Nicole M. de Roos

Within-subject variability of flow-mediated vasodilation of the brachial artery in healthy men and women: implications for experimental studies

Flow-mediated vasodilation (FMD) of the brachial artery is used as a marker of cardiovascular disease risk. It is defined as the percentage dilation from the baseline diameter in response to a provoked increase in blood flow. The within-subject variability, crucial in the design of trials with FMD as an endpoint, appears to vary widely between studies. We assessed the analytical and within-subject variability of FMD in healthy subjects and estimated the number of subjects needed to detect various treatment effects in intervention trials and observational studies. FMD was assessed with B-mode high-resolution ultrasound (US). A total of 13 volunteers were measured on six occasions, after they had fasted overnight. Within-subject variability was assessed from all six scans per subject. Analytical variation or reading variation was assessed by reading one scan of each subject twice by one observer. The mean (+/-SD) FMD was 5.60 +/- 2.15 FMD% of the baseline diameter. The within-subject SD was 2.8 FMD%, resulting in a coefficient of variation (CV) of 2.8/5.6 x 100% = 50.3%. The CVs for the baseline and maximum diameter were much smaller: 4.8% (SD 0.193 mm at a mean of 4.060 mm) for the baseline and 5.2% (SD 0.222 mm at a mean of 4.285 mm) for the maximum. The CV for reading variation was 34%. The number of subjects needed to detect a treatment difference of 2 FMD% with a probability of 0.05 and a power of 0.80 would be 31 in a crossover design and 62 per group in a parallel design for comparison of group changes. We conclude that the within-subject variability of FMD is large, about 50% of the mean response. This includes biologic and reading variation. Repeated measurements and repeated readings of recorded measurements are recommended to reduce variability.

Promises and Problems of Functional Foods

“Functional” foods are branded foods, which claim, explicitly or implicitly, to improve health or well being. We review typical functional foods and their ingredients, efficacy, and safety. We also review regulations for health claims for foods worldwide. These regulations often allow manufacturers to imply that a food promotes health without providing proper scientific evidence. At the same time, regulations may ban claims that a food prevents disease, even when it does. We offer a plea for regulations that will permit all health claims that are supported by the totality of scientific evidence, and ban all claims that suggest an unproven benefit.

Migraine associated with gastrointestinal disorders: review of the literature and clinical implications.

Recent studies suggest that migraine may be associated with gastrointestinal (GI) disorders, including irritable bowel syndrome (IBS), inflammatory bowel syndrome, and celiac disease. Here, an overview of the associations between migraine and GI disorders is presented, as well as possible mechanistic links and clinical implications. People who regularly experience GI symptoms have a higher prevalence of headaches, with a stronger association with increasing headache frequency. Children with a mother with a history of migraine are more likely to have infantile colic. Children with migraine are more likely to have experienced infantile colic compared to controls. Several studies demonstrated significant associations between migraine and celiac disease, inflammatory bowel disease, and IBS. Possible underlying mechanisms of migraine and GI diseases could be increased gut permeability and inflammation. Therefore, it would be worthwhile to investigate these mechanisms further in migraine patients. These mechanisms also give a rationale to investigate the effects of the use of pre- and probiotics in migraine patients.

24-Hour Indirect Calorimetry in Mechanically Ventilated Critically Ill Patients:

BACKGROUND Energy imbalance in critically ill, mechanically ventilated patients may lead to medical complications. The nutrition care team needs accurate, noninvasive, rapid methods to estimate energy requirements. We investigated whether brief measurements of indirect calorimetry at any time of the day would give valid estimates of 24-hour energy expenditure (EE). METHODS EE of 12 mechanically ventilated critically ill patients (6 men, 6 women, mean ± SD age 67 ± 18 years, weight 70.2 ± 8.8 kg) was recorded every minute during 24 hours by indirect calorimetry. All patients were continuously fed enteral nutrition. RESULTS Mean± SD EE was 1658 ± 279 kcal/d (6941 ± 1167 kJ/d). Within patients, EE during the day fluctuated by 234 kcal in the most constant patient to 1190 kcal in the least constant patient, with a mean fluctuation of 521 kcal (12 patients). No statistically significant difference ( p = .53) in mean EE between morning (6-12 hours, 1676 kcal), afternoon (12-18 hours, 1642 kcal), evening (18-24 hours, 1658 kcal), and night (0-6 hours, 1655 kcal) was found. A 2-hour instead of a 24-hour measurement resulted in a maximal error of 128 kcal (536 kJ), which was<10% of the average EE. The maximal error decreased with longer time intervals. CONCLUSIONS In mechanically ventilated critically ill patients, 24-hour indirect calorimetry measurements can be replaced by shorter (≥2 hours) measurements. Time of day did not affect EE.

Self-reported use of vitamins and other nutritional supplements in adult patients with cystic fibrosis. Is daily practice in concordance with recommendations?

