Macronutrients effects on satiety and food intake in older and younger adults: A randomised controlled trial.

Older adults are advised to increase their protein intake to maintain their muscle mass. However, protein is considered the most satiating macronutrient and this recommendation may cause a decrease in total energy intake. To date, satiety studies comparing all three macronutrients have been undertaken in young adults, and it is unclear if the same response is seen in older adults. The objective of this study was to compare the effect of preloads high in protein, fat, and carbohydrate but equal in energy (∼300 kcal) and volume (250 ml) on energy intake, perceived appetite, and gastric emptying in younger and older adults. Twenty older and 20 younger adults completed a single-blinded randomised crossover trial involving three study visits. Participants consumed a standard breakfast, followed by a preload milkshake high in either carbohydrate, fat, or protein. Three hours after the preload, participants were offered an ad libitum meal to assess food intake. Visual analogue scales were used to measure perceived appetite and gastric emptying was measured via the 13C-octanoic acid breath test. There was no significant effect of preload type or age on energy intake either at the ad libitum meal, self-recorded food intake for the rest of the test day or subjective appetite ratings. There was a significant effect of preload type on gastric emptying latency phase and ascension time, and an effect of age on gastric emptying latency and lag phase such that older adults had faster emptying. In conclusion, energy intake, and perceived appetite were not affected by macronutrient content of the preloads in both younger and older adults, but gastric emptying times differed.

Does dietary fat cause a dose dependent glycemic response in youth with type 1 diabetes?

OBJECTIVE: To determine the glycemic impact of dietary fat alone consumed without prandial insulin in individuals with T1D. RESEARCH DESIGN AND METHODS: Thirty participants with T1D (aged 8-18 years) consumed a test drink with either 20 g glucose or 1, 13, 26, 39, 51 g of fat with negligible carbohydrate/protein on 6 consecutive evenings, in a randomized order without insulin. Continuous glucose monitoring was used to measure glucose levels for 8 h postprandially. Primary outcome was mean glycemic excursion at each 30 min interval for each test condition. Generalized linear mixed models with a random effect for people with diabetes were used to test for an increase in blood glucose excursion with increasing quantity of fat. RESULTS: Glycemic excursions after 20 g glucose were higher than after fat drinks over the first 2 h (p < 0.05). Glycemic excursion for the fat drinks demonstrated a dose response, statistically significant from 4 h (p = 0.026), such that increasing loads of fat caused a proportionally larger increase in glycemic excursion, remaining statistically significant until 8 h (p < 0.05). Overall, for every 10 g fat added to the drink, glucose concentrations rose by a mean of 0.28 mmol L-1 from 330 min (95% CI 0.15 to 0.39, p < 0.001). CONCLUSIONS: Fat ingested without other macronutrients increases glucose excursions from 4 to 8 h after ingestion, in a dose dependent manner. These observations may impact on insulin dosing for high-fat foods in individuals with T1D.

A comparison of the satiating properties of medium-chain triglycerides and conjugated linoleic acid in participants with healthy weight and overweight or obesity.

PURPOSE: Inconsistent evidence exists for greater satiety after medium-chain triglycerides (MCT) or conjugated linoleic acid (CLA) compared to long-chain triglycerides (LCT). Furthermore, the mechanisms are poorly understood and effects in people with a healthy weight and those with overweight/obesity have not been compared. This study aimed to compare appetite responses in these groups and examine the mechanisms behind any differences. METHODS: Fifteen participants with healthy weight (BMI: 22.7 ± 1.9 kg·m-2) and fourteen participants with overweight/obesity (BMI: 30.9 ± 3.9 kg·m-2) consumed a breakfast containing either 23.06 g vegetable oil (CON), 25.00 g MCT oil (MCT), or 6.25 g CLA and 16.80 g vegetable oil (CLA). Appetite, peptide YY (PYY), total ghrelin (TG), ß-hydroxybutyrate, and gastric emptying (GE) were measured throughout. Energy intake was assessed at an ad libitum lunch and throughout the following ~ 36 h. RESULTS: Neither MCT nor CLA decreased ad libitum intake; however MCT decreased day 1 energy intake (P = 0.031) and the 48-h period (P = 0.005) compared to CON. MCT delayed GE (P ≤ 0.01) compared to CON, whereas CLA did not. PYY and TG concentrations were not different (P = 0.743 and P = 0.188, respectively), but MCT increased ß-hydroxybutyrate concentrations compared to CON (P = 0.005) and CLA (P < 0.001). ß-hydroxybutyrate concentrations were higher in participants with overweight/obesity (P = 0.009). CONCLUSION: Consumption of MCT reduces energy intake in the subsequent 48 h, whereas CLA does not. Delayed gastric emptying or increased ß-hydroxybutyrate concentrations may mediate this.

