Iron Helps Maintain Gut Health and Beneficial Bacteria in Older Adults

Jim Crocker
18th September, 2025

Iron Helps Maintain Gut Health and Beneficial Bacteria in Older Adults

Growth curves of the S7 consortium and difference (Δ) in the log of 16S rRNA gene copy number of S7 members after incubation with (A) apo (LF-A), (B) native (LF-N) and (C) holo (LF-H) lactoferrin forms for a 24 h-period.

Image adapted from: Ruiz-Rico et al. / CC BY (Source)

Key Findings

  • This study, conducted with elderly participants and a simulated gut environment, investigated how different forms of lactoferrin (a milk protein) affect gut bacteria
  • Iron-saturated lactoferrin slightly altered the gut microbiome composition, increasing the variety of bacterial species present, particularly in healthy individuals
  • Supplementing with iron-saturated lactoferrin helped restore beneficial bacteria like Coprococcus, Alistipes, and Bifidobacterium, which often decline with age, in the simulated gut environment
Iron deficiency is a widespread problem, affecting people of all ages, and is the most common nutritional deficiency globally[2]. It’s a key cause of anemia, a condition where the blood lacks enough healthy red blood cells to carry adequate oxygen to the body’s tissues, leading to fatigue and impaired physical and cognitive function[2]. While supplementation and food fortification are common strategies to combat this[2], researchers are continually seeking more effective and holistic approaches. A recent study conducted by scientists at University College Cork and Wageningen Universiteit[1] investigated the potential of lactoferrin, a protein naturally found in milk, to address iron deficiency and improve gut health. The core issue lies in the complex relationship between iron, the gut microbiome – the community of bacteria living in our digestive system – and overall health. Iron is essential for numerous bodily functions, including brain development and immune response[3]. However, free iron can also promote the growth of harmful bacteria in the gut. Lactoferrin, in its iron-depleted form, is known to have antimicrobial properties, potentially hindering the growth of these undesirable bacteria. But the effect of lactoferrin with varying levels of iron saturation on gut bacteria is less understood. The study began by examining the impact of lactoferrin in different iron states on a simplified group of gut bacteria. Researchers found that both iron-depleted and native (naturally occurring) lactoferrin inhibited the growth of this bacterial consortium. Interestingly, when lactoferrin was saturated with iron, it didn’t inhibit growth but instead altered the composition of the bacterial group, specifically increasing the abundance of Alistipes putredinis. This suggests that iron-saturated lactoferrin doesn’t necessarily kill bacteria, but rather shifts the balance of the gut microbiome. To further investigate this, the researchers moved on to a more complex system – an in vitro colon model, essentially a simulated gut environment using fecal samples from elderly individuals, both healthy and frail. This is particularly relevant because the gut microbiome tends to change with age, often becoming less diverse and less stable, potentially contributing to health problems[4]. The results showed that iron-saturated lactoferrin modified the gut microbiome composition, particularly in the healthy subjects. This modification was characterized by an increase in alpha diversity – a measure of the variety of bacterial species present. Specifically, the researchers observed changes in the abundance of bacteria associated with healthy aging, including Coprococcus, Alistipes, and Bifidobacterium. These are bacterial groups that are commonly found in the gut of healthy individuals but often decrease in abundance as people age and become frail. The study showed that iron-saturated lactoferrin helped to restore these beneficial bacteria in the simulated gut environment of healthy elderly individuals. This research builds on previous understanding of iron’s role in health and disease[2][3]. It addresses a gap in knowledge by demonstrating that lactoferrin’s effect on the gut microbiome is dependent on its iron saturation state. The findings suggest that providing iron-saturated lactoferrin could be a targeted strategy to modulate the gut microbiome in the elderly, potentially improving gut health and overall wellbeing. The fact that the most pronounced effects were seen in healthy individuals suggests that lactoferrin may be particularly beneficial as a preventative measure, helping to maintain a healthy gut microbiome and delay the transition to a frail state. It’s important to note that this study was conducted in vitro, meaning it was performed in a laboratory setting and doesn't perfectly replicate the complexity of the human gut. Further research, including clinical trials, is needed to confirm these findings and determine the optimal dosage and long-term effects of iron-saturated lactoferrin in humans.

NutritionHealthBiochem

References

Main Study

1) Iron-saturated bovine lactoferrin preserves microbiota diversity and healthy ageing-associated taxa in an in vitro colon model of elderly gut microbiota (Iron-saturated bovine lactoferrin impact on elderly gut microbiota)

Published 17th September, 2025

https://doi.org/10.1371/journal.pone.0332631

Related Studies

2) Prevalence and approaches to manage iron deficiency anemia (IDA).

https://doi.org/10.1080/10408398.2021.1935442

3) Iron deficiency during the first 1000 days of life: are we doing enough to protect the developing brain?

https://doi.org/10.1017/S0029665121002858

4) Molecular Aspects and Treatment of Iron Deficiency in the Elderly.

https://doi.org/10.3390/ijms21113821


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