Association of Vitamins D, B₉ and B₁₂ with Obesity-Related Diseases and Oral Microbiota Composition in Obese Women in Croatia

Research background. Oral microbiota has become an important factor in obesity, but its association with obesity-related diseases and serum 25-hydroxy vitamin D [25(OH)D] and B complex amounts is still uncertain. The main aim of the paper is to determine the variation in oral microbiota composition as a response to the vitamin status and obesity-related diseases in obese females from Croatia. We hypothesized that the prevalence of probiotic or pathogenic bacteria in the oral cavity of obese women in Croatia depends on the amounts of vitamin B-9 (folic acid), B-12 and 25(OH)D in serum and/or hypertension, diabetes and prediabetes diagnosis. Experimental approach. To test the defined research hypothesis, female individuals with body mass index (BMI)=30 kg/m(2) (N=70) were recruited to participate in this study. Obese women were divided into groups according to BMI value, diagnosis of obesity-related diseases and amount of micronutrient in blood. For the quantitative determination of folic acid, vitamin B-12 and 25(OH)D in serum, an electrochemiluminescence protein binding assay (ECLIA) was performed. Microorganisms isolated from the saliva of obese women were analyzed by MALDI-TOF mass spectrometer. Results and conclusions. The presented results do not support the hypothesis that the prevalence of probiotic or pathogenic bacteria in the oral cavity of obese women in Croatia depends on the amount of micronutrients. On the other hand, hypertension and diabetes/prediabetes favour the growth of oral pathogens, specifically increased levels of Candida sp. Novelty and scientific contribution. To the best of our knowledge, this is the first study showing the relationship between obesity, micronutrient amount, oral microbiota composition, and the incidence of obesity-related disease. We included only obese women from Croatia, so it is regionally specific. Also, we have shown that oral microbiota composition is not connected with micronutrient deficiencies but only with obesity-related diseases.