A comprehensive review article highlighting the effects of the well-characterized probiotic strain L. plantarum 299v (LP299V®) for iron absorption and iron status was recently accepted for publication in the renowned journal Frontiers in Nutrition.

Researchers at Probi, part of Symrise Group, authored the review, which brings together evidence from 10 peer-reviewed studies, including research in populations with increased iron requirements. It examines how LP299V® may influence iron bioavailability through multiple complementary mechanisms, from supporting iron solubility and uptake to potentially influencing factors involved in iron metabolism.

Iron deficiency remains the most prevalent micronutrient deficiency worldwide, affecting an estimated 2 billion people. ⁽¹⁾ Health effects of prolonged iron deficiency include heart irregularities, weakened immunity, and cognitive impairment. The primary source of dietary iron consumed globally is non-heme iron; however, this form is poorly absorbed. While iron replacement is standard of care, it is marked by low compliance due to unpleasant side effects like GI distress.

The review includes validated isotope studies showing relative increases in fractional non-heme iron absorption of approximately 20% to 50% across different dietary contexts. It also includes randomized controlled trials investigating the impact of LP299V® on iron status in populations including women of reproductive age, pregnant women, and female athletes with low iron stores.

The strength of this research has also received widespread industry recognition with Probi's iron absorption concept winning the Nutra Ingredients Award for Innovation in Women's Health in Europe, North America and Asia in 2025.

“Iron status depends not only on how much iron is consumed, but also on how effectively it is absorbed,” said Brandy Webb, N.D., Scientific Affairs Manager at Probi. “The research reviewed provides insights into how LP299V® may support this process through several complementary mechanisms. Importantly, the evidence positions LP299V® as a bioavailability enhancer that can complement dietary iron and iron supplementation rather than replace them.”

The mechanism behind iron absorption

The review explores several potential mechanisms through which LP299V® may influence non-heme iron bioavailability.

These include the production of organic acids that can lower luminal pH and support iron solubility, potential mitigation of dietary inhibitors such as phytates, and increased expression of the gene for DCYTB, the enzyme that converts ferric iron into the bioavailable ferrous form. The review notes that the evidence for effects on DMT1, the primary transporter protein, remains inconclusive.

The review also considers the relationship between LP299V®, intestinal barrier function, short-chain fatty acid production, and inflammation. These factors may contribute to the strain’s effects on iron uptake and its demonstrated ability to reduce gastrointestinal side effects associated with iron replacement.

Clinical research extends beyond absorption

In a randomized, double-blind, placebo-controlled study of 326 pregnant women, LP299V® combined with folic acid, vitamin C, and low-dose iron helped preserve iron status during pregnancy. At 35 weeks, women receiving LP299V® had higher serum ferritin (16.0 vs 13.8 μg/L) and hemoglobin levels (122.5 vs 117.4 g/L) than controls. Iron deficiency was less common in the LP299V® group (59% vs 78%), as was iron deficiency anemia (7.4% vs 21%).

In a randomized controlled trial of 295 people with newly diagnosed iron deficiency anemia, adding LP299V® to oral iron therapy improved iron status and reduced gastrointestinal side effects. After three months, the LP299V® group showed greater increases in ferritin and hemoglobin, with higher serum iron and transferrin saturation. Gastrointestinal intolerance was markedly lower (13.0% vs 46.5%), as was treatment discontinuation within 30 days (3.6% vs 15.9%).

Research in female athletes with low iron stores has also explored the potential of LP299V® in addition to iron supplementation. In a 12-week randomized controlled study, the LP299V® group showed a significantly more rapid increase in serum ferritin, as well as nearly double the increase in reticulocyte hemoglobin. Additionally, the study reported a significant improvement in vigor and increases in V0₂ max.

A microbiome approach to iron uptake

The review supports further investigation of LP299V® as a strain-specific approach to enhancing non-heme iron bioavailability.

The authors emphasize that LP299V® should be viewed as a bioavailability enhancer rather than a source or replacement for dietary iron or iron supplements. The review also notes that responses can vary according to the dietary matrix, intervention characteristics, and individual factors, highlighting the need for further research.

The findings underscore the potential of targeted, strain-specific probiotics to influence nutrient metabolism and bioavailability beyond traditional health applications.

Read the full review, “Probiotics and iron availability: mechanisms, clinical evidence and translational applications – a comprehensive review of the probiotic strain Lactiplantibacillus plantarum 299v (LP299V®),” in Frontiers in Nutrition here.

For more information on LP299V®, find out more here.