Nutrition in Clinical Practice

The currently available, standard soybean oil (SO)–based intravenous fat emulsions (IVFEs) meet the needs of most parenteral nutrition (PN) patients. There are alternative oil-based fat emulsions, such as medium-chain triglycerides (MCTs), olive oils (OOs), and fish oils (FOs), that, based on extensive usage in Europe, have an equivalent safety profile to SO. These alternative IVFEs are metabolized via different pathways, which may lead to less proinflammatory effects and less immune suppression. These alternative oil-based IVFEs are not currently available in the United States. Many patients who require IVFEs are already in a compromised state. Such patients could potentially have better clinical outcomes when receiving one of the alternative IVFEs to diminish the intake of the potentially proinflammatory ω-6 fatty acid—linoleic acid—which comprises more than 50% of the fatty acid profile in SO. Further research is needed on these alternative oil-based IVFEs to identify which IVFE oils or which combination of oils may be most clinically useful for specific patient populations.

For decades, if not centuries, a variety of products with what would now be regarded as prebiotic and probiotic properties have been consumed by the general public and advocated for their benefits on health and, in particular, gastrointestinal well-being. More recently, medical science has taken a great interest in the population of micro-organisms, the gut microbiota that normally populates the human gut, and the range of important functions carried out by the microbiota in health is being progressively defined. As a corollary, the list of disorders and diseases that may result from disruption of the normal microbiota and/or its interaction with the host continues to grow. A scientific basis for the use of probiotics and prebiotics is, therefore, beginning to emerge. Unfortunately, although progress has been made, the clinical evidence to support the use of these preparations lags behind. Nevertheless, a number of human disease states may benefit from the use of probiotics, most notably, diarrheal illnesses, some inflammatory bowel diseases, certain infectious disorders, and irritable bowel syndrome. Prebiotics promote the growth of “good” bacteria, and although a variety of health benefits have been attributed to their use, prebiotics have been subjected to few large-scale clinical trials.

Malnutrition may manifest as either obesity or undernutrition. Accumulating evidence suggests that the gut microbiota plays an important role in the harvest, storage, and expenditure of energy obtained from the diet. The composition of the gut microbiota has been shown to differ between lean and obese humans and mice; however, the specific roles that individual gut microbes play in energy harvest remain uncertain. The gut microbiota may also influence the development of conditions characterized by chronic low-level inflammation, such as obesity, through systemic exposure to bacterial lipopolysaccharide derived from the gut microbiota. In this review, the role of the gut microbiota in energy harvest and fat storage is explored, as well as differences in the microbiota in obesity and undernutrition.

The human intestinal tract comprises a rich and complex microbial ecosystem. This intestinal microbota provides a large reservoir of potentially toxic molecules, including bacterial endotoxin (ie, lipopolysaccharide [LPS]). This potent inflammatory molecule is detectable in the circulation of healthy individuals, and levels transiently increase following ingestion of energy-rich meals. Chronic exposure to circulating endotoxin has been associated with obesity, diabetes, and cardiovascular disease. Western-style meals augment LPS translocation and by this mechanism may contribute to the pathogenesis of these diseases. By contrast, the gut and other organs have evolved mechanisms to detoxify endotoxin and neutralize the potentially inflammatory qualities of circulating endotoxin. Of specific interest to clinicians is evidence that acute postprandial elevation of circulating endotoxin is dependent on meal composition. In this review, the authors present an overview of the biochemical and cellular mechanisms that lead to endotoxemia, with emphasis on the interplay between microbial and nutrition determinants of this condition. The link between endotoxemia, diet, and changes in the intestinal microbiota raise the possibility that dietary interventions can, at least in part, ameliorate the detrimental outcomes of endotoxemia.

The intestinal microbiota is a functional organ with a variety of important metabolic, trophic, immunologic, and digestive activities. Current data suggest that alterations in the intestinal microbiota may be related to disease conditions. Manipulation of the intestinal microbiota such as with probiotics, prebiotics, and synbiotics may be beneficial in preventing and treating certain disease conditions. This article provides an overview of the evidence gathered through randomized clinical trials, reviews, and meta-analyses on probiotics and prebiotics in commonly studied conditions in the pediatric population. It concludes with current recommendations for their use, noting safety and gaps in clinical evidence.

Probiotics are living microorganisms that, when ingested in adequate amounts, provide benefits to the host. The benefits include either a shortened duration of infections or decreased susceptibility to pathogens. Proposed mechanisms of beneficial effects include improving gastrointestinal barrier function, modification of the gut flora by inducing host cell antimicrobial peptides and/or local release of probiotic antimicrobial factors, competition for epithelial adherence, and immunomodulation. With increasing intensive care unit (ICU) antibacterial resistance rates and fewer new antibiotics in the research pipeline, focus has been shifted to non-antibiotic approaches for the prevention and treatment of nosocomial infections. Probiotics offer promise to ICU patients for the prevention of antibiotic-associated diarrhea, Clostridium difficile infections, multiple organ dysfunction syndrome, and ventilator-associated pneumonia. Our current understanding of probiotics is confounded by inconsistency in probiotic strains studied, optimal dosages, study durations, and suboptimal sample sizes. Although probiotics are generally safe in the critically ill, adverse event monitoring must be rigorous in these vulnerable patients. Delineation of clinical differences of various effective probiotic strains, their mechanisms of action, and optimal dosing regimens will better establish the role of probiotics in various disorders. However, probiotic research will likely be hindered in the future given a recent ruling by the U.S. Food and Drug Administration.

