David St-Jules


Photo of David St-Jules
david st-jules

Assistant Professor

Department of Nutrition
University of Nevada/Mail Stop 202
1664 N. Virginia Street
Reno,  Nevada   89557

Office: (775) 682-6635
Email: stjules@unr.edu
Building: Sarah Fleischmann,  Office 110

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EDUCATION
BSc - University of British Columbia, 2008
PhD - University of Hawaii at Manoa, 2013

ACADEMIC & RESEARCH INTEREST

My research aims to help establish evidence-based clinical practice guidelines for managing chronic diseases and their complications. My primary research focus is on dietary factors affecting potassium and phosphorus disorders, and malnutrition in people with advanced kidney disease, and translating these factors into food-based recommendations.

REPRESENTATIVE PUBLICATIONS

Journals
Determinants and the role of self-efficacy in a sodium-reduction trial in hemodialysis patients.
OBJECTIVE: This study was to assess the impact of baseline dietary self-efficacy on the effect of a dietary intervention to reduce sodium intake in patients undergoing hemodialysis (HD) and to identify determinants of low dietary self-efficacy. METHODS: This is a post hoc analysis of the BalanceWise study, a randomized controlled trial that aimed to reduce dietary sodium intake in HD patients recruited from 17 dialysis centers in Pennsylvania. The main outcome measures include dietary self-efficacy and reported dietary sodium density. Analysis of variance with post hoc group-wise comparison was used to examine the effect of baseline dietary self-efficacy on changes in reported sodium density in the intervention and control groups at 8 and 16 weeks. Chi-square test, independent t tests, or Wilcoxon rank-sum tests were used to identify determinants of low dietary self-efficacy. RESULTS: The interaction between dietary self-efficacy and the impact of the intervention on changes in reported dietary sodium density approached significance at 8 and 16 weeks (P interaction = 0.051 and 0.06, respectively). Younger age and perceived income inadequacy were significantly associated with low self-efficacy in patients undergoing HD. CONCLUSION: The benefits of dietary interventions designed to improve self-efficacy may differ by the baseline self-efficacy status. This may be particularly important for HD patients who are younger and report inadequate income as they had lower dietary self-efficacy.
Hu L, St-Jules DE, Popp CJ, Sevick MA. 2019, J Ren Nutr.
Evaluating steady-state resting energy expenditure using indirect calorimetry in adults with overweight and obesity.
Background Determining a period of steady state (SS) is recommended when estimating resting energy expenditure (REE) using a metabolic cart. However, this practice may be unnecessarily burdensome and time-consuming in the research setting. Aim The aim of the study was to evaluate the use of SS criteria, and compare it to alternative approaches in adults with overweight and obesity. Methods In this cross-sectional, ancillary analysis, participants enrolled in a bariatric (study 1; n = 13) and lifestyle (study 2; n = 51) weight loss intervention were included. Indirect calorimetry was performed during baseline measurements using a metabolic cart for 25 min, including a 5-min stabilization period at the start. SS was defined as the first 5-min period with a coefficient of variation (CV) =10% for both VO2 and VCO2 (hereafter REE5–SS). Body composition was measured using bioelectrical impedance analysis in study 2 participants only. REE5–SS was compared against the lowest CV (REECV–lowest), 5-min time intervals (REE6–10, REE11–15, REE16–20, REE21–25), 4-min and 3-min SS intervals (REE4–SS and REE3–SS), and time intervals of 6–15, 6–20 and 6–25 min (REE6–15, REE6–20, and REE6–25) using repeated measures ANOVA and Bland–Altman analysis to test for bias, limits of agreement and accuracy (±6% measured REE). Results Participants were 54 ± 13 years old, mostly women (75%) and had a BMI of 35 ± 5 kg/m2. Overall, 54/63 (84%) of participants reached REE5–SS, often (47/54, 87%) within the first 10-min (6–15 min). Alternative approaches to estimating REE had a relatively low bias (-16 to 13 kcals), narrow limits of agreement and high accuracy (83–98%) when compared to REE5–SS, in particular, outperforming standard prediction equations (e.g., Mifflin St. Joer). Conclusion Indirect calorimetry measurements that utilize the 5-min SS approach to estimate REE are considered the gold-standard. Under circumstances of non-SS, it appears 4-min and 3-min SS periods, or fixed time intervals of at least 5 min are accurate and practical alternatives for estimating REE in adults with overweight and obesity. However, future trials should validate alternative methods in similar populations to confirm these findings.
