Discussion
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| No Super Hero can't save for AIDS |
Human immunodeficiency virus (HIV) is a retrovirus, transmitted through contact with blood or body fluids from an infected person. This virus attacks helper T lymphocytes in the blood, often referred to as CD4 cells or T cells. The systematic destruction of the CD4 cells leads to a weakening of the body’s immune function, increasing the host’s vulnerability to opportunistic infections. Acquired immunodeficiency syndrome (AIDS) defines a specific stage of HIV infection when the progression of the virus has advanced and the immune system is severely compromised. There are a number of specific opportunistic infections as well as counts of the CD4 cells that define when a person has AIDS. The impact of nutrition on HIV and AIDS is significant.
A major component of the clinical syndrome in HIV infection and AIDS is HIV wasting. The Centers for Disease Control and Prevention (CDC) define the HIV wasting syndrome as profound involuntary weight loss of greater than 10% of baseline body weight, plus at least one of the following :
chronic diarrhea (at least two stools a day for 30 days or longer)
chronic weakness and documented fever for 30 days or longer in the absence of a concurrent illness or condition other than HIV infection that could explain the findings
Previous estimates of the prevalence of HIV wasting as the first AIDS-defining diagnosis ranged up to 37% (2). However, with the advent of the highly active antiretroviral therapy (HAART), researchers have shown that the prevalence of all AIDS-defining diagnoses has decreased. In a more recent study, while 63% of the patients showed evidence of malnutrition, the prevalence of wasting had decreased to 21%.
The causes of wasting and malnutrition in HIV disease are complex and multifactorial. Suspected mechanisms of weight loss and malnutrition include reduced intestinal absorption, abnormal utilization of nutrients, anorexia, altered metabolism, hypogonadism, and increased cytokine production.
It has been shown that there is an increase in resting energy expenditure (REE) with HIV infection that may contribute to weight loss. However, there is now increasing evidence to show that whereas REE does increase slightly, total energy expenditure (TEE) decreases. This decrease in TEE illustrates that HIV may increase the metabolic rate, but it more significantly decreases the infected individual’s activity level and energy intake. This decline in general functional ability affects a person’s exercise and eating patterns in ways that may greatly contribute to HIV wasting.
Wasting and weight loss also influences the timing of the progression from HIV to AIDS and death in AIDS. Studies have shown that a 5% to 10% weight loss over 4 months increases the relative risk for death and opportunistic infections twofold. Other research has demonstrated that an overall weight loss of 34% of ideal body weight (IBW) or 46% of usual body cell mass is linked to the occurrence of death. Evidence also exists that a combination of therapies to combat weight loss, malnutrition, and loss of lean body mass will be more effective in helping to reduce associated morbidity. There are many new and developing treatment options to choose from, including nutritional supplements, appetite-stimulating drugs, testosterone and testosterone analogues, growth hormone, resistance exercise, and cytokine modulation.
Nutritional Priorities
All patients with a new diagnosis of HIV infection should have a thorough nutrition assessment. Early referral to medical nutrition therapy in HIV-infected patients can improve nutritional status and may lead to an increased ability to fight opportunistic infections and a decreased number of hospitalizations. Early intervention efforts should be focused on optimizing nutrient stores before the onset of nutrition-related complications in an attempt to prevent or delay the onset of malnutrition and wasting.
Initial assessment: The assessment should include the patient’s medical-surgical history, profile of medications and nutritional supplements, anthropometrics (calculation of body cell mass) if possible, laboratory data, diet history, financial evaluation, psychosocial assessment, and physical symptoms.
Establish energy requirements: Energy needs can be estimated by using the Harris-Benedict equation and multiplying by a stress factor of 1.2 to 1.8, with allowance for extra needs associated with fever and exercise. An alternative method to estimate energy needs is 25 to 45 kcal/kg of usual body weight. Both methods are acceptable and commonly used in practice.
Establish protein requirements: Protein needs for males and females can be estimated using a range of 1 to 2 g/kg. Consider renal and hepatic function, nitrogen balance studies, prealbumin, serum albumin, transferrin levels, and exercise regimen.
Establish fluid requirements: Water requirements for patients with normal fluid status can be estimated using 30 to 35 mL/kg of body weight or 9 to 12 (8-oz) cups per day. Coffee and other caffeine-containing beverages do not count as fluids and should be avoided because of their dehydrating effects. Consider increasing fluid requirements when the patient has fever, nausea, vomiting, or diarrhea or with initiation of medication, exercise, and inclement weather. Fluid restrictions may be indicated with renal or hepatic failure .
Vitamin and mineral recommendations: Researchers have identified vitamin and mineral deficiencies in individuals infected with HIV. Clinicians routinely recommend the use of a multivitamin and mineral supplement that provides 100% of the Dietary Reference Intakes (DRI) for vitamins and minerals. It is often recommended to take these multivitamin and mineral supplements twice daily. Other vitamins and mineral recommendations have been published that are not verified by research but may be considered within the realm of prudent practice. For example, some practitioners recommend additional supplementation of antioxidants such as vitamin E, vitamin C, beta-carotene, magnesium and selenium.
Exercise recommendations: Resistance exercise has been shown to help increase lean body mass, and HIV wasting has been shown to deplete lean body mass. Maintenance of lean body mass is very important in helping the body to resist opportunistic infections and to rebound after infection. Therefore, dietitians should recommend that all patients who are physically able begin a routine of resistance exercise. A physician or physical therapist should monitor program intensity and scope.
Determine appropriate mode of nutrition support based on diagnostic findings:
Oral feedings are preferred over any other feeding method. Efforts to maintain the oral feeding route should be maximized. Nutrient-dense foods and supplements should be used to support maintenance and restoration of nutritional status and body weight. Appetite stimulants may be indicated for patients experiencing anorexia. Two appetite stimulants have been approved for this purpose, megestrol acetate and dronabinol. It should be noted, however, that typically the weight gain associated with the use of these appetite stimulants is in the form of fat mass and not the desired lean body mass. Additionally, megestrol acetate may exacerbate diabetes mellitus .
- The enteral feeding route is preferred over parenteral administration in order to preserve gut structure and function. Assess patients carefully and reassess them on a regular basis .
- Parenteral nutrition may become necessary when a patient meets the criteria for initiation of total parenteral nutrition (TPN). Continual assessment and routine monitoring of laboratory values is essential.
References
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