Jane L. Murphy

Effect of fatty acid chain length and saturation on the gastrointestinal handling and metabolic disposal of dietary fatty acids in women.

The gastrointestinal handling and metabolic disposal of [1-13C]palmitic acid, [1-13C]stearic acid and [1-13C]oleic acid administered within a lipid-casein-glucose-sucrose emulsion were examined in normal healthy women by determining both the amount and nature of the 13C label in stool and label excreted on breath as 13CO2. The greatest excretion of 13C label in stool was in the stearic acid trial (9.2% of administered dose) whilst comparatively little label was observed in stool in either the palmitic acid (1.2% of administered dose) or oleic acid (1.9% of administered dose) trials. In both the palmitic acid and oleic acid trials, all of the label in stool was identified as being present in the form in which it was administered (i.e. [13C]palmitic acid in the palmitic acid trial and [13C]oleic acid in the oleic acid trial). In contrast, only 87% of the label in the stool in the stearic acid trial was identified as [13C]stearic acid, the remainder was identified as [13C]palmitic acid which may reflect chain shortening of [1-13C]stearic acid within the gastrointestinal tract. Small, but statistically significant, differences were observed in the time course of recovery of 13C label on breath over the initial 9 h of the study period (oleic acid = palmitic acid > stearic acid). However, when calculated over the 24 h study period, the recovery of the label as 13CO2 was similar in all three trials (approximately 25% of absorbed dose). These results support the view that chain length and degree of unsaturation may influence the gastrointestinal handling and immediate metabolic disposal of these fatty acids even when presented within an emulsion.

Energy content of stools in normal healthy controls and patients with cystic fibrosis.

Stool energy losses and the sources of energy within the stool were determined in 20 healthy controls and 20 patients with cystic fibrosis while on their habitual pancreatic enzyme replacement treatment. Stool energy losses were equivalent to 3.5% of gross energy intake in healthy children (range 1.3-5.8%). Despite a comparable gross energy intake, stool energy losses were three times greater in patients with cystic fibrosis than controls averaging 10.6% of gross energy intake (range 4.9-19.7%). Stool lipid could account for only 29% and 41% of the energy within the stool in controls and patients with cystic fibrosis respectively and was poorly related to stool energy. Approximately 30% of the energy within the stool could be attributable to colonic bacteria in both the healthy children and patients with cystic fibrosis. These results suggest that stool energy losses in healthy children are relatively modest but that even when patients with cystic fibrosis are symptomatically well controlled on pancreatic enzyme replacement, raised stool energy losses may continue to contribute towards an energy deficit sufficient to limit growth in cystic fibrosis. As the energy content per gram wet weight remains relatively constant (8 kJ/g), stool energy losses may be estimated from simple measurements of stool wet weight.

The gastrointestinal handling and metabolism of [1-13C]palmitic acid in healthy women

The gastrointestinal handling and metabolism of [1-13C]palmitic acid given as the free fatty acid was examined in six healthy women by measuring the excretion of13C-label in stool and in breath as13CO2. The gastrointestinal handling of [1-13C]palmitic acid was compared with the apparent absorption of dietary lipid by measuring lipid losses in stool. The variation both within and between subjects was determined by repeating the study in the same individuals on separate occasions. The time course for excretion of label in stool over the five-day study period followed a common pattern, with most of the label excreted over the first two days of the stool collection.13C-Label excreted in stool over the five-day study period was 14.3±9.8% of that administered and on repeating the trial was 31.6±24.7% (not significantly different due to variability); there was poor agreement within subjects. Lipid excreted in stool expressed as a percentage of ingested lipid was 5.2±4.4% in Trial 1 and 5.9±4.0% in Trial 2, and was the same in each individual on repeating the trial. There was no clear relationship between the excretion of13C-label and lipid in stool (Trial 1:R=−0.43,P>0.40; Trial 2:R=−0.02,P>0.97). On the first occasion, 22.0±4.5% of the administered label was excreted on breath over the 15-h study period and on repeating the trial was 15.8±9.5% (not significantly different) with poor repeatability in a given individual. There was an inverse relationship between the proportion of13C-label excreted in stool and that excreted on breath in Trial 1 (R=−0.80,P>0.06) with a weaker association observed in Trial 2 (R=−0.49,P>0.32). Correcting for differences in the apparent absorption of label reduced the variability in its excretion in breath observed between subjects, particularly in Trial 2. It is concluded that although there are differences in the gastrointestinal handling of [1-13C]palmitic acid both within and between healthy adults, the postprandial oxidation of absorbed substrate was similar. The assumptions underlying these observations need to be examined by characterizing the nature of13C-label in stool.