Effect of medium-chain TAG and exercise on satiety, energy intake and energy balance.

The present study examined whether the combination of medium-chain TAG (MCT) along with exercise suppresses energy intake to a greater extent compared with either intervention alone. Twelve participants consumed a porridge breakfast containing 692·9 kJ of either vegetable or MCT oil on two separate occasions: one followed by rest for 240 min and another followed by rest broken up with 1 h of cycling at 65 % $\dot V$O2peak starting at 120 min. At 240 min, participants consumed a buffet lunch to satiation and recorded their food intake for the rest of the day. Expired air samples (for calculation of energy expenditure (EE)) and subjective ratings of appetite on visual analogue scales were taken every 30 min, and gastric emptying (GE) breath samples were taken every 15 min. No effect of either breakfast or exercise condition was observed on energy intake at any time point (P > 0·05) or no effect was observed on subjective appetite ratings (P > 0·05). Exercise trials resulted in significantly higher EE compared with resting trials (2960·6 kJ, 95 % CI 2528·9, 3392·2; P < 0·001), and MCT increased resting EE over 4 h compared with long-chain TAG (LCT) (124·8 kJ, 95 % CI 13·5, 236·0; P = 0·031). GE was accelerated by exercise, regardless of the breakfast consumed, but delayed by MCT in both resting and exercise trials. The results show that exercise causes energy deficits via increased EE without promoting dietary compensation. MCT has no effect on energy intake or satiety but increases EE under resting conditions. There is no additive effect of MCT and exercise on EE, intake or appetite ratings.

Changes in PYY and gastric emptying across the phases of the menstrual cycle and the influence of the ovarian hormones.

Nutrition-related studies avoid the participation of pre-menopausal women due to the potential effect of the menstrual cycle (MC) on their appetite regulation. It is generally accepted that women increase their energy intake during the luteal phase (LPh) compared to the follicular (FPh), however what happens in the menstrual phase (MPh) and how this might be regulated remains uncertain. Although some research indicates changes in the gastric emptying (GE) velocity, whether PYY is affected by the MC phase, remains unknown. The aim of this study was to assess whether eating the same breakfast in each of the three MC phases would change the GE time, the PYY response and post-prandial satiety such that they might affect subsequent food intake. Furthermore, the aim was to associate any potential differences to the fluctuations in estradiol (E2) and progesterone (P4) within a MC. Nine naturally cycling women attended to the laboratory to consume a standardised breakfast on three occasions, each of them representing one of the MC phases. Breath samples to measure GE time, plasma samples to quantify PYY levels and hunger scores were collected for a total of 4 h after which food intake was assessed by an ad-libitum buffet lunch. GE and PYY levels changed significantly across the phases of the MC (p < 0.05). GE was correlated to P4 and E2-P4 ratio (r = -0.5 and 0.4, respectively). To conclude, the appetite regulators PYY and GE time change depending upon the MC phases with GE time associated with the ovarian hormone levels which suggests the necessity of controlling the MC phase in studies looking at the appetite response.

The Role of Dietary Protein and Fat in Glycaemic Control in Type 1 Diabetes: Implications for Intensive Diabetes Management.

A primary focus of the management of type 1 diabetes has been on matching prandial insulin therapy with carbohydrate amount consumed. However, even with the introduction of more flexible intensive insulin regimes, people with type 1 diabetes still struggle to achieve optimal glycaemic control. More recently, dietary fat and protein have been recognised as having a significant impact on postprandial blood glucose levels. Fat and protein independently increase the postprandial glucose excursions and together their effect is additive. This article reviews how the fat and protein in a meal impact the postprandial glycaemic response and discusses practical approaches to managing this in clinical practice. These insights have significant implications for patient education, mealtime insulin dose calculations and dosing strategies.

