Release of bioactive peptides from whey proteins across digestion in adult humans and a static in vitro digestion model
Whey protein digestion is more complex than previously thought, and the breakdown products could provide health benefits beyond just basic nutrition. The study also shows we need better lab methods to study food digestion.
College of Health researcher(s)
College unit(s)
Highlights
- Peptide profiles after in vitro and in vivo digestions of whey protein were assessed.
- In vivo and in vitro intestinal digesta had moderately similar peptide patterns.
- Digestion of WPI released bioactive peptides with 18 distinct bioactivities.
- The release of antimicrobial peptides may be biologically relevant in the gut.
Abstract
Proteolysis of whey proteins during gastrointestinal digestion releases bioactive peptides with potential health benefits. Our study examined whey-derived peptide release after digestion under static in vitro conditions and in three adults following whey protein isolate ingestion. Using LC-MS/MS-based peptidomics, we identified 1187 unique peptides in the in vitro gastric digesta, 449 in the in vitro intestinal digesta and 1041 in the human jejunum. Among these peptides, 61 were known to exert bioactivities including ACE inhibitory, antimicrobial, DPP-IV inhibitory, antioxidant, immunomodulatory, anticancer and opioid activities. The release of antimicrobial, antioxidant and opioid peptides suggests their potential role in promoting gut health. The peptide patterns produced across digestion in the in vitro model and in adult humans were strongly similar by amino acid frequency and moderately similar in terms of peptide abundances.
Whey Protein Digestion and Bioactive Peptides: FAQ
What are bioactive peptides, and how are they released from whey protein?
Bioactive peptides are short protein fragments with potential health benefits beyond their basic nutritional value. They are encrypted within larger proteins, like whey proteins, and released during digestion. When we consume whey protein, digestive enzymes (like pepsin in the stomach and pancreatic enzymes in the small intestine) break down the protein, liberating these bioactive peptides.
What kinds of health benefits are associated with whey protein-derived bioactive peptides?
Whey protein-derived bioactive peptides have been linked to a wide range of potential health benefits, including:
- Antimicrobial activity: May help fight harmful bacteria in the gut.
- Antihypertensive effects: May help regulate blood pressure.
- Antidiabetic activity: May help manage blood sugar levels.
- Hypocholesterolemic effects: May help lower cholesterol levels.
- Anti-cancer effects: May inhibit the growth of cancer cells.
- Antioxidant properties: May protect cells from damage caused by free radicals.
- Immunomodulatory effects: May help regulate the immune system.
- Opioid activity: May have pain-relieving effects.
How does digestion in the stomach affect the release of bioactive peptides from whey protein?
Gastric digestion, primarily by the enzyme pepsin, plays a crucial role in initiating the breakdown of whey proteins and the release of bioactive peptides. However, some whey proteins, like beta-lactoglobulin, are partially resistant to pepsin and remain mostly intact in the stomach.
What happens to the bioactive peptides during intestinal digestion?
Intestinal digestion, mainly carried out by pancreatic enzymes, further breaks down the whey proteins and releases more bioactive peptides. However, some peptides generated in the stomach are also degraded by these intestinal enzymes, while new ones are formed.
Do in vitro digestion models accurately reflect what happens in the human gut?
While in vitro models are valuable tools for studying digestion, they don't perfectly replicate the complex environment of the human gut. This study found that in vitro models had moderate success in mimicking human digestion, particularly in terms of the specific types and amounts of peptides released.
Where in the body might these bioactive peptides exert their beneficial effects?
Bioactive peptides can act within the gut itself or be absorbed into the bloodstream to reach other organs. For example, antimicrobial peptides might act directly in the intestine to fight pathogens, while antihypertensive peptides would need to enter the circulation to influence blood pressure.
What are some of the key bioactive peptides found in the human jejunum (part of the small intestine) after whey protein ingestion?
This study identified several bioactive peptides in the human jejunum after whey protein ingestion, including:
- Beta-casomorphin-7: This peptide has potential ACE-inhibitory, anti-anxiety, anticancer, antioxidant, immunomodulatory, mucin-stimulating, opioid, and satiety-promoting effects.
- Peptide 141TPEVDDEALEK151 (from beta-lactoglobulin): This peptide has shown antimicrobial activity against specific pathogenic bacteria.
What are some areas for future research in the field of bioactive peptides?
Further research is needed to:
- Determine the absolute concentrations of bioactive peptides needed to exert their effects in the body.
- Improve in vitro digestion models to better represent human digestion.
- Investigate the potential bioactivities of peptides derived from other milk proteins besides beta-casein.
- Conduct clinical trials with larger and more diverse populations to confirm the health benefits of whey-derived bioactive peptides.