Postprandial blood amino acid concentrations in older adults after consumption of dairy products : The role of the dairy matrix

This study investigated postprandial aminoacidemia after consumption of different dairy products using a single-blinded cross-over design wherein 10 participants (66.7 ± 4.3 y) received low-fat UHT-treated milk (LF–UHT), low-fat pasteurised milk (LF–PAS), full-fat UHT-treated milk (FF–UHT), full-fat pasteurised milk (FF–PAS), low-fat yoghurt, full-fat cheese, whey protein concentrate (WPC), and micellar casein isolate (MCI). Blood samples were collected postabsorptive and (up to 5 h) postprandial and maximal amino acid concentration (Cmax), timepoint corresponding to Cmax (Tmax) and incremental area under the curve (iAUC) were determined. The highest increase in blood essential amino acid (EAA) levels occurred after WPC and yoghurt consumption, whereas MCI and cheese consumption resulted in extended EAA response curves. Fat delayed the postprandial EAA blood response (FF–UHT versus LF–UHT and FF–PAS versus LF–UHT), whereas no effect of heating milk was found (P > 0.05). The findings highlight that the product matrix could be as important as protein composition in postprandial aminoacidemia.</p

A Double‐Blind, Randomized Intervention Study on the Effect of a Whey Protein Concentrate on E. coli‐Induced Diarrhea in a Human Infection Model

Infectious diseases are a major cause of morbidity and mortality worldwide. Nutritional interventions may enhance resistance to infectious diseases or help to reduce clinical symptoms. Here, we investigated whether a whey protein concentrate (WPC) could decrease diarrheagenic Escherichia coli‐induced changes in reported stool frequency and gastrointestinal complaints in a double‐blind, parallel 4‐week intervention study. Subjects were randomly assigned to a whey hydrolysate placebo group, a low‐dose WPC group or a high‐dose WPC group. After 2 weeks of consumption, subjects (n = 121) were orally infected with a high dose of live but attenuated diarrheagenic E. coli (strain E1392/75‐2A; 1E10 colony‐forming units). Subjects recorded information on stool consistency and the frequency and severity of symptoms in an online diary. The primary outcome parameters were a change in stool frequency (stools per day) and a change in Gastrointestinal Symptom Rating Scale (GSRS) diarrhea score between the first and second days after infection. Neither dose of the whey protein concentrate in the dietary treatment affected the E. coli‐induced increase in stool frequency or GSRS diarrhea score compared to placebo treatment. The composition of the microbiota shifted between the start of the study and after two weeks of consumption of the products, but no differences between the intervention groups were observed, possibly due to dietary guidelines that subjects had to adhere to during the study. In conclusion, consumption of the whey protein concentrate by healthy adults did not reduce diarrhea scores in an E. coli infection model compared to a whey hydrolysate placebo control