Vegetarian diet in early childhood poses risk of underweight

Children with a vegetarian diet are more likely to be underweight compared with those who have nonvegetarian diets, although their growth or biochemical nutrition outcomes are similar, according to a study.

The study included 8,907 children aged 6 months to 8 years (mean age 2.2 years, 52.4 percent male) who participated in the longitudinal cohort study TARGet Kids. Researchers used linear mixed-effect modelling to examine the relationships between vegetarian diet and body mass index z-score (zBMI), height-for-age z-score, serum ferritin, 25-hydroxyvitamin D, and serum lipids. They also applied generalized estimating equation modelling to explore weight status categories.

Of the children, 248 were vegetarian at baseline (including 25 who were vegan) and 338 who ever reported vegetarian diet between 6 months and 8 years of age. Growth measures were available for 8,794 children who were included in the growth analysis, and venous blood was obtained from 4,673 children who were included in the biochemical analysis. All children were followed for an average of 2.8 years.

Compared with those who had nonvegetarian diet, children with vegetarian diet had longer breastfeeding duration (12.6 vs 10.0 months) and were more likely to be Asian (33.8 percent vs 19.0 percent).

Vegetarian diet showed no association with zBMI, height-for-age z-score, serum ferritin, 25-hydroxyvitamin D, or serum lipids. However, children with vegetarian diet had a greater likelihood of being underweight (zBMI <−2; odds ratio, 1.87, 95 percent confidence interval, 1.19–2.96; p=0.007).

When the possible effect modification by age and cow’s milk consumption was examined, cow’s milk intake was associated with increased levels of nonhigh-density lipoprotein cholesterol (p=0.03), total cholesterol (p=0.04), and low-density lipoprotein cholesterol (p=0.02) among children with vegetarian diet. This was despite the fact that children in the vegetarian and nonvegetarian diet groups who consumed the recommended 2 cups of cow’s milk per day had comparable serum lipid levels.

The findings highlight the need for careful dietary planning for underweight children when considering vegetarian diets.