The acute effect of the menstrual cycle and oral contraceptive cycle on measures of body composition.

PURPOSE: This study aimed to investigate the effect of fluctuating female hormones during the menstrual cycle (MC) and oral contraceptive (OC) cycle on different measures of body composition. METHODS: Twenty-two women with a natural MC and thirty women currently taking combined monophasic OC were assessed over three phases of the menstrual or oral contraceptive cycle. Body weight, skinfolds, bioelectric impedance analysis (BIA), ultrasound, dual-energy X-ray absorptiometry (DXA), and peripheral quantitative computed tomography (pQCT) measurements were performed to assess body composition. Urine specific gravity (USG) was measured as an indication of hydration, and serum oestradiol and progesterone were measured to confirm cycle phases. RESULTS: Five participants with a natural MC were excluded based on the hormone analysis. For the remaining participants, no significant changes over the MC and OC cycle were found for body weight, USG, skinfolds, BIA, ultrasound and pQCT measures. However, DXA body fat percentage and fat mass were lower in the late follicular phase compared to the mid-luteal phase of the MC, while for the OC cycle, DXA body fat percentage was higher and lean mass lower in the early hormone phase compared with the late hormone phase. CONCLUSION: Our findings suggest that assessment of body fat percentage through BIA and skinfolds may be performed without considering the MC or OC cycle. Body adiposity assessment via DXA, however, may be affected by female hormone fluctuations and therefore, it may be advisable to perform repeat testing using DXA during the same phase of the MC or OC cycle.

Relationship between maternal global nutrient restriction during pregnancy and offspring kidney structure and function: a systematic review of animal studies.

Maternal undernutrition during pregnancy is prevalent across the globe, and the origins of many chronic diseases can be traced back to in utero conditions. This systematic review considers the current evidence in animal models regarding the relationship between maternal global nutrient restriction during pregnancy and offspring kidney structure and function. CINAHL, Cochrane, EMBASE, MEDLINE, and Scopus were searched to November 2017. Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines were followed, and articles were screened by two independent reviewers. Twenty-eight studies met the inclusion criteria: 16 studies were on rats, 9 on sheep, 2 on baboons, and 1 on goats. The majority of the rat studies had maternal global nutrient restriction during pregnancy at 50% of ad libitum while restriction for sheep and baboon studies ranged from 50% to 75%. Because of the heterogeneity of outcome measures and the large variation in the age of offspring at followup, no meta-analysis was possible. Common outcome measures included kidney weight, nephron number, glomerular size, glomerular filtration rate, and creatinine clearance. To date, there have been no studies assessing kidney function in large animal models. Most studies were rated as having a high or unknown risk of bias. The current body of evidence in animals suggests that exposure to maternal global nutrient restriction during pregnancy has detrimental effects on offspring kidney structure and function, such as lower kidney weight, lower nephron endowment, larger glomerular size, and lower glomerular filtration rate. Further long-term followup of studies in large animal models investigating kidney function through to adulthood are warranted.

Hypoxia During Resistance Exercise Does Not Affect Physical Performance, Perceptual Responses, or Neuromuscular Recovery.

