The role of L-valine in the antioxidant defense system

As one of the essential branched-chain amino acids in humans, L-valine exerts its effects in the antioxidant defense system through multiple pathways, including direct participation in the synthesis of antioxidant substances, regulation of cellular metabolism, and maintenance of enzyme activity. Its mechanisms are elaborated as follows:

First, L-valine indirectly supports the synthesis of glutathione (GSH). Glutathione, a key intracellular antioxidant molecule, scavenges free radicals and neutralizes reactive oxygen species (ROS). Its synthesis relies on the supply of glutamic acid, cysteine, and glycine. Although L-valine does not directly participate in glutathione composition, it maintains the balance of intracellular amino acid metabolism, providing an environmental support for the absorption and utilization of glutathione precursors (especially cysteine). For example, an adequate supply of valine reduces the competitive consumption of glutathione synthesis raw materials by other amino acid 代谢 processes, indirectly promoting glutathione production and enhancing cellular resistance to oxidative damage.

Second, L-valine is involved in maintaining the structure and function of antioxidant enzymes. The activity of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) depends on normal protein synthesis and structural stability. As an essential amino acid for protein synthesis, L-valine is a component of these enzyme molecules. When valine is deficient, the synthesis of antioxidant enzymes may be impaired, leading to decreased activity and weakened cellular ability to clear ROS. Conversely, sufficient L-valine ensures the normal synthesis and renewal of antioxidant enzymes, maintaining their catalytic efficiency and thus enhancing the body’s antioxidant defense.

In addition, L-valine indirectly reduces oxidative stress by regulating cellular energy metabolism. Branched-chain amino acids (including valine) are important energy sources for tissues such as muscles. Their metabolic process can reduce excessive cellular dependence on glucose, avoiding excessive ROS production caused by glucose metabolism disorders (e.g., excessive glycolysis). Meanwhile, intermediate products of valine metabolism (such as α-ketoisovalerate) can participate in the tricarboxylic acid cycle, providing energy for cells while maintaining stable mitochondrial function. Mitochondria are the main source of ROS; their normal function helps reduce the source of oxidative stress, indirectly supporting the balance of the antioxidant system.

Finally, L-valine plays a role in the synergy between immune cell function and antioxidant activity. The activation and proliferation of immune cells (such as lymphocytes and macrophages) require a large amount of valine as a raw material for protein synthesis. However, immune cells release ROS when resisting pathogens. If immune function is low, the body’s efficiency in clearing pathogens decreases, which may trigger chronic inflammation and accumulation of oxidative stress. By supporting the normal function of immune cells, L-valine enhances the body’s ability to clear infections, reduces oxidative damage caused by persistent inflammation, and forms a synergistic protective effect with the antioxidant system.

Although L-valine is not a direct antioxidant, it indirectly participates in and strengthens the body’s antioxidant defense system by ensuring the synthesis of antioxidant molecules, maintaining enzyme activity, regulating metabolism, and supporting immune function. It is an important nutritional basis for maintaining cellular redox balance.