The study aimed to explore the impact of whole egg supplementation on circulating insulin-like growth factor 1 (IGF-1) levels, the production of short-chain fatty acids (SCFAs), and the interconnected relationships between SCFAs and the gut microbiota in children.
A total of 635 participants, aged 8 to 14, were recruited from six rural primary schools in Thailand. To ensure homogeneity, they were randomly assigned to three groups based on weight-for-age criteria.
These groups were the whole egg (WE), requiring participants to consume 10 additional whole chicken eggs per week. The protein substitute (PS) where participants consumed a yolk-free egg substitute equivalent to 10 eggs per week, and a control group.
Participants were instructed to maintain their regular egg consumption and dietary cholesterol intake for a four-week washout period. Subsequently, the WE group (238 participants) received ready-to-eat commercial menus comprising items like hard-boiled whole eggs, scrambled eggs, and stewed eggs.
The PS group (200 participants) was provided with ready-to-eat commercial options such as egg white or chicken sausages. On average, during school day, WE participants received 800 to 850 kcal, 2100 to 2260 milligrams of dietary cholesterol, and 70 to 80 grams of protein while PS participants were given 810 to 850 kcal, 50 to 220 milligrams of dietary cholesterol, and 70 to 80 grams of protein.
The control group (197 participants) received standard school lunches aligned with the Thai school lunch programme and no additional meals or supplements were provided on weekends. The study spanned 35 weeks, with participants undergoing follow-up assessments on week zero, week 14, and week 35.
At week 35, researchers identified a significant increase in IGF-1 levels in the WE group. , This suggests whole egg supplementation led to a significant enhancement in growth hormone levels, which support both bone formulation and skeletal growth.
In comparison to the baseline (week zero), the WE group exhibited a substantial elevation in IGF-1 levels by 79.4 ± 13.4 ng/mL.
The PS group and control group showed increases of 57.4 ± 12.1 ng/mL and 41.7 ± 9.8 ng/mL respectively.
In addition, researchers also identified a positive correlation between circulating IGF-1 and all SCFAs, except for acetate.
Nevertheless, it remains unclear whether these correlations extend to microbiota metabolites, and the underlying mechanisms of this association remains unexplored. But the overall content of SCFAs, including acetate, propionate, and butyrate, remained relatively stable with whole egg supplementation.
The reserachers also notred that the WE group exhibited notable changes in the relative abundance of the Bifidobacterium and Prevotella genera.
But they also observed that the increase in the quantity of beneficial bacteria had no impact on SCFA levels. This highlights the complex nature of microbial metabolite production in the gut, which may be influenced by various factors that require further study.
Benefits of whole egg supplementation
Researchers believe the present study could be improved by controlling and monitoring additional egg consumption by participants in both PS and control groups on weekends and school breaks.
Additionally, efforts could be made to reduce the time taken to transport samples from rural schools to laboratories. While extending the intervention period beyond 35 weeks to a year could offer more comprehensive insights.
Despite these suggestions, researchers recognised the study’s valuable contribution to understanding the intricate relationship between dietary interventions, gut microbiota, SCFAs, and growth factors.
“The positive impact of whole egg supplementation on IGF-1 levels suggests a potential avenue for promoting bone health and growth in children.” Researchers wrote.
“The associations between SCFAs and specific gut microbiota genera highlight the intricate connections between diet, microbiota, and host health. As research in this field advances, it promises to provide valuable insights into optimising health through dietary interventions that harness the power of the gut microbiota and its metabolites.”
Influence of Prolonged Whole Egg Supplementation on Insulin-like Growth Factor 1 and Short-Chain Fatty Acids Product: Implications for Human Health and Gut Microbiota
Authors: Sophida Suta et al.