyperactivity Disorder- ADHD) and neurodevelopment of the offspring. 

Typically, personal traits are presented as five different traits that include conscientiousness, imagination, extraversion, neuroticism, and benevolence. These character traits are referred to as the big five personality traits. Few studies have analyzed the association between early childhood diet and later mental health status.

A recent Nutrients study investigated the relationship between maternal and child diet and a child's personality traits and mental health, i.e., depression and anxiety.

About the study

The authors of the current study have previously developed the New Nordic Diet (NND) score, which helps determine the level of adherence to a healthy and sustainable dietary pattern. The present study is based on the data obtained from the Medical Birth Registry of Norway (MBRN) and the Norwegian Mother, Father, and Child Cohort Study (MoBa).

MoBa is a prospective population-based pregnancy cohort study that recruited participants from 1999 to 2008. This cohort included around 114,500 children, 95,200 mothers, and 75,200 fathers. All participants who completed the baseline questionnaire, i.e., food frequency questionnaire (FFQ), around gestational week 17, were included in the study. Another inclusion criterion was that the mothers answered the given questionnaire when the child was eight.

Study findings

A total of 40,566 mother–child pairs were included in the present study who answered the questionnaires at different periods, i.e., when the child was six months, 18 months, three years, seven years, and eight years. Based on MoBa data, this study established a robust relationship between the early life diet and the big five personality traits.

Additionally, an association between early diet and mental health conditions, particularly anxiety and depression in later childhood, was investigated. It was observed that children exposed to a less healthy and sustainable diet in early life were susceptible to psychiatric symptoms in the later stage.

During pregnancy, the mother's adherence to the NND was associated with lower scoring on the depression scale when the child was eight years old. However, no significant association with anxiety was observed. A healthy and sustainable maternal diet was linked with higher trait scores on conscientiousness, extraversion, benevolence, and imagination and lower scores on neuroticism. 

The current study revealed that a child's early diet at six months, 18 months, three, and seven years was associated with the incidence of symptoms of anxiety and depression at eight years. However, compared to diet at earlier ages, the diet at ages three and seven years was found to play a more active role in the incidence of anxiety and depression in a child.

Strengths and limitations 

A key strength of the study is the analysis of a large, well-described, prospective population-based birth cohort, which presents the possibility of adjusting for potential confounders. In addition, the tool used to assess a child's mental health and personality trait is reliable and valid.

The current study also has some limitations, including self-reported data for analysis. In addition, all participating mothers were non-smokers, older, and regular users of multivitamins and folic acid supplements; therefore, it does not represent the general population. The authors pointed out that the questions related to the child's diet were less detailed than the maternal questionnaire.

Conclusions

The current study emphasized the importance of maternal pregnancy diet as well as early childhood diet on a child's mental health, i.e., the incidence of anxiety and depression and personality development. To date, no study has reported the association between early life diet and the five big personality traits.