Nutrition in Clinical Practice

Malnutrition and weight loss negatively affect outcomes in surgical cancer patients. Decades of research have sought to identify the most appropriate use of nutrition support in these patients. National and international guidelines help to direct clinicians’ use of nutrition support in surgical patients, but a number of specific issues concerning the use of nutrition support continue to evolve. This review focuses on 5 key issues related to perioperative nutrition support in cancer patients: (1) Which perioperative cancer patients should receive nutrition support? (2) How can the nutrition status and requirements of these patients be optimally assessed? (3) What is the optimal route of administration (parenteral nutrition vs enteral nutrition) and composition of nutrition support in this setting? (4) When should feedings be initiated? (5) What is the role of glycemic control in these patients?

Loss of lean body develops from an imbalance in protein synthesis and catabolism and is associated with a variety of different disease and nondisease states, including severe malnutrition, cachexia, and physiologic age-related loss (sarcopenia). Loss of lean body mass is prevalent among a significant proportion of the elderly population and has been associated with increased adverse clinical outcomes. Recognition of individuals at risk for low lean body mass may be difficult due to unequal distribution of losses across muscle and adipose compartments, and individuals who are both obese and sarcopenic demonstrate the highest risk for adverse events. Cross-sectional imaging modalities provide an accessible and easily interpretable means of quantifying lean muscle content and are routine diagnostic tests for cancer patients. As a result, a growing body of literature has developed characterizing the importance of low lean body mass as a poor prognostic factor among cancer patients, regardless of age. Cancer patients, especially those with sarcopenic obesity, are at increased risk for treatment-related toxicities from chemotherapy and increased overall mortality. Further investigations into the pathogenesis of muscle wasting among cancer patients are critical, as therapeutic oncologic interventions may inadvertently accelerate muscle catabolism. This review provides an overview of the definitions of low lean body mass, etiologic causes, clinical significance among cancer patients, and potential therapeutic interventions.

A number of epidemiological studies have investigated associations between various phytochemicals and cancer risk. Phytoestrogens and carotenoids are the two most commonly studied classes of phytochemicals; phytosterols, isothiocyanates, and chlorophyll also have been investigated, although to a much lesser extent. Because there have been no systematic reviews of the literature on all phytochemicals and cancer risk to date, this article systematically reviews 96 published epidemiological studies that examined associations between phytochemicals and cancer risk. Most studies found null associations between individual phytochemicals and cancer risk at various sites. In addition, results from past studies have been largely inconsistent, and observed associations have been of relatively modest magnitude. The most consistent protective effects were observed for higher levels—dietary intake, serum, plasma, or urinary metabolites—of β-carotene and renal cell cancer, β-cryptoxanthin and lung cancer, isothiocyanates and lung cancer, isothiocyanates and gastrointestinal cancer, lignans and postmenopausal breast cancer, and flavonoids and lung cancer. Although elevated risk of certain cancers with higher levels of certain phytochemicals was observed, an insufficient pool of studies examining the same associations or inconsistent findings across studies limit the ability to conclude that any one phytochemical increases cancer risk. Additional research is needed to support previously identified associations in cases where only one study has examined a particular relationship. Importantly, continued research efforts are needed to evaluate the cumulative and interactive effects of numerous phytochemicals and phytochemical-rich foods on cancer risk.

Diet and nutrition are estimated to explain as much as 30%–50% of the worldwide incidence of colorectal cancer. In 2007, the World Cancer Research Fund (WCRF), in conjunction with the American Institute for Cancer Research (AICR), released the second expert report that summarizes the current scientific evidence linking diet to the prevention of cancer. This text provides an expert summary and level of evidence of the research relating diet/nutrients to factors that influence cancers of multiple organs, including colon and rectum, with an important emphasis on global patterns. Specific examples include dietary fat, red and processed meat, and dairy, as well effects of nutrients such as calcium, folate, and vitamin D. Evidence is obtained from ongoing systematic literature reviews conducted by experts in both the United States and Europe. The expert panel applies standard practices to evaluate the strength and quality of individual studies to draw summary conclusions. In 2011, the report was updated to include findings from a series of meta-analyses published in 2010. To complement the WCRF/AICR report, the authors review the evidence favoring the role for diet and nutrition in the etiology of colorectal cancer. Specifically, they have integrated information gained from more recent meta-analyses and high-quality, prospective study findings, some of which have been included in the 2011 updated WCRF/AICR summary.

