Changes in the gut microbial communities following addition of walnuts to the diet

Abstract

Walnuts are rich in omega-3 fatty acids, phytochemicals and antioxidants making them unique compared to other foods. Consuming walnuts has been associated with health benefits including a reduced risk of heart disease and cancer. Dysbiosis of the gut microbiome has been linked to several chronic diseases. One potential mechanism by which walnuts may exert their health benefit is through modifying the gut microbiome. This study identified the changes in the gut microbial communities that occur following the inclusion of walnuts in the diet. Male Fischer 344 rats (n=20) were randomly assigned to one of two diets for as long as 10 weeks: (1) walnut (W), and (2) replacement (R) in which the fat, fiber, and protein in walnuts were matched with corn oil, protein casein, and a cellulose fiber source. Intestinal samples were collected from the descending colon, the DNA isolated, and the V3-V4 hypervariable region of 16S rRNA gene deep sequenced on an Illumina MiSeq for characterization of the gut microbiota. Body weight and food intake did not differ significantly between the two diet groups. The diet groups had distinct microbial communities with animals consuming walnuts displaying significantly greater species diversity. Walnuts increased the abundance of Firmicutes and reduced the abundance of Bacteriodetes. Walnuts enriched the microbiota for probiotic-type bacteria including Lactobacillus, Ruminococcaceae, and Roseburia while significantly reducing Bacteroides and Anaerotruncus. The class Alphaproteobacteria was also reduced. Walnut consumption altered the gut microbial community suggesting a new mechanism by which walnuts may confer their beneficial health effects.

Yeast fermentate prebiotic improves intestinal barrier integrity during heat stress by modulation of the gut microbiota in rats

“…High‐throughput 16S rRNA gene sequencing revealed that in all groups of rats Firmicutes was a dominant phylum that is in accordance with the data of other authors (Golubeva et al, ; Byerley et al, ). Significant changes of the gut microbiota in different groups were found at the genus taxonomic level.…”

Prevention of excessive exercise‐induced adverse effects in rats withBacillus subtilisBSB3

“…Results of pyrosequencing showed that Firmicutes , Bacteroidetes and Actinobacteria are the dominant phyla in all groups of rats, which correspond to observations by other authors (Byerley et al ). No difference in phyla presentation was found in different groups, but the Firmicutes to Bacteroidetes ratio was highest in the BEx group.…”

Calcium Oxalate Nephrolithiasis and Gut Microbiota: Not just a Gut-Kidney Axis. A Nutritional Perspective

“…Adaptive changes of gut microbiota composition in stone formers following a high-oxalate diet could also help to explain why, in the Suryavanshi study mentioned above [44], stone formers had a high representation of oxalate-degrading species, a finding that is not coherent with the other studies listed in Table 3. A high intake of foods with elevated oxalate content, such as almonds, hazelnuts, walnuts, and pistachios, has been associated with specific changes of gut microbiota composition [110][111][112][113][114][115]. These changes are generally considered beneficial for human health and include an increased relative abundance of Lachnospira, Roseburia, Dialister, Faecalibacterium, and Lactobacillus with increased production of SCFA [110][111][112][113][114][115].…”