Scott, BR, Slattery, KM, Sculley, DV, and Dascombe, BJ. Hypoxia during resistance exercise does not affect physical performance, perceptual responses, or neuromuscular recovery. J Strength Cond Res 32(8): 2174-2182, 2018-This study aimed to determine whether performing resistance exercise in hypoxia affects markers of physical performance, perceptual responses, and neuromuscular function. Fourteen male subjects (age: 24.6 ± 2.7 years; height: 179.7 ± 5.9 cm; body mass: 84.6 ± 11.6 kg) with >2 years resistance training experience performed moderate-load resistance exercise in 2 conditions: normoxia (FIO2 = 0.21) and hypoxia (FIO2 = 0.16). Resistance exercise comprised 3 sets of 10 repetitions of back squats and deadlifts at 60% of 1 repetition maximum (1RM), with 60 seconds inter-set rest. Physical performance was assessed by quantifying velocity and power variables during all repetitions. Perceptual ratings of perceived exertion, physical fatigue, muscle soreness, and overall well-being were obtained during and after exercise. Neuromuscular performance was assessed by vertical jump and isometric mid-thigh pull (IMTP) tasks for up to 48 hours after exercise. Although physical performance declined across sets, there were no differences between conditions. Similarly, perceived exertion and fatigue scores were not different between conditions. Muscle soreness increased from baseline at 24 and 48 hours after exercise in both conditions (p ≤ 0.001). Jump height and IMTP peak force were decreased from baseline immediately after exercise (p ≤ 0.026), but returned to preexercise values after 24 hours. These findings suggest that hypoxic resistance exercise does not affect exercise performance or perceived exercise intensity. In addition, neuromuscular recovery and perceptual markers of training stress were not affected by hypoxia, suggesting that hypoxic resistance training may not add substantially to the training dose experienced.

Running performance in the heat is improved by similar magnitude with pre-exercise cold-water immersion and mid-exercise facial water spray.

This investigation compared the effects of external pre-cooling and mid-exercise cooling methods on running time trial performance and associated physiological responses. Nine trained male runners completed familiarisation and three randomised 5 km running time trials on a non-motorised treadmill in the heat (33°C). The trials included pre-cooling by cold-water immersion (CWI), mid-exercise cooling by intermittent facial water spray (SPRAY), and a control of no cooling (CON). Temperature, cardiorespiratory, muscular activation, and perceptual responses were measured as well as blood concentrations of lactate and prolactin. Performance time was significantly faster with CWI (24.5 ± 2.8 min; P = 0.01) and SPRAY (24.6 ± 3.3 min; P = 0.01) compared to CON (25.2 ± 3.2 min). Both cooling strategies significantly (P < 0.05) reduced forehead temperatures and thermal sensation, and increased muscle activation. Only pre-cooling significantly lowered rectal temperature both pre-exercise (by 0.5 ± 0.3°C; P < 0.01) and throughout exercise, and reduced sweat rate (P < 0.05). Both cooling strategies improved performance by a similar magnitude, and are ergogenic for athletes. The observed physiological changes suggest some involvement of central and psychophysiological mechanisms of performance improvement.

Acute Physiological Responses to Moderate-Load Resistance Exercise in Hypoxia.

Scott, BR, Slattery, KM, Sculley, DV, Lockhart, C, and Dascombe, BJ. Acute physiological responses to moderate-load resistance exercise in hypoxia. J Strength Cond Res 31(7): 1973-1981, 2017-This study assessed whether hypoxia augments anabolic responses to moderate-load resistance exercise. Fourteen trained men performed moderate-load resistance exercise in normoxia (NORM; fraction of inspired oxygen [FIO2] = 21%) and moderate-level hypoxia (MH; FIO2 = 16%). Exercise comprised 3 sets of 10 repetitions of squats and deadlifts at 60% of 1 repetition maximum, with 60-second interset rest. Blood lactate (BLa) was quantified after each exercise, whereas arterial oxygen saturation and heart rate (HR) were assessed after each set. Thigh circumference was measured before and after exercise. Muscle activation and oxygenation were monitored by surface electromyography (EMG) and near-infrared spectroscopy, respectively. Relative BLa concentrations were significantly higher following squats (p = 0.041) and deadlifts (p = 0.002) in MH than NORM. Arterial oxygen saturation was lower after each set in MH compared with NORM (p < 0.001), although HR and thigh circumference were not different between conditions. Integrated EMG was higher in MH than in NORM for the squat during several repetitions (p ≤ 0.032). Measures of muscle oxygen status were not significantly different between conditions (p ≥ 0.247). The main findings from this study suggest that hypoxia during moderate-load resistance exercise augments metabolite accumulation and muscle activation. However, a significant hypoxic dose was not measured at the muscle, possibly because of the moderate level of hypoxia used. The current data support previous hypotheses that have suggested hypoxia can augment some physiological responses that are important for muscular development, and may therefore provide benefit over the equivalent training in normoxia.