The effect of agar jelly on energy expenditure, appetite, gastric emptying and glycaemic response.

BACKGROUND AND PURPOSE: Agar contains a high amount of soluble fibre and has been shown to delay gastric emptying (GE) without impacting on glycaemic response (GR). The current study aimed to further the limited data on the effect of agar on metabolism by assessing the effects on GE and GR as well as appetite- and diet-induced thermogenesis (DIT). METHODS: In this randomized control trial, eleven healthy volunteers were tested on two occasions following an overnight fast. Following baseline and resting measurements, volunteers were either fed a fruit-flavoured drink (liquid) or consumed a fruit-flavoured jelly (jelly). The two were exactly the same in composition except the jelly contained 4 g of agar crystals. Both contained 50 g of available carbohydrate. DIT was measured using indirect calorimetry, GE using the (13)C sodium acetate breath test, appetite using visual analogue scale and GR using finger prick blood samples. RESULTS: The jelly significantly delayed GE across all time points-latency phase (p = 0.07), lag phase (p = 0.04), half-time (p < 0.0001), ascension time (p = 0.025). The jelly also increased all appetite parameters-hunger (p = 0.006), fullness (p = 0.035), desire to eat (p = 0.03) and prospective consumption (p = 0.011). However, there were no significant differences in either GR or postprandial DIT between the liquid and jelly. CONCLUSION: Agar delays GE and increases appetite but does not change GR or DIT most probably due to the increase in viscosity caused by the agar jelly.

The carbon dioxide production rate assumption biases gastric emptying parameters in healthy adults.

RATIONALE: An altered gastric emptying (GE) rate has been implicated in the aetiology of obesity. The (13)C-octanoic acid breath test (OBT) is frequently used to measure GE, and the cumulative percentage of (13)C recovered (cPDR) is a common outcome measure. However, true cPDR in breath is dependent on accurate measurement of carbon dioxide production rate (VCO(2)). The current study aimed to quantify differences in the (13)C OBT results obtained using directly measured VCO(2) (VCO(2DM)) compared with (i) predicted from resting VCO(2) (VCO(2PR)) and (ii) predicted from body surface area VCO(2) (VCO(2BSA)). METHODS: The GE rate of a high-fat test meal was assessed in 27 lean subjects using the OBT. Breath samples were gathered during the fasted state and at regular intervals throughout the 6-h postprandial period for determination of (13)C-isotopic enrichment by continuous-flow isotope-ratio mass spectrometry. The VCO(2) was measured directly from exhaled air samples and the PDR calculated by three methods. The bias and the limits of agreement were calculated using Bland-Altman plots. RESULTS: Compared with the VCO(2DM), the cPDR was underestimated by VCO(2PR) (4.8%; p = 0.0001) and VCO(2BSA) (2.7%; p = 0.02). The GE T(half) was underestimated by VCO(2PR) (13 min; p = 0.0001) and VCO(2BSA) (10 min; p = 0.01), compared with VCO(2DM). CONCLUSIONS: The findings highlight the importance of directly measuring VCO(2)production rates throughout the (13)C OBT and could partly explain the conflicting evidence regarding the effect of obesity on GE rates.

Effect of cinnamon on gastric emptying, arterial stiffness, postprandial lipemia, glycemia, and appetite responses to high-fat breakfast.

