In a recent study published in Signal Transduction and Targeted Therapy, researchers investigated how dietary protein affects the gut microbiome and the timing of puberty in children. This study, part of the Chinese Adolescent Cohort (CAC) study, included 1,826 children aged six to eight and examined the effects of animal and vegetable protein intake on their gut bacteria and puberty onset.
Impact of Different Proteins on Gut Microbiota
Children in the highest tertile of dietary protein intake consumed 59.4 grams per day of animal protein, exceeding the recommended daily allowance. Those consuming higher levels of vegetable protein had a greater abundance of beneficial gut bacteria, such as Butyricicoccus, Enterococcus, Dorea, and Romboutsia. These bacteria produce short-chain fatty acids (SCFAs) like butyrate, which have multiple health benefits, including anti-inflammatory and cardioprotective effects. Conversely, higher animal protein intake was linked to increased levels of unidentified_Saccharimonad bacteria.
Protein Intake, Microbiome, and Puberty
Researchers calculated three indices from gut microbiome characteristics: Total Protein-Microbial Index (TPMI), Animal Protein-Microbial Index (APMI), and Vegetable Protein-Microbial Index (VPMI). They found that the highest APMI tertile was associated with earlier puberty markers, such as menarche in girls and voice breaking in boys. Conversely, the highest VPMI tertile was linked to later puberty onset. Notably, 15% of the association between animal protein intake and puberty timing was explained by the APMI, while 40% of the effect of vegetable protein intake on puberty timing was attributed to the VPMI.
Protein Intake, Metabolites, and Puberty Timing
The study highlighted that digestive enzymes break down more animal protein, leaving less for gut bacteria to digest, whereas vegetable protein digestion is primarily microbiome-dependent. Children consuming more vegetable protein had distinct metabolic profiles, with higher levels of certain metabolites like citric acid and alpha-ketoglutaric acid, which are involved in hormone secretion pathways. These metabolites were positively associated with puberty timing. Butyric acid, which helps regulate blood sugar, was less abundant with higher animal protein intake, suggesting a role in pubertal changes.
Soy Protein and Puberty
In China, soy protein is a major vegetable protein source. The study found that higher soy intake was associated with later puberty timing, supporting dietary recommendations to include more soy. However, the exact mechanism by which soy protein affects puberty timing remains unknown.
Conclusions
The study’s strengths include a large sample size and a long follow-up period. Findings indicate that excessive animal protein intake, beyond dietary recommendations, is linked to early puberty. Therefore, dietary guidelines for children should emphasize vegetable protein intake and caution against excessive animal protein consumption to promote healthier pubertal development.
This research underscores the importance of a balanced diet during childhood and its potential long-term effects on health and development.