A Comparison of Mixed-Method Cooling Interventions on Preloaded Running Performance in the Heat.

Stevens, CJ, Bennett, KJM, Sculley, DV, Callister, R, Taylor, L, and Dascombe, BJ. A comparison of mixed-method cooling interventions on preloaded running performance in the heat. J Strength Cond Res 31(3): 620-629, 2017-The purpose of this investigation was to assess the effect of combining practical methods to cool the body on endurance running performance and physiology in the heat. Eleven trained male runners completed 4 randomized, preloaded running time trials (20 minutes at 70% V[Combining Dot Above]O2max and a 3 km time trial) on a nonmotorized treadmill in the heat (33° C). Trials consisted of precooling by combined cold-water immersion and ice slurry ingestion (PRE), midcooling by combined facial water spray and menthol mouth rinse (MID), a combination of all methods (ALL), and control (CON). Performance time was significantly faster in MID (13.7 ± 1.2 minutes; p < 0.01) and ALL (13.7 ± 1.4 minutes; p = 0.04) but not PRE (13.9 ± 1.4 minutes; p = 0.24) when compared with CON (14.2 ± 1.2 minutes). Precooling significantly reduced rectal temperature (initially by 0.5 ± 0.2° C), mean skin temperature, heart rate and sweat rate, and increased iEMG activity, whereas midcooling significantly increased expired air volume and respiratory exchange ratio compared with control. Significant decreases in forehead temperature, thermal sensation, and postexercise blood prolactin concentration were observed in all conditions compared with control. Performance was improved with midcooling, whereas precooling had little or no influence. Midcooling may have improved performance through an attenuated inhibitory psychophysiological and endocrine response to the heat.

The validity of endurance running performance on the Curve 3(TM) non-motorised treadmill.

This study aimed to test the validity of a non-motorised treadmill (NMT) for the measurement of self-paced overground endurance running performance. Ten male runners performed randomised 5-km running time trials on a NMT and an outdoor athletics track. A range of physiological and perceptual responses was measured, and foot strike was classified subjectively. Performance time was strongly correlated (r = 0.82, ICC = 0.86) between running modes, despite running time being significantly longer on the NMT (1264 ± 124 s vs. 1536 ± 130 s for overground and NMT, respectively; P < 0.001). End blood lactate concentration and rating of perceived exertion were significantly higher on the NMT compared to overground. Integrated electromyography was significantly lower on the NMT for three muscles (P < 0.05), and mean stride rate was also significantly lower on the NMT (P = 0.04). Cardiorespiratory responses of heart rate, oxygen uptake and expired air volume demonstrated strong correlations (r = 0.68-0.96, ICC = 0.75-0.97) and no statistical differences (P > 0.05). Runners were consistently slower on the NMT, and as such it should not be used to measure performance over a specific distance. However, the strong correlations suggest that superior overground performance was reflected in relative terms on the NMT, and therefore, it is a valid tool for the assessment of endurance running performance in the laboratory.

Physical performance during high-intensity resistance exercise in normoxic and hypoxic conditions.

