L-Theanine and Immunity: A Review

Area of Science:

• Nutritional Immunology
• Amino Acid Biochemistry

Background:

• L-theanine, a primary amino acid in tea leaves, is known for its flavor contribution and health benefits.
• While its calming effects are well-documented, L-theanine's immunomodulatory properties are less explored.

Purpose of the Study:

• To review research on L-theanine's immunoregulatory effects and underlying mechanisms.
• To explore the application of L-theanine as an immunomodulator in animal production.

Main Methods:

• Review of clinical, epidemiological, cell, and animal studies on L-theanine and immunity.
• Analysis of L-theanine's impact on immune cells, cytokine secretion, and neurotransmitter pathways.

Main Results:

• L-theanine mitigates exercise-induced immunosuppression and improves resistance to infections like colds and influenza.
• It regulates inflammation, nerve damage, gut health, and tumor progression via pathways including γδT lymphocyte function and glutathione synthesis.

Conclusions:

• L-theanine exhibits significant immunomodulatory effects, impacting various physiological processes and disease states.
• Its potential as an immunomodulator in both human health and animal husbandry warrants further investigation.