BACKGROUND: Cinnamon has been shown to delay gastric emptying of a high-carbohydrate meal and reduce postprandial glycemia in healthy adults. However, it is dietary fat which is implicated in the etiology and is associated with obesity, type 2 diabetes and cardiovascular disease. We aimed to determine the effect of 3 g cinnamon (Cinnamomum zeylanicum) on GE, postprandial lipemic and glycemic responses, oxidative stress, arterial stiffness, as well as appetite sensations and subsequent food intake following a high-fat meal. METHODS: A single-blind randomized crossover study assessed nine healthy, young subjects. GE rate of a high-fat meal supplemented with 3 g cinnamon or placebo was determined using the 13C octanoic acid breath test. Breath, blood samples and subjective appetite ratings were collected in the fasted and during the 360 min postprandial period, followed by an ad libitum buffet meal. Gastric emptying and 1-day fatty acid intake relationships were also examined. RESULTS: Cinnamon did not change gastric emptying parameters, postprandial triacylglycerol or glucose concentrations, oxidative stress, arterial function or appetite (p < 0.05). Strong relationships were evident (p < 0.05) between GE Thalf and 1-day palmitoleic acid (r = -0.78), eiconsenoic acid (r = -0.84) and total omega-3 intake (r = -0.72). The ingestion of 3 g cinnamon had no effect on GE, arterial stiffness and oxidative stress following a HF meal. CONCLUSIONS: 3 g cinnamon did not alter the postprandial response to a high-fat test meal. We find no evidence to support the use of 3 g cinnamon supplementation for the prevention or treatment of metabolic disease. Dietary fatty acid intake requires consideration in future gastrointestinal studies. TRIAL REGISTRATION NUMBER: at http://www.clinicaltrial.gov: NCT01350284.

A high-fat diet temporarily accelerates gastrointestinal transit and reduces satiety in men.

High-fat (HF) diets of 2 weeks have been shown to accelerate gastrointestinal (GI) transit and decrease satiety. However, the effects of HF diets on GI transit over longer periods than 2 weeks are unknown. We hypothesize that over 4 weeks, GI transit of a HF test meal will accelerate. The study was a repeated measures design with 10 male volunteers completing a 1-week HF diet intervention and 7 completing a 4-week HF diet intervention with testing once a week on the same day throughout the 4 weeks. Gastric emptying (GE) was measured using the (13)C-octanoic acid breath test and mouth-to-caecum transit time (MCTT) using the inulin H(2) breath test. Satiety was analysed using visual analogue scales and an ad libitum buffet meal. Body mass increased by 1.3 kg over the 4 weeks (p = 0.036). GE latency time decreased from 45 ± 8 to 41 ± 10 min (p = 0.047) over 1 week but there were no changes in any GE parameters over the 4 weeks. MCTT was accelerated over 1 week (p = 0.036) from 308 ± 43 to 248 ± 83 min. However, over the 4-week period, there was no change. Volunteers became more hungry and desire to eat became greater after 1 week (p = 0.01). Changes in satiety were also evident over the 4 weeks. Satiety was reduced in the primary weeks and then returned to baseline towards the end of the intervention. GI adaptation to a HF diet occurred over a 1-week period and returned to pre-diet levels at the end of 4 weeks.

The impact of acute moderate intensity exercise on arterial regional stiffness, lipid peroxidation, and antioxidant status in healthy males.

There is a paucity of research examining the influence of acute exercise on pulse wave velocity (PWV) and oxidative stress. The purpose of this study was to examine the effects of acute moderate aerobic exercise on PWV and oxidative stress in healthy males. Eight apparently healthy males (age 23.6 ± 2.8 yrs; stature 181.4 ± 8.1 cm; weight 83.4 ± 16.2 kg; all data mean ±SD) participated in a randomized crossover design consisting of (i) a one hour bout of moderate aerobic exercise and (ii) a control trial of one hour rest. Pre- and post-exercise blood samples were drawn for the determination of lipid hydroperoxides (LOOHs) and lipid-soluble antioxidants (lycopene, retinol, and ß-carotene). Exercise had no effect on stiffness and LOOHs (P > 0.05). Retinol and lycopene were increased following exercise (P < 0.05). These findings suggest that acute moderate exercise has no effect on PWV and LOOHs, but it can increase systemic antioxidants, which may be of benefit to health.

Gastric emptying and orocaecal transit time of meals containing lactulose or inulin in men.