This study aimed to determine whether different levels of hypoxia affect physical performance during high-intensity resistance exercise or subsequent cardiovascular and perceptual responses. Twelve resistance-trained young men (age, 25.3 ± 4.3 years; height, 179.0 ± 4.5 cm; body mass, 83.4 ± 9.1 kg) were tested for 1 repetition maximum (1RM) in the back squat and deadlift. Following this, participants completed 3 separate randomized trials of 5 × 5 repetitions at 80% 1RM, with 3 minutes rest between sets, in normoxia (NORM; fraction of inspired oxygen [FIO2] = 0.21), moderate-level hypoxia (FIO2 = 0.16), or high-level hypoxia (FIO2 = 0.13) by a portable hypoxic unit. Peak and mean force and power variables were monitored during exercise. Arterial oxygen saturation (SpO2), heart rate (HR), and rating of perceived exertion (RPE) were assessed immediately following each set. No differences in force or power variables were evident between conditions. Similar trends were evident in these variables across each set and across the exercise session in each condition. SpO2 was lower in hypoxic conditions than in NORM, whereas HR was higher following sets performed in hypoxia. There were no differences between conditions in RPE. These results indicate that a hypoxic stimulus during high-intensity resistance exercise does not alter physical performance during repetitions and sets or affect how strenuous exercise is perceived to be. This novel training strategy can be used without adversely affecting the physical training dose experienced and may provide benefits over the equivalent training in NORM.

The validity and reliability of a customized rigid supportive harness during Smith machine back squat exercise.

Although the back squat exercise is commonly prescribed to both athletic and clinical populations, individuals with restricted glenohumeral mobility may be unable to safely support the bar on the upper trapezius using their hands. The aims of this study were to investigate the validity and reliability of a back squat variation using a rigid supportive harness that does not require unrestricted glenohumeral mobility for quantifying 1 repetition maximum (1RM). Thirteen young men (age = 25.3 ± 4.5 years, height = 179.2 ± 6.9 cm, and body mass = 86.6 ± 12.0 kg) with at least 2 years resistance training experience volunteered to participate in the study. Subjects reported to the lab on 3 occasions, each separated by 1 week. During testing sessions, subjects were assessed for 1RM using the traditional back squat (session 1) and harness back squat (HBS; sessions 2 and 3) exercises. Mean 1RM for the traditional back squat, and 2 testing sessions of the HBS (HBS1 and HBS2) were 148.4 ± 25.0 kg, 152.5 ± 25.7 kg, and 150.4 ± 22.6 kg, respectively. Back squat and mean HBS 1RM scores were very strongly correlated (r = 0.96; p < 0.001). There were no significant differences in 1RM scores between the 3 trials. The test-retest 1RM scores with the HBS demonstrated high reliability, with an intraclass correlation coefficient of 0.98 (95% confidence interval [CI] = 0.93-0.99), and a coefficient of variation of 2.6% (95% CI = 1.9-4.3). Taken together, these data suggest that the HBS exercise is a valid and reliable method for assessing 1RM in young men with previous resistance training experience and may be useful for individuals with restricted glenohumeral mobility.

The Effect of the Menstrual Cycle and Oral Contraceptive Cycle on Muscle Performance and Perceptual Measures.

Most reproductive-aged women are exposed to fluctuating female steroid hormones due to the menstrual cycle or oral contraceptive use. This study investigated the potential effect of the menstrual cycle and combined monophasic oral contraceptive cycle on various aspects of muscle performance. Thirty active females (12 with a natural menstrual cycle, 10 taking a high-androgenicity oral contraceptive and 8 taking a low-androgenicity oral contraceptive), aged 18 to 30 years, were tested three times throughout one menstrual or oral contraceptive cycle. Counter-movement jumps, bilateral hop jumps, handgrip strength, isometric knee extensor strength and isokinetic knee flexion and extension were assessed. Perceptual ratings of fatigue, muscle soreness, pain and mood were recorded. Most variables showed no significant changes over the menstrual or oral contraceptive cycle. However, for the menstrual cycle group, isokinetic knee flexion at 240° s-1, and time of flight in bilateral hopping and counter movement jumps showed better results during the mid-luteal phase compared with the late follicular phase. For the high-androgenicity oral contraceptive group, isokinetic knee flexion at 240° s-1 was significantly higher in the late hormone phase compared with the early hormone phase. For the low-androgenicity oral contraceptive group, time of flight for the counter-movement jumps was lower in the late hormone phase compared with the early hormone phase. The findings indicate that faster and explosive aspects of muscle performance may be influenced by endogenous and exogenous female hormones.

