1.1 Background
Eating disorders (ED) are illnesses that are defined as persistent disturbed eating and eating-related behaviors that result in altered consumption or absorption of food and potential physical or psychological function disruption. EDs have four major types as described by The Diagnostic and Statistical Manual of Mental Disorders (DSM-5): anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), and eating disorder not otherwise specified (EDNOS) [1].
AN is defined as a psychological illness or syndrome. It is characterized by an intense fear of fatness or seeking low body weight. The body mass index (BMI) is reported to be very low at less than 17.5 kg\m2. Affected individuals restrict their high-fat food intake and participate in excessive exercise [2].
BN is the second type of ED and is a life-threatening psychiatric illness, characterized by overeating by eating high caloric food in a short time with self-induced vomiting, laxative and diuretic use, fasting, or over-exercising to avoid weight gain [3].
BED is considered the third ED type and is characterized by eating a large amount of food in a short time compared to normal individuals. Sufferers also feel guilty or depressed after eating, consume food alone to avoid embarrassment, and eat food even when not hungry. To diagnose BED, the binge episodes must occur once/week for 3 months or more, and the syndrome must not be influenced by any normal compensating behavior [4].
EDNOS is defined in DSM-5 as those who have an ED but have not satisfied the diagnostic criteria for any of the previous ED types. The most recent DSM-5 update renamed this type as other specified feeding or eating disorder (OSFED), which includes several illnesses such as purging disorder, atypical AN, subthreshold BN, and subthreshold BED [5].
Unspecified feeding or eating disorder (UFED) is applied to those who have an ED but have not achieved the diagnostic criteria for any of the previous types or for OSFED.
1.2 Nutritional status of eating disorders
Nutrition plays a major role among ED individuals. Malnutrition is common because of the low consumption of macro- and micronutrients in AN and BN. Moreover, the restricting behavior can affect micronutrient availability, resulting in compromised immunity, loss of lean body mass, fatigue, altered brain function, and deficiencies in vitamin D, calcium, folate, cobalamin, zinc, magnesium, thiamine, riboflavin, niacin, pyridoxine, C, E, K, and iron, leading to anemia. Replacing these nutrients is an important part of nutrition therapy to enhance recovery [6, 7].
1.3 Health consequences of eating disorders
EDs can affect multiple organ systems and are potentially life threatening. These disorders can lead to changes in the gastrointestinal system. Food restriction and vomiting can cause digestion and normal stomach functions to be interrupted, thus leading to nausea, blotting, gastroparesis, constipation, anemia, and blood sugar fluctuations. EDs can also affect the cardiovascular system [8].
AN has specific health consequences due to caloric distraction. Symptoms include hypokalemia, hypoglycemia, abdominal discomfort, and loss of bone mineral density [9]. BN is associated with subsequent xerosis, an electrolyte imbalance leading to arrhythmias, early satiety, gastroparesis, constipation related to laxative abuse, gastroesophageal reflux, and malnutrition [10]. BED also has its own particular complications, such as diabetes, dysphagia, diarrhea, blotting, nutrient deficiencies, and increased risk of cancer, hypertension, and obstructive sleep apnea [11].
1.4 Epidemiology of eating disorders
The epidemiological incidence of EDs in the United Kingdom was reported to be AN 7.4%; BN 0.8%, BED 3.6%, and OSFED 2.4%. In Finland, the prevalence of AN among females was 3.6%, and OSFED 0.6%. In Holland, ED among females was 3.7%, AN 1.2%, BN 0.6%, BED 1.6%, and OSFED 0.3%, and among males EDs were 0.5%, AN and BN each 0.1%, and BED 0.3. In Switzerland, among females, AN was 1.9%, and among males 0.2%. In Germany, AN was found to be 0.3%, BN 0.4%, and BED 0.5%. In Sweden, for females, BN was 1.6% and BED 0.4%. In Australia, ED was reported to be 16.3%, AN 0.46%, BN 0.66%, and BED 5.58%. In the United States, AN among females was found to be 1.37% and BED 1.7%, and BED among males was 0.8%. In Canada, female EDs were reported to be at a level of 4.46%, AN 0.06%, BN 2.01%, and BED 0.68%; among males, ED was 2.21%, BN 1.31%, and BED 0.16% [12].
The prevalence of EDs in the Middle East and North Africa (MENA) region was found to be 16.9% in the UAE (for BED, specifically). Egypt had a 65.0% prevalence of EDs. In Saudi Arabia (Dammam), 29.4% of females had an ED, whereas this figure was 35% and 23.3% for Taif and Arar cities, respectively [13, 14, 15, 16]