Popp CJ, Butler M, Curran M, Illiano P, Sevick MA, St-Jules DE. 2019, Clin Nutr.
Managing protein-energy wasting in hemodialysis patients: A comparison of animal- and plant-based protein foods.
Protein-energy wasting (PEW) is a major diet-related complication in hemodialysis (HD) patients. Nutrient-based dietary guidelines emphasize animal-based protein foods for preventing and managing PEW in HD patients. Although dietary protein intake is important for protein anabolism, other dietary factors contribute to PEW. In this article, we examine the diet-related etiologies of PEW in HD patients, and discuss how they may be affected differently by animal- and plant-based protein foods. In general, animal foods are superior sources of protein, but may contribute more to metabolic derangements that cause PEW. Given the potential mixed effects of animal-based protein foods on PEW, human research studies are needed to determine the impact of liberalizing the diet to allow plant-based protein foods on protein status.
St-Jules DE, Goldfarb DS, Popp CJ, Pompeii ML, Liebman SE. 2019, Semin Dial.
Managing hyperkalemia: Another benefit of exercise in people with chronic kidney disease?
People with chronic kidney disease (CKD) are at increased risk of hyperkalemia, an electrolyte abnormality that can cause serious, sometimes fatal, cardiac arrhythmias. Muscle contraction causes potassium to be released from cells, increasing serum potassium concentrations. However, these effects are transient, and the
St-Jules DE, Marinaro M, Goldfarb DS, Byham-Gray LD, Wilund KR. 2019, J Ren Nutr.
The Healthy Hearts and Kidneys (HHK) study: Design of a 2x2 RCT of technology-supported self-monitoring and social cognitive theory-based counseling to engage overweight people with diabetes and chronic kidney disease in multiple lifestyle changes.
Patients with complex chronic diseases usually must make multiple lifestyle changes to limit and manage their conditions. Numerous studies have shown that education alone is insufficient for engaging people in lifestyle behavior change, and that theory-based behavioral approaches also are necessary. However, even the most motivated individual may have difficulty with making lifestyle changes because of the information complexity associated with multiple behavior changes. The goal of the current Healthy Hearts and Kidneys study was to evaluate, different mobile health (mHealth)-delivered intervention approaches for engaging individuals with type 2 diabetes (T2D) and concurrent chronic kidney disease (CKD) in behavior changes. Participants were randomized to 1 of 4 groups, receiving: (1) a behavioral counseling, (2) technology-based self-monitoring to reduce information complexity, (3) combined behavioral counseling and technology-based self-monitoring, or (4) baseline advice. We will determine the impact of randomization assignment on weight loss success and 24-hour urinary excretion of sodium and phosphorus. With this report we describe the study design, methods, and approaches used to assure information security for this ongoing clinical trial.
Sevick MA, Woolf K, Mattoo A, Katz SD, Li H, St-Jules DE, et al. 2018, Contemp Clin Trials.
Assessment and misassessment of potassium, phosphorus, and protein in the hemodialysis diet.
Diet is a key determinant of several common and serious disease complications in hemodialysis (HD) patients. The recommended balance and variety of foods in the HD diet is designed to limit high potassium and phosphorus foods while maintaining protein adequacy. In this report, we examine the potassium, phosphorus, and protein content of foods, and identify critical challenges, and potential pitfalls when translating nutrient prescriptions into dietary guidelines. Our findings highlight the importance of individualized counseling based on a comprehensive dietary assessment by trained diet professionals, namely renal dietitians, for managing diet-related complications in HD patients.
St-Jules DE, Goldfarb DS, Pompeii ML, Liebman SE, Sherman RA. 2018, Semin Dial.
