Iron is an essential micronutrient for oxygen transport and mitochondrial metabolism and is critical for physical performance. Compromised iron stores are more commonly found among athletes, and females are especially at risk. Iron deficiency is generally treated using oral iron supplements. However, only a small proportion of ingested iron is absorbed, necessitating higher intakes, which may result in adverse side effects, reduced compliance, and inefficient repletion of iron stores. The probiotic strain Lactobacillus plantarum 299v (Lp299v) significantly increases intestinal iron absorption in meal studies. The present study was conducted to explore the effects of 20 mg of iron with or without Lp299v on iron status, mood state, and physical performance. Fifty-three healthy non-anemic female athletes with low iron stores (ferritin < 30 μg/L) were randomized, and 39 completed the study. Intake of Lp299v with iron for four weeks increased ferritin levels more than iron alone (13.6 vs. 8.2 µg/L), but the difference between the groups was not significant (p = 0.056). The mean reticulocyte hemoglobin content increased after intake of Lp299v compared to control (1.5 vs. 0.82 pg) after 12 weeks, but the difference between the group was not significant (p = 0.083). The Profile of Mood States (POMS) questionnaire showed increased vigor with Lp299v vs. iron alone after 12 weeks (3.5 vs. 0.1, p = 0.015). No conclusive effects on physical performance were observed. In conclusion, Lp299v, together with 20 mg of iron, could result in a more substantial and rapid improvement in iron status and improved vigor compared to 20 mg of iron alone. A larger clinical trial is needed to further explore these findings as well as the impact of Lp299v on physical performance.

Background: The usage of probiotics has expanded beyond the areas of gut and immune health improvement. Several studies have shown the positive impact associated between probiotics and stress, cognition, and mood; a relationship referred to as the gut–brain axis. Method: The aim of this exploratory study was to evaluate the effect of the probiotic strain Lactiplantibacillus plantarum HEAL9 (LPHEAL9) on the gut–brain axis in subjects with moderate stress. One hundred and twenty-nine subjects aged 21–52 years completed the study, randomized to consume either LPHEAL9 (n = 65) or placebo (n = 64) for 12 weeks. Results: Perceived stress and awakening cortisol were significantly reduced over time in both groups. A significant improvement in four cognition tests after consumption of LPHEAL9 compared to placebo was observed (rapid information processing test, numeric working memory test, paired associated learning, and word recall, p < 0.05). There was a tendency for a significantly better improvement in the LPHEAL9 group for three mood subscales (Confusion–Bewilderment, Anger–Hostility, and Depression–Dejection) and for fewer subjects with poor sleep in the LPHEAL9 group compared to placebo (p < 0.10). Conclusions: Intake of LPHEAL9 significantly improved cognitive functions compared to the placebo, potentially by ameliorating aspects of mood and sleep.

Several human interventions have indicated that Lactobacillus plantarum 299v (L. plantarum 299v) increases intestinal iron absorption. The aim of the present study was to investigate possible effects of L. plantarum 299v on the mechanisms of iron absorption on the cellular level. We have previously shown that lactic fermentation of vegetables increased iron absorption in humans. It was revealed that the level of ferric iron [Fe (H₂O)₅]²⁺ was increased after fermentation. Therefore, we used voltammetry to measure the oxidation state of iron in simulated gastrointestinal digested oat and mango drinks and capsule meals containing L. plantarum 299v. We also exposed human intestinal co-cultures of enterocytes and goblet cells (Caco-2/HT29 MTX) to the supplements in order to study the effect on proteins possibly involved (MUC5AC, DCYTB, DMT1, and ferritin). We detected an increase in ferric iron in the digested meals and drinks containing L. plantarum 299v. In the intestinal cell model, we observed that the ferric reductase DCYTB increased in the presence of L. plantarum 299v, while the production of mucin (MUC5AC) decreased independently of L. plantarum 299v. In conclusion, the data suggest that the effect of L. plantarum 299v on iron metabolism is mediated through driving the Fe³⁺/DCYTB axis.

The disparity between increased lifespan and healthy aging, marked by prevalent “inflammaging”, highlights the global challenge in care of older persons. This study explored the anti-inflammatory effects of Lactiplantibacillus plantarum HEAL9 (LpHEAL9), alone or combined with berries, on older volunteers with chronic low-grade inflammation (LGI). It was a randomized, double-blind, placebo-controlled trial, with a total of 66 volunteers (> 70 years old), randomly assigned, and equally distributed, to placebo, LpHEAL9 or LpHEAL9 + Berries group. After a 2-week run-in period, participants underwent a 4-week dietary intervention. Intake of LpHEAL9 showed a trend towards reduction in serum CRP but without reaching statistical significance. However, LpHEAL9 significantly decreased fecal calprotectin levels compared to placebo. LpHEAL9+Berries did not show any effect on inflammation. Both probiotic groups showed a trend in improving cognitive function albeit not reaching statistical significance. Our findings suggest that the probiotic strain L. plantarum HEAL9 has a modest impact on LGI in a healthy older population (ClinicalTrials.gov ID: NCT02342496).

Background: Different microorganisms from the environment will begin to colonise the infant during and immediately after the delivery. It could be advantageous to influence the microbiome early on by giving infants probiotic bacteria. The aim of the study was to investigate the tolerance of two probiotic lactobacilli in infants. The effect on the microbiota was also followed. Methods: Thirty-six healthy infants, aged 4–83 days at the start of the study, were given a daily supplementation of probiotics (Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus rhamnosus 271, 10⁹ CFU (colony-forming units)) or placebo for 8 weeks. Adverse events, growth parameters, the faecal microbiome and intestinal performance were followed. Results: No differences between the groups in growth parameters, adverse events and intestinal performance were observed. The faecal levels of L. plantarum, L. rhamnosus and lactobacilli increased after the intake of probiotics and were significantly higher compared with the placebo group after 4 and 8 weeks of intake. The faecal microbial diversity was similar in the two groups at the end of the study. Conclusions: The intervention with the probiotic formulation was well tolerated and increased the level of lactobacilli in the intestine. The developed probiotic formulation will be further evaluated for clinical efficacy in infants. Impact: New data for the development of the gut function and the microbiome in breastfed and/or formula-fed young infants over time and the effect of adding two probiotic strains are presented. Lactiplantibacillusplantarum is a species that seldom has been analysed in infants, but it could be detected in 25% of the subjects before administration (mean age 41 days). Lactiplantibacillusplantarum and L. rhamnosus establish well in the intestine of infants and are well tolerated. The microbiota was positively affected by the intake of probiotics.

The intestine and the brain are connected via the brain-gut axis and the intestinal microbiota influences the immune activation and signaling molecules that are involved in the stress response. The aim of the study was to investigate if intake of the probiotic strain Lactiplantibacillus plantarum HEAL9 (LPHEAL9) for four weeks could counteract elevated cortisol and inflammation levels in subjects with chronic stress that are exposed to an acute stress test (Trier Social Stress Test, TSST). Seventy participants were included, and 63 participants completed the study (LPHEAL9, n = 32; placebo, n = 31). Cardiovascular reactivity and cortisol levels were affected by the TSST, but no differences between the groups were observed. Intake of LPHEAL9 did, however, result in significantly decreased plasma levels of two inflammatory markers (soluble fractalkine and CD163) compared to placebo. In conclusion, intake of LPHEAL9 for four weeks may reduce inflammatory markers coupled to acute stress in chronically stressed individuals.