Detection of milk-derived peptides in human blood post-digestion, using LC-MS/MS

2024  Journal Article

Detection of milk-derived peptides in human blood post-digestion, using LC-MS/MS

Pub TLDR

The study investigates the absorption of milk peptides into the blood after WPI consumption. While a spiking study confirmed the ability to detect milk peptides in blood, only one out of 18 subjects showed detectable milk peptides in their blood after WPI consumption. This suggests that absorption of WPI-derived peptides into the bloodstream is limited and highly variable between individuals. The study highlights the need for further research into factors influencing milk peptide absorption and their potential bioactivity beyond the gut.

 

College of Health researcher(s)

OSU Profile

Highlights

  • Analytical approach can detect milk peptides in blood at ≤0.094 μg/mL.
  • Milk peptides were not detected in the blood of most subjects.
  • Casein peptides are more persistent in blood than whey.
  • Most absorbed peptides had ≥80 % homology to known bioactive sequences.

Abstract

Milk-derived whey protein isolate (WPI) and glycomacropeptide (GMP) have an array of bioactivities such as antibacterial and immunomodulation. However, it is unclear whether they exert their bioactive functions beyond the gastrointestinal tract. Therefore, this study aimed to detect GMP-derived fragments in blood post-in vitro digestion and spiking and determine the presence of WPI- or GMP-derived peptides in vivo from the blood of three young adults and 15 elderly adults post-ingestion of a WPI shake. Milk-derived peptides were extracted from all plasma samples using size exclusion chromatography and solid phase extraction and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Forty-three peptides were detected in the digested GMP-spiked plasma samples. Seventy-five milk-derived peptides were discovered in the plasma of one WPI-fed subject, many of which were homologous to bioactive sequences. No milk peptides were identified in other subjects’ plasma samples. This work provides evidence for inter-individual variation in milk-derived peptide absorption.

Biondi Ryan, M., Kim, B., Qu, Y., Dallas, D.C. (2024) Detection of milk-derived peptides in human blood post-digestion, using LC-MS/MSJournal of Functional Foods122
 
Publication FAQ

FAQ: Absorption of Milk Peptides

What are milk peptides and why are they important?

Milk peptides are short chains of amino acids that are released from milk proteins during digestion. They have been shown to have a variety of potential health benefits, including antimicrobial, anti-inflammatory, and blood pressure-regulating effects.

Can milk peptides be absorbed into the bloodstream?

There is conflicting evidence on whether intact milk peptides can be absorbed into the bloodstream. Some studies have detected milk peptides in the blood after milk consumption, while others have not. This suggests that absorption may vary depending on factors such as the type of milk product consumed, individual differences in gut permeability, and the sensitivity of the detection methods used.

What did this study investigate?

This study investigated whether milk peptides derived from whey protein isolate (WPI), a common dietary supplement, could be detected in the blood of healthy young and elderly adults after consuming a WPI shake. The study also aimed to identify specific peptides and predict their potential bioactivities.

What were the main findings of the study?

Milk peptides were only detected in the blood of one out of three young adult subjects and none of the 15 elderly subjects who consumed WPI. This suggests that the absorption of peptides from WPI might be limited. In the subject where peptides were detected, they were present at all time points, including the baseline measurement before consuming the WPI shake. This raises the possibility that these peptides were already present in the subject's blood and were not derived from the WPI shake.

Why might milk peptides not be detected in the blood of some individuals?

Several factors could explain the lack of detectable milk peptides in the blood of most study participants. These include:

  • Low concentrations: Milk peptides may be present in the blood at concentrations too low to be detected by current methods.
  • Rapid degradation: Milk peptides may be rapidly broken down by enzymes in the gut or bloodstream, preventing their detection.
  • Individual variations: Differences in gut permeability or digestive processes could lead to variability in absorption between individuals.

What are the implications of these findings?

The findings suggest that the absorption of milk peptides from WPI might be less efficient than from whole milk. Further research is needed to confirm these findings and to investigate factors that may influence the absorption of milk peptides.

What are the potential health implications of milk peptide absorption?

If milk peptides can be absorbed intact, they may be able to exert their bioactivities beyond the digestive system. This could have implications for conditions such as high blood pressure, inflammation, and infections. However, more research is needed to understand the potential systemic effects of milk peptides.

What are the next steps in this research area?

Future research should focus on:

  • Developing more sensitive methods for detecting milk peptides in the blood.
  • Investigating factors that influence the absorption of milk peptides, such as gut permeability and dietary factors.
  • Conducting clinical trials to determine the potential health benefits of milk peptides in humans.