Benefits
Non-heme iron absorption from meals and drinks
In isotope studies in healthy women, adding Lp299v to a meal or fruit drink raised the share of non-heme (plant-type) iron absorbed. A meta-analysis of eight such studies found a moderate pooled increase. The studies were small, mostly in healthy European women, some were co-authored by the strain's maker, and one found no effect on absorption.
Iron status alongside iron supplements
In a 12-week trial in 53 female athletes with low iron stores (39 finished), Lp299v plus 20 mg iron raised ferritin more than iron alone at 4 weeks, but the difference was not statistically significant. In a trial in children with low iron taking low-dose iron, adding Lp299v did not improve ferritin.
Iron status in pregnancy with a low-iron combination capsule
In a maker-sponsored trial in 326 healthy pregnant women, a capsule of Lp299v with 4.2 mg iron, vitamin C and folic acid taken twice daily slowed the fall in ferritin and lowered iron deficiency (59% vs 78%) at week 35. The placebo had no iron or vitamins, so the effect cannot be credited to Lp299v alone. Follow your clinician's advice on iron in pregnancy.
Abdominal pain, gas and bloating comfort
Lp299v (DSM 9843) has been tested against placebo in six trials in people with IBS. Three found an advantage: less abdominal pain and bloating over 4 weeks in 214 adults, pain resolution in a trial of 40 patients, and less gas in 60 patients, where pain fell in both groups and bloating did not differ. Three others, in 12 and 120 patients and an 8-week trial in South Africa, found no significant difference.
Mechanism of action
More ferric iron in digested meals (lab research)
In simulated digestion of drinks and meals, Lp299v increased the amount of ferric iron, and in a human intestinal cell model it raised the iron-reducing enzyme DCYTB. The authors suggest this may explain the higher absorption seen in people, but it has not been confirmed in humans.
Mucin gene expression in gut cells (lab research)
In cultured human intestinal cells, Lp299v increased expression of the mucin genes MUC2 and MUC3 and reduced attachment of a pathogenic E. coli strain. Whether this happens in the human gut, or explains any symptom effects, has not been shown.
Clinical trials
Systematic review of 15 studies with a random-effects meta-analysis of the eight studies that measured iron absorption with Lp299v (Vonderheid et al. 2019, Nutrients).
950 participants across all 15 studies; the absorption studies were in healthy, mostly female, white Europeans.
Lp299v increased non-heme iron absorption (pooled standardized mean difference 0.55, 95% CI 0.22 to 0.88, p = 0.001). Of seven trials of various bacterial strains that measured iron status, only one, using Lp299v, reported improved serum iron; the others found no improvement in iron status markers.
Two single-blind crossover trials using double-isotope labeling, each drink with about 5 mg iron as ferrous lactate (Hoppe et al. 2015, Br J Nutr).
Healthy women of reproductive age: 10 in the 10⁹ CFU trial and 11 in the 10¹⁰ CFU trial.
Iron absorption was 28.6% from the drink with 10⁹ CFU versus 18.5% from the control drink (significant). With 10¹⁰ CFU it was 29.1% versus 20.1%, which was not statistically significant. The two doses did not differ from each other. Two authors were employed by Probi, the strain's maker.
12-week randomized, double-blind, parallel trial of Lp299v (10¹⁰ CFU) plus 20 mg iron versus 20 mg iron alone; an exploratory study whose registered primary outcome, the metabolic response during submaximal cycling, did not differ, with p-values not adjusted for multiple testing; funded by Probi and Nature's Bounty (Axling et al. 2020, Nutrients).
53 healthy, non-anemic female athletes with ferritin under 30 µg/L; 39 completed.
Ferritin rose more with Lp299v plus iron at 4 weeks (13.6 vs 8.2 µg/L), but the difference was not significant (p = 0.056). Self-rated vigor on a mood questionnaire rose more with Lp299v at 12 weeks (p = 0.015); total mood and the other five mood scores did not differ, and physical performance did not clearly change. Two authors worked for Probi and two for a supplement company.
