A cohort of 51 patients diagnosed with IBS reported improvements in abdominal pain severity and frequency, bloating, and bowel habits with daily LAGS administration for four weeks.
Geraniol also had a favourable impact on gut microbiome (GM) and promoted production of short-chain fatty acids in the Ruminococcaceae family, especially Faecalibacterium.
The authors explain: “Faecalibacterium is known to produce butyrate (a multifaceted molecule, crucial for metabolic and immunological homeostasis), is positively associated with improved Bristol Stool Scale score, and is typically reduced in IBS and other intestinal and non-intestinal disorders (probably because of increased oxidative stress and decreased barrier functions).”
Moreover, LAGS reduced the relative abundance of Oscillospira (linked to IBS and constipation), as well as pro-inflammatory bacteria Erysipelotrichaeceae.
IBS is a chronic and debilitating disorder with multiple symptoms due to changes in intestinal motor function, visceral hypersensitivity, increased intestinal permeability, low-grade inflammation, and changes in the GM.
Experts recommend lifestyle and dietary adjustments as first-line treatment, along with psychological therapy, fibre supplementation, and medication.
Studies have established the important relationship between GM composition and IBS pathogenesis and note reductions in the abundance of Lactobacillus, Bifidobacterium, and other butyrate producers, as well as increased proportions of potential pathobionts, such as Streptococcus and Ruminococcus, in IBS patients.
Investigations on the impact of therapeutic agents on GM modulation recognise the potential of essential oils (EOs). Peppermint oil has been proposed to relieve global symptoms, but some trials refute its efficacy and reported several side-effects.
On the other hand, geraniol is a natural, highly active antimicrobial compound with antioxidant and anti-inflammatory properties - and is more effective than commensal species at targeting human pathogenic bacterial, the authors write.
Researchers set out to determine the efficacy of LAGS in treating IBS symptoms and modulating GM. Subjects were aged 18 to 65 years, IBS diagnosed (based on Rome III Criteria), and weighed between 48 and 104kg. The total population was 60.7% female.
Exclusion criteria included lactose intolerance or known food allergy, concomitant treatment with non-steroidal anti-inflammatory drug antibiotics, and consumption of functional food, food supplements, probiotics, and prebiotics two months prior to screening.
The supplement was composed of 450mg patented LAG formulation (BIOintestil) and excipients (vegetal magnesium stearate and silicon dioxide) designed to minimise intestinal absorption and deliver 85% monoterpenes to the colon. The placebo comprised 450mg of corn starch plus excipients.
Dosage was calculated according to body weight and varied from two to four capsules per day.
Outcomes were evaluated using a validated score for assessing IBS symptoms and analysis of GM and inflammatory cytokine levels.
At four weeks, patients in the LAGS group reported reduced intensity and frequency of abdominal pain and intensity of bloating, and improvements to bowel habits, compared to the placebo. Reports of symptom relief were largely confined to subjects in the IBS-M subtype.
There were no reported variations in cytokine and permeability markers among the placebo and treatment arms, which could be attributed to the antispasmodic effects of geraniol, the authors write.
While LAGS inhibited Erysipelotrichaceae in the treatment group, proportions increased in the placebo, together with other potential opportunistic pathogens, such as Enterobacteriaceae and Streptococcaceae species.
Alpha diversity significantly decreased in the subjects receiving placebo treatment, although there were some positive results, including reductions in pro-inflammatory Ruminococcus (possibly through impaired tryptamine production) and increased abundance of the short-chain fatty acid producer Coprococcus.
The authors acknowledge that lifestyle, environmental factors, and changes in disease activity may contribute to the GM fluctuations described but were not explored in the current study.
Limitations that potentially dilute study robustness are the prevalence of the IBS-M clinical type among subjects and selection bias in the criteria for IBS diagnosis.
However, the authors assert that results “in terms of improved symptomatology and reduced dysbiosis are certainly promising”.
“It is possible to speculate that geraniol, in this low-adsorbable formula, can be used as a first-line treatment for IBS, especially for IBS-M patients, with both an antispasmodic and GM-modulating effect,” they add.
Published online, October 10, 2022: http://doi.org/10.3390/nu14194208
‘Geraniol Treatment for Irritable Bowel Syndrome: A Double-Blind Randomized Clinical Trial’
Authors: Chiara Ricci, Fernando Rizzello, Maria Chiara Valerii, Enzo Spisni, Paolo Gionchetti, Silvia Turroni, Marco Candela, Federica D’Amico, Renato Spigarelli, Irene Bellocchio, Giovanni Marasco and Giovanni Barbara