Valine
amino-acidOne of three branched-chain amino acids (BCAAs).
Definition
One of three branched-chain amino acids (BCAAs). Helps regulate nitrogen balance, supports muscle metabolism, and is used as an energy source by muscle cells during exercise.
What Is Valine?
Valine is an essential branched-chain amino acid (BCAA) that the body must obtain from dietary sources. It is the third member of the BCAA group, alongside leucine and isoleucine. Valine is an aliphatic, nonpolar amino acid that plays important roles in energy metabolism, muscle tissue maintenance, and the regulation of nitrogen balance. The Recommended Dietary Allowance (RDA) for valine in adults is approximately 24 mg per kilogram of body weight per day.
Key Functions
Valine contributes to several critical physiological processes:
- Energy substrate: Valine is a glucogenic amino acid, meaning it can be converted into glucose through gluconeogenesis in the liver, providing energy during fasting or prolonged exercise.
- Muscle metabolism: Valine is preferentially metabolized in skeletal muscle rather than the liver, where it contributes to energy production and nitrogen balance within muscle tissue.
- Nervous system support: Valine is involved in the maintenance of the myelin sheath around nerve fibers and may play a role in regulating nitrogen levels in the brain, potentially influencing cognitive function.
- Tissue repair: As a component of muscle protein, valine is necessary for the repair and growth of muscle tissue following exercise or injury.
- Immune function: Valine supports lymphocyte proliferation and overall immune response, particularly during periods of physiological stress.
Food Sources and Dietary Considerations
Valine is abundant in high-protein foods. Notable dietary sources include:
- Beef (cooked): approximately 1.7 g per 100 g
- Chicken breast: approximately 1.6 g per 100 g
- Parmesan cheese: approximately 2.5 g per 100 g
- Pumpkin seeds: approximately 1.6 g per 100 g
- Soybeans (cooked): approximately 0.9 g per 100 g
BCAA supplements typically provide leucine, isoleucine, and valine in a ratio of 2:1:1, though ratios of 4:1:1 and higher are also available. The synergistic interaction of all three BCAAs is considered more beneficial than valine in isolation for supporting exercise performance and recovery.
Top Food Sources
| # | Food | Amount per 100g |
|---|---|---|
| 1 | Seeds, sesame flour, low-fat | 7.4g |
| 2 | Seeds, cottonseed flour, low fat (glandless) | 6.7g |
| 3 | Soy protein isolate | 6.7g |
| 4 | Soy protein isolate, potassium type | 6.7g |
| 5 | Seeds, cottonseed meal, partially defatted (glandless) | 6.6g |
| 6 | Gelatins, dry powder, unsweetened | 6.6g |
| 7 | Peanut flour, defatted | 6.2g |
| 8 | Seeds, sesame flour, partially defatted | 6.0g |
| 9 | Seeds, cottonseed flour, partially defatted (glandless) | 5.5g |
| 10 | Seeds, pumpkin and squash seed kernels, dried | 5.3g |
Related Terms
Leucine
The most anabolic of the branched-chain amino acids (BCAAs), leucine directly activates the mTOR pathway to stimulate muscle protein synthesis.
Isoleucine
A branched-chain essential amino acid that supports muscle metabolism, immune function, and hemoglobin production.
BCAA (Branched-Chain Amino Acids)
The three essential amino acids — leucine, isoleucine, and valine — with aliphatic side chains.