Screening, assessment and management of perioperative malnutrition: a survey of UK practice.

BACKGROUND: Perioperative malnutrition is common and is associated with increased mortality, complications and healthcare costs. Patients having surgery for cancer and gastro-intestinal disease are at particular risk. It is a modifiable pre-operative risk factor and perioperative clinicians are well placed to identify those at risk and instigate interventions shown to improve outcome. Thus, we conducted a survey of Perioperative Medicine Leads with the aim of assessing the current provision of nutritional screening and intervention pathways in the UK. METHODS: Perioperative Medicine Leads registered with the Royal College of Anaesthetists were asked to complete an online survey exploring current practice in screening, assessment and management of malnutrition in the perioperative period. The survey included a mixture of open and closed questions, graded response questions and options for free text. Where a response was not received, departments were phoned directly and e-mails sent to non-responders. RESULTS: We received 121 completed questionnaires from 167 Perioperative Medicine Leads (response rate of 72.5%). Seventy respondents (57.9%) reported using the Malnutrition Universal Screening Tool to screen patients; however, only 61 (50.4%) referred patients at nutritional risk onto a dietitian. Sixty (49.6%) lacked confidence in local ability to identify and manage malnutrition perioperatively, with 28 (23.1%) reporting having a structured pathway for managing malnourished patients. One hundred eleven respondents (91.7%) agreed that malnutrition impacts on quality of life after surgery and 105 (86.8%) felt adopting a standard protocol would improve outcomes for patients. Those reporting a lack of confidence in dealing with malnutrition perioperatively cited a lack of organisational support, patients being seen too close to surgery and lack of clarity around responsibility as key reasons for difficulties in managing this group of patients. CONCLUSIONS: Malnutrition in the perioperative period is a modifiable risk factor which is common and results in increased morbidity for patients and increased cost to healthcare systems. This survey highlights areas of practice where perioperative clinicians can improve the assessment and management of patients at nutritional risk prior to elective surgery.

The use of bioelectrical impedance analysis to predict post-operative complications in adult patients having surgery for cancer: A systematic review.

BACKGROUND: Patients undergoing surgery for cancer are at particular risk of post-operative complications. The pre-operative period is an opportunity to identify and mitigate risk factors and improve outcome. Bioelectrical impedance analysis (BIA) may offer an additional means of identifying patients at risk of post-operative morbidity. AIMS: The aim of this systematic review was to assess the use of measures and estimates of body composition determined by BIA as markers of peri-operative risk in adult patients undergoing elective surgery for cancer. METHODS: This review was performed in accordance with the PRISMA guidelines. The electronic databases of MEDLINE, EMBASE, CINAHL, CENTRAL and the Web of Science were searched from inception. Studies of adult participants having elective surgery for cancer were included if participants underwent BIA in the peri-operative period and were assessed for post-operative complications. RESULTS: 2578 studies were identified, of which 12 were eligible for inclusion. In total the studies report data from 1508 subjects. Five studies examined phase angle or standardized phase angle, six examined derived measures and one examined both. Eight of the 12 demonstrated an association between phase angle and/or body composition and an increased risk of post-operative complications. CONCLUSIONS: Bioelectrical impedance analysis in the peri-operative period may be useful in predicting the risk of complications following elective cancer surgery. Phase angle more consistently demonstrates an association than derived estimates. Further high quality studies are needed and should report the raw impedance values, standardized phase angle and the equations used to derive body composition.

Bioimpedance spectroscopy measurements of phase angle and height for age are predictive of outcome in children following surgery for congenital heart disease.

