Mild dehydration: a risk factor for dental disease?

Oral dysbacteriosis in type 2 diabetes and its role in the progression to cardiovascular disease

Background

Salivary changes and proliferation of specific bacterial communities are known to result in oral disease which may adversely impact on systemic conditions like diabetes and cardiovascular diseases.

Objectives

This study reports on the changes in oral ecology of healthy and diseased adults and the possible role in disease causation.

Methods

The study comprised 150 participants divided into control (healthy), diabetic and cardiac groups. After dental examination for (Decayed Missing Filled Teeth (DMFT) and Oral Rating Index (ORI), stimulated saliva was sampled to determine flow rate and buffering capacity. Salivary microbial load of Streptococcus mutans and Lactobacilli were subsequently quantified.

Results

DMFT, ORI, buffering capacity and flow rate were inferior for both diabetic and cardiac patients, who had higher bacterial counts (p<0.05). Long standing diabetics harboured a higher load of Streptococcus mutans. The microbial load of Streptococcus mutans in cardiac patients was double that of diabetics.

Conclusion

Disruption in the salivary environment and changes in microbial ecology with increased load of cariogenic bacteria were found in diabetic and cardiac patients. This study brings forward new evidence of a markedly higher load of Streptococcus mutans in cardiac patients which may underlie the progression of diabetes to cardiovascular disease in this population.

Effect of Caffeinated Soft Drinks on Salivary Flow

BACKGROUND

Soft drinks containing caffeine have been associated with more aggressive forms of dental decay. Cariogenicity of caffeinated soft drinks may be attributed to the effect of caffeine on salivary flow. This study assessed whether caffeinated soft drinks produced short-term oral dryness in healthy adults.

METHODS

The authors collected saliva on two separate days from 35 participants before and one hour after drinking a soft drink. On one of the days the soft drink was caffeinated and on the other day it was not. Saliva collection involved 15 minutes unstimulated whole saliva, 5 minutes paraffin-stimulated whole saliva, and 10 seconds labial minor salivary gland output.

RESULTS

Unstimulated and stimulated flow rates slightly increased and minor gland output slightly decreased one hour after the soft drink consumption regardless of caffeine content. These changes were not statistically significant (two-period two-treatment crossover trial using two-stage Grizzle model, p>0.05). A linear mixed model statistic did not show the caffeine effect on salivary flow rate.

CONCLUSIONS

Caffeinated soft drink consumption had no significant effect on salivary flow rate after one hour by any of the three measures employed in this study. Caffeine's contribution to the cariogenicity of soft drinks is likely by centrally-mediated effects on consumption patterns.

Dehydration decreases saliva antimicrobial proteins important for mucosal immunity

The aim of the study was to investigate the effect of exercise-induced dehydration and subsequent overnight fluid restriction on saliva antimicrobial proteins important for host defence (secretory IgA (SIgA), α-amylase, and lysozyme). On two randomized occasions, 13 participants exercised in the heat, either without fluid intake to evoke progressive body mass losses (BML) of 1%, 2%, and 3% with subsequent overnight fluid restriction until 0800 h in the following morning (DEH) or with fluids to offset losses (CON). Participants in the DEH trial rehydrated from 0800 h until 1100 h on day 2. BML, plasma osmolality (Posm), and urine specific gravity (USG) were assessed as hydration indices. Unstimulated saliva samples were assessed for flow rate (SFR), SIgA, α-amylase, and lysozyme concentrations. Posm and USG increased during dehydration and remained elevated after overnight fluid restriction (BML = 3.5% ± 0.3%, Posm = 297 ± 6 mosmol·kg–1, and USG = 1.026 ± 0.002; P < 0.001). Dehydration decreased SFR (67% at 3% BML, 70% at 0800 h; P < 0.01) and increased SIgA concentration, with no effect on SIgA secretion rate. SFR and SIgA responses remained unchanged in the CON trial. Dehydration did not affect α-amylase or lysozyme concentration but decreased secretion rates of α-amylase (44% at 3% BML, 78% at 0800 h; P < 0.01) and lysozyme (46% at 3% BML, 61% at 0800 h; P < 0.01), which were lower than in CON at these time points (P < 0.05). Rehydration returned all saliva variables to baseline. In conclusion, modest dehydration (~3% BML) decreased SFR, α-amylase, and lysozyme secretion rates. Whether the observed magnitude of decrease in saliva AMPs during dehydration compromises host defence remains to be shown.

