Introduction

Proline is a non-essential amino acid that the body can synthesize, and it is a key component of collagen, the most abundant protein in human connective tissues. Consuming proline-rich foods contributes to overall dietary protein intake and supports collagen structure.

In the following sections, we review established functions of proline, its dietary sources, considerations around supplementation, and practical ways to include it in your diet, based on current research and nutrition guidelines.

Role in the Body

Specific Functions

Proline contributes to several physiological processes:

• Collagen Synthesis: Proline and its hydroxylated form, hydroxyproline, are major amino acids in collagen, providing tensile strength and structural support to skin, bones, tendons, and ligaments.
• Protein Folding: The cyclic structure of proline influences the folding and stability of many proteins.
• Metabolic Intermediary: Proline can be converted into other metabolites, such as glutamate, and may participate in cellular metabolism, though further research is ongoing.

Effects of Deficiency

Proline deficiency is rare and not well characterized in healthy humans. The body synthesizes proline from other amino acids, and there is no recognized clinical deficiency syndrome when dietary protein intake meets general requirements.

Dietary Sources

Best Food Sources

Proline is found in protein-containing foods. Notable sources include:

• Beef, pork, and lamb – rich in muscle proteins and connective tissue
• Poultry – especially in skin and connective tissues
• Fish and shellfish – such as salmon, cod, and shrimp
• Dairy products – including milk, cheese, and yogurt
• Gelatin and collagen-derived products – used in cooking and supplements

Supplementation

Proline supplements, such as L‑proline capsules, collagen peptides, and bone broth powders, are commercially available. Clinical evidence supporting specific health benefits of isolated proline supplementation is limited. Individuals considering supplements should consult a healthcare professional, particularly if pregnant, breastfeeding, or managing medical conditions.

Health Benefits

Proline is a major building block of collagen. Some studies of collagen-containing supplements have reported modest improvements in skin elasticity and joint comfort; however, evidence is preliminary and varies across trials. More rigorous research is needed to determine the direct effects of proline on health outcomes.

Daily Requirements

There is no established Recommended Dietary Allowance (RDA) for proline. General protein intake recommendations—such as 0.8 grams of protein per kilogram of body weight per day for adults—are intended to meet requirements for all amino acids, including proline. Individuals with higher protein needs (e.g., athletes or those recovering from injury) should seek personalized guidance from a healthcare provider or registered dietitian.

Tips for Incorporation

To include proline-rich foods in your diet, consider these strategies:

• Add collagen peptides or gelatin powder to smoothies, coffee, or soups.
• Prepare bone broth by simmering animal bones with vegetables, herbs, and vinegar for several hours.
• Use dairy products—such as yogurt or cheese—as snacks or recipe ingredients.
• Rotate protein sources across meals, including meats, poultry, fish, dairy, and plant-based proteins.
• Pair protein-rich meals with vitamin C–containing foods (e.g., citrus fruits, berries, bell peppers) to support collagen formation.

Call to Action

Including a variety of proline-rich foods can contribute to overall protein intake and support connective tissue structure. For personalized advice on dietary protein and amino acid needs, consult a registered dietitian or healthcare professional.

Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult a healthcare professional before making significant changes to your diet or starting any supplementation.