OBJECTIVE: Children with congenital heart disease (CHD) are often growth restricted (low weight- and/or height-for-age) which may increase risk of poor post operative resilience. Bioelectrical impedance spectroscopy (BIS) has been used to determine body composition in different clinical settings and has been shown to mark differences in nutritional state and clinical outcome. In disease conditions were fluid is not normally distributed it is proposed that raw impedance values and BIS derived phase-angle may serve as prognostic indicators of clinical outcome. We sought to describe the relationship between nutritional status, phase-angle and post-operative outcomes in children with congenital heart disease. DESIGN: Single centre prospective cohort study. SETTING: Paediatric Intensive Care Unit (PICU), Southampton Children's Hospital. PATIENTS: 122 children with CHD following cardiac surgery (March 2015-April 2016). Outcome variables included growth, mechanical-ventilation, PICU length of stay (PICU-LOS) and phase-angle at 50 Hz. MEASUREMENTS AND MAIN RESULTS: BIS measurements were taken before and on the day of surgery (day 0), day 2 post-operatively and on discharge from hospital. Pre-operative moderate malnutrition defined as height-for-age-z-score (HAZ) ≤-2 was observed in 28.5% of infants and 20.6% of children. Regression analysis was used to investigate the relationship between phase-angle, HAZ and clinical outcomes. Moderate-malnutrition (HAZ ≤-2) was associated with an increased PICU-LOS (odds ratios (OR) with 95% confidence interval: 1.8; 1.1-2.7, p = 0.008) whilst a low phase-angle (≤2.7° on day 2 was associated with longer PICU-LOS (OR 7.8; 2.7-22.45, p < 0.001)); When the model was adjusted for age, known risk factors and length of surgery, HAZ ≤-2 and phase-angle ≤2.7° on day 2 were associated with longer PICU-LOS (p = 0.001 and p = 0.04 respectively) and together explained 81.7% of the variability in PICU-LOS. CONCLUSIONS: Moderate malnutrition (HAZ ≤-2) in infants and children undergoing cardiac surgery is associated with longer PICU-LOS. Post-operative measures of BIS phase angle may further improve our ability to identifying hose children with an increased risk of prolonged PICU-LOS compared to using pre-operative anthropometry alone.

Nutritional perspectives of children with Crohn's disease: a single-centre cohort observation of disease activity, energy expenditure and dietary intake.

BACKGROUND/OBJECTIVES: Children with Crohn's disease often demonstrate nutritional recovery during primary therapy at diagnosis, but long-term nutritional support is sometimes necessary. Evidence to inform best nutritional practice including energy and micronutrient requirements is limited. The principal objective of this study was to determine how energy expenditure and physical activity vary with disease activity over the first year following diagnosis. SUBJECTS/METHODS: Twenty children were studied at diagnosis with Crohn's disease and were followed up over 1 year while receiving treatment according to national guidelines. The majority of children (13) were treated with exclusive enteral nutrition. At study visits, height, weight, bioelectrical impedance, resting energy expenditure by indirect calorimetry, tri-axial accelerometer and blood investigations were performed alongside clinical assessment. RESULTS: There was no significant effect of disease activity on resting energy expenditure (REE). Physical activity was greater after primary therapy (Z=3.31, P<0.01). Median wPCDAI fell from 58 at diagnosis to 7.5 after primary therapy and was 7.5 at 1 year. Weight s.d.s increased from -1.67 to -0.86 and lean index s.d.s increased from -2.93 to -1.64, although the increase was mostly in the first 2 months. Median height s.d.s was unchanged throughout this study. There was a significant association between dietary intake and weight gain (r=0.8 P<0.01) but not height gain. Persistent micronutrient deficits beyond diagnosis were seen for both iron and vitamin D. CONCLUSIONS: This study has demonstrated that REE does not change significantly through different phases of disease activity, but physical activity is low at diagnosis. Children with Crohn's disease should be screened for deficiencies of iron and vitamin D.

Postprandial effects of long-term niacin/laropiprant use on glucose and lipid metabolism and on cardiovascular risk in patients with polycystic ovary syndrome.