The importance of nutrition, diet and lifestyle advice for cancer survivors - the role of nursing staff and interprofessional workers.

AIMS AND OBJECTIVES To examine current guidelines and the evidence base to illustrate the importance of nutrition, diet and lifestyle advice to support people who have survived cancer and help them integrate back into normal life, improve their quality of life and potentially improve their chance of long-term survival. BACKGROUND Cancer survivors need to know about nutrition and other lifestyle behaviour changes to help them recover and potentially reduce the risk of the same cancer recurring or a new cancer developing. From this perspective, frontline registered nurses are in a prime position to support cancer survivors who are in their care. DESIGN Discursive paper. METHODS On the basis of the international research evidence and a critical analysis of recent policy and practice literature, themes emerged, which illustrate the importance of nutrition, diet and lifestyle advice for cancer survivors. This paper discusses the need for more focused education and greater interprofessional working for quality care delivery. CONCLUSION New professional guidance for emerging frontline nurses indicates they should be able to provide appropriate and more consistent advice on nutritional issues, physical activity and weight management, although more research is needed to understand the right mode of nutrition training. Additionally, interprofessional working needs improving as well as encouraging cancer survivors to respond. RELEVANCE TO CLINICAL PRACTICE High-quality nutrition education and training is required for nurses working across both the acute and primary care sectors. They require this to effectively monitor and advise patients and to know when, where and from whom they can access more specialist help. Interprofessional collaborative working across multi-centre settings (National Health Service and non-National Health Service) is key to provide the best effective care and support for cancer survivors.

Variation in [U-13C] |[alpha]| Linolenic Acid Absorption, |[beta]|-oxidation and Conversion to Docosahexaenoic Acid in the Pre-Term Infant Fed a DHA-Enriched Formula

Docosahexaenoic acid (DHA) is an integral component of neural cell membranes and is critical to the development and function of the CNS. A premature delivery interrupts normal placental supply of DHA such that the infant is dependent on the nature of the nutritional support offered. The most abundant omega-3 fatty acid in pre-term formulas is α linolenic acid (ALNA), the precursor of DHA. This project studied the absorption, β-oxidation and conversion of ALNA to DHA by pre-term infants ranging from 30-37 wk of corrected gestation. [U-13C] ALNA was administered emulsified with a pre-term formula to 20 well pre-term infants on full enteral feeds. Enrichment of 13C in stool and as 13CO2 in breath was used to estimate absorption across the gut and partitioning toward β-oxidation respectively. Excretion of the administered dose of 13C in stool ranged from 2.0 to 26.2%; excretion decreased with increasing birth gestation. Appearance as 13CO2 on breath ranged from 7.6 to 19.0%. All infants synthesised eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and DHA with the least mature having the highest cumulative plasma DHA. These results show considerable variation suggesting that the worst absorption of ALNA and the greatest production of DHA occur in infants born at the earliest gestation.

