ABSTRACT
BACKGROUND: Honey improves probiotic survival in vitro. However, if this effect translates to humans has not been investigated. OBJECTIVES: We aimed to determine effects of honey plus yogurt containing the probiotic Bifidobacterium animalis subsp. lactis DN-173 010/CNCM I-2494 (B. animalis) on intestinal transit time, probiotic enrichment, digestive health, mood, and cognition in adults. METHODS: Sixty-six healthy adults (34 female; 33.6 ± 9.8 y; 24.6 ± 3.0 kg/m2) in a crossover trial were randomly assigned to 2-wk yogurt conditions in a counterbalanced order with ≥4-wk washout: 1) Honey (HON): yogurt plus honey and 2) Negative Control (NC): heat-treated yogurt plus sugar. Of the participants, n = 62 completed the trial, and n = 37 (17 female; 32.0 ± 8.3 y; 25.0 ± 2.9 kg/m2) elected to enroll in a third condition (a nonrandomized study extension) after ≥4-wk washout with a reference Positive Control (PC): yogurt plus sugar. At baseline and end of each of the 3 conditions, intestinal transit time was measured with dye capsules; probiotic abundance with fecal DNA 16S sequencing; digestive health with symptom/function records, Bristol stool consistency, Gastrointestinal Tolerability, and Gastrointestinal Quality of Life Index; mood with Positive and Negative Affect Schedule-Short Form, Depression Anxiety Stress Scales-42, Patient-Reported Outcomes Measurement Information System questionnaires, and an emotional image task; and cognition with a spatial reconstruction task. Data were analyzed using linear mixed-effects models (LMMs) with significance at P ≤ 0.05. Baseline and end data were included in the LMM, with fixed effects being treatment, time, treatment by time interaction, and baseline covariate, and the random effect being the participant. RESULTS: B. animalis was enriched in HON (d = 3.54; P = 0.0002) compared to controls with linear discriminant analysis effect size. Intestinal transit time, gastrointestinal health, mood, and cognition did not differ between conditions (LMM: Ps > 0.05). CONCLUSIONS: Yogurt + honey enriched B. animalis but did not reduce intestinal transit time or have other functional gastrointestinal, mood, or cognitive effects in adults. This trial was registered at www. CLINICALTRIALS: gov as NCT04187950 and NCT04901390.
ABSTRACT
Historically, humans have interacted with soils, which contain a rich source of microorganisms. Fruit and vegetable gardening is the primary interaction humans have with soil today. Animal research reveals that soil microorganisms can be transferred to the rodent intestine. However, studies on fecal and soil microbial changes associated with gardening in humans are lacking. The current case-controlled cohort study aimed to characterize the fecal and soil microbiota of gardening families (n = 10) and non-gardening (control) families (n = 9). Families included two adults and one child (5-18 years) for a total of 56 participants. All participants provided a fecal sample, soil sample, and diet history questionnaires before the gardening season (April) and during the peak of the gardening season (August). Healthy Eating Index (HEI-2015) scores and nutrient analysis were performed. Fecal and soil DNA were extracted and amplified. Sequence data were then processed and analyzed. Peak season gardening families tended to have greater fecal operational features, a greater Faith's Phylogenetic Diversity score, greater fiber intake, and higher abundances of fiber fermenting bacteria than peak control families. Soil endemic microbes were also shared with gardening participant's fecal samples. This study revealed that the fecal microbiota of gardening families differs from non-gardening families, and that there are detectable changes in the fecal microbial community of gardeners and their family members over the course of the gardening season. Additional research is necessary to determine if changes induced by gardening on the gut microbiota contribute to human health.