AIM: This study investigated the effect of long-term niacin/laropiprant therapy on CV risk and IR in obese women with PCOS. METHODS: In this double-blind randomized placebo-controlled trial, 13 and 12 PCOS women completed a 12 week course of niacin/laropiprant or placebo, respectively. Fasted subjects had an endothelial function test (EndoPat2000) and then consumed a mixed meal with blood sampled postprandially for 6 h before and after intervention. RESULTS: By 12 weeks, niacin/laropiprant lowered low-density lipoprotein cholesterol (LDL-c) (13%) and increased HDL-c (17%). Despite a reduction in fasting triglycerides (21%), the drug had no effect on their postprandial rise (2.69 ± 1.44 vs. 2.49 ± 1.14 mmol/l, p = 0.72). However, following the mixed meal, plasma glucose area under the response curve increased from 13.1 ± 2.9 to 14.0 ± 2.8 mmol/l, p = 0.05, as a consequence of both increased insulin resistance [HOMA-IR: 2.2 (1.2, 4.2) vs. 3.8(1.3, 5.5), p = 0.02] and a reduced acute insulin response to glucose [424 (211, 975) vs. 257(122, 418) pmol/mmol, p = 0.04]. Niacin/laropiprant did not improve RHI (1.97 ± 0.40 vs. 2.05 ± 0.58, p = 0.33) or hsCRP. CONCLUSIONS: In PCOS, niacin/laropiprant had a significant negative impact on postprandial glucose and no improvement in postprandial hypertriglyceridaemia, with at least the former mediated through increased IR and reduced ß-cell function. This data may help explain why the improvement in fasting lipids has not translated into improved CV risk markers in PCOS.

The 'not so short-bowel syndrome': potential health problems in patients with an ileostomy.

AIM: The study aimed to determine whether an ileostomy compromises nutritional, hydration and electrolyte status and bone mineral density. METHOD: Body weight, body mass index (BMI) and fat and lean body mass (LBM) were measured in 60 patients with an ileostomy [14 small-bowel resection (SBR); 46 non-small-bowel resection (NSBR)] and in 60 age- and sex-matched normal controls. Measurement of plasma sodium, potassium, calcium, magnesium, urea and creatinine and 24-h urinary output of water, Na, K, Ca and Mg was made in 45 NSBR and 14 SBR ileostomists and in all the controls. Forty-six NSBR and 13 SBR ileostomists had bone mineral density (BMD) measurements of lumbar spine (LS) and femoral neck (FN). RESULTS: The body weight of ileostomists was less than controls [median 67.8 (36.4-115.1) vs 77.7 (48.0-103.3) kg; P < 0.05]. BMI was also less [25.0 (14.3-43.0) vs 27.3 (20.2-32.2) kg/m(2) ; P < 0.05] with a lower LBM [47.8 (19.3-73.0) vs 52.9 (34.0-73.8) kg; P < 0.05]. The 24-h urinary output of the ileostomists was lower than for controls [1380 (430-4690) vs 2000 (840-4440) ml/24 h; P < 0.05] suggesting some degree of dehydration. In 62.7% of ileostomists 24-h urinary Na excretion was < 100 mmol/day vs 16.7% of controls, and ileostomists with lower urinary Na were more likely than ileostomists with normal Na excretion to have a low BMI [23.9 (14.3-33.0) vs 28.4 (16.6-43.0) kg/m(2) ; P < 0.001] and LBM [44.1 (19.3-73.0) vs 59.5 (36.6-67.9) kg; P < 0.001]. The respective 24-h output of Ca was [2.2 (0-6.1) vs 4.7 (0-13) mmol; P < 0.001] and Mg was [2.0 (0-13.7) vs 3.9 (1.2-5.4) mmol; P < 0.001], and BMD Z-score LS was -0.15 (-2.0 to 5.2) vs 0.3 (-2.5 to 2.1), Z-score FN -0.5 (-1.9 to 3.1) vs 0.2 (-1.2 to 1.4), both P < 0.05. CONCLUSION: Patients with an ileostomy tend to have low body weight, BMI, LBM and BMD. They also tend to have low urine volumes, and some are depleted of Na, Ca and Mg. Abnormalities are greater in those with a lower urinary Na and measuring this will identify ileostomists at risk of Na depletion who will be benefitted by Na supplements.

Clinical utility of 13C-liver-function breath tests for assessment of hepatic function.

13C-Liver-function breath tests have been used in clinical diagnostics and, to a limited extent, to investigate hepatic function. From a practical perspective, tests such as the 13C-aminopyrine and 13C-methacetin breath tests are simple to administer, safe, and relatively inexpensive to perform. Surprisingly, they have not entered the mainstream of clinical practice, because they are perceived to lack the specificity and adequate precision needed to give accurate results in real time. The dynamic nature of 13C-liver-function breath tests, their possible versatility in terms of assessing a range of different liver functions, and the ease with which they can be repeated to follow relative changes in liver function with time, all imply the potential for wider clinical application. Therefore, there is a need for these tests to be critically evaluated and their potential clinical application be tested systematically against defined objectives. We describe refinements in the methodology of the tests and propose several situations in which currently reliable methods for assessment of liver function do not exist and where 13C-liver-function breath tests might be of use. We propose that use has been constrained by practical methodological considerations which could be addressed to offer tests better suited to routine application in the out-patient or community setting.