The effect of age and gender on the metabolic disposal of [1-13C]palmitic acid

Objective: To examine the effect of age and gender on the metabolic disposal of [1-13C] palmitic acid.Design: Cross-sectional.Setting: Clinical Nutrition and Metabolism Unit at Southampton General Hospital, Institute of Human Nutrition, University of Southampton.Subjects and measurements: Twelve children (5 boys and 7 girls; aged 5–10 y) and six men (BMI 23.3±2.6 kg/m2; aged 20–30 y) were recruited. Following oral administration of a bolus dose of [1-13C]palmitic acid (10 mg/kg body weight) consumed with a test meal (1667 kJ) the excretion of 13C-label was measured on breath as 13CO2 over 24 h and in stool over 5 d to account for differences in absorption of [1-13C]palmitic acid. The 13C-enrichment of samples was determined by continuous flow-isotope ratio mass spectrometry. Net substrate oxidation was estimated from gaseous exchange measurements in the postabsorptive state and over 6 h postprandially.Results: The excretion of 13CO2 on breath varied between subjects both in the pattern and amount excreted over 24 h. Breath 13CO2 was not different between boys (61.0±22.4% of absorbed dose) and girls (54.2±17.9% of absorbed dose). The excretion of breath 13CO2 was less in the men (35.1±9.3% of absorbed dose; P=0.005) and that observed previously by our group in women (30.7±6.7% of absorbed dose; P=0.005) than in the children. Net fat oxidation was greater in the children in both the postabsorptive (2.43±0.78 g/h) and postprandial (11.89±3.13 g/6 h) states than in the men (0.93 g/h±1.50; P=0.016; 9.86±10.53 g/6 h; NS) and women studied previously (0.53±0.68 g/h; P=0.003; 0.03±3.21 g/6 h; P=0.001).Conclusions: Our observations that children oxidised nearly twice the amount of [1-13C] palmitic acid than adults in conjunction with greater net fat oxidation in children than adults in both the postabsorptive and postprandial states should be considered before current UK dietary recommendations for fat and saturated fats, developed for adults, are applied to growing children. For dietary recommendations to be developed further more information is required, particularly in groups of infants and the elderly, about the factors that influence the postprandial handling of dietary fat.Sponsorships: This work was supported by The Ministry of Agriculture, Fisheries and Food, Scientific Hospital Supplies, UK Ltd. and The Wessex Medical Trust.

Excessive faecal losses of vitamin A (retinol) in cystic fibrosis.

Vitamin A (retinol) deficiency is a recognised complication of cystic fibrosis and is presumed to be a consequence of an impairment in the digestion and absorption of dietary fats. The dietary intake of fat and retinol was assessed from a seven day weighed food intake in 11 subjects with cystic fibrosis and 12 matched controls. Faecal excretion of retinol and fat were measured from three day stool collections. There was little difference between the two groups in the intake of fat or retinol equivalents. When studied the subjects with cystic fibrosis were clinically stable and the apparent absorption of fat was not significantly different to that in the controls. There was a significant increase in the faecal losses of retinol in cystic fibrosis, which was unrelated to the degree of fat in the stool. In cystic fibrosis the median retinol recovered in the stool was 40% of the intake, compared with 1.8% in the controls. It is concluded that there is a specific defect in the handling of retinol by the gastrointestinal tract in cystic fibrosis, which may be unrelated to the digestion and absorption of dietary fat.

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 13C labelled triglycerides (trilaurin, triolein, or trilinolein). The recovery of 13C 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 [13C]-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 13C 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 [13C]-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.

Gastrointestinal handling of [1-13C]palmitic acid in healthy controls and patients with cystic fibrosis

AIM To examine the gastrointestinal handling of [1-13C]palmitic acid given as the free acid by measuring the excretion of 13C label in stool in 16 healthy children and 11 patients with cystic fibrosis on their habitual enzyme replacement treatment. METHODS After an overnight fast, each child ingested 10 mg/kg body weight [1-13C]palmitic acid with a standardised test meal of low natural 13C abundance. A stool sample was collected before the test and all stools were collected thereafter for a period of up to five days. The total enrichment of 13C in stool and the species bearing the13C label was measured using isotope ratio mass spectrometry. RESULTS The proportion of administered13C label excreted in stool was 24.0% (range 10.7–64.9%) in healthy children and only 4.4% (range 1.2–11.6%) in cystic fibrosis patients. The enrichment of 13C in stool was primarily restricted to the species consumed by the subjects (that is as palmitic acid). CONCLUSION There does not appear to be a specific defect in the absorption of [1-13C]palmitic acid in patients with cystic fibrosis. The reasons why cystic fibrosis patients appear to absorb more of this saturated fatty acid than healthy children is not clear and requires further investigation.

Total family unit Helicobacter pylori eradication and pediatric re-infection rates

Background.  Re‐infection with Helicobacter pylori is more common in children than adults, and it is generally accepted that the family unit plays a significant role in primary childhood infection. We investigated whether the family unit plays a significant role in pediatric re‐infection and if eradication of H. pylori from the entire family reduces the risk of childhood re‐infection.