Oral administration of a probiotic preparation was shown to be effective in preventing the recurrence of chronic pouchitis in a classic double-blind, placebo-controlled trial. This was a novel and unique approach to the care of these patients. Dysbiosis, a condition of microbial imbalance, has been implicated in the pathogenesis of inflammatory bowel disease. Rather than administering antibiotics to treat the microflora with each relapse of pouchitis, the emphasis was placed on preventing chronic flare-ups by administering probiotics to correct dysbiosis. The paradigm was shifted from treatment to prevention and from antibiotics to probiotics. These data were validated by this same group and others in subsequent trials. However, despite the promising results, many questions will need to be answered before routine use becomes universally accepted. The exact etiology and pathophysiology of pouchitis have not been fully elucidated. In addition, the choice of bacteria, optimal dose, and timing of administration have yet to be determined. Finally, the mechanisms by which probiotics provide their beneficial effects remain unresolved.

Background: The efficacy of some probiotic strains for the management of lactose intolerance remains to be established. Aim :To evaluate the effects of a 4-week consumption of a probiotic product containing Lactobacillus casei Shirota and Bifidobacterium breve Yakult (10⁷–10⁹ CFU of each strain) on symptoms and breath hydrogen exhalation after a lactose load in lactose-intolerant patients and whether the beneficial results persisted after probiotic discontinuation. Methods: Twenty-seven patients with lactose maldigestion and intolerance participated in this study, which comprised 4 hydrogen breath tests: baseline condition (20 g lactose), after lactase ingestion (9000 FCC units), at the end of 4-week probiotic supplementation, and a follow-up test performed 3 months after probiotic discontinuation. For each test, the area under the breath hydrogen concentration vs time curve (AUC_{180 min}) was calculated, and symptom scores were recorded. Results: The probiotic combination significantly reduced symptom scores (P < .01) and breath hydrogen AUC (P = .04) compared with the baseline condition. The comparison with the lactase test showed that symptom scores were similar (P > .05), despite the significantly higher (P = .01) AUC values after probiotic use. In the follow-up test, symptom scores and breath hydrogen AUC values remained similar to those found at the end of probiotic intervention. Conclusion: Four-week consumption of a probiotic combination of L casei Shirota and B breve Yakult seems to improve symptoms and decrease hydrogen production intake in lactose-intolerant patients. These effects may persist for at least 3 months after suspension of probiotic consumption.

Background: Diarrhea is a common complication in patients receiving enteral nutrition (EN), and understanding this problem among patients and healthcare professionals is required. The aim of the study was to investigate patients’, nurses’, and dietitians’ definitions of diarrhea during EN, the attitudes of nurses and patients toward it, and the management practices of nurses and dietitians in response to diarrhea during EN. Methods: Twenty-two patients receiving EN, 57 nurses, and 33 dietitians were recruited and interviewed in a cross-sectional study, using a questionnaire that had been developed following an extensive literature review and pretested for clarity. Results: The ratings assigned by the 3 groups differed significantly for all the characteristics used to define diarrhea: frequency (P = .006), quantity (P < .001), consistency (P = .003), color (P < .001), odor (P < .001), and incontinence (P < .001). Patients gave incontinence the highest rank when defining diarrhea, whereas the healthcare professionals gave fecal consistency and frequency the highest ranks. Patients and nurses rated the unpleasantness of each characteristic of diarrhea during EN differently, with patients rating incontinence and fecal frequency and nurses rating odor and changing the patients’ underwear as the most unpleasant characteristics. Nurses and dietitians differed in the frequency with which they adopted various strategies to manage patients who developed diarrhea during EN. Conclusions: Patients have different definitions and attitudes toward diarrhea during EN from those of nurses and dietitians. Patients’ perceptions need to be understood and respected by healthcare professionals to improve patient-centered care.

