Jane McKenzie

Use of a renal-specific oral supplement by haemodialysis patients with low protein intake does not increase the need for phosphate binders and may prevent a decline in nutritional status and quality of life

BACKGROUND Protein-energy wasting is a frequent and debilitating condition in maintenance dialysis. We randomly tested if an energy-dense, phosphate-restricted, renal-specific oral supplement could maintain adequate nutritional intake and prevent malnutrition in maintenance haemodialysis patients with insufficient intake. METHODS Eighty-six patients were assigned to a standard care (CTRL) group or were prescribed two 125-ml packs of Renilon 7.5(R) daily for 3 months (SUPP). Dietary intake, serum (S) albumin, prealbumin, protein nitrogen appearance (nPNA), C-reactive protein, subjective global assessment (SGA) and quality of life (QOL) were recorded at baseline and after 3 months. RESULTS While intention to treat analysis (ITT) did not reveal strong statistically significant changes in dietary intake between groups, per protocol (PP) analysis showed that the SUPP group increased protein (P < 0.01) and energy (P < 0.01) intakes. In contrast, protein and energy intakes further deteriorated in the CTRL group (PP). Although there was no difference in serum albumin and prealbumin changes between groups, in the total population serum albumin and prealbumin changes were positively associated with the increment in protein intake (r = 0.29, P = 0.01 and r = 0.27, P = 0.02, respectively). The SUPP group did not increase phosphate intake, phosphataemia remained unaffected, and the use of phosphate binders remained stable or decreased. The SUPP group exhibited improved SGA and QOL (P < 0.05). CONCLUSION This study shows that providing maintenance haemodialysis patients with insufficient intake with a renal-specific oral supplement may prevent deterioration in nutritional indices and QOL without increasing the need for phosphate binders.

Effect of Oatmeal on Postprandial Vascular Compliance Following a High Fat Meal

Background and aim: Postprandial hyperlipidaemia has been associated with acute cardiovascular effects e.g. endothelial dysfunction and peripheral vasodilatation. Oats have known health benefits, and may reduce the transient, post-prandial endothelial dysfunction. The aim of this short study was to investigate if markers of endothelial function pulse wave velocity (PWV) and augmentation index corrected for heart rate (AIx@75) are affected by a meal with varying levels of saturated fat, with or without oatmeal. Methods and results: Fourteen subjects (aged between 22 and 51 years) were recruited. On their first visit, following baseline measurements of anthropometry, blood pressure (BP), heart rate (HR), PWV and AIx@75, they were given one of three meals (low fat, high fat, and high fat with 60g oatmeal) in a randomised order. Subjects returned three hours later for re-assessment of BP, PWV and AIx@75. Visits two and three followed the same protocol, but only BP, HR, PWV and AIx@75 were measured. There was a significant correlation between baseline PWV and systolic pressure (p<0.02), and AIx@75 and diastolic pressure (p<0.005). AIx@75 was positively related to BMI and waist circumference (p<0.01 and p<0.005 respectively). AIx@75 fell following the high fat meal (p<0.05), but not when oats were taken. Heart rate increased following the high fat meal with oats (p<0.05), but no differences were found between fasting and postprandial PWV after any of the meals. Conclusion: AIx@75 was correlated with BMI and waist circumference. The decrease in AIx@75 following the high fat meal requires further investigation, and AIx@75 is possibly a more sensitive marker of arterial compliance than PWV in a young healthy population.

5-Hydroxyvitamin D concentration in paediatric cancer patients from Scotland: a prospective cohort study