Examining the dietary intake of hemodialysis patients on treatment days and non-treatment days.
Previous literature has shown that hemodialysis patients have impaired dietary intakes on dialysis days (DDs), which may contribute to malnutrition and poor outcomes. In this study, we examined dietary intakes of 140 hemodialysis patients based on 3 nonconsecutive days food records (collected on 1 DD and 2 non-DDs). Patients had lower energy intake and other key nutrient intake on DDs; however, upon adjusting for energy intake, nutrient differences were no longer significant. None of the patient characteristics examined were associated with impaired intakes on DDs (p >.05).
Mirza M, Shahsavarian N, St-Jules DE, Rhee CM, Pompeii ML, Kalantar-Zadeh K, Sevick MA. 2017, Top Clin Nutr.
Phosphate additive avoidance in chronic kidney disease.
Dietary guidelines for patients with diabetes extend beyond glycemic management to include recommendations for mitigating chronic disease risk. This review summarizes the literature suggesting that excess dietary phosphorus intake may increase the risk of skeletal and cardiovascular disease in patients who are in the early stages of chronic kidney disease (CKD) despite having normal serum phosphorus concentrations. It explores strategies for limiting dietary phosphorus, emphasizing that food additives, as a major source of highly bioavailable dietary phosphorus, may be a suitable target. Although the evidence for restricting phosphorus-based food additives in early CKD is limited, diabetes clinicians should monitor ongoing research aimed at assessing its efficacy.
St-Jules DE, Goldfarb DS, Pompeii ML, Sevick MA. 2017, Diabetes Spectr.
Examining the proportion of dietary phosphorus from plants, animals, and food additives excreted in urine.
Phosphorus bioavailability is an emerging topic of interest in the field of renal nutrition that has important research and clinical implications. Estimates of phosphorus bioavailability, based on digestibility, indicate that bioavailability of phosphorus increases from plants to animals to food additives. In this commentary, we examined the proportion of dietary phosphorus from plants, animals, and food additives excreted in urine from four controlled-feeding studies conducted in healthy adults and patients with chronic kidney disease. As expected, a smaller proportion of phosphorus from plant foods was excreted in urine compared to animal foods. However, contrary to expectations, phosphorus from food additives appeared to be incompletely absorbed. The apparent discrepancy between digestibility of phosphorus additives and the proportion excreted in urine suggests a need for human balance studies to determine the bioavailability of different sources of phosphorus.
St-Jules DE, Jagannathan R, Gutekunst L, Kalantar-Zadeh K, Sevick MA. 2017, J Ren Nutr.
North American experience with low protein diet for non-dialysis-dependent chronic kidney disease.
Whereas in many parts of the world a low protein diet (LPD, 0.6-0.8 g/kg/day) is routinely prescribed for the management of patients with non-dialysis-dependent chronic kidney disease (CKD), this practice is infrequent in North America. The historical underpinnings related to LPD in the USA including the non-conclusive results of the Modification of Diet in Renal Disease Study may have played a role. Overall trends to initiate dialysis earlier in the course of CKD in the US allowed less time for LPD prescription. The usual dietary intake in the US includes high dietary protein content, which is in sharp contradistinction to that of a LPD. The fear of engendering or worsening protein-energy wasting may be an important handicap as suggested by a pilot survey of US nephrologists; nevertheless, there is also potential interest and enthusiasm in gaining further insight regarding LPD's utility in both research and in practice. Racial/ethnic disparities in the US and patients' adherence are additional challenges. Adherence should be monitored by well-trained dietitians by means of both dietary assessment techniques and 24-h urine collections to estimate dietary protein intake using urinary urea nitrogen (UUN). While keto-analogues are not currently available in the USA, there are other oral nutritional supplements for the provision of high-biologic-value proteins along with dietary energy intake of 30-35 Cal/kg/day available. Different treatment strategies related to dietary intake may help circumvent the protein- energy wasting apprehension and offer novel conservative approaches for CKD management in North America.
