Dataset Information

An Apple a Day: Which Bacteria Do We Eat With Organic and Conventional Apples?

ABSTRACT: Apples are among the most consumed fruits world-wide. They represent a source of direct human exposure to bacterial communities, which is less studied. We analyzed the apple microbiome to detect differences between tissues and the impact of organic and conventional management by a combined approach of 16S rRNA gene amplicon analysis and qPCR, and visualization using fluorescence in situ hybridization and confocal laser scanning microscopy (FISH-CLSM). Each apple fruit harbors different tissues (stem, peel, fruit pulp, seeds, and calyx), which were colonized by distinct bacterial communities. Interestingly, fruit pulp and seeds were bacterial hot spots, while the peel was less colonized. In all, approximately 108 16S rRNA bacterial gene copy numbers were determined in each g apple. Abundances were not influenced by the management practice but we found a strong reduction in bacterial diversity and evenness in conventionally managed apples. In addition, despite the similar structure in general dominated by Proteobacteria (80%), Bacteroidetes (9%), Actinobacteria (5%), and Firmicutes (3%), significant shifts of almost 40% of bacterial genera and orders were monitored. Among them, especially bacterial signatures known for health-affecting potential were found to be enhanced in conventionally managed apples. Our results suggest that we consume about 100 million bacterial cells with one apple. Although this amount was the same, the bacterial composition was significantly different in conventionally and organically produced apples.

SUBMITTER: Wassermann B

PROVIDER: S-EPMC6667679 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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An Apple a Day: Which Bacteria Do We Eat With Organic and Conventional Apples?

Wassermann Birgit B Müller Henry H Berg Gabriele G

Frontiers in microbiology 20190724

Apples are among the most consumed fruits world-wide. They represent a source of direct human exposure to bacterial communities, which is less studied. We analyzed the apple microbiome to detect differences between tissues and the impact of organic and conventional management by a combined approach of 16S rRNA gene amplicon analysis and qPCR, and visualization using fluorescence <i>in situ</i> hybridization and confocal laser scanning microscopy (FISH-CLSM). Each apple fruit harbors different ti ...[more]

PMID: 31396172

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Project description:Our study was part of the large European project ISAFRUIT aiming to reveal the biological explanations for the epidemiologically well-established health effects of fruits. The objective was to identify effects of apple and apple product consumption on the composition of the cecal microbial community in rats, as well as on a number of cecal parameters, which may be influenced by a changed microbiota.Principal Component Analysis (PCA) of cecal microbiota profiles obtained by PCR-DGGE targeting bacterial 16S rRNA genes showed an effect of whole apples in a long-term feeding study (14 weeks), while no effects of apple juice, purée or pomace on microbial composition in cecum were observed. Administration of either 0.33 or 3.3% apple pectin in the diet resulted in considerable changes in the DGGE profiles.A 2-fold increase in the activity of beta-glucuronidase was observed in animals fed with pectin (7% in the diet) for four weeks, as compared to control animals (P < 0.01). Additionally, the level of butyrate measured in these pectin-fed animal was more than double of the corresponding level in control animals (P < 0.01). Sequencing revealed that DGGE bands, which were suppressed in pectin-fed rats, represented Gram-negative anaerobic rods belonging to the phylum Bacteroidetes, whereas bands that became more prominent represented mainly Gram-positive anaerobic rods belonging to the phylum Firmicutes, and specific species belonging to the Clostridium Cluster XIVa.Quantitative real-time PCR confirmed a lower amount of given Bacteroidetes species in the pectin-fed rats as well as in the apple-fed rats in the four-week study (P < 0.05). Additionally, a more than four-fold increase in the amount of Clostridium coccoides (belonging to Cluster XIVa), as well as of genes encoding butyryl-coenzyme A CoA transferase, which is involved in butyrate production, was detected by quantitative PCR in fecal samples from the pectin-fed animals.Our findings show that consumption of apple pectin (7% in the diet) increases the population of butyrate- and beta-glucuronidase producing Clostridiales, and decreases the population of specific species within the Bacteroidetes group in the rat gut. Similar changes were not caused by consumption of whole apples, apple juice, purée or pomace.

Project description:Fruit consumption is believed to have beneficial health effects, and some claim, "An apple a day keeps the doctor away."To examine the relationship between eating an apple a day and keeping the doctor away.A cross-sectional study of a nationally representative sample of the noninstitutionalized US adult population. A total of 8728 adults 18 years and older from the 2007-2008 and 2009-2010 National Health and Nutrition Examination Survey completed a 24-hour dietary recall questionnaire and reported that the quantity of food they ate was reflective of their usual daily diet.Daily apple eaters (consuming the equivalent of at least 1 small apple daily, or 149 g of raw apple) vs non-apple eaters, based on the reported quantity of whole apple consumed during the 24-hour dietary recall period.The primary outcome measure was success at "keeping the doctor away," measured as no more than 1 visit (self-reported) to a physician during the past year; secondary outcomes included successful avoidance of other health care services (ie, no overnight hospital stays, visits to a mental health professional, or prescription medications).Of 8399 eligible study participants who completed the dietary recall questionnaire, we identified 753 adult apple eaters (9.0%)--those who typically consume at least 1 small apple per day. Compared with the 7646 non-apple eaters (91.0%), apple eaters had higher educational attainment, were more likely to be from a racial or ethnic minority, and were less likely to smoke (P<.001 for each comparison). Apple eaters were more likely, in the crude analysis, to keep the doctor (and prescription medications) away: 39.0% of apple eaters avoided physician visits vs 33.9% of non-apple eaters (P=.03). After adjusting for sociodemographic and health-related characteristics, however, the association was no longer statistically significant (OR, 1.19; 95% CI, 0.93-1.53; P=.15). In the adjusted analysis, apple eaters also remained marginally more successful at avoiding prescription medications (odds ratio, 1.27; 95% CI, 1.00-1.63). There were no differences seen in overnight hospital stay or mental health visits.Evidence does not support that an apple a day keeps the doctor away; however, the small fraction of US adults who eat an apple a day do appear to use fewer prescription medications.

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Dataset Information

An Apple a Day: Which Bacteria Do We Eat With Organic and Conventional Apples?

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An Apple a Day: Which Bacteria Do We Eat With Organic and Conventional Apples?

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