Acute physiological and perceptual responses to high-load resistance exercise in hypoxia.

This study assessed whether hypoxia during high-load resistance exercise could enhance the acute physiological responses related to muscular development. Twelve trained men performed exercise in three conditions: normoxia (fraction of inspired oxygen [FI O2 ] = 21%), moderate-level hypoxia (FI O2  = 16%) and high-level hypoxia (FI O2  = 13%). Exercise comprised high-load squats and deadlifts (5 × 5 using 80% of 1-repetition maximum with 180-s rest). Muscle oxygenation and activation were monitored during exercise. Metabolic stress was estimated via capillary blood sampling. Perceived fatigue and soreness were also quantified following exercise. While the hypoxic conditions appeared to affect muscle oxygenation, significant differences between conditions were only noted for maximal deoxyhaemoglobin in the deadlift (P = 0·009). Blood lactate concentration increased from 1·1 to 1·2 mmol l-1 at baseline to 9·5-9·8 mmol l-1 after squats and 10·4-10·5 mmol l-1 after deadlifts (P≤0·001), although there were no between-condition differences. Perceived fatigue and muscle soreness were significantly elevated immediately and at 24 h following exercise, respectively, by similar magnitudes in all conditions (P≤0·001). Muscle activation did not differ between conditions. While metabolic stress is thought to moderate muscle activation and subsequent muscular development during hypoxic resistance training, it is not augmented during traditional high-load exercise. This may be explained by the low number of repetitions performed and the long interset rest periods employed during this training. These findings suggest that high-load resistance training might not benefit from additional hypoxia as has been shown for low- and moderate-load training.

The association between birthweight and longevity in the rat is complex and modulated by maternal protein intake during fetal life.

Maternal protein restriction in rat pregnancy has been suggested to reduce lifespan of the resulting offspring by inducing fetal growth retardation, followed by postnatal catch-up growth. We tested the hypothesis that lifespan could be programmed in both males and females by exposure to undernutrition at specific stages of fetal development. Protein restriction throughout gestation significantly reduced lifespan in both males and females. Low birthweight increased longevity, whilst rapid postnatal growth had a detrimental effect. There was no evidence that undernutrition programmed lifespan through oxidative processes in the major organs. Fetal programming is an important contributor to the ageing process.

Programming of hepatic antioxidant capacity and oxidative injury in the ageing rat.

Exposure to undernutrition in fetal life increases the susceptibility of humans and animals to major disease states in adult life. Studies of rodents exposed to protein restriction during fetal life indicate that lifespan is reduced, a finding that is the opposite of the well-documented improvement in longevity noted with post-weaning caloric restriction. The maternal low-protein (MLP) model of rat pregnancy therefore provides a suitable vehicle to consider how nutrition in fetal life may programme mechanisms of ageing. Pregnant rats were fed control (n = 7) or MLP diet (n = 7) throughout pregnancy. At birth, increased oxidation of hepatic proteins was noted, and this appeared related to activity of glutathione reductase. Older offspring were studied at 4, 16, 30 and 44 weeks of age and analyses revealed that MLP exposure in utero produced sex-specific differences in oxidant:antioxidant balance. In male offspring, MLP increased protein carbonyl concentrations in the liver (P = 0.013) and increased glutathione peroxidase activity (P = 0.018). These programmed changes were absent in the female offspring. The data support the hypothesis that reduced lifespan in rats subject to prenatal protein restriction is a consequence of enhanced oxidative processes promoting apoptosis and loss of tissue function. Mechanisms of ageing appear to be subject to nutritional programming during early development.

Reliability of telemetric electromyography and near-infrared spectroscopy during high-intensity resistance exercise.

