Alterations in the Oral Microbiome Associated With Diabetes, Overweight, and Dietary Components

Abstract

The Mediterranean diet (MedDiet) represents the traditional food consumption patterns of people living in countries bordering the Mediterranean Sea and is associated with a reduced incidence of obesity and type-2 diabetes mellitus (T2DM). The objective of this study was to examine differences in the composition of the oral microbiome in older adults with T2DM and/or high body mass index (BMI) and whether the microbiome was influenced by elements of a MedDiet. Using a nested case-control design individuals affected by T2DM were selected from the Seniors-ENRICA-2 cohort concurrently with non-diabetic controls. BMI was measured, a validated dietary history taken, and adherence to a Mediterranean diet calculated using the MEDAS (Mediterranean Diet Adherence Screener) index. Oral health status was assessed by questionnaire and unstimulated whole mouth saliva was collected, and salivary flow rate calculated. Richness and diversity of the salivary microbiome were reduced in participants with T2DM compared to those without diabetes. The bacterial community structure in saliva showed distinct “signatures” or “salivatypes,” characterized by predominance of particular bacterial genera. Salivatype 1 was more represented in subjects with T2DM, whilst those with obesity (BMI ≥ 30 kg/m2) had a predominance of salivatype 2, and control participants without T2DM or obesity had an increased presence of salivatype 3. There was an association of salivatype 1 with increased consumption of sugary snacks combined with reduced consumption of fish/shellfish and nuts. It can be concluded that the microbial community structure of saliva is altered in T2DM and obesity and is associated with altered consumption of particular food items. In order to further substantiate these observations a prospective study should be undertaken to assess the impact of diets aimed at modifying diabetic status and reducing weight.

Huoxue Jiangtang Decoction Alleviates Type 2 Diabetes Mellitus by Regulating the Oral Microbiota and Food Preferences

“…The results confirmed the impacts of DM on the dysbiosis of oral microbiota in diabetic rats and showed a significantly higher diversity of oral microbiota in samples of diabetic rats in contrast to that of rats in the CON group, in agreement with what several clinical studies had reported previously. 12,27 However, those results were contrary to the conclusion reported by Shaalan et al, 28 who found decreasing abundance and diversity of oral microbiota in subjects with T2DM. At the phylum level, it was found that the main species of oral bacterial colony of both diabetic rats and healthy ones were constituted by Firmicutes, Proteobacteria and Actinobacteria, which was similar to the findings of previous study.…”

Oral Microbiome Diversity Predicts All-cause Mortality in the General Population: A Prospective Population-based Cohort Study

“…Gut microbiome diversity decrease emblematizes that pathogenic strains occupy the ecological niche of the intestinal mucosa, causing harmful bacterial metabolites or gut bacteria to enter the blood through the disrupted intestinal barrier and promote systematic chronic subacute in ammation [22,23]. This ongoing systemic in ammation can drive the progression of metabolic disease [24], cardiovascular disease [25],…”

Impact of oral microbiota on pathophysiology of GVHD

“…In the diet, the intake of sugars and certain foods such as farmed animal meat, dairy products, refined vegetable oils, and processed grains affects the composition of the microbiota. Although the oral microbiota is not dependent on diet as an energy source ( 76 ), persistent sugar intake results in dysbiosis associated with a shift to glycolytic and acidophilic microbiota ( 77 ). Regarding smoking, the oral microbiota of smokers differs from that of nonsmokers in many respects, including reduced diversity, bacterial abundance, and metabolites.…”

“…Diabetes and periodontal disease are mutually aggravating ( 107 ); oral microbiota dysbiosis induces insulin resistance by affecting the body’s immune inflammation and oxidative stress, adversely affecting diabetes ( 95 ). Conversely, elevated glucose levels in the saliva and tissues in patients with diabetes result in oral microbiota dysbiosis, with a shift to glycolytic and acidophilic microbiota ( 76 , 77 ). Patients with rheumatoid arthritis, systemic lupus erythematosus, and Sjögren’s syndrome also have reduced oral microbiota diversity; the individual candidate pathogens differ among studies ( 108 , 109 ).…”

“…Conversely, high Veillonella abundance was associated with a low risk of aGVHD. This may be because lactic acid metabolism by Veillonella contributes to the resilience of the oral microbiota against acidification ( 77 ). Furthermore, Enterococcus faecalis bloom during transplantation was associated with acute and severe aGVHD risks ( 137 ).…”