Recent advances in our ability to identify and characterize the human microbiota have transformed our appreciation of the function of the colon from an organ principally involved in the reabsorption of secretory fluids to a metabolic organ on a par with the liver. High-throughput technology has been applied to the identification of specific differences in microbial DNA, allowing the identification of trillions of microbes belonging to more than 1000 different species, with a metabolic mass of approximately 1.5 kg. The close proximity of these microbes with the mucosa and gut lymphoid tissue helps explain why a balanced microbiota is likely to preserve mucosal health, whereas an unbalanced composition, as seen in dysbiosis, may increase the prevalence of diseases not only of the mucosa but also within the body due to the strong interactions with the gut immune system, the largest immune organ of the body. Such abnormalities have been pinpointed as etiological factors in a wide range of diseases, including autoimmune disorders, allergy, irritable bowel syndrome, inflammatory bowel disease, obesity, and colon cancer. Recognition of the strong potential for food to manipulate microbiota composition has opened up new therapeutic strategies against these diseases based on dietary intervention.

Background: Breast cancer is the most commonly diagnosed cancer among women in the United States. Extensive research has been completed to evaluate the relationship between dietary factors and breast cancer risk and survival after breast cancer; however, a summary report with clinical inference is needed. Materials and Methods: This review summarizes the current epidemiological and clinical trial evidence relating diet to breast cancer incidence, recurrence, survival, and mortality. The review includes emerging epidemiological studies that assess risk within breast cancer subtypes as well as a summary of previous and ongoing dietary intervention trials designed to modify breast cancer risk. Results: The available literature suggests that both low-fat and high-fiber diets may be weakly protective against breast cancer, whereas total energy intake and alcohol appear to be positively associated. Fiber may be weakly protective possibly through modulation of estrogen, whereas fruit and vegetable intake is not clearly associated with risk. Obesity is a risk factor for postmenopausal disease, and adult weight gain should be avoided to reduce risk. In survivors, diet has the greatest potential influence on overall mortality rather than breast cancer–specific events. Conclusion: Diet is modestly associated with breast cancer risk; associations appear more pronounced for postmenopausal disease, and healthy choices after diagnosis and treatment likely support longevity more so than reduced risk for recurrent disease.

Nutrition management of patients undergoing a hematopoietic stem cell transplant (HSCT) can be challenging. Fluid, macronutrient, and micronutrient needs are often altered due to a variety of therapy-associated complications and changes in metabolism. Sinusoidal obstructive syndrome (SOS) is a complication characterized by fluid retention, ascites, and painful hepatomegaly that may complicate provision of adequate nutrition to HSCT patients. The nutrition implications and interventions in a patient who developed SOS following an allogeneic matched unrelated donor (Allo/MUD) HSCT are reviewed in the case report.

This study explored the current medical nutrition therapy (MNT) provided to adult patients undergoing hematopoietic stem cell transplantation (HSCT) and examined the current and desired role of registered dietitians (RDs) in providing MNT. A total of 60 RDs (57% response rate) responded to an electronic questionnaire. Descriptive statistics and χ² analyses (SPSS; version 18) were used. Results revealed the primary form of diet was oral, and for patients on nutrition support, parenteral nutrition (PN) was used more frequently (16%–31%) than enteral nutrition (EN) (5%–9%; P ≤ .05). Nutrition support decisions were based on patients’ individualized needs rather than established protocol or policies. Mucositis was the most common reason for implementing PN (31%), and intubation or being in the intensive care unit was the most common reason for implementing EN (28%). The RDs had varying degrees of autonomy in order writing and were most often recommending MNT to the physician or writing the MNT order with a physician cosignature. Many RDs reported desiring higher autonomy than what they were currently practicing (P < .05). Those who held a certified specialist in oncology (CSO) or certified nutrition support dietitian/clinician (CNCD/C) certification were significantly more likely to have and desire greater autonomy in order writing than those without specialty credentials (P ≤ .05). No difference was found in current practice or desired autonomy based on the years of experience or educational degree.