This study quantified the inter- and intra-test reliability of telemetric surface electromyography (EMG) and near infrared spectroscopy (NIRS) during resistance exercise. Twelve well-trained young men performed high-intensity back squat exercise (12 sets at 70-90% 1-repetition maximum) on two occasions, during which EMG and NIRS continuously monitored muscle activation and oxygenation of the thigh muscles. Intra-test reliability for EMG and NIRS variables was generally higher than inter-test reliability. EMG median frequency variables were generally more reliable than amplitude-based variables. The reliability of EMG measures was not related to the intensity or number of repetitions performed during the set. No notable differences were evident in the reliability of EMG between different agonist muscles. NIRS-derived measures of oxyhaemoglobin, deoxyhaemoglobin and tissue saturation index were generally more reliable during single-repetition sets than multiple-repetition sets at the same intensity. Tissue saturation index was the most reliable NIRS variable. Although the reliability of the EMG and NIRS measures varied across the exercise protocol, the precise causes of this variability are not yet understood. However, it is likely that biological variation during multi-joint isotonic resistance exercise may account for some of the variation in the observed results.

Hypoxia and resistance exercise: a comparison of localized and systemic methods.

It is generally believed that optimal hypertrophic and strength gains are induced through moderate- or high-intensity resistance training, equivalent to at least 60% of an individual's 1-repetition maximum (1RM). However, recent evidence suggests that similar adaptations are facilitated when low-intensity resistance exercise (~20-50% 1RM) is combined with blood flow restriction (BFR) to the working muscles. Although the mechanisms underpinning these responses are not yet firmly established, it appears that localized hypoxia created by BFR may provide an anabolic stimulus by enhancing the metabolic and endocrine response, and increase cellular swelling and signalling function following resistance exercise. Moreover, BFR has also been demonstrated to increase type II muscle fibre recruitment during exercise. However, inappropriate implementation of BFR can result in detrimental effects, including petechial haemorrhage and dizziness. Furthermore, as BFR is limited to the limbs, the muscles of the trunk are unable to be trained under localized hypoxia. More recently, the use of systemic hypoxia via hypoxic chambers and devices has been investigated as a novel way to stimulate similar physiological responses to resistance training as BFR techniques. While little evidence is available, reports indicate that beneficial adaptations, similar to those induced by BFR, are possible using these methods. The use of systemic hypoxia allows large groups to train concurrently within a hypoxic chamber using multi-joint exercises. However, further scientific research is required to fully understand the mechanisms that cause augmented muscular changes during resistance exercise with a localized or systemic hypoxic stimulus.

Prenatal exposure to a low-protein diet programs disordered regulation of lipid metabolism in the aging rat.

The nutritional environment encountered during fetal life is strongly implicated as a determinant of lifelong metabolic capacity and risk of disease. Pregnant rats were fed a control or low-protein (LP) diet, targeted to early (LPE), mid-(LPM), or late (LPL) pregnancy, or throughout gestation (LPA). The offspring were studied at 1, 9, and 18 mo of age. All LP-exposed groups had similar plasma triglyceride, cholesterol, glucose, and insulin concentrations to those of controls at 1 and 9 mo of age, but by 18 mo there was evidence of LP-programmed hypertriglyceridemia and insulin resistance. All LP-exposed groups exhibited histological evidence of hepatic steatosis and were found to have two- to threefold more hepatic triglyceride than control animals. These phenotypic changes were accompanied by age-related changes in mRNA and protein expression of the transcription factors SREBP-1c, ChREBP, PPARgamma, and PPARalpha and their respective downstream target genes ACC1, FAS, L-PK, and MCAD. At 9 mo of age, the LP groups exhibited suppression of the SREBP-1c-related lipogenic pathway but between 9 and 18 mo underwent a switch to increased lipogenic capacity with a lower expression of PPARgamma and MCAD, consistent with reduced lipid oxidation. The findings indicate that prenatal protein restriction programs development of a metabolic syndrome-like phenotype that develops only with senescence. The data implicate altered expression of SREBP-1c and ChREBP as key mediators of the programmed phenotype, but the basis of the switch in metabolic status that occurred between 9 and 18 mo of age is, as yet, unidentified.