Paediatric nutrition risk scores in clinical practice: children with inflammatory bowel disease.

BACKGROUND: There has been increasing interest in the use of nutrition risk assessment tools in paediatrics to identify those who need nutrition support. Four non-disease specific screening tools have been developed, although there is a paucity of data on their application in clinical practice and the degree of inter-tool agreement. METHODS: The concurrent validity of four nutrition screening tools [Screening Tool for the Assessment of Malnutrition in Paediatrics (STAMP), Screening Tool for Risk On Nutritional status and Growth (STRONGkids), Paediatric Yorkhill Malnutrition Score (PYMS) and Simple Paediatric Nutrition Risk Score (PNRS)] was examined in 46 children with inflammatory bowel disease. Degree of malnutrition was determined by anthropometry alone using World Health Organization International Classification of Diseases (ICD-10) criteria. RESULTS: There was good agreement between STAMP, STRONGkids and PNRS (kappa > 0.6) but there was only modest agreement between PYMS and the other scores (kappa = 0.3). No children scored low risk with STAMP, STRONGkids or PNRS; however, 23 children scored low risk with PYMS. There was no agreement between the risk tools and the degree of malnutrition based on anthropometric data (kappa < 0.1). Three children had anthropometry consistent with malnutrition and these were all scored high risk. Four children had body mass index SD scores < -2, one of which was scored at low nutrition risk. CONCLUSIONS: The relevance of nutrition screening tools for children with chronic disease is unclear. In addition, there is the potential to under recognise nutritional impairment (and therefore nutritional risk) in children with inflammatory bowel disease.

Energy expenditure, nutrition and growth.

Fundamental to appropriate nutritional prescription is an understanding of the conditions necessary for growth that include the requirements for energy in health and illness. Energy requirements need to be met by the dietary intake to prevent weight loss. A positive energy balance will result in weight gain. Energy requirement includes several components; the largest is the basal metabolic rate, although physical activity level and the energy needs of growth are important components. All aspects of energy metabolism are likely to be influenced by illness and impact on energy balance. Changes in dietary intake and physical activity are observed clinically but poorly described in most childhood illnesses. Changes in metabolic rate are poorly described in part owing to methodological problems. This review explores changes in energy expenditure associated with health and disease, highlights the lack of evidence underpinning this aspect of practical nutritional support and provides the clinician with a guide to the factors involved in estimating energy requirements, emphasising the importance of measuring the child's response to nutritional support.

Improving peri-operative fluid management in a large teaching hospital: pragmatic studies on the effects of changing practice.

Concerns about the over-prescription of peri-operative fluids, particularly normal saline, culminated in the recent publication of UK national guidelines on fluid prescription during and after surgery. A working group comprising members of the nutrition support team, surgeons, anaesthetists and pharmacists therefore sought to reduce the overall levels of fluid prescription and to limit normal saline usage in our large Teaching Hospital by producing written local fluid prescribing guidelines and holding a series of fluid prescription education sessions for consultants and junior staff. Ideally, the success of such measures would have been determined by studies on fluid balance, body weight and/or measured body water in large numbers of individual patients in a large cluster-randomised controlled trial. However, this would have proved logistically difficult and very costly especially as it is notoriously difficult to rely on the accuracy of daily fluid balance charts in large numbers of patients on busy post-operative surgical wards. We therefore undertook a pragmatic study, comparing historical data on fluid type/volume prescribed (from both individual and ward level pharmacy records), oedema status and clinical outcomes from 2002 with two prospective audits of similar data carried out during 2008 and 2009. Our data showed that in the comparable, elective surgical patients within each audit, there was a decline in total intravenous fluids prescribed over the first 5 post-operative days from 21·1 litres per patient in 2002 to 14·2 litres per patient in 2009 (P<0·05), while pharmacy records showed that the proportion of 0·9% saline supplied declined from 60% to 35% of all fluids supplied to the surgical wards involved, with a concomitant increase in the use of 4%/0·18% dextrose-saline and Hartmann's solution. Alongside these changes in fluid prescribing, the number of patients with clinically apparent oedema declined from 53% in 2002 to 36% in 2009; gut function returned more quickly (6 d in 2002 v. 4 d in 2009, P<0·05) and the length of stay improved from 13 d in 2002 to 10 d in 2009, P<0·05). Although we accept that other factors might have contributed to the observed changes in these clinical parameters, we believe that the measures to reduce fluid and saline administration were the major contributors to these improved clinical outcomes.

