Work

Lactoferrin supplementation enhances natural killer cell activity in adults: findings from a 12-week randomized, double-blind, placebo-controlled trial

Year: 2026

Type: article

Study designs: Randomized Controlled Trial, Clinical Trial

Abstract: Lactoferrin (LF), a component of the innate immune system found in human mucus, is known for its antimicrobial properties. It plays a crucial role in shaping immune function in newborns. Despite its biological significance and therapeutic potential, the clinical efficacy of LF in humans remains unclear. We conducted a 12-week, randomized, double-blind, placebo-controlled trial to evaluate the effects and safety of LF supplementation in adults. A total of 100 participants aged 20 years or older were randomly assigned in a 1:1 ratio to receive either LF (300 mg/day) or placebo. The primary endpoint was defined as the change in natural killer (NK) cell activity. Between-group differences in changes in NK cell activity varied according to the assessment time point and E:T ratio. At week 6, a significant difference was observed only at the 12.5:1 ratio ( p = 0.012), whereas at week 12, significant differences were observed at the 50:1 and 25:1 ratios ( p = 0.014 and p = 0.040, respectively). No significant between-group differences were observed for the other E:T ratios at each time point. Cytokine levels, white blood cell (WBC) counts, fatigue severity scores (FSS), and upper respiratory tract infections showed no significant differences between the two groups. These findings suggest that LF supplementation enhances NK cell activity and may contribute to immune-related responses in adults while maintaining a favorable safety profile. However, the absence of significant differences in clinical and inflammatory outcomes indicates that the clinical implications of increased NK cell activity should be interpreted with caution.

Source: Journal of Functional Foods

DOI: 10.1016/j.jff.2026.107537

Authors: Jong-Hwan Park, Seongryu Bae, Minwoo Jang, Manh Heun Kim, Hyuntae Park, Myung-Jun Shin

Institutions: Dong-A University, Pusan National University, Pusan National University Hospital

Language: English

Topic: Immune Cell Function and Interaction

Subfield: Immunology

Field: Immunology and Microbiology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,800