Randomized, double-blind, placebo-controlled trial from gestational week 10 to 12 until delivery, sponsored by Probi (Axling et al. 2021, Acta Obstet Gynecol Scand).
326 healthy, non-anemic pregnant women in Sweden.
The capsule (Lp299v 10¹⁰ CFU, 4.2 mg iron, 12 mg vitamin C, 30 µg folic acid, twice daily) reduced the fall in ferritin at week 28 (primary outcome, p = 0.003) and lowered iron deficiency (59% vs 78%) and iron deficiency anemia (7.4% vs 21%) at week 35. The placebo contained no iron or vitamins, so results apply to the combination, not Lp299v alone.
Randomized, double-blinded controlled trial of low-dose ferrous sulfate (1 to 3 mg/kg/day) with or without Lp299v for 6 to 8 weeks (Rosen et al. 2019, J Pediatr).
Children presenting with iron deficiency.
Ferritin rose in all children, but the increase did not differ with Lp299v versus without it (23.2 vs 20.0 ng/mL). The authors concluded Lp299v did not enhance treatment.
4-week double-blind, placebo-controlled, parallel trial of one Lp299v capsule daily (Ducrotté et al. 2012, World J Gastroenterol).
214 adults with IBS meeting Rome III criteria.
Abdominal pain severity and frequency were lower with Lp299v than placebo at week 4 (P < 0.05), with similar results for bloating. 78.1% rated the effect excellent or good versus 8.1% with placebo.
Randomized placebo-controlled trial of Lp299v at a hospital in Peshawar, Pakistan (Moeen-Ul-Haq et al. 2022, J Pak Med Assoc).
120 adults with IBS; 108 completed.
There was no significant difference between Lp299v and placebo in abdominal pain, bloating or rectal emptying (p > 0.05).
Controlled, double-blind, randomized 4-week trial of Lp299v in liquid suspension versus placebo (Niedzielin et al. 2001, Eur J Gastroenterol Hepatol).
40 patients with IBS (20 per group).
All 20 patients on Lp299v reported resolution of abdominal pain, versus 11 on placebo (P = 0.0012), and improvement in all IBS symptoms was reported by 95% versus 15% (P < 0.0001). A trend toward normal stool frequency in constipated patients did not reach significance (P = 0.17).
Randomized 4-week trial of 400 ml a day of a rose-hip drink with L. plantarum DSM 9843 (5 × 10⁷ CFU/ml) and a little oat flour versus a plain rose-hip drink, with 12-month follow-up (Nobaek et al. 2000, Am J Gastroenterol).
60 patients with IBS meeting the Rome criteria and with a normal colonoscopy or barium enema.
Flatulence fell faster and further with Lp299v than with the plain drink (days with abundant gas 6.5 to 3.1 vs 7.4 to 5.6). Abdominal pain fell in both groups and bloating did not differ. At 12 months the Lp299v group reported better overall gastrointestinal function.
Randomized placebo-controlled trial at a referral hospital: two capsules a day of Lp299v at 5 × 10⁹ CFU each, or placebo, for 8 weeks; the abstract does not give the sample size (Stevenson et al. 2014, Nutrition).
Patients at a referral hospital in South Africa meeting the Rome II criteria for IBS.
Abdominal pain relief did not differ between groups (P = 0.800), nor did quality of life scores (P = 0.687). Pain scores fell in both groups, which the authors described as a large placebo effect.
Double-blind, placebo-controlled, crossover 4-week trial measuring symptoms daily and colonic fermentation by calorimetry and breath hydrogen (Sen et al. 2002, Dig Dis Sci).
12 previously untreated patients with IBS.
Symptom scores, gas production and hydrogen production did not differ significantly between Lp299v and placebo. Breath hydrogen after a lactulose test was lower on Lp299v (P = 0.019). The authors concluded Lp299v did not improve symptoms.