Accelerometers for measuring physical activity behavior in Indian children.

OBJECTIVE: To examine the validity of accelerometers for characterizing habitual physical activity patterns in Indian children. DESIGN: Cohort study. SETTING: Holdsworth Memorial Hospital, Mysore. SUBJECTS: Children (N=103, mean age 6.6 years) selected from an ongoing birth cohort study. METHODS: Physical activity was measured over 7 days using accelerometers (MTI Actigraph) and concurrent parent-maintained activity diaries. Actigraph counts per minute representing sedentary (<10), light (< 400), moderate (<3000) and vigorous activity were determined using a structured activity session in a separate group of 10 children. In 46 children chosen for validating accelerometers, time spent in different activity levels according to diaries was determined. Energy Expenditure (EE) was calculated from diaries using a factorial method. RESULTS: Ninety-eight children wore the monitor for > or = 4 days. Total counts and time spent in different activity levels were similar in boys and girls (P>0.2). Among 46 children chosen for comparisons, time spent in sedentary (r =0.48, P=0.001), light (r=0.70, P<0.001) and moderate activities (r=0.29, P=0.054) according to diaries correlated with those derived from counts, and total Actigraph counts correlated with EE (r=0.42, P=0.004). Bland-Altman analysis showed systematic bias, and wide limits of agreement between these methods for time spent in different activity levels. CONCLUSIONS: Accelerometers are a well tolerated and objective way of measuring activity behavior in free-living children. Though accelerometer counts correlate with time spent in activity of varying intensity and energy expenditure derived from parent-maintained diaries, wide limits of agreement show that the limitations of accelerometers need to be recognized in interpreting the data that they generate.

The benefits of oestrogens on postprandial lipid metabolism are lost in post-menopausal women with Type 2 diabetes.

AIMS: Women with Type 2 diabetes appear to lose the protection against cardiovascular disease (CVD) afforded by oestrogens. We examined the effects of oestrogen hormone replacement therapy (HRT) on postprandial clearance of dietary fat in non-diabetic and diabetic post-menopausal women. METHODS: In a cross-sectional study, fasting subjects [HRT+ and HRT- control and diabetic women; Type 2 diabetes (DM) HRT+n = 8, DM HRT-n = 14, control HRT+n = 7, control HRT-n = 11] consumed a meal containing the stable isotope 1,1,1-[13]C-tripalmitin, with blood and breath sampled for 6 and 24 h, respectively, in the postprandial period. RESULTS: In diabetic women, there were no differences between the HRT+ and HRT- groups for any of these parameters. In contrast, in HRT+ compared with HRT- control women, the triglyceride (TG) area under the curve was lower [AUC; HRT+ median (range) 7.7 (4.1, 12.8) mmol/l per 6 h, HRT- 9.7 (3.9, 18.5) mmol/l per 6 h, P < 0.05] and [13]C-palmitic acid in the TG fraction was also lower [HRT+ 23.2 (10.3, 41.3) ng/ml per 6 h, HRT- 47.7 (12.6, 77.2) ng/ml per 6 h, P < 0.05], suggesting the lower postprandial triglyceridaemia associated with HRT in non-diabetic women is because of better chylomicron clearance. CONCLUSIONS: The oestrogen-associated advantage in clearance of dietary lipid we observed in non-diabetic post-menopausal women is not seen in post-menopausal diabetic women. This is likely to promote an atherogenic lipoprotein profile and may contribute to the loss of CVD protection seen in diabetic women.

Measured versus predicted energy expenditure in children with inactive Crohn's disease.