Children with cancer are potentially at a high risk of plasma 25-hydroxyvitamin D (25(OH)D) inadequacy, and despite UK vitamin D supplementation guidelines their implementation remains inconsistent. Thus, we aimed to investigate 25(OH)D concentration and factors contributing to 25(OH)D inadequacy in paediatric cancer patients. A prospective cohort study of Scottish children aged 75 nmol/l). In all, eighty-two patients (median age 3·9, interquartile ranges (IQR) 1·9-8·8; 56 % males) and thirty-five controls (median age 6·2, IQR 4·8-9·1; 49 % males) were recruited. 25(OH)D inadequacy was highly prevalent in the controls (63 %; 22/35) and in the patients (64 %; 42/65) at both baseline and during treatment (33-50 %). Non-supplemented children had the highest prevalence of 25(OH)D inadequacy at every stage with 25(OH)D median ranging from 32·0 (IQR 21·0-46·5) to 45·0 (28·0-64·5) nmol/l. Older age at baseline (R -0·46; P<0·001), overnutrition (BMI≥85th centile) at 3 months (P=0·005; relative risk=3·1) and not being supplemented at 6 months (P=0·04; relative risk=4·3) may have contributed to lower plasma 25(OH)D. Paediatric cancer patients are not at a higher risk of 25(OH)D inadequacy than healthy children at diagnosis; however, prevalence of 25(OH)D inadequacy is still high and non-supplemented children have a higher risk. Appropriate monitoring and therapeutic supplementation should be implemented.

Re-evaluation of a food frequency questionnaire to estimate total n-3 fatty acid intake in primary school children

Long-chain omega-3 PUFA (LC n-3 PUFA), including DHA and EPA, contribute significantly to neurological and cognitive development in children (1) . Dietary sources of intake of LC n-3 PUFA, however, are limited only to relatively few and less commonly eaten foods and there are currently no data available on LC n-3 PUFA intakes in primary-aged school children. Recent studies have shown that endogenous synthesis of LC n-3 PUFA from a-linolenic acid (ALA), which is abundant in the diet, is not as efficient as previously thought (2) . This casts doubt on the adequacy of the supply of LC n-3 PUFA based on the conversion of ALA. In response to this evidence, food manufacturers have developed several foods fortified with ‘omega-3 fats’ marketed at parents by suggesting benefits to children’s learning and behaviour. There is currently no validated method of collecting intake data. A FFQ 2 was previously design to measure the n-3 PUFA intake in children with the breakdown of each single n-3 PUFA. However, the FFQ was found to underestimate ALA intake. The aim of this study was to re-design the previous FFQ to overcome the main limitation of ALA underestimation and then re-evaluate it. Thirty-nine primary school children (16 males and 23 female), aged 5–8 years participated in the study. A comparison with the National Diet and Nutrition Survey (3 ) showed that intakes of total n-3 PUFA for 5–6-year-old males (P = 0.77), 5–7-year-old females (P = 0.66), and 7–8-year-old males (P = 0.79) were in line with the expected frequencies, whereas intakes in 7–8year-old females were significantly lower (P < 0.001). Data for total n-3 PUFA (P < 0.001), ALA (P < 0.001), DHA (P < 0.001), were significantly greater compared to data from the previous study (4) , whereas intakes for and total n-3 LC PUFA (P = 0.5) and EPA (P = 0.22) were not significantly different. The mean intakes of total LC n-3 PUFA in both male (0.180.005 g/d) and female (0.180.04 g/d) groups, were significantly lower (P < 0.001) than recommendations (5) . ‘Omega-3’-fortified foods did not account for any of the total n-3 LC PUFA intake; however, 3 children (1 male, 2 female) took omega-3 supplements which accounted for 21 % of the total n-3 LC PUFA intake from all children. The study indicates that the FFQ was successful in overriding the main limitation of the original design, which involved underestimation of ALA intake. Furthermore, it illustrated that intakes of LC n-3 PUFA were far below that of recommendations. Validation of the FFQ, against a more comprehensive method of assessing dietary intake, is now fundamental to assess its accuracy. 1. Richardson AJ (2004) Long-chain polyunsaturated fatty acids in childhood developmental and psychiatric disorders. Lipids 39, 1215–1222. 2. Burdge GC, Jones AE & Wooton SA (2002) Eicosapentanoic and docosapentanoic acids are the principal products of a-linolenic acid metabolism in

Relative validation of a food frequency questionnaire against diet records to estimate n -3 fatty acid intake in adults