A study of fluid intake from beverages in a sample of healthy French children, adolescents and adults

Background/Objectives:

To assess the intake of fluid in healthy French children, adolescents, adults and seniors, considering amounts, types of beverages, time and place of consumption.

Subjects/Methods:

Data regarding fluid intake were extracted and analyzed from the National Intake Survey, which was conducted in quota samples of the French population (Comportement et Consommations Alimentaires en France study). Seven-day questionnaires were administered to free-living individuals in 2002–2003. A total of 566 children (aged 6–11 years), 333 adolescents (aged 12–19 years), 831 adults (aged 20–54 years) and 443 seniors (aged ⩾55 years) were included in this study.

Results:

The average total intake of fluid was 1–1.3 l per day depending on age groups. Water accounted for about one-half of daily fluid intake. The contribution of other types of beverages varied with age (for example, dairy drinks in children and adolescents; alcoholic drinks in adults and seniors). Intake of sodas (including regular and light) was highest in adolescents (169 ml a day). Beverages were mainly consumed at home during meals.

Conclusions:

This is the first description of fluid intake in French children, adolescents, adults and seniors, considering amounts, types of beverages, time and place of intake. It shows that water is the main source of fluid in all age groups. Selection of various types of beverages is different according to age.

An exploration of factors that influence the regular consumption of water by Irish primary school children

BACKGROUND

Inadequate hydration has been linked to many factors that may impact on children's education and health. Teachers play an important role in the education and behaviour of children. Previous research has demonstrated low water intake amongst children and negative teachers' attitudes to water in the classroom. The present study aimed to explore teachers' knowledge about water and the perceived barriers to allowing children access to water during lesson time.

METHODS

In-depth interviews were conducted with 12 teachers from primary schools in the Midlands of Ireland. Interviews were continued until there was saturation of the data. Thematic analysis of the data was conducted.

RESULTS

Participants had a poor knowledge of hydration requirements and the associated health benefits and effect on concentration. Low water intake amongst teachers and pupils, and barriers such as disruption to class and increased need to urinate, were reported. Teachers identified the hydration effect on learning as the education message most likely to influence the decision to allow water in the classroom.

CONCLUSIONS

The issues, opinions and perceived barriers raised by teachers as part of this qualitative research provide a basis for future health promotion around water.

Serum markers of chronic dehydration are associated with saliva spinability

Findings of a relationship between saliva and dehydration have been observed, but the precise nature of these relationships is unclear and no evidence of a direct link has been found. In particular, no study reports a relationship between chronic dehydration and saliva conditions in community-dwelling older adults. This study aimed to identify whether salivary conditions are sensitive to body hydration markers in an elderly population. A total of 403 subjects aged 76 years participated in the study. Stimulated saliva flow rate and spinability of saliva were measured. In addition, determinations of serum levels of uric acid, blood urea nitrogen (BUN), creatinine, sodium and potassium were made. Dehydration was defined as uric acid >/= 7 mg dL(-1) according to the standard value. The salivary spinability were significantly associated with the concentration of uric acid (OR=2.06, P=0.044) according to multiple logistic regression analysis. In addition, after adjusting for gender, the uric acid concentration and the salivary spinability was significantly associated with BUN, potassium and creatinine levels. The subjects with high uric acid levels (>/= 7 mg dL(-1)) had the most elastic saliva. Both BUN and serum creatinine are the most commonly used indicators of renal function. Therefore, our findings might demonstrate that older adults who are dehydrated showed highly elastic saliva, which was associated with renal function. In conclusion, this study suggests that there is a significant relationship between chronic dehydration status and salivary spinability level.

The Importance of Good Hydration for the Prevention of Chronic Diseases

There is increasing evidence that mild dehydration plays a role in the development of various morbidities. In this review, the effects of hydration status on chronic diseases are categorized according to the strength of the evidence. Positive effects of maintenance of good hydration are shown for urolithiasis (category lb evidence); constipation, exercise asthma, hypertonic dehydration in the infant, and hyperglycemia in diabetic ketoacidosis (all category IIb evidence); urinary tract infections, hypertension, fatal coronary heart disease, venous thromboembolism, and cerebral infarct (all category III evidence); and bronchopulmonary disorders (category IV evidence). For bladder and colon cancer, the evidence is inconsistent.