INTRODUCTION: The aim of the study was to assess if the estimated average requirements for energy for normal children (EAR) and the Schofield equation could reliably predict energy requirements in children with inactive Crohn's disease (CD). METHODS: Twenty-three children with inactive CD were studied, median age 14.3 years (range 7.8-16.9). Resting energy expenditure (REE) was measured by indirect calorimetry and compared with that predicted using the Schofield equation (BMR). Total energy expenditure (TEE) was measured using REE and a 3-day activity diary and compared with EAR. RESULTS: REE ranged from 79% to 136% of BMR. Mean REE was not significantly greater than mean BMR (P=0.25 2-tailed t-test). TEE ranged from 72% to 163% of estimated average requirements for energy for children of that weight (EARw). EARw tended to underestimate TEE in large children and overestimate TEE in small children (Bland-Altman plot R=0.5, P=0.002). EARw was a poor predictor of TEE (R=0.35, P=0.1). EAR underestimated energy requirements by >500 kcal/day in 40% of the children. CONCLUSIONS: The Schofield equation and EAR are unreliable methods of predicting total energy requirements in children with inactive CD with a significant potential to underestimate energy needs. When energy requirements were greater than EAR it was due to physical activity and body habitus rather than raised REE.

Laboratory markers predict bone loss in Crohn's disease: relationship to blood mononuclear cell function and nutritional status.

BACKGROUND: Crohn's disease is associated with reduced bone density. The power of simple markers of systemic inflammation to identify higher rates of bone loss, in Crohn's disease, is uncertain. This relationship and the role of circulating (peripheral blood) mononuclear cells were investigated in a case-control study. METHODS: Urinary deoxypyridinoline/creatinine and serum osteocalcin concentrations were compared in male and premenopausal females with "active" Crohn's disease (C-reactive protein > or = 10 and/or erythrocyte sedimentation rate > or = 20) (n = 22) and controls with "quiescent" Crohn's disease (C-reactive protein < 10 and erythrocyte sedimentation rate < 20) (n = 21). No patients were receiving corticosteroid therapy. Production of tumour necrosis factor-alpha, interferon-gamma and prostaglandin E(2) by peripheral blood mononuclear cells were measured. RESULTS: Active Crohn's disease was associated with a higher deoxypyridinoline/creatinine (P = 0.02) and deoxypyridinoline/creatinine:osteocalcin ratio (P =0.01) compared with quiescent Crohn's disease, but similar osteocalcin (P = 0.24). These were not explained by vitamin D status, dietary intake or nutritional status. However, production of interferon-gamma by concanavalin A-stimulated peripheral blood mononuclear cells was lower in active Crohn's disease (P = 0.02) and correlated negatively with the deoxypyridinoline/creatinine:osteocalcin ratio (r = -0.40, P = 0.004). CONCLUSION: In Crohn's disease, raised C-reactive protein and erythrocyte sedimentation rate may indicate higher rates of bone loss and, if persistent, the need to assess bone mass even where disease symptoms are mild. This may be partly explained by altered production of interferon-gamma by peripheral blood mononuclear cells.

Effect of meal sequence on postprandial lipid, glucose and insulin responses in young men.

OBJECTIVE: To investigate whether the postprandial changes in plasma triacylglycerol (TAG), nonesterified fatty acids (NEFA), glucose and insulin concentrations in young men were the same if an identical meal was fed at breakfast and lunch, and if the response to lunch was modified by consumption of breakfast. METHODS: In two trials (1 and 2) healthy subjects (age 22+/-1 y, body mass index 22+/-2 kg/m(2)) were fed the same mixed macronutrient meal at breakfast at 08:00 h and lunch at 14:00 h. In the third trial, no breakfast was fed and the overnight fast extended until lunch at 14:00 h. Addition of [1,1,1-(13)C]tripalmitin to one meal in each trial was used to distinguish between endogenous and meal-derived lipids. RESULTS: The postprandial changes in TAG, NEFA and glucose concentrations were similar in trials 1 and 2. The change in plasma total TAG concentration was about two fold less (P<0.05) after lunch compared to breakfast. Postprandial NEFA suppression was the same after breakfast and lunch. Glucose and insulin responses were significantly greater following lunch suggesting decreasing insulin sensitivity during the day. Consumption of breakfast did not alter the postprandial total TAG or NEFA responses after lunch. Measurement of [(13)C]palmitic acid concentration showed that handling of TAG and NEFA from the meal was the same after breakfast and lunch, and was not altered by consumption of breakfast. CONCLUSIONS: Overall, these data suggest that in young, healthy men regulation of plasma TAG from endogenous sources, principally VLDL, but not chylomicrons during the postprandial period leads to differences in the magnitude of lipaemic response when the same meal was consumed at breakfast or at lunch 6 h later.