The H(2) breath test is ideal for orocaecal transit time (OCTT) measurement, as it is non-invasive and inexpensive. Indigestible substrates added to a test meal are metabolised by the colonic bacteria, resulting in the production of H(2) which is detected in end-exhalation breath. However, the substrates themselves can alter the transit times in the gastrointestinal tract. The aim of the present study is to compare OCTT and gastric emptying (GE) when lactulose in liquid (L-L), solid lactulose (L-S) and solid inulin (IN-S) are added to a test meal, and subsequently, to examine if inulin alters GE. Firstly, ten male volunteers were tested on three occasions. Volunteers ate a pancake breakfast containing 100 mg of (13)C-octanoic acid and either 12 g of L-L, 12 g of L-S or 12 g of IN-S in a randomised order. Secondly, seven male volunteers were tested twice with meals containing either 12 g of IN-S or no substrate (NO-S). L-L induced the shortest OCTT (85.3 (sd 42.8) min) compared with L-S (162.4 (sd 62.6) min) and inulin (292.4 (sd 66.7) min; P = 0.007). GE half-time and lag phase (L-L: 61 (sd 9); L-S: 57 (sd 10); IN-S: 52 (sd 10) min; P = 0.005) were also affected, with L-L being the slowest. Thirdly, inulin reduced GE lag and latency phases (P < 0.05) compared with NO-S. Lactulose accelerates OCTT but delays GE compared with inulin. Inulin accelerates the onset of stomach emptying, but it has no effect on GE half-time. For these reasons, inulin is the preferred substrate for the H(2) breath test.

Procedures in the 13C octanoic acid breath test for measurement of gastric emptying: analysis using Bland-Altman methods.

OBJECTIVE: The (13)C octanoic acid breath test (OBT) was first developed as an alternative method of measuring gastric emptying (GE) to scintigraphy. There has been much debate about the test duration and how often measurements need to be taken. This study aims to address these issues. MATERIAL AND METHODS: For 78 GE tests using the (13)C OBT, GE lag phase (T(lag)) was calculated while sampling more frequently than the recommended every 15 min. Comparisons between T(lag) were completed using Bland-Altman plots. Similarly, 4 or 6 h test durations were assessed to establish if they yield the same GE half time (T(half)). From one volunteer, samples were taken every 1 min for the first 30 min and then every 15 min until 6 h. GE times were then calculated using different combinations of sampling times. Evidence of a visible T(lag) was also explored from this data. RESULTS: Findings indicated that taking samples every 5 min for the first 30 min instead of every 15 min did not change the GE T(lag) based on Bland-Altman plots. The correlation between these two methods was also high (r(2) = 0.9957). The findings showed that the difference between the two sampling durations 4 and 6 h was large and the correlation between the methods was low (r(2) = 0.8335). Samples taken at a rate of one breath per min indicated lack of a visible T(lag). CONCLUSIONS: Sampling for the (13)C OBT should be completed every 15 min for 6 h.

Energy and macronutrient composition of breakfast affect gastric emptying of lunch and subsequent food intake, satiety and satiation.

Satiety and food intake are closely related to gastrointestinal transit and specifically gastric emptying. High-fat (HF) meals empty more slowly from the stomach yet are less satiating than isoenergetic low-fat (LF) meals. The current study examines how gastric emptying and satiety at lunch are affected by energy and macronutrient content of breakfast. Nine male volunteers consumed either (1) a HF breakfast, (2) a LF breakfast isoenergetic to HF (LFE) or (3) a LF breakfast of equal mass to HF (LFM). Gastric emptying half time measured using the sodium [(13)C] acetate breath test was delayed after HF compared to LF meals (HF: 102 + or - 11, LFE: 96 + or - 13, LFM: 95 + or - 13 min, mean + or - SD). Fullness increased and desire to eat decreased following the LFE breakfast measured using visual analogue scales. Eating a HF breakfast increased the energy, fat and protein from an ad libitum buffet meal given 4h after lunch. In conclusion, eating a HF breakfast delayed gastric emptying of lunch and increased food intake 7 h later compared to a LFM breakfast. These data suggest both mass and energy content of food regulate subsequent appetite and feeding and demonstrate the hyperphagic effect of a single HF meal.

The Oral Glucose Tolerance Test-Is It Time for a Change?-A Literature Review with an Emphasis on Pregnancy.

