The DQI was developed under the ongoing GUSTO (Growing Up in Singapore Towards Healthy Outcomes) study, which is part of a Translational and Clinical Research (TCR) flagship programme called Developmental Origins: Singapore (DevOS).
Based on the premise that diet in early childhood can have lifelong effects on health outcomes and the lack of diet quality assessment indices for toddlers, especially in Asia, the researchers sought to develop and evaluate a DQI in a multi-ethnic Asian cohort of women and their offspring in order to identify perinatal correlates of early childhood diet.
The researchers recruited pregnant women between the ages of 18 and 50, who were of Chinese, Malay or Indian descent and had parents of homogenous ethnic background.
After it was determined they would deliver at the National University Hospital (NUH) or KK Women's and Children's Hospital (KKH), and to reside in Singapore for the next five years, they agreed to donate cord, cord blood and placenta for the study.
Designed according to Singapore dietary guidelines, the DQI covers seven food components: rice, bread and alternatives, fruits, vegetables, meat and alternatives, milk and dairy products, whole grains, and high-sugar foods.
The researchers then used parental reports of data from food frequency questionnaires (FFQ) for 561 of the children at the age of 1.5 years to develop the DQI.
They subsequently observed that a higher DQI (indicative of better diet quality) was linked to higher consumption of certain nutrients and food groups, such as vegetables, beta-carotene, vitamin A and dietary fibre, as well as sodium and cholesterol.
The researchers wrote: "A possible explanation for this is that many healthy food items are rich sources of naturally occurring sodium, such as cereal products, milk products and meat.
"Furthermore, estimation of sodium intake using questionnaire is challenging, and its associated measurement errors might have affected our observations.
"Dietary cholesterol is also present in healthy foods from animal sources — such as egg yolk and meat — that are valuable sources of proteins, nutrients and vitamins."
Higher DQI was also associated with lower energy intake from carbohydrates, which is consistent with dietary guidelines to limit carbohydrate consumption in toddlers’ diets.
On the other hand, independent predictors of lower DQI included higher maternal pre-pregnancy BMI, "Malay ethnicity, lower household income, lower education level", a shorter breastfeeding duration, and the complete absence of breastfeeding.
Conversely, according to previous research mothers with lower pre-pregnancy BMI or who breastfeed for a longer period also tend to have healthier dietary habits, suggesting that their dietary choices may influence those they make for their offspring.
The researchers also found that under 30% of the toddlers consumed the recommended servings of fruits and vegetables. Even among those in the high tertile, the incidence of fruit intake was just 52.4 % of the recommended amount, while that of vegetables was a mere 24.1%.
However, they noted that there might be biological reasons behind these associations: "Dietary flavours (e.g., those from garlic, anise, carrots) can be transferred from the mothers’ diet to their child through breast milk. Exposure to breast milk containing these dietary flavours has been shown to increase toddlers’ acceptance and enjoyment of these flavours.
"Therefore, in the case of mothers with shorter breastfeeding duration, lower toddlers' acceptance and enjoyment of healthier foods could be one reason for a lower DQI.
"Maternal pre-pregnancy BMI has also been shown to cause epigenetic modifications in offspring, which may in turn alter their appetite regulation and risks of developing eating disorders."
They added that there should be further investigation into whether shorter breastfeeding duration and higher maternal pre-natal BMI were causes or markers of lower diet quality among toddlers.
In conclusion, they wrote: "We successfully developed a DQI as an instrument to measure the diet quality of Asian toddlers. The DQI showed adequate construct validity in our study population.
"In addition, we identified at-risk groups of poor toddler diet quality, which may be useful in guiding future interventions by public health organisations.
"The DQI may also be adapted and applied to measure the diet quality of young children in other populations, and to further elucidate the relationship between early childhood diet and later health outcomes."
“The Development and Evaluation of a Diet Quality Index for Asian Toddlers and Its Perinatal Correlates: The GUSTO Cohort Study”
Authors: Ling-Wei Chen, et al.