Essential fatty acid status in paediatric Crohn's disease: relationship with disease activity and nutritional status.

BACKGROUND: Active paediatric Crohn's disease is associated with nutritional deficiencies and altered nutrient intake. The availability of essential fatty acids (linoleic and alpha-linolenic acids) or their derivatives (arachidonic and eicosapentaenoic acids) may alter in plasma and cell membrane phospholipid in protein-energy malnutrition in children and in Crohn's disease in adults. AIM: To investigate the relationship of fatty acid phospholipid profiles with disease activity and nutritional status in paediatric Crohn's disease. METHODS: The fatty acid (proportionate) composition of plasma and erythrocyte phosphatidylcholine was determined in 30 patients (10.3-17.0 years) stratified into active and quiescent Crohn's disease (paediatric Crohn's disease activity index) and high and low body mass (body mass index centile). RESULTS: In plasma phosphatidylcholine, active disease activity was associated with a lower level of alpha-linolenic acid compared with that in quiescent disease (P < 0.05). A body mass index below the 50th centile was associated with active Crohn's disease, low linoleic and alpha-linolenic acids and high arachidonic acid (P < 0.05) in plasma phosphatidylcholine, and low alpha-linolenic acid in erythrocyte phosphatidylcholine. These findings could not be explained through differences in habitual dietary fat intake. CONCLUSION: In paediatric Crohn's disease, a low body mass index centile and high disease activity are associated with altered profiles of essential fatty acids and their derivatives, which may reflect altered metabolic demand.

Conversion of alpha-linolenic acid to palmitic, palmitoleic, stearic and oleic acids in men and women.

The purpose of this study was to determine whether adult humans can recycle carbon from alpha-linolenic acid (18:3n-3) into saturated (SFA) and monounsaturated (MUFA) fatty acids. Six men and six women consumed 700 mg [U-13C]-18:3n-3. Blood was collected over 21 days and breath over 24h. [13C]-labelled SFA and MUFA were detected in plasma phosphatidylcholine (PC) and triacylglycerol (TAG). Total labelled fatty acid incorporation into SFA and MUFA was five- and 25-fold greater in PC than TAG in men and women, respectively. [13C]-16:0 was the major labelled fatty acid in both fractions. Total [13C] incorporation into SFA and MUFA was 20% greater in men than women, and related positively (r(2) = 0.35, P<0.05) to the fractional recovery of labelled 18:3n-3 as 13CO2 on breath. These results suggest that the extent of partitioning towards beta-oxidation and carbon recycling may regulate the availability of 18:3n-3 for conversion to longer-chain fatty acids.

Maldigestion and malabsorption of dietary lipid during severe childhood malnutrition.

BACKGROUND: Diets rich in lipid are used to provide energy density in treating children with severe malnutrition, but the extent to which their digestion and absorption can cope with the load effectively is uncertain. AIM: To determine the extent of impaired digestion or absorption, in three groups of eight malnourished children (aged 5-23 months) using isotopic probes of the predominant fatty acids in coconut and corn oil used to fortify the diet. METHODS: Each child received oral doses of one of three (13)C labelled triglycerides (trilaurin, triolein, or trilinolein). The recovery of (13)C label in stool either as triglyceride (TAG) or fatty acid (FA), was used to assess digestion and absorption. In a separate test, the recovery of label in stool following an oral dose of [(13)C]-glycocholate was measured to assess bile salt malabsorption. RESULTS: The median recovery of label in stool was 9% (range 1-29%) of administered dose. Following treatment there was a reduction in stool (13)C excretion for the labelled TAG (<1%). In half the subjects, label was recovered as TAG in stool (median 0.6%, range 0-44%). Most label in stool was recovered as FA (median 30%, range 0-100%). Following [(13)C]-glycocholate, label was recovered in excess in about one third of studies. CONCLUSION: Abnormalities in the gastrointestinal handling of lipid were observed in over 50% of children with severe malnutrition, reflecting problems in absorption, although impaired solubilisation or hydrolysis could also be contributory factors. The underlying lesion improves as treatment progresses, leading to concomitant improvement in function.