Background: The identification of useful quality indicators for nutrition therapy (QINTs) is of great interest and a challenge. This study attempted to identify the 10 QINTs that best suit the practice of quality control in nutrition therapy (NT) by evaluating the opinion of experts in NT with the use of psychometric techniques and statistical tools. Methods: Thirty-six QINTs available for clinical application in Brazil were assessed in 2 distinct phases. In phase 1, 26 nutrition experts ranked QINTs by scoring 4 attributes (utility, simplicity, objectivity, low cost) to assess each QINT on a 5-point Likert scale. The top 10 QINTs were identified from the 10 best scores obtained, and the reliability of expert opinion for each indicator was assessed by Cronbach’s α. In phase 2, experts provided feedback regarding the selected top 10 QINTs by answering 2 closed questions. Results: The top 10 QINTs, in descending order, are the frequency of nutrition screening of hospitalized patients, diarrhea, involuntary withdrawal of enteral feeding tubes, feeding tube obstruction, fasting longer than 24 hours, glycemic dysfunction, estimated energy expenditure and protein needs, central venous catheter infection, compliance of NT indication, and frequency of application of subjective global assessment. Opinions were consistent among the interviewed experts. During feedback, 96% of experts were satisfied with the top 10 QINTs, and 100% had considered them in accordance with their previous opinion. Conclusion: The top 10 QINTs were identified according to their usefulness in clinical practice by obtaining adequate agreement and representativeness of opinion of nutrition experts.

Background: The mechanism for cycling parenteral nutrition (PN) varies from institution to institution. However, the types and frequency of adverse events (AEs) involved with this process are not well understood. Purpose: To determine the type and prevalence of AE in patients during PN cycling and identify factors associated with the occurrence of AEs. Methods: Patients without severe organ dysfunction or uncontrolled diabetes mellitus scheduled to be discharged on cyclic PN with a goal of 12 hours were eligible. Patients were cycled from 24 to 12 hours over 2 or 3 days based on previously established criteria. Demographic, nutrition, and monitoring data were collected. AEs were documented and graded as mild or serious. Results: Mild AEs occurred in 35 of 38 patients (92.1%) consisting primarily of mild hyperglycemia (86.8%) and tachycardia (29.0%). Serious AEs occurred in 8 of 38 patients (21.1%), including 7 patients (18.4%) with capillary blood glucoses between 255 and 324 mg/dL and 1 (2.6%) with tachypnea/tachycardia requiring immediate medical attention. No significant associations were made between demographic, medical, nutrition, or laboratory factors and serious AEs. No significant differences in demographic information, nutrition information, comorbidities, diet, medications, or composition of PN were found except for lower body weight in unsuccessful cyclers compared with successful cyclers (P = .042). Conclusions: Most patients incur AEs during PN cycling, primarily mild hyperglycemia and tachycardia. These findings suggest patients need to be monitored closely and treated aggressively for complications during PN cycling.

Background: The prevalence of disease-related malnutrition in hospital inpatients is high; many patients do not meet individual nutrition requirements while hospitalized. To better understand the reasons for inadequate nutrition intake, this study describes patient satisfaction, food provision, food intake, and waste of hospital meals. Methods: Over 6 days, 150 hospital meals were weighed and nutrient composition was calculated. On return from the wards, waste was weighed. In addition, nutrition intake was compared to nutrition requirements in 42 patients. In a separate study, the authors studied patient satisfaction with the hospital food service using interviews (n = 112). Results: The 3 main meals accounted for a mean of 1809 ± 143 kcal and 76 ± 13 g of protein per day. In total, 38% of the food provided by the kitchen was wasted. As a consequence, the main meals supplied an average of 1105 ± 594 kcal and 47 ± 27 g of protein to patients. Sixty-one percent of patients had an energy intake <90% and 75% had a protein intake <90% of requirements. Most patients were satisfied or fairly satisfied with the choices, taste, and presentation of the main meals. Satisfaction with snack meals and information was inadequate. Conclusions: The standard meals provided by the hospital kitchen provide adequate amounts of energy and protein. However, most patients do not consume complete meals. It may be concluded that food waste is largely attributed to the inadequate intake of many hospitalized patients. Patients who experienced the worst health status ate the least.

Nucleotides are low molecular weight biological molecules key to biochemical processes. Sources include de novo synthesis, recovery via salvage mechanisms, and dietary intakes. Although endogenous production serves as the main nucleotide source, evidence suggests that exogenous sources are essential to immune competence, intestinal development, and recovery. Dietary nucleotides serve a marked role in rapidly proliferating cells where they are necessary for optimal function. Accordingly, dietary nucleotides are deemed conditionally essential in the presence of various physiological stresses, including growth and development, recovery from injury, infection, and certain disease states. Clinical studies that evaluated nutrition formulations of nucleotides in combination with other specific nutrient substances demonstrated improved clinical outcomes in patients characterized as critically ill, injured, immune suppressed, or with chronic gastrointestinal conditions. However, conclusions regarding specific benefits of nucleotides are limited. Scientific substantiation of nucleotide supplementation in infant formula has been reported to improve the maturation and development of the intestinal tract as well as immune function. All medical nutrition products except for one immune-modulating formulation are devoid of nucleotides. In an effort to build on this, the current review presents the data to support potential clinical applications for nucleotides in enteral nutrition that may contribute to improved outcomes in physiologically stressed patients.

Mohammad MK, Zhou Z, Cave M, Barve A, McClain CJ. Zinc and liver disease. Nutr Clin Pract. 2012;27:8-20. (Original DOI 10.1177/0884533611433534)