Hyperglycemia is frequently seen in acutely ill patients and has historically been viewed as a normal response to stress. Treatment is often not initiated unless blood glucose exceeds 200 to 250 mg/dL. Recent evidence suggests that hyperglycemia is associated with worse outcomes within the population of medical and surgical intensive care units. Hyperglycemia in this population of patients develops from increased gluconeogenesis and insulin resistance. Although the specific mechanisms by which hyperglycemia contributes to poor outcomes are as yet unknown, disruption of normal mitochondrial respiration, direct glucose toxicity, accumulation of asymmetric dimethylarginine, and impairment of immune cell function are among the possibilities implicated. Studies demonstrate that intensive insulin therapy to achieve euglycemia reduces mortality and morbidity in critically ill patients. In addition to recognizing and treating hyperglycemia, it is as important to identify other frequently overlooked factors that contribute to hyperglycemia, such as medications, intravenous fluids, and enteral and parenteral nutrition.
Total parenteral nutrition (TPN) is sometimes utilized in cancer patients. Previous studies suggest that TPN provides clinical benefit in the perioperative setting among severely malnourished cancer patients and among those who are receiving blood or marrow transplants. However, the negative impact of TPN on quality of life, its adverse event profile, and its cost all suggest that this intervention must be used judiciously in cancer patients. Although a few case reports and other studies imply that TPN may benefit select patients with metastatic cancer, this approach represents a departure from the standard of care and therefore must be clearly thought through and justified prior to implementation.
In patients with chronic kidney disease (CKD), specialized nutritional therapy may help reduce the risk of electrolyte imbalances, vitamin deficiencies, and protein energy malnutrition. Protein-restricted diets may slow the progression of renal disease and decrease the risk of morbidity and mortality in patients with CKD. In this review, we discuss some of the major nutritional concerns in individuals with CKD and offer practical recommendations for dietary therapy.
The rapid increase in the prevalence of obesity in children and adolescents is alarming, particularly in light of its many medical and psychosocial consequences. In this review, we discuss key concepts of nutrition and physical activity. Etiology, prevention, and treatment strategies are also discussed, focusing on the macronutrient content of the diet, portion control, meal patterns, physical activity, and sedentary behaviors. Television viewing, lack of physical activity, and intake of fast food and soft drinks are also examined as potential contributing factors in the obesity epidemic. Children should be helped to develop healthy nutrition and exercise habits early, since interventions are most effective when behaviors are still being formed.
Celiac disease (CD) is an inflammatory small intestinal disorder that can lead to severe villous atrophy, malabsorption, and malignancy. It is triggered by the gluten proteins of wheat, barley, and rye. All patients express the antigen-presenting molecules human leukocyte antigen-DQ2 (HLA-DQ2) and/or HLA-DQ8, which bind gluten peptides and thus activate destructive intestinal T cells. Patients with untreated CD have circulating IgA autoantibodies to the enzyme tissue transglutaminase (tTG), a component of endomysium. Testing for serum IgA tTG has a high predictive value. Therapy of CD is a lifelong gluten-free diet. Counseling by an expert dietitian and association with a celiac support group are important in helping the patient embark on a healthy gluten-free diet. Current research focuses on non-dietary therapies and treatment of refractory (diet-unresponsive) CD.
HIV infection has become increasingly prevalent globally, with more than 40 million infected individuals worldwide, the majority of whom live in the resource-limited world, especially sub-Saharan Africa and Asia. There are nutritional and metabolic issues that significantly impact morbidity and mortality in HIV-infected populations. In addition, malnutrition has been associated with an increased risk of transmission of HIV from infected mothers to infants, and malnutrition may further compromise HIV-infected individuals who have tuberculosis or persistent diarrheal disease. The introduction of highly active antiretroviral therapy will have a significant impact on the mortality of HIV, but will not completely alleviate the malnutrition associated with HIV infection in the global setting.
Nutrition assessment is a vital component of the general care of HIV-infected adults. With access to highly active antiretroviral therapy (HAART), HIV infection may become a chronic, manageable disease. Nutritional and metabolic complications traditionally associated with HIV infection such as hypertriglyceridemia, low levels of high-density lipoprotein (HDL) cholesterol, and weight loss continue to occur. However, emerging abnormalities such as regional alterations in body shape (fat re-distribution syndrome or HIV-associated lipodystrophy), increasing body weight, high levels of low-density lipoprotein (LDL) cholesterol, insulin resistance, and other metabolic derangements may also be present. In addition, as patients are living longer, they may be susceptible to other age-related diseases such as diabetes, cardiovascular disease, and obesity. In this article, we review strategies for nutrition assessment and management in HIV-infected adults. Attention is focused on specific symptoms such as weight loss and diarrhea and specific disorders such as lipodystrophy, micronutrient deficiencies, and dyslipidemia, which commonly affect HIV-infected individuals. Proper attention to nutritional status may help to reduce the burden of disease and promote an enhanced quality of life in HIV-infected individuals.
Hypertriglyceridemia and insulin resistance have been seen in patients with HIV. Beneficial effects of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported for these conditions. One study of n-3 fatty acid supplementation in patients with HIV reported a decrease in serum triglyceride levels. These marine fatty acids appear to be working at a number of sites to achieve an improvement in lipid metabolism and insulin sensitivity. There is disagreement about the amount of n-3 fatty acids needed to achieve different effects and about the optimal ratio of dietary n-6 and n-3 fatty acids.
This review examines the relationship among malabsorption, diarrhea, dietary intake, and body composition in an outpatient cohort of individuals with HIV infection. Twenty-three percent of the participants had malabsorption, which was not associated with the presence of current or chronic diarrhea. In this "outpatient" HIV cohort with a mean body-mass index (BMI) of 25 kg/m2, the presence of malabsorption did not have adverse nutritional outcomes in terms of body weight, lean body mass, hemoglobin, or albumin. The diets of those with or without malabsorption did not meet the goals of the Dietary Guidelines for Americans. Median dietary intake was high in percentage of total fat and saturated fat and low in total fiber intake and some key micronutrients.
Low serum micronutrient levels are common in HIV-positive individuals and have been associated with immune impairment, HIV disease progression, and increased mortality. Studies of micronutrient supplementation have yielded conflicting results, although several large trials suggest that multivitamin supplements, but not vitamin A, may decrease morbidity and mortality in some HIV-positive populations. Studies also suggest that antioxidant supplementation may decrease markers of oxidative stress in individuals with HIV, while selenium may enhance immune function by modulating cytokine production. Clearly, more research is needed, but current knowledge supports the use of a multivitamin supplement as a low-cost adjunct to antiretroviral treatment.
HIV-associated body shape changes and metabolic abnormalities, called HIV-associated lipodystrophy, are being seen with increased frequency. These issues may be associated with an increased risk of other diseases, such as cardiovascular disease, or with poor adherence to antiretroviral medications. Diet may be useful in the prevention and treatment of lipodystrophy and is a cost-effective and non-toxic intervention. At present, there are limited data on nutrition and HIV-related body shape changes. The purpose of this article is to review the roles that diet may play in the development and treatment of fat deposition and fat atrophy.