BACKGROUND In cystic fibrosis (CF), prophylactic supplementation of the fat-soluble vitamins A, D, E, and K is recommended. Limited data is available describing vitamin prescription adherence by adult patients. The aim of this study was to assess the use of prescribed vitamins and other nutritional supplements by adult CF patients. METHODS All adult CF patients (n=111) registered at the Utrecht CF Center were invited to participate in a telephone survey on supplement use. Supplemental vitamin intakes were compared with recommendations. In a subsample, associations between supplemental intake and serum vitamin D and E values were assessed. RESULTS In this study 80% of the patients reported the use of vitamin and/or mineral supplements. Fat-soluble vitamins were used by 43% of pancreatic-sufficient (PS) and 81% of pancreatic-insufficient (PI) patients. Of PI patients reporting supplemental vitamin use, only 9% met the recommendations for vitamin A, 32% for vitamin D, 59% for vitamin E, and 81% for vitamin K. Multivitamin supplements were used by 42% of PI and by 29% of PS patients. Other nutritional supplements were rarely used. CONCLUSION A high percentage of PI patients use fat-soluble vitamins below recommendations. Therefore adequate monitoring of vitamin supplementation and status is warranted.

Indicators for Enteral Nutrition Use and Prophylactic Percutaneous Endoscopic Gastrostomy Placement in Patients With Head and Neck Cancer Undergoing Chemoradiotherapy

Background: Chemoradiotherapy (CRT) is a major risk factor for malnutrition and dehydration in patients with head and neck cancer. Enteral support is often needed, and a percutaneous endoscopic gastrostomy (PEG) is frequently placed. Specific indicators for PEG placement remain unclear. This study retrospectively determined which factors contributed to enteral nutrition (EN) use and PEG placement in a large patient group to gain insight on potential indicators for PEG placement protocol creation. Methods: A retrospective chart review of 240 patients with head and neck cancer who underwent CRT in 2012–2015 was conducted. Lifestyle, oncological, treatment, and nutrition outcome characteristics were examined and compared between patients who used EN and those who did not, as well as between patients who received a PEG and those who did not. Results: In total, 195 patients used EN (via PEG or nasogastric tube). Multivariate analysis showed that nodal disease presence (P = .01) and bilateral neck irradiation (P = .01) were significantly related to EN use while increased age (P = .01), nodal disease presence (P = .02), reconstruction extent other than primary closure (P = .02), bilateral neck irradiation (P < .01), and an adapted intake consistency prior to treatment (P = .03) were significantly related to PEG placement. Conclusion: Important factors for EN usage and PEG placement consideration include nodal disease and planned bilateral neck irradiation. Results from this study in combination with existing literature can be taken into consideration in the design of a PEG placement protocol. A better understanding of predictive indicators to PEG placement should be explored in further prospective studies.

The optimal approach to nutrition and cystic fibrosis : latest evidence and recommendations

Purpose of review Cystic fibrosis (CF) is a progressive genetic disease that affects multiple organ systems. Therapy is directed to maintain and optimize nutritional status and pulmonary function, as these are key factors in survival. In this review, the most recent findings regarding nutritional management associated with pulmonary function and outcome will be explored. Recent findings Evidence-based and expert-based guidelines emphasize the need for adequate nutritional intake to improve nutritional status. For infants and young children, the aim is to achieve the 50th percentile of weight and length for a healthy same-age population up to age 2 years. For older children and adolescents 2–18 years, the target is a BMI of at or above the 50th percentile for healthy children. For CF adults of at least 18 years, the target is a BMI of at or above 22 kg/m2 for women and at or above 23 kg/m2 for men. Recently, new drugs are developed with the aim to treat the malfunction of the cystic fibrosis transmembrane conductance regulator gene. This potentiator/corrector therapy improves lung function and nutritional status and decreases the number of infective exacerbations. As survival is improving and the CF population is aging, it is important to focus on micronutrient and macronutrient intake of CF patients in different age and disease stages. Summary Recent evidence-based nutritional guidelines and improved medical treatment support the nutritional monitoring and interventions in CF patients. Nutritional care should be personalized and provided by a specialized CF dietitian because patients’ care needs may change dramatically during their disease progress.