Long chain omega-3 PUFA (LC n-3 PUFA) are important for health and well-being. Recent studies suggest in vivo synthesis of LC n-3 PUFA from their dietary precursor, a-linolenic acid (ALA), may be limited. Preformed LC n-3 PUFA are found in a limited number of foods that are not commonly eaten in the UK diet. The potential for insufficient conversion of ALA, which is found in plentiful supply in the diet, has therefore raised questions as to whether intakes of LC n-3 PUFA are sufficient. Very little information is currently available on intakes of LC n-3 PUFA and, consequently, there is a need to develop an efficient method to estimate intakes. As intakes of LC n-3 PUFA in the diet are somewhat sporadic, an accurate assessment of intake would traditionally involve recording dietary intake over a long period of time. This approach is not efficient for use in many population groups. An FFQ has previously been developed to assess children’s total n-3 PUFA intake, including intakes of DHA and EPA, and estimated intakes appear to be comparable to intakes reported in the National Diet and Nutrition Survey. The aim of this study was to investigate the relative validity of the FFQ in comparison to a 14-d diet record in estimating n-3 PUFA intakes in adults aged 19 to 64 years. Forty-four participants (24 females) completed a 14-d diet record, followed by the FFQ. Dietary intakes were estimated manually using nutrient composition tables and modification of the FFQ spreadsheet to account for adult portion sizes. Comparison of methods by Bland– Altman analysis indicated that the FFQ over estimated total n-3 PUFA intakes by an average of 0.6 g/d, yet underestimated intakes of LC n-3 PUFA by an average of 30 mg/d. Agreement between the methods was very good for both total n-3 PUFA intake and total LC n-3 PUFA intake. Only two subjects consistently showed discrepancies outside the 95% limits of agreement, due to exceptionally high intakes being reported. Results were compared with the SACN recommendations indicating that, when assessed by either method, 82% of subjects had intakes below the 450 mg/d recommendation. The results of the study showed the FFQ to be a good tool to establish LC n-3 PUFA intakes in groups of adults; however, its use in assessing the adequacy of individual intakes may be limited. Further validation, potentially against a biomarker of fatty acid intake, is warranted.

The adequacy of long-chain n-3 fatty acid intakes in primary schoolchildren

By JM McKENZIE, MC CLAPHAM, and A MacGREGOR. Queen Margaret University, Edinburgh, Scotland, EH21 6UU Long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA), particularly eicosapentanoic acid (EPA), and dococosahexanoic acid (DHA), play an important role in neurological and cognitive development in children (1) . Recent evidence suggests that the in vivo synthesis of these LC n-3 PUFA from α-linolenic acid (ALA) is less efficient than previously thought, which puts into question the adequacy of dietary intakes based on the conversion of ALA. Although sources of ALA can be found throughout the diet, intakes of preformed LC n-3 PUFA are restricted to relatively few, less commonly eaten foods, such as oily fish. In response, food producers have developed innovative approaches to increasing dietary intakes of LC n-3 PUFA, targeting many of these foods at parents by implying benefits in children’s learning and behaviour. There is currently no information available on the current intake of LC n-3 PUFA in children and no validated method of collecting intake data. The aim of this study was to assess the total intake of n-3 PUFA, with determination of the contributions of ALA, EPA, and DHA, in children aged 5-8 years old, using a food frequency questionnaire (FFQ), developed to incorporate both traditional and newly developed food products assumed to contribute to dietary intakes of n-3 PUFA’s. When compared against the DRV minimum recommendation for total n-3 PUFA, 0.2% of total energy (2) , intakes in females were significantly greater (n=22, p=0.007), however, intakes in males were not significantly different (n=11, p=0.184). Intakes of total LC n-3 PUFA appeared to be significantly lower that recommendations of 0.45g/day (3) (p<0.0005 for both males and females). This study indicates that despite the adequacy of dietary intakes of total n-3 PUFA in children, intakes of LC n-3 PUFA may be lower than the recommendations. Intakes of total n-3 PUFA, predominantly from ALA, were, however, significantly lower than the intakes reported in the National Diet and Nutrition Survey (4) (p<0.0005 for both males and females) indicating that the use of this FFQ to estimate n-3 PUFA intakes requires further validation.