Globally, gestational diabetes (GDM) is increasing at an alarming rate. This increase is linked to the rise in obesity rates among women of reproductive age. GDM poses a major global health problem due to the related micro- and macro-vascular complications of subsequent Type 2 diabetes and the impact on the future health of generations through the long-term impact of GDM on both mothers and their infants. Therefore, correctly identifying subjects as having GDM is of utmost importance. The oral glucose tolerance test (OGTT) has been the mainstay for diagnosing gestational diabetes for decades. However, this test is deeply flawed. In this review, we explore a history of the OGTT, its reproducibility and the many factors that can impact its results with an emphasis on pregnancy.

Energy density in cafeteria diet induced hyperphagia in the rat.

Rats that are fed cafeteria diet (CD) are a widely used model of obesity. Presenting a varied and energy-dense diet often leads to hyperphagia and weight gain. However, the exact macronutrient composition of ingested food remains difficult to measure accurately. The current investigation aims to improve the accuracy of food intake calculations using a novel compensation for water evaporation, and to examine the role of energy density in CD-induced hyperphagia. Seven rats were presented daily with four foods, on rotation from a list of 36 different items, for a period of 43 days and compared to chow-fed controls (n=6). Correcting for evaporation corrected an overestimation by 8% of energy intake in rats fed CD. Rats consumed 25% more food by weight when fed CD as compared to controls. Similar to human studies, exposure to CD resulted in a 58% increase in energy intake. Energy density was positively correlated with energy intake in rats fed CD. Body weight gain was significantly elevated from day 20 onwards, suggesting the onset of obesity. This study removes evaporation bias from measurements of food intake in CD and supports the conclusion that a varied, energetically dense diet induces hyperphagia and obesity in the rat.

Food Intake and Satiety Response after Medium-Chain Triglycerides Ingested as Solid or Liquid.

Consuming medium-chain triglycerides (MCT) may reduce subsequent energy intake and increase satiety compared to long-chain triglycerides (LCT) but this may be dependent on the physical form in which MCT is ingested. Twenty-nine participants completed four trials where they consumed a breakfast containing either LCT or MCT in solid (Con-S and MCT-S, respectively) or liquid (Con-L and MCT-L, respectively) form. Appetite ratings and gastric emptying (GE) were taken at baseline and at 15 min intervals for 4 h. Energy intake was assessed at an ad libitum meal and via weighed food records for the remainder of the day. Ad libitum energy intake was highest in Con-L (4101 ± 1278 kJ vs. Con-S, 3323 ± 1196; MCT-S, 3516 ± 1058; MCT-L, 3257 ± 1345; p = 0.001). Intake over the whole day was significantly lower in MCT-L (7904 ± 3244) compared to Con-L (9531 ± 3557; p = 0.001). There were significant differences in GE times (p < 0.05), with MCT breakfasts delaying GE to a greater extent than LCT, and MCT-L having the longest GE times. There were no differences in appetite sensations. MCT reduce subsequent intake without affecting subjective sensations of appetite when consumed in liquid form.

The relationship between previous hamstring injury and the concentric isokinetic knee muscle strength of Irish Gaelic footballers.

BACKGROUND: Hamstring injury is one of the most common injuries affecting gaelic footballers, similar to other field sports. Research in other sports on whether residual hamstring weakness is present after hamstring injury is inconsistent, and no study has examined this factor in irish gaelic footballers. The aim of this study was to examine whether significant knee muscle weakness is present in male Irish gaelic footballers who have returned to full activity after hamstring injury. METHODS: The concentric isokinetic knee flexion and extension strength of 44 members of a university gaelic football team was assessed at 60, 180 and 300 degrees per second using a Contrex dynamometer. RESULTS: Fifteen players (34%) reported a history of hamstring strain, with 68% of injuries affecting the dominant (kicking) limb. The hamstrings were significantly stronger (p < 0.05) on the dominant limb in all uninjured subjects. The previously injured limbs had a significantly lower (p < 0.05) hamstrings to quadriceps (HQ) strength ratio than all other non-injured limbs, but neither their hamstrings nor quadriceps were significantly weaker (p > 0.05) using this comparison. The previously unilaterally injured hamstrings were significantly weaker (p < 0.05) than uninjured limbs however, when matched for dominance. The hamstring to opposite hamstring (H:oppH) strength ratio of the previously injured players was also found to be significantly lower (p < 0.05) than that of the uninjured players. CONCLUSION: Hamstring muscle weakness was observed in male Irish gaelic footballers with a history of hamstring injury. This weakness is most evident when comparisons are made to multiple control populations, both within and between subjects. The increased strength of the dominant limb should be considered as a potential confounding variable in future trials. The study design does not allow interpretation of whether these changes in strength were present before or after injury.