Prediction Equations Underestimate Resting Energy Expenditure in Patients With End-Stage Cystic Fibrosis

Background: Resting energy expenditure (REE) is increased in patients with cystic fibrosis (CF) with end-stage lung disease due to chronic inflammation and pulmonary infections. After lung transplantation (LTx), energy expenditure is expected to be lower because inflammation will decrease. We assessed the agreement between measured and predicted REE in pre-LTx CF and post-LTx patients with CF and differences in REE in pre-LTx CF and post-LTx patients with CF in a cross-sectional study. Methods: Included were 12 pre-LTx patients with CF (9 women; median age 31.6 years; interquartile range [IQR], 23.3–40.0) and 12 patients with CF within 2 years after LTx (6 women; median age 33.5 years; IQR, 22.3–40.3). REE was measured in a fasted state using indirect calorimetry. Values were compared with predicted REE calculated by formulas of Harris-Benedict (1919 and 1984), Schofield, and the World Health Organization (1985). A calculated REE between 90% and 110% of REE measured was considered adequate. Results: Prediction equations underestimate REE in at least 75% of pre-LTx and 33% of post-LTx patients with CF. Mean (SD) REE measured by indirect calorimetry was 1735 (251) kcal pre-LTx and 1650 (235) kcal post-LTx (P = .40). REE expressed per kilogram of fat-free mass (FFM) was 40.5 kcal/kg in pre-LTx patients with CF, which was higher than the 34.3 kcal/kg in post-LTx patients with CF (P = .01). Conclusions: Prediction equations underestimate REE in patients with end-stage CF. REE per kg of FFM is lower post-LTx than pre-LTx in patients with CF. Measurement of REE is recommended for patients with CF, especially pre-LTx, to optimize energy requirements for improving nutrition status.

Undernutrition: who cares? Perspectives of dietitians and older adults on undernutrition

BackgroundMany older adults are at risk of undernutrition. Dietitians play a key role in the management and treatment of undernutrition, but older adults have difficulties to comply with dietetic recommendations. This qualitative study investigated which barriers older adults experience in adhering to treatment for undernutrition. Current dietetic practices and older adults’ experiences were studied, and the potential to use protein-enriched regular products in undernutrition treatment was investigated.MethodsWe interviewed 18 older adults who were under treatment for undernutrition, and 13 dietitians. Semi-structured interview guides were used, and all interviews were audiotaped and transcribed verbatim. The interviews were coded with qualitative analysis software NVivo9, followed by content analysis to formulate main themes.ResultsThe interviews resulted in seven themes, which related to three main topics: barriers for treating undernutrition in older adults, current dietetic treatment, and new strategies to complement current treatment. Low awareness and a lack of knowledge regarding undernutrition, physical limitations, and loss of appetite were found to be major barriers for treating undernutrition in older adults. Dietitians said to focus mostly on increasing energy and protein intake by recommending the use of regular food products that fit the needs and habits of the patient, before prescribing oral nutritional supplements. Dietitians considered enriched regular products to be useful if they fit with the habits of older adults, the portion sizes were kept small, if products were easy to open and prepare, had good palatability, and were offered in a variety of taste and textures.ConclusionsResults from the interviews suggest that undernutrition awareness is low among older adults and they lack knowledge on how to manage undernutrition despite efforts taken by dietitians. Enriched regular products could enable older adults to better adhere to undernutrition treatment, provided that these products meet the needs and eating habits of older adults. If protein-enriched food products can replace regular, low-protein variants, older adults do not need to consume more, but can adhere to their usual pattern while consuming more protein.

Association Between Preoperative Vitamin D Status and Short-Term Physical Performance after Total Hip Arthroplasty: A Prospective Study

Background: Insufficient serum vitamin D concentrations (50–75 nmol/L) are prevalent in 40–65% of patients who require total hip arthroplasty (THA). This could impair physical recovery after surgery. This study investigated the association between preoperative vitamin D status and physical performance after THA. Additionally, postoperative changes in vitamin D concentrations were measured. Methods: We included 87 patients scheduled for elective THA and aged ≥65 years. Three groups were recruited: patients classified as vitamin D deficient (< 50 nmol/L, n = 23), insufficient (50–75 nmol/L, n = 32), or sufficient (> 75 nmol/L, n = 32). Serum 25-hydroxyvitamin D3 (25[OH]D3) concentration and physical performance were measured perioperatively. Linear mixed models were used to examine differences between groups. Results: Change in physical performance over time was not affected by preoperative vitamin D status. In contrast, for physical activity, both vitamin D (p = 0.021) and time (p < 0.001) effect was seen: from 80.2 ± 25.8 to 58.1 ± 17.8 min/day in the deficient group, 143.7 ± 19.8 to 92.9 ± 11.5 min/day in the insufficient group, and 108.1 ± 20.9 to 62.3 ± 12.9 min/day in the sufficient group. The Chair Stand Test, Timed Up and Go test, and 10-Meter Walking Test also improved significantly over time, but independent of vitamin D status. An increase in 25(OH)D3 concentration 6 weeks postoperatively was correlated with improved hip function (Pearson’s r = –0.471, p = 0.018). Overall, serum 25(OH)D3 declined with 32% one day after surgery (p < 0.001), to nearly return to baseline values 6 weeks later in all groups. Conclusion: Vitamin D status did not appear to affect physical recovery after THA. The drop in vitamin D after surgery deserves further investigation, but could possibly be explained by hemodilution.