Eating Disorders Flashcards
Define the term ‘eating disorder’
Mental health conditions driven by several psychological factors with physiological consequences.
The control of food intake is used as a coping mechanism to deal with painful emotion, distress and psychological trauma.
Abnormal eating behaviours are severe and persistent enough to impair nutritional status, physical health and social functioning.
disordered eating behaviour can take many forms:
- Restricted intake
- Bingeing
- Binge-restrict cycle
- Self-induced vomiting
- Laxative abuse
- Excessive exercise
What is the definition and central features of AN?
The central features of AN is a severe restriction of food intake and the irrational fear of weight gain.
AN has two subtypes: restricting and binge-purge.
The foods most frequently avoided are those perceived to be ‘fattening’ which become fear foods. The selection of foods deemed ‘acceptable’ reduces as the disease progresses and can eventually lead to restriction of fruits & vegetables and fluids.
Vegetarianism and veganism are common in AN.
What are some of the underlying reasons that contribute to the development of AN?
- Over-valuation of body weight and shape as a determiner of self-worth leading to an overwhelming urge to lose weight.
- Unconscious need for control during times of turbulence or uncontrollable events.
- Masking painful emotions such as grief and seeking illusory safety
- Striving for spiritual purity
- Response to managing symptoms that appear to be food related e.g., dealing with multiple food allergies
Often, people with AN are in denial that their behaviour is harmful or that they are severely physically unwell even when BMI reaches critical levels.
What is the WHO diagnostic criteria for AN?
WHO diagnostic criteria for AN:
- Refusal to maintain reasonable body weight
- Body weight below 85% of that expected OR BMI <17.5kg/m2
- Intense fear of weight gain and dread of fatness
- Denial of seriousness of low body weight
- Self-induced weight loss by food restriction and 1) excessive exercise 2) purging 3) appetite suppressants 4) diuretics/laxatives
- Widespread endocrine disorder (thyroid, gonads, adrenal)
Describe the incidence and prevalence of AN, BN and EDNOS/BED.
What are some limitations to understanding rates of eating disorders?
Anorexia Nervosa:
- Highest incidence is age 15-19
- Incidence rate is 8 in 100,000
- Female to male ratio around 1:10
- Prevalence higher within Western cultures
Bulimia Nervosa:
- Female to male ratio around 1:10
- Incidence rate is 12 in 100,000
EDNOS/Binge Eating Disorder:
- 25% among people being treated for severe obesity
- 3% of whole populations in Western societies
Figures likely under-represent the amount of people suffering with ED’s due to reluctance to seek help and secrecy typical of having an ED.
E.g., in one community sample, half the cases of AN had not been detected.
What is the aetiology of ED’s?
Interaction of biological, psychological and environmental (social) factors.
Genetics:
- There is heritability in eating disorders, especially AN
(similar to that of other psychiatric disorders such as OCD, depression, substance misuse) - Genetic predisposition may be determined by personality traits: perfectionism, rigid thinking and compulsivity (associated with AN)
Novelty seeking and compulsivity (associated with binge eating) - Puberty:
Particularly common time for ED to develop due to body changes, weight gain and increased social awareness.
- Environmental:
Exposure to trauma or unsettling life event such as parental divorce, sexual abuse, grief, break-ups, bullying, etc.
Dieting is widespread among young girls in western culture.
Cultural over-valuation of thinness in the media.
Social media plays a role.
Sexual orientation:
By mid-adolescence, sexual minority youth in the UK had elevated risk for eating disorder symptoms, suggesting the need for early prevention efforts.
Describe some medical complications of ED’s
Starvation & low BMI
Musculoskeletal system
- Reduced muscle strength/stamina
- Osteopenia/osteoporosis caused by suppression of oestrogen, Vit D and calcium deficiency, less bone remodelling due to low body weight.
Central nervous system
- Reduced tissue mass in the brain causing cognitive impairment
Cardiovascular system
- Loss of muscle tissue from the heart and blood vessels causing low pulse, heart rate and blood pressure and
impaired peripheral circulation = cold sensitivity and fainting
Endocrine dysfunction:
Adrenal - hypercortisolaemia
Gonadal - amenorrhea
Thyroid - bradycardia, hypotension, hypothermia
Gastrointestinal system:
- Loss of muscle function in gut causes delayed gastric emptying: bloating, gas and early satiety
poor dentition caused by self-induced vomiting
Immune function:
- Low adiposity = reduced WBC count
- Impaired immune system = susceptibility to infection
Compensatory behaviours:
- Laxative/diuretic use = loss of fluid & electrolytes causing dehydration
- Low blood electrolytes = fatal cardiac and renal complications
Binge eating:
- obesity and weight cycling
- gastric dilation following large binges can be fatal
Explain refeeding syndrome and how it occurs.
How is refeeding syndrome managed?
A collection of symptoms arising in severely malnourished individuals when intake is suddenly increased (particularly CHO intake).
Occurs due to a shift in fluid and electrolyte concentrations causing fluid retention, acute thiamine deficiency and heart failure.
- Severe starvation = depleted carbohydrate intake/store
- micronutrients needed to metabolise CHO, and insulin production is low
- energy produced by ketones derived from fatty acid and amino acids
- CHO intake is increased suddenly
- pancreatic beta cells release insulin and the uptake of phosphate to generate ATP increases
- potassium, phosphate and magnesium are taken into the cells and blood levels of these electrolytes fall rapidly
- Acute