Most studies examining the commensal human oral microbiome are focused on disease or are limited in methodology. In order to diagnose and treat diseases at an early and reversible stage an in-depth definition of health is indispensible. The aim of this study therefore was to define the healthy oral microbiome using recent advances in sequencing technology (454 pyrosequencing).

Background: An understanding of the relation of commensal microbiota to health is essential in preventing disease. Here we studied the oral microbial composition of children (N = 74, aged 3 - 18 years) in natural transition from their deciduous to a permanent dentition and related the microbial profiles to their oral health status. The microbial composition of saliva was assessed by barcoded pyrosequencing of the V5-V6 hypervariable regions of the 16 S rRNA, as well as by using phylogenetic microarrays. Results: Pyrosequencing reads (126174 reads, 1045 unique sequences) represented 8 phyla and 113 higher taxa in saliva samples. Four phyla - Firmicutes, Bacteriodetes, Proteobacteria and Actinobacteria - predominated in all groups. The deciduous dentition harboured a higher proportion of Proteobacteria (Gammaproteobacteria, Moraxellaceae) than Bacteroidetes, while in all other groups Bacteroidetes were at least as abundant as Proteobacteria. Bacteroidetes (mainly genus Prevotella), Veillonellaceae family, Spirochaetes and candidate division TM7 increased with increasing age, reflecting maturation of the microbiome driven by biological changes with age. Microarray analysis enabled further analysis of the individual salivary microbiota. Of 350 microarray probes, 156 gave a positive signal with, on average, 77 (range 48-93) probes per individual sample. A caries-free oral status significantly associated with the higher signal of the probes targeting Porphyromonas catoniae and Neisseria flavescens. Conclusions: The potential role of P. catoniae and N. flavescens as oral health markers should be assessed in large-scale clinical studies. The combination of both, open-ended and targeted molecular approaches provides us with information that will increase our understanding of the interplay between the human host and its microbiome.

The variation of microbial communities associated with the human body can be the cause of many factors, including the human genetic makeup, diet, age, surroundings, and sexual behavior. In this study, we investigated the effects of intimate kissing on the oral microbiota of 21 couples by self-administered questionnaires about their past kissing behavior and by the evaluation of tongue and salivary microbiota samples in a controlled kissing experiment. In addition, we quantified the number of bacteria exchanged during intimate kissing by the use of marker bacteria introduced through the intake of a probiotic yoghurt drink by one of the partners prior to a second intimate kiss.

Age-related declines in taste and smell function are widely assumed to contribute to the decrease in appetite and the development of undernutrition in older adults. Here we aim to assess the associations of both taste and smell function with several nutrition-related outcomes in a single study, with poor appetite and undernutrition as primary outcomes. This is a cross-sectional cohort study of 359 community-dwelling Dutch older adults, aged 65–93 y. Taste function was measured for all 5 basic tastes. Smell function was assessed with 3 tests: for odor identification, discrimination, and threshold. Self-reported taste and smell, appetite, energy (kcal/d) and macronutrient (% energy) intake, and covariates were assessed with extensive questionnaires. Dietary quality was calculated using the Dutch Healthy Diet index 2015, Alternative Healthy Eating Index 2010, and Mediterranean Diet Score. Body measurements included body weight (current and 2 y prior), height, and body impedance analysis. Data were analyzed via multiple logistic and linear regression. Of our sample, 9.2% had poor taste and 17.0% poor smell, 6.1% had poor appetite, and 21.4% were undernourished. Self-reported poor taste (OR: 8.44; 95% CI: 1.56, 45.56; P = 0.013) was associated with poor appetite, but no other taste or smell score was associated with either poor appetite or undernutrition. Some associations were found of individual taste and smell scores with macronutrient intake and dietary quality. Self-reported poor taste and smell were both consistently associated with poorer dietary quality. In community-dwelling older adults, specific taste and smell impairments may have diverse consequences for appetite, food intake, or dietary quality. However, this does not necessarily result in undernutrition. The consistent associations of self-reported poor taste and smell with poor dietary quality do underline the usefulness of this information when screening for nutritional risk.

Poor oral health might be a modifiable determinant of malnutrition in older age. We aimed to investigate the associations of multiple oral health characteristics with incident malnutrition in community-dwelling older adults. This exploratory analysis is based on prospective data from 893 participants, aged 55-80 years without malnutrition in 2005/06 from the Longitudinal Aging Study Amsterdam. In 2007, 19 oral health characteristics from the domains teeth/dentures, oral hygiene, oral problems, and self-rated oral health were assessed by questionnaire. Incident malnutrition was defined as presence of low body mass index (<20 kg/m² in people <70 years, <22 kg/m² ≥70 years) and/or self-reported involuntary weight loss ≥5% in previous 6 months at any of the follow-ups (2008/09, 2012/13, 2015/16). Associations of oral aspects with incident malnutrition were analyzed by cox proportional hazard models and adjusted for confounders. The 9-year incidence of malnutrition was 13.5%. Sixteen of 19 oral health aspects were not associated with incident malnutrition in the crude models. Adjusted hazard ratios for incident malnutrition were 2.14 (1.10-4.19, p = 0.026) for toothache while chewing, 2.10 (0.88-4.98, p = 0.094) for an unhealthy oral health status, and 1.99 (0.93-4.28, p = 0.077) for xerostomia in edentulous participants, however, the two latter ones failing to reach statistical significance. We identified toothache while chewing as determinant of incident malnutrition in community-dwelling older adults, and found indications that poor oral health and xerostomia in combination with having no teeth may play a role in developing malnutrition. However, these outlined tendencies need to be proven in further studies. Regarding the development of strategies to prevent malnutrition in older people toothache while chewing, xerostomia, and self-rated oral health would be of specific interest as these factors are modifiable and can be easily assessed by self-reports.

Vitamin D deficiency is frequently found in patients with Chronic Obstructive Pulmonary Disease (COPD). Vitamin D has antimicrobial, anti-inflammatory and immunomodulatory effects. Therefore, supplementation may prevent COPD exacerbations, particularly in deficient patients. To assess the effect of vitamin D supplementation on exacerbation rate in vitamin D-deficient patients with COPD We performed a multi-center, double-blind, randomized controlled trial. COPD patients with one or more exacerbations in the preceding year and a vitamin D deficiency (15–50 nmol/L) were randomly allocated in a 1:1 ratio to receive either vitamin D3 16.800 IU or placebo once a week during 1 year. Primary outcome of the study was exacerbation rate. Secondary outcomes included time to first and second exacerbation, time to first and second hospitalization, use of antibiotics and corticosteroids, pulmonary function, maximal respiratory mouth pressure, physical performance, skeletal muscle strength, systemic inflammatory markers, nasal microbiota composition, and quality of life. The intention-to-treat population consisted of 155 participants. Mean (SD) serum 25-hydroxyvitamine D (25(OH)D) concentrations after one year was 112 (34) nmol/L in the vitamin D group, compared to 42 (17) nmol/L in the placebo group. Vitamin D supplementation did not affect exacerbation rate (incidence rate ratio (IRR):0.90; 95%-confidence interval (95%-CI): 0.67,1.21). In a prespecified subgroup analysis in participants with 25(OH)D levels 15–25 nmol/L (n = 31) no effect of vitamin D supplementation was found (IRR:0.91; 95%-CI:0.43,1.93). No relevant differences were found between the intervention and placebo group in secondary outcomes. Vitamin D supplementation did not reduce exacerbation rate in COPD patients with a vitamin D deficiency.