Plain language summary
Fortification of cow milk was initially intended to increase the available micronutrients to meet the needs of growing toddlers. These products are now used among the adolescent and adult populations for caloric regulation or protein enrichment. The aim of this randomised controlled trial was to examine the digestive and metabolic responses to commercially available fortified milks in 30 young adults. Participants were randomised to consume 500-900 mL of fortified milks with either whole milk cow-protein, whole milk goat-protein, or partially-hydrolysed whey cow-protein fortified milk. Plasma amino acid and hormonal responses were measured at baseline and at 5 hours after ingestion, and bowel transit time and digestive comfort were recorded. This study found whole-cow milk and whole-goat milk had similar protein and digestive responses, whereas partially hydrolysed whey led to delayed gastric emptying and increased insulin levels. Based on these results, the authors recommend further studies be done to address the impact of fortified milk consumption on appetite and protein metabolism.
Abstract
Fortified milk drinks are predominantly manufactured from bovine (cow) sources. Alternative formulations include those prepared with hydrolysed bovine milk proteins or from alternate bovidae species, such as caprine (goat) milk. Currently, there is little data on protein digestive and metabolic responses following ingestion of fortified milk drinks. To examine the digestive and metabolic responses to commercially-available fortified milks, young adults (n = 15 males: 15 females), in a randomised sequence, ingested isonitrogenous quantities of whole cow-protein (WC), whole goat-protein (WG), or partially-hydrolysed whey cow-protein (HC), commercial fortified milks. Plasma amino acid (AA) and hormonal responses were measured at baseline and again at 5 h after ingestion. Paracetamol recovery, breath hydrogen, and subjective digestive responses were also measured. Postprandial plasma AA was similar between WC and WG, while AA appearance was suppressed with HC. Following HC, there was a negative incremental AUC in plasma branched-chain AAs. Further, HC had delayed gastric emptying, increased transit time, and led to exaggerated insulin and GLP-1 responses, in comparison to whole protein formulas. Overall, WC and WG had similar protein and digestive responses with no differences in digestive comfort. Contrastingly, HC led to delayed gastric emptying, attenuated AA appearance, and a heightened circulating insulin response.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
