The effects of dairy and dairy derivatives on the gut microbiota: a systematic literature review

Abstract

The effects of dairy and dairy-derived products on the human gut microbiota remains understudied. A systematic literature search was conducted using Medline, CINAHL, Embase, Scopus, and PubMed databases with the aim of collating evidence on the intakes of all types of dairy and their effects on the gut microbiota in adults. Risk of bias was assessed using the Cochrane risk-of-bias tool. The search resulted in 6,592 studies, of which eight randomized controlled trials (RCTs) met predetermined eligibility criteria for inclusion, consisting of a total of 468 participants. Seven studies assessed the effect of type of dairy (milk, yogurt, and kefir) and dairy derivatives (whey and casein) on the gut microbiota, and one study assessed the effect of the quantity of dairy (high dairy vs low dairy). Three studies showed that dairy types consumed (milk, yogurt, and kefir) increased the abundance of beneficial genera Lactobacillus and Bifidobacterium. One study showed that yogurt reduced the abundance of Bacteroides fragilis, a pathogenic strain. Whey and casein isolates and the quantity of dairy consumed did not prompt changes to the gut microbiota composition. All but one study reported no changes to bacterial diversity in response to dairy interventions and one study reported reduction in bacterial diversity in response to milk intake.In conclusion, the results of this review suggest that dairy products such as milk, yogurt, and kefir may modulate the gut microbiota composition in favor to the host. However, the broader health implications of these findings remain unclear and warrant further studies.

Are there any concerns about dairy food consumption and cardiovascular health?

“…Fifth, milk and dairy product consumption has been reported to affect gut microbiota, with favourable effects on beneficial genera (such as Lactobacillus and Bifidobacterium) and inhibition of pathogenic strains (such as Bacteroides fragilis) (Aslam et al 2020). Gut microbiota have been reported to play a role in systemic chronic inflammation, which has been established as a key factor for cardiovascular risk (Salvucci 2019).…”

Dairy Lactic Acid Bacteria and Their Potential Function in Dietetics: The Food–Gut-Health Axis

“…In a preliminary study, Butler and co-authors observed that dietary changes based on the intake of dairy products promote the Lactobacillus abundance and suggest a link with the psychological status in participants by measuring the predictive neuroactive potential using a gut–brain module approach [ 12 ]. Accordingly, a recent survey indicated that the intake of dairy products such as milk, yogurt, and kefir may modulate the gut microbiota by increasing the Lactobacillus population [ 13 ], while consumption of a fermented dairy product containing a probiotic Lactobacillus casei strain reduces the duration of respiratory infections in the elderly [ 14 ]. However, the influence of dairy consumption in conjunction with other factors such as host genetics, age, sex, and lifestyle influences the gut microbiota composition and functionality.…”

Microbiota and Metabolite Modifications after Dietary Exclusion of Dairy Products and Reduced Consumption of Fermented Food in Young and Older Men

“…For example, indoles (that are products of microbial tryptophan metabolism [6]) stimulate host intestinal mucin production, thereby providing an energy source to commensal bacteria and protecting the host intestinal layer from pathogen invasion [14]. Both LAB and metabolites derived from the fermentation process in dairy products thus have the potential to modulate the gut microbiota composition and mediate some of the health benefits of dairy products [15][16][17][18]. However, these effects are dependent on multiple factors including the metabolite flux across the digestive tract after dairy product consumption, the host microbiota composition, and the metabolic or health status of the consumer.…”