Kalantar-Zadeh K, Moore LW, Tortorici AR, Chou JA, St-Jules DE, Aoun A, et al. 2016, BMC Nephrol.
Effect of high-protein meals during hemodialysis combined with lanthanum carbonate in hypoalbuminemic dialysis patients: Findings from the FrEDI randomized clinical trial.
BACKGROUND: Inadequate protein intake and hypoalbuminemia, indicators of protein-energy wasting, are among the strongest mortality predictors in hemodialysis patients. Hemodialysis patients are frequently counseled on dietary phosphorus restriction, which may inadvertently lead to decreased protein intake. We hypothesized that, in hypoalbuminemic hemodialysis patients, provision of high-protein meals during hemodialysis combined with a potent phosphorus binder increases serum albumin without raising phosphorus levels. METHODS: We conducted a randomized controlled trial in 110 adults undergoing thrice-weekly hemodialysis with serum albumin <4.0 g/dL recruited between July 2010 and October 2011 from eight Southern California dialysis units. Patients were randomly assigned to receive high-protein (50-55 g) meals during dialysis, providing 400-500 mg phosphorus, combined with lanthanum carbonate versus low-protein (<1 g) meals during dialysis, providing <20 mg phosphorus. Prescribed nonlanthanum phosphorus binders were continued over an 8-week period. The primary composite outcome was a rise in serum albumin of =0.2 g/dL while maintaining phosphorus between 3.5-<5.5 mg/dL. Secondary outcomes included achievement of the primary outcome's individual endpoints and changes in mineral and bone disease and inflammatory markers. RESULTS: Among 106 participants who satisfied the trial entrance criteria, 27% ( n = 15) and 12% ( n = 6) of patients in the high-protein versus low-protein hemodialysis meal groups, respectively, achieved the primary outcome (intention-to-treat P-value = 0.045). A lower proportion of patients in the high-protein versus low-protein intake groups experienced a meaningful rise in interleukin-6 levels: 9% versus 31%, respectively (P = 0.009). No serious adverse events were observed. CONCLUSION: In hypoalbuminemic hemodialysis patients, high-protein meals during dialysis combined with lanthanum carbonate are safe and increase serum albumin while controlling phosphorus.
Rhee CM, You AS, Parsons TK, Tortorici AR, Bross R, St-Jules DE, et al. 2016, Nephrol Dial Transplant.
No difference in average interdialytic weight gain observed in a randomized trial in adults undergoing maintenance hemodialysis in the United States: Primary outcomes of the BalanceWise Study.
OBJECTIVE: To evaluate the efficacy of behavioral counseling combined with technology-based self-monitoring for sodium restriction in hemodialysis (HD) patients. DESIGN: Randomized clinical trial. SUBJECTS: English literate adults undergoing outpatient, in-center intermittent HD for at least 3 months. INTERVENTIONS: Over a 16-week period, both the intervention and the attention control groups were shown 6 educational modules on the HD diet. The intervention group also received social cognitive theory-based behavioral counseling and monitored their diets daily using handheld computers. MAIN OUTCOME MEASURES: Average daily interdialytic weight gain (IDWGA) was calculated for every week of HD treatment over the observation period by subtracting the post-dialysis weight at the previous treatment time (t-1) from the pre-dialysis weight at the current treatment time (t), dividing by the number of days between treatments. Three 24-hour dietary recalls were obtained at baseline, 8 weeks, and 16 weeks and evaluated using the Nutrient Data System for Research. RESULTS: A total of 179 participants were randomized, and 160 (89.4%) completed final measurements. IDWGA did not differ significantly by treatment group at any time point considered (P > .79 for each). A significant differential change in dietary sodium intake observed at 8 weeks (-372 mg/day; P = .05) was not sustained at 16 weeks (-191 mg/day; P = .32). CONCLUSION: The BalanceWise Study intervention appeared to be feasible and acceptable to HD patients although IDWGA was unchanged and the desired behavioral changes observed at 8 weeks were not sustained. Unmeasured factors may have contributed to the mixed findings, and further research is needed to identify the appropriate patients for such interventions.
