Hoppe · PloS one 2017 · single-blind sequential controlled trial · n=42

Freeze-dried Lactobacillus plantarum 299v increases iron absorption in young females-Double isotope sequential single-blind studies in menstruating women.

Cited 66 times in the scientific literature.

Level 2 - randomized trial

Individual single-blind sequential controlled crossover trial in humans

PubMed 29236734 · doi:10.1371/journal.pone.0189141 · record verified 2026-08-29

What was done

Researchers evaluated whether capsule-administered freeze-dried *Lactobacillus plantarum* 299v (Lp299v, DSM 9843; 10¹⁰ CFU) enhanced non-heme iron absorption. Two sequential, single-blind, placebo-controlled studies were conducted in healthy menstruating female volunteers using a double-isotope technique (⁵⁹Fe and ⁵⁵Fe) to measure iron absorption from an identical light breakfast meal consumed with or without the probiotic capsule.

What was found

In Study 1 (n = 14), mean iron absorption was 17.4 ± 13.4% without Lp299v versus 22.4 ± 17.3% with Lp299v (p = 0.040). In Study 2 (n = 28), mean iron absorption was 20.9 ± 13.1% without Lp299v versus 24.5 ± 12.0% with Lp299v (p = 0.003).

Why it matters

These findings show that *L. plantarum* 299v retains its ability to enhance non-heme iron absorption when delivered in a freeze-dried capsule format rather than integrated directly into fermented food matrices.

Limits

The sample sizes were small (n = 14 and n = 28), and the trials were single-blind with a sequential rather than fully randomized crossover design. The study only examined acute absorption from a single meal with high baseline bioavailability in healthy young women, without measuring long-term iron status or efficacy in iron-deficient populations.

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