Exercise and postprandial lipaemia: effects on peripheral vascular function, oxidative stress and gastrointestinal transit.

Postprandial lipaemia may lead to an increase in oxidative stress, inducing endothelial dysfunction. Exercise can slow gastric emptying rates, moderating postprandial lipaemia. The purpose of this study was to determine if moderate exercise, prior to fat ingestion, influences gastrointestinal transit, lipaemia, oxidative stress and arterial wall function. Eight apparently healthy males (age 23.6 +/- 2.8 yrs; height 181.4 +/- 8.1 cm; weight 83.4 +/- 16.2 kg; all data mean +/- SD) participated in the randomised, crossover design, where (i) subjects ingested a high-fat meal alone (control), and (ii) ingested a high-fat meal, preceded by 1 h of moderate exercise. Pulse Wave Velocity (PWV) was examined at baseline, post-exercise, and in the postprandial period. Gastric emptying was measured using the 13C-octanoic acid breath test. Measures of venous blood were obtained prior to and following exercise and at 2, 4 and 6 hours post-ingestion. PWV increased (6.5 +/- 1.9 m/sec) at 2 (8.9 +/- 1.7 m/sec) and 4 hrs (9.0 +/- 1.6 m/sec) post-ingestion in the control group (time x group interaction, P < 0.05). PWV was increased at 2 hrs post-ingestion in the control compared to the exercise trial; 8.9 +/- 1.7 vs. 6.2 +/- 1.5 m/sec (time x group interaction, P < 0.05). Lipid hydroperoxides increased over time (pooled exercise and control data, P < 0.05). Serum triacylglycerols were elevated postprandially (pooled exercise and control data, P < 0.05). There were no changes in gastric emptying, cholesterol, or C-reactive protein levels. These data suggest that acute exercise prior to the consumption of a high-fat meal has the potential to reduce vascular impairments.

Lower back pain in physically demanding college academic programs: a questionnaire based study.

BACKGROUND: Lower back pain (LBP) is ranked first as a cause of disability and inability to work, and is expected to affect up to 90% of the worlds population at some point in their lifetime. The annual first time incidence of LBP is 5%, and the annual prevalence (i.e. those suffering at time of questioning) is between 15 and 63%. Prospective studies demonstrate that low back problems do not display a six-week spontaneous recovery pattern, as was once believed. The condition is regularly seen to worsen over time, becoming a chronic disorder, influenced by both physical and psychosocial factors. METHODS: The current study assessed the level of LBP amongst students engaged in educational programs that were physically demanding, and its influence on lower back problems. A 1-year retrospective questionnaire consisting of 37 closed, open and multi-choice questions was designed to ascertain self-reported information on the occurrence, cause and type of LBP. Treatment, care seeking and general knowledge regarding LBP were also recorded. Students were enrolled in BSc Equine Science, BSc Physical Education and BSc Sports & Exercise Science degree programs and a total number of 188 valid questionnaires were collected. RESULTS: The self reported, anthropometrical data for participants in this study are: age 20.9 +/- 2.7 yrs; height 171.8 +/- 9.3 cm; weight 66.7 +/- 10.4 kg; female 64% (n = 120), male 36% (n = 68). The overall self reported prevalence of LBP was 32% (n = 61). Within the LBP population, 77% reported their problem as recurring. Two factors showed significance as having an influence on LBP. They were age (21.6 +/- 3.5 yrs, p = 0.005) and hours of personal training physical activity (14.0 +/- 8.2 hrs per week, p = 0.02). LBP sufferers also displayed poor management of their condition and an interest in education and treatment of their problem. CONCLUSION: The current study revealed high prevalence of LBP consistent with that of the literature, and unveiled a recurrence rate and behavioral habits of sufferers, which are warning signs of a more chronic state to come. Novel data presented here offers strong support for the need for prospective injury tracking, plus educational intervention and treatment aimed at prevention of LBP.