Introduction
Aloe barbadensis Mill. (Aloe) with its complex polysaccharide composition has been suggested to have prebiotic properties, however no human intervention trials have previously been undertaken to study this effect.
Aims & Methods
With the aim of designing prebiotic strategies for human gut health promotion, this randomized, placebo-controlled study evaluated the effects of increasing doses of chemically characterized Aloe extract on gastrointestinal function and overall gastrointestinal microenvironment, including fecal microbiota and metabolite composition in healthy adults.
Fecal samples were collected from healthy subjects (56 females and 21 males, age 19 - 69) at baseline, and week 3 and week 6 after intervention with placebo or 0.5 g, 1.0 g or 3.0g of Aloe extract/day. Gastrointestinal symptoms were assessed using validated questionnaires and stool consistency was evaluated using the Bristol Stool Form Scale. A food questionnaire was used to evaluate dietary quality, adapted using an index created by the Swedish National Food Agency. Fecal microbiota was evaluated by GA-mapTM Dysbiosis Test, while H-1 nuclear magnetic resonance (NMR) spectroscopy was used for metabolomic profiling. Multivariate Orthogonal Projections to Latent Structures Discriminatory Analysis (OPLS-DA) was applied to fecal microbiota and metabolite data sets. Statistical analyses were carried out using non-parametric tests.
Results
All participants completed the study and demographic parameters such as age, sex, diet quality and BMI did not differ between the study groups at baseline. Intervention with increasing doses of Aloe was safe and well tolerated and did not cause gastrointestinal symptoms, as assessed using the gastrointestinal symptoms rating scale. Stool consistency changed after supplementation with Aloe, (n= 57; 3.9 (3.2 – 4.4) vs 3.6 (2.8 – 4.2), P = 0.005), but not for placebo (n= 20; 3.9 (3.2 – 4.5) vs. 3.7 (3.2 – 4.3), P = 0.82), comparing baseline vs. end of intervention, without difference between the groups (P = 0.33).
No alterations were seen in the fecal microbiota profiles before vs. after intervention, in either of the groups, indicative of a stable overall gut microbiota. Furthermore, the fecal metabolite profiles remained unaltered after intervention with Aloe. However, Aloe modulated the fecal metabolite profile in healthy subjects with BMI ≥25 (n = 24; R2 = 0.87, Q2 = 0.51), but not healthy subjects with BMI ≤24 (n = 32; R2 = 0.44, Q2 = 0.12), when comparing baseline vs. end of intervention by OPLS-DA. Moreover, Aloe intervention showed potential to reduce the difference seen in the fecal metabolite profiles between subjects with BMI ≤24 and those with BMI ≥25 from R2 = 0.57 and Q2 = 0.30 at baseline to R2 = 0.38 and Q2 = -0.11 at end of intervention. No such tendencies were seen in the smaller placebo group (BMI ≤24, n = 12 vs. BMI ≥25, n =6).
Conclusion
Supplementation with increasing doses of Aloe extract is safe and well tolerated in healthy adults. Overall, our findings support safety of Aloe extract, and show that supplementing diet with Aloe extract has the potential to modulate intestinal microbiota function, especially in healthy adults with a BMI ≥25, with an altered intestinal microenvironment.
Disclosure
Presenting Author - Bani Ahluwalia is employed by Calmino Group AB, while carrying out Post-doctoral research at the University of Gothenburg.