Sevick MA, Piraino BM, St-Jules DE, Hough LJ, Hanlon JT, et al. 2016, J Ren Nutr.
Nutrient non-equivalence: Does restricting high-potassium plant foods help to prevent hyperkalemia in hemodialysis patients?
Hemodialysis patients are often advised to limit their intake of high-potassium foods to help manage hyperkalemia. However, the benefits of this practice are entirely theoretical and not supported by rigorous randomized controlled trials. The hypothesis that potassium restriction is useful is based on the assumption that different sources of dietary potassium are therapeutically equivalent. In fact, animal and plant sources of potassium may differ in their potential to contribute to hyperkalemia. In this commentary, we summarize the historical research basis for limiting high-potassium foods. Ultimately, we conclude that this approach is not evidence-based and may actually present harm to patients. However, given the uncertainty arising from the paucity of conclusive data, we agree that until the appropriate intervention studies are conducted, practitioners should continue to advise restriction of high-potassium foods.
St-Jules DE, Goldfarb DS, Sevick MA. 2016, J Ren Nutr.
Re-examining the phosphorus-protein dilemma: Does phosphorus restriction compromise protein status?
Dietary phosphorus restriction is recommended to help control hyperphosphatemia in hemodialysis patients, but many high-phosphorus foods are important sources of protein. In this review, we examine whether restricting dietary phosphorus compromises protein status in hemodialysis patients. Although dietary phosphorus and protein are highly correlated, phosphorus intakes can range up to 600 mg/day for a given energy and protein intake level. Furthermore, the collinearity of phosphorus and protein may be biased because the phosphorus burden of food depends on: (1) the presence of phosphate additives, (2) food preparation method, and (3) bioavailability of phosphorus, which are often unaccounted for in nutrition assessments. Ultimately, we argue that clinically relevant reductions in phosphorus intake can be made without limiting protein intake by avoiding phosphate additives in processed foods, using wet cooking methods such as boiling, and if needed, substituting high-phosphorus foods for nutritionally equivalent foods that are lower in bioavailable phosphorus.
St-Jules DE, Woolf K, Pompeii M, Kalantar-Zadeh K, Sevick MA. 2016, J Ren Nutr.
Exploring problems in following the hemodialysis diet, and their relation to energy and nutrient intakes: The BalanceWise Study
OBJECTIVE: To identify the problems experienced by hemodialysis (HD) patients in attempting to follow the HD diet and their relation to energy and nutrient intakes. DESIGN: Cross-sectional analysis of baseline data from the BalanceWise Study. SUBJECTS: Participants included community-dwelling adults recruited from outpatient HD centers. After excluding participants with incomplete dietary analyses (n = 50), 140 African American and white (40/60%) men and women (52/48%) on chronic intermittent HD for at least 3 months (median 3 years) were included. INTERVENTION: Participant responses, on a 5-point Likert scale ranging from "not at all a problem" to "a very important problem for me," to 34 questions pertaining to potential barriers to following the HD diet in the previous 2 months were classified as either a problem (1) or not a problem (2-5). MAIN OUTCOME MEASURE: Energy and nutrient intakes determined using the Nutrition Data System for Research® based on 3, non-consecutive, unscheduled, 2-pass 24-hour dietary recalls collected on 1 dialysis and 1 non-dialysis weekday, and 1 non-dialysis weekend day. RESULTS: More than half of participants reported having problems related to specific behavioral factors (e.g., feeling deprived), technical difficulties (e.g., tracking nutrients), and physical condition (e.g., appetite), but issues of time and food preparation and behavioral factors tended to be most deterministic of reported dietary intakes. Longer duration of HD was associated with lower intakes of protein, potassium, and phosphorus (P < .05). CONCLUSION: Registered dietitian nutritionists should consider issues of time and food preparation, and behavioral factors in their nutrition assessment of HD patients and should continually monitor HD patients for changes in protein intake that may occur over time.
St-Jules DE, Woolf K, Pompeii M, Sevick MA. 2016, J Ren Nutr