Influence of glucose ingestion by humans during recovery from exercise on substrate utilisation during subsequent exercise in a warm environment.

Carbohydrate (CHO) ingestion during short-term recovery from prolonged running has been shown to increase the capacity for subsequent exercise in a warm environment. The aim of this study was to examine the effects of the amount of glucose given during recovery on substrate storage and utilisation during recovery and subsequent exercise in a warm environment. A group of 11 healthy male volunteers took part in two experiments in a controlled warm environment (35 degrees C, 40% relative humidity), 1 week apart. On each occasion the subjects completed two treadmill runs (T1 and T2) at a speed equivalent to 60% of maximal oxygen uptake, for 90 min, until they were fatigued, or until aural temperature (T(aur)) reached 39 degrees C. The two runs were separated by a 4 h recovery period (REC), during which subjects consumed 55 g of naturally enriched [U-(13)C]-glucose in the form of a 7.5% carbohydrate-electrolyte solution (CES, mass of solution 667 g) immediately after T1. The subjects then consumed either: the same quantity of CES, or an equivalent volume of an electrolyte placebo, at 60, 120 and 180 min during REC, providing a total of 220 g (C220) or 55 g (C55) of [U-(13)C]-glucose, respectively. Expired gases were collected at 15 min intervals during exercise and 60 min intervals during REC, for determination of total CHO and fat oxidation by indirect respiratory calorimetry, and orally ingested [U-(13)C]-glucose oxidation, estimated from the (13)C:(12)C ratio of expired CO(2). Substrate metabolism did not differ between conditions during T1. Despite the fact that total CHO (P < 0.05) and ingested glucose oxidation (P < 0.01) were greater during REC of the C220 condition, glycogen synthesis was estimated to be approximately fivefold greater (P < 0.01) than in the C55 condition. During T2 the rate of total CHO oxidation was higher (P < 0.01) and total fat oxidation lower (P < 0.01) at all times during the C220 compared to the C55 condition. The greater CHO oxidation during C220 appeared to be met from ingested sources, as the rate of [U-(13)C]-glucose oxidation was greater (P < 0.01) at all times during T2, compared to C55. Whilst more of the ingested substrate remained unoxidised on completion of T2 during C220, exercise duration was similar in the two experimental conditions, and was limited by thermoregulatory incapacity (T(aur) > 39 degrees C) rather than substrate availability per se.

The paradox of improved antiretroviral therapy in HIV: potential for nutritional modulation?

Chronic infection with HIV type 1 is associated with alterations in macronutrient metabolism, specifically elevated plasma lipids, glucose and reduced insulin sensitivity. These alterations are most severe in patients at the later stages of AIDS, indicating a relationship with disease progression. Recently, a metabolic syndrome, termed lipodystrophy, has been described in successfully-treated HIV patients in whom the altered macronutrient metabolism of HIV infection appears to be amplified markedly, with concurrent alterations in adipose tissue patterning. This syndrome presents a paradox, as before the development of highly-active antiretroviral therapy (HAART) the most severe perturbations in metabolism were observed in the sickest patients. Now, the patients that respond well to therapy are showing metabolic perturbations much greater than those seen before. The implications of this syndrome are that, whilst life expectancy may be increased by reducing viral load, there are concomitant increases in the risk of cardiovascular disease, diabetes and pancreatitis within this patient population. The aetiology of the syndrome remains unclear. In a collaborative trial with the Chelsea and Westminster Hospital in London we have used stable-isotope-labelled fatty acids to examine the hypothesis that treatment with HAART causes a delayed clearance of dietary lipid from the circulation, resulting in the retention of lipid within plasma and the downstream changes in insulin and glucose homeostasis. This hypothesis would indicate a role for low-fat diets, exercise and drugs that reduce plasma lipid or insulin resistance, in modulating the response to antiretroviral therapy in HIV infection.