Fetal exposure to a maternal low-protein diet during mid-gestation results in muscle-specific effects on fibre type composition in young rats.

This study assessed the impact of reduced dietary protein during specific periods of fetal life upon muscle fibre development in young rats. Pregnant rats were fed a control or low-protein (LP) diet at early (days 0-7 gestation, LPEarly), mid (days 8-14, LPMid), late (days 15-22, LPLate) or throughout gestation (days 0-22, LPAll). The muscle fibre number and composition in soleus and gastrocnemius muscles of the offspring were studied at 4 weeks of age. In the soleus muscle, both the total number and density of fast fibres were reduced in LPMid females (P = 0.004 for both, Diet x Sex x Fibre type interactions), while both the total number and density of glycolytic (non-oxidative) fibres were reduced in LPEarly, LPMid and LPLate (but not LPAll) offspring compared with controls (P < 0.001 for both, Diet x Fibre type interaction). In the gastrocnemius muscle, only the density of oxidative fibres was reduced in LPMid compared with control offspring (P = 0.019, Diet x Fibre type interaction), with the density of slow fibres being increased in LPAll males compared with control (P = 0.024, Diet x Sex x Fibre type interaction). There were little or no effects of maternal diet on fibre type diameters in the two muscles. In conclusion, a maternal low-protein diet mainly during mid-pregnancy reduced muscle fibre number and density in 4-week-old rats, but there were muscle-specific differences in the fibre types affected.

Salivary antioxidants and periodontal disease status.

Periodontal disease is a common chronic adult condition. The bacterium Porphyromonas gingivalis has been implicated in the aetiology of this disease, which causes destruction of the connective tissue and bone around the root area of the tooth. It has been observed that invading P. gingivalis bacteria trigger the release of cytokines such as interleukin 8 and tumour necrosis factor a, leading to elevated numbers and activity of polymorphonucleocytes (PMN). As a result of stimulation by bacterial antigens, PMN produce the reactive oxygen species (ROS) superoxide via the respiratory burst as part of the host response to infection. Patients with periodontal disease display increased PMN number and activity. It has been suggested that this proliferation results in a high degree of ROS release, culminating in heightened oxidative damage to gingival tissue, periodontal ligament and alveolar bone. Antioxidant constituents in plasma have been well-documented, being chiefly ascorbate, albumin and urate, and these are known to display sensitivity to dietary antioxidant intakes. The concentration of antioxidants in saliva does not appear to mirror those of plasma. The extent of dietary influence upon salivary antioxidant status is unclear. Urate is the predominant salivary antioxidant, with albumin and ascorbate providing minor contributions. Previous research has found reduced salivary antioxidant activity in patients suffering from periodontal disease. An improved understanding of the role antioxidants play in periodontitis, and the influence of nutrition on antioxidant status, may lead to a possible nutritional strategy for the treatment of periodontal disease.

Periodontal disease is associated with lower antioxidant capacity in whole saliva and evidence of increased protein oxidation.

The aim of this cohort study was to determine whether periodontitis and gingivitis are associated with impaired salivary antioxidant status and increased oxidative injury. One hundred and twenty-nine patients attending a routine dental check-up were recruited for the study. Periodontal disease status was characterized using the Community Periodontal Index of Treatment Needs (CPITN) system. Total salivary antioxidant capacity and salivary ascorbate, urate and albumin were determined in a sample of whole unstimulated saliva. Protein carbonyl concentrations were determined as an index of oxidative injury. Patients in the lowest tertile of CPITN score exhibited decreased salivary delivery of antioxidants and specifically urate than patients in the upper tertile. Poor periodontal health was associated with increased concentrations of protein carbonyls in saliva. Women had significantly lower total antioxidant status than men, regardless of periodontal health. Periodontal disease is associated with reduced salivary antioxidant status and increased oxidative damage within the oral cavity.