Nutrition Intervention in the Treatment of Anorexia Nervosa, Bulimia Nervosa, and Eating Disorder Not Otherwise Specified (EDNOS) - Nutrition Intervention in the Treatment of Anorexia Nervosa

Written by HealthyPlace.com Staff Writer

Anorexia nervosa can also significantly affect the gastrointestinal tract and brain mass of these individuals. Self-induced starvation can lead to delayed gastric emptying, decreased gut motility, and severe constipation. There is also evidence of structural brain abnormalities (tissue loss) with prolonged starvation, which appears early in the disease process and may be of substantial magnitude. While it is clear that some reversibility of brain changes occurs with weight recovery, it is uncertain whether complete reversibility is possible. To minimize the potential long-term physical complication of AN, early recognition and aggressive treatment is essential for young people who develop this illness (31-34).

Amenorrhea is a primary characteristic of AN. Amenorrhea is associated with a combination of hypothalamic dysfunction, weight loss, decreased body fat, stress, and excessive exercise. The amenorrhea appears to be caused by an alteration in the regulation of gonadotropin-releasing hormone. In AN, gonadotropins revert to prepubertal levels and patterns of secretion (4,7,35).

Osteopenia and osteoporosis, like brain changes, are serious and possibly irreversible medical complications of anorexia nervosa. This may be serious enough to result in vertebra compression and stress fractures (36-37). Study results indicate that some recovery of bone may be possible with weight restoration and recovery, but compromised bone density has been evident 11 years after weight  restoration and recovery (38,39). In adolescents, more bone recovery may be possible. Unlike other conditions in which low circulating estrogen concentrations are associated with bone loss (eg, perimenopause), providing exogenous estrogen has not been shown to preserve or restore bone mass in the anorexia nervosa patient (40). Calcium supplementation alone (1500 mg/dL) or in combination with estrogen has not been observed to promote increased bone density (2). Adequate calcium intake may help to lessen bone loss (6). Only weight restoration has been shown to increase bone density.

In patients with AN, laboratory values usually remain in normal ranges until the illness is far advanced, although true laboratory values may be masked by chronic dehydration. Some of the earliest lab abnormalities include bone marrow hypoplasia, including varying degrees of leukopenia and thrombocytopenia (41-43). Despite low-fat and low-cholesterol diets, patients with AN often have elevated cholesterol and abnormal lipid profiles. Reasons for this include mild hepatic dysfunction, decreased bile acid secretion, and abnormal eating patterns (44). Additionally, serum glucose tends to be low, secondary to a deficit of precursors for gluconeogenesis and glucose production (7). Patients with AN may have repeated episodes of hypoglycemia.

Despite dietary inadequacies, vitamin and mineral deficiencies are rarely seen in AN. This has been attributed to a decreased metabolic need for micronutrients in a catabolic state. Additionally, many patients take vitamin and mineral supplements, which may mask true deficiencies. Despite low iron intakes, iron deficiency anemia is rare. This may be due to decreased needs due to amenorrhea, decreased needs in a catabolic state and altered states of hydration (20). Prolonged malnutrition leads to low levels of zinc, vitamin B12, and folate. Any low nutrient levels should be treated appropriately with food and supplements as needed.

Medical and Nutritional Management

Treatment for anorexia nervosa may be inpatient or outpatient based, depending upon the severity and chronicity of both the medical and behavioral components of the disorder. No single professional or professional discipline is able to provide the necessary broad medical, nutritional, and psychiatric care necessary for patients to recover. Teams of professionals who communicate regularly must provide this care. This teamwork is necessary whether the individual is undergoing inpatient or outpatient treatment.

Although weight is a critical monitoring tool to determine a patient's progress, each program must individualize its own protocol for weighing the patient on an inpatient program. The protocol should include who will do the weighing, when the weighing will occur, and whether or not the patient is allowed to know their weight. In the outpatient setting, the team member weighing the patient may vary with the setting. In a clinic model, the nurse may weigh the patient as part of her responsibilities in taking vital signs. The patient then has the opportunity to discuss their reaction to the weight when seen by the registered dietitian. In a community outpatient model, the nutrition session is the appropriate place for weighing the patient, discussing reactions to weight and providing explanations for weight changes. In some cases such as a patient expressing suicidality, alternatives to the weight procedure may be used. For example, the patient may be weighed with their back to the scale and not told their weight, the mental health professional may do the weighing or if the patient is medically stable the weight for that visit may be skipped. In such cases, there are many other tools to monitor the patient's medical condition, such as vital signs, emotional health, and laboratory measurements.

Outpatient

In AN the goals of outpatient treatment are to focus on nutritional rehabilitation, weight restoration, cessation of weight reduction behaviors, improvement in eating behaviors, and improvement in psychological and emotional state. Clearly weight restoration alone does not indicate recovery, and forcing weight gain without psychological support and counseling is contraindicated. Typically, the patient is terrified of weight gain and may be struggling with hunger and urges to binge but the foods he/she allows himself/herself are too limited to enable sufficient energy intake (3,45). Individualized guidance and a meal plan that provides a framework for meals and snacks and food choices (but not a rigid diet) is helpful for most patients. The registered dietitian determines the individual caloric needs and with the patient develops a nutrition plan that allows the patient to meet these nutrition needs. In the early treatment of AN, this may be done on a gradual basis, increasing the caloric prescription in increments to reach the necessary caloric intake. MNT should be targeted at helping the patient understand nutritional needs as well as helping them begin to make wise food choices by increasing variety in diet and by practicing appropriate food behaviors (2). One effective counseling technique is CBT, which involves challenging erroneous beliefs and thought patterns with more accurate perceptions and interpretations regarding dieting, nutrition and the relationship between starvation and physical symptoms (15). In many cases, monitoring skinfolds can be helpful in determining composition of weight gain as well as being useful as an educational tool to show the patient the composition of any weight gain (lean body mass vs. fat mass). Percent body fat can be estimated from the sum of four skinfold measurements (triceps, biceps, subscapular and suprailiac crest) using the calculations of Durnin (46-47). This method has been validated against underwater weighing in adolescent girls with AN (48). Bioelectrical impedance analysis has been shown to be unreliable in patients with AN secondary to changes in intracellular and extracellular fluid changes and chronic dehydration (49,50).