Background: Many patients with advanced head and neck cancer become unable to obtain sufficient nutrition and hydration orally, leading to considerable weight loss and compromised clinical outcomes. The percutaneous endoscopic gastrostomy (PEG) tube is ideal for this population who require longer term nutrition support due to the effects of cancer treatment. Although clinical experts at the Odette Cancer Centre (OCC) report positive patient feedback with PEG tubes, there is debate in the literature regarding the associated quality of life (QoL). The study objective was to learn about the experience of patients living with a PEG tube. Materials and Methods: A neutral questionnaire with closed- and open-ended questions was developed, tested, and used to collect data. Quantitative data were analyzed using descriptive statistics to determine whether the patients’ experiences were positive/neutral or negative. Qualitative data were assessed for common themes, and frequency was counted. Results: Of the 51 participants, 84% felt the PEG tube had a positive/neutral effect on their QoL. Ninety percent felt that the PEG tube was “very much” or “quite a bit” worthwhile. In addition, 96% would recommend it to another patient. The 11 questions reflecting domains of QoL affected by living with a PEG tube were answered positively or neutrally at least 71% of the time. Conclusion: Results indicate that the patient experience with the PEG tube is generally positive or neutral, thus demonstrating a different outcome than recent literature. This study will help improve understanding regarding the experience of living with a PEG tube from the patient perspective.

Background: Traditionally, energy requirements have been calculated using predictive equations. These methods have failed to calculate energy expenditure accurately. Routine indirect calorimetry has been suggested, but this method is technically demanding and costly. This study aimed to develop a new predictive equation to estimate energy requirements for critically ill children. Methods: This prospective, observational study on ventilated children included patients with an endotracheal tube leak of <10% and fractional inspired oxygen of <60%. An indirect calorimetry energy expenditure measurement was performed and polynomial regression analysis was used to develop new predictive equations. The new formulas were then compared with existing prediction equations. Results: Data from 369 measurements were included in the formula design. Only weight and diagnosis influenced energy expenditure significantly. Three formulas (A, B, C) with an R² > 0.8 were developed. When we compared the new formulas with commonly used equations (Schofield, Food and Agriculture Organization/World Health Organization/United Nations University, and White equation), all formulas performed very similar, but the Schofield equation seemed to have the lowest SD. Conclusions: All 3 new pediatric intensive care unit equations have R² values of >0.8; however, the Schofield equation still performed better than other predictive methods in predicting energy expenditure in these patients. Still, none of the predictive equations, including the new equations, predicted energy expenditure within a clinically accepted range, and further research is required, particularly for patients outside the technical scope of indirect calorimetry.

Background: Nutrition management of cirrhosis in hospitalized patients is overlooked despite the clinical significance of sarcopenia or loss of muscle mass in cirrhosis. Determining optimal nutrition requirement needs precise measurement of resting energy expenditure (REE) in the cirrhotic patient. Predictive equations are not accurate, and the metabolic cart is expensive and cumbersome. The authors therefore performed a prospective study to examine the feasibility and accuracy of a handheld respiratory calorimeter (HHRC) in quantifying the REE in hospitalized cirrhotic patients not in the intensive care unit. Materials and Methods: The study was done in 2 phases: in the first phase, the REE of 24 consecutive healthy volunteers was measured using an HHRC in different positions. The objective of this phase was to identify the impact of body and arm position on measured REE. Subsequently, in the second phase of the study, REE was measured using the HHRC and the metabolic cart in 25 consecutive well-characterized, hospitalized cirrhotic patients. The degree of concordance was calculated. Results: Body position and arm position did not significantly affect the measured REE using HHRC. In patients with cirrhosis, the mean measured REE (kcal/d) using the HHRC was 1453.2 ± 319.3 in the hospital room, 1525.6 ± 305.2 in a quiet environment, and 1553.7 ± 270.6 with the metabolic cart (P > .1). Predicted REE using 2 widely used equations did not correlate either with each other or with the measured REE. Conclusions: HHRC is a valid, feasible, and rapid method to determine optimal caloric needs in hospitalized cirrhotic patients)

Background: Hypomagnesemia in patients with eating disorders is poorly characterized, particularly among adolescents. Methods: To determine the prevalence of hypomagnesemia (Mg ≤1.7 mg/dL) and clinical characteristics of adolescents hospitalized with a DSM-IV-diagnosed eating disorder who developed hypomagnesemia, a retrospective chart review was conducted on all adolescents aged 10–21 years with an eating disorder were hospitalized at a tertiary care children’s hospital from 2007 to 2010. Patients were refed orally with standard nutrition and high-energy liquid supplements. Serum magnesium and phosphorus were obtained on admission, every 24–48 hours for the first week, and thereafter as clinically indicated. Clinical characteristics of patients with hypomagnesemia were compared with those of individuals with normal magnesium levels and those with hypophosphatemia. Results: Eighty-six of 541 eligible participants (15.9%) developed hypomagnesemia. Forty (47%) with hypomagnesemia admitted to purging in the year before admission, with 88% purging during the prior month. Compared with those with normal serum magnesium levels, patients with hypomagnesemia were older (P = .0001), ill longer (P = .001), more likely to be purging (P = .04), and more likely to have an alkaline urine (P = .01). They did not differ in eating disorder diagnosis, BMI, or other electrolyte disturbances. Hypomagnesemia developed 4.9 ± 5.5 days after refeeding was initiated, significantly later than the onset of hypophosphatemia, 0.95 ± 2.6 days (P < .001). Conclusions: Hypomagnesemia is prevalent in adolescents hospitalized for an eating disorder and is associated with purging and alkaline urine. Hypomagnesemia develops later in the course of refeeding than hypophosphatemia. Magnesium levels should continue to be monitored after the more immediate risk of hypophosphatemia has passed, especially in those with alkaline urine.

Background: Hyperhomocysteinemia might be at least partially due to compromised B vitamin status in critically ill patients and has been linked with critical illness. This study was conducted to examine the association between plasma homocysteine with B vitamins and clinical outcomes in critically ill surgical patients. Methods: Thirty-two patients in the surgical intensive care unit (SICU) were enrolled. Disease severity (Acute Physiology and Chronic Health Evaluation II score), hematological values, serum and erythrocyte folate, serum vitamin B₁₂, plasma, and erythrocyte pyridoxal 5′-phosphate (PLP) were determined within 24 hours of admission and again after 7 days. Results: The prevalence of hyperhomocysteinemia in the patients was either 46.9% (plasma homocysteine ≥12 µmol/L) or 31.3% (plasma homocysteine ≥15 µmol/L) on day 1 in the SICU and increased to 62.5% (plasma homocysteine ≥12 µmol/L) and 37.5% (plasma homocysteine ≥15 µmol/L) on day 7 after admission to the SICU. Plasma homocysteine, serum folate, and vitamin B₁₂ significantly increased by day 7, whereas plasma and erythrocyte PLP remained constant throughout the study. Plasma homocysteine was not correlated with serum folate and vitamin B₁₂. However, plasma and erythrocyte PLP on day 1 were adversely associated with day 1 levels of plasma homocysteine after adjusting for potential confounders. Plasma homocysteine on day 1 or changes (Δ day 7 – day 1) did not show any association with clinical outcomes. Conclusions: Lower plasma PLP might be a significant factor for increased plasma homocysteine in critically ill surgical patients. The association between plasma homocysteine and clinical outcomes was not found.