What are the natural sources of tripeptides VPP (Valine-Proline-Proline) and IPP (Isoleucine-Proline-Proline) besides milk and dairy products?

Natural Sources of Tripeptides VPP and IPP

The tripeptides Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP) are found naturally in various fermented foods, particularly in cheese varieties, with Swiss Appenzeller 1/4 fat cheese containing the highest concentration at 182.2 mg/kg.

Dairy Sources of VPP and IPP

Dairy products are the primary natural sources of these bioactive tripeptides, which are formed during:

1. Fermentation processes

   • Fermented milk products contain significant amounts of VPP and IPP 1
   • These peptides are produced during bacterial fermentation of milk proteins

2. Cheese varieties

   • Swiss cheese varieties contain varying levels of VPP and IPP 2
   • Concentration ranges in different cheese varieties:
     • Appenzeller 1/4 fat: highest average at 182.2 mg/kg
     • L'Etivaz à rebibes: lowest average at 19.1 mg/kg
     • Individual samples range from 1.6 to 424.5 mg/kg
   • VPP is generally present in higher concentrations than IPP in most cheese samples 2

3. Factors affecting tripeptide content in cheese

   • Milk pretreatment methods
   • Bacterial cultures used
   • Scalding conditions during cheese production
   • Ripening time 2

Non-Dairy Sources

While the evidence primarily focuses on dairy sources, these bioactive peptides may potentially be found in other protein-rich foods that undergo fermentation or enzymatic processes:

1. Fermented plant proteins

   • Soy products like tofu, tempeh, and miso contain various bioactive peptides 3
   • These fermented soy foods contain naturally occurring soy constituents that may include bioactive peptides

2. Legumes

   • Legumes are recommended as protein sources in dietary guidelines 3
   • They contain various peptides that may be released during digestion or fermentation

3. Whole grains

   • Fermentation of whole grains may potentially release bioactive peptides
   • Whole grains contain unique hemicellulose fibers and other components 3

Health Effects of VPP and IPP

These tripeptides have demonstrated several health benefits:

1. Antihypertensive effects

   • Act as ACE inhibitors in vitro 4
   • Fermented milk containing IPP and VPP attenuated hypertension development by 19 mmHg in animal models 4
   • Long-term intake of fermented milk products containing these peptides significantly reduced systolic blood pressure in hypertensive rats 5

2. Cholesterol-lowering effects

   • A spread containing IPP, VPP, and plant sterols decreased total cholesterol and LDL cholesterol significantly compared to placebo 1

Clinical Implications

For individuals seeking natural sources of these bioactive peptides:

1. Cheese selection

   • Swiss cheese varieties, particularly Appenzeller, contain the highest concentrations
   • Fermented cheeses generally contain more of these peptides than non-fermented varieties

2. Fermented dairy products

   • Yogurt, sour milk, and other fermented dairy products are excellent sources of bioactive peptides 6

3. Consideration of non-dairy alternatives

   • For those avoiding dairy, fermented plant proteins may offer alternative sources of bioactive peptides

Caveats and Considerations

• The concentration of these tripeptides varies substantially between products and even between samples of the same variety
• Processing methods significantly affect the content of these bioactive compounds
• While these peptides show promising health effects, they should be considered as part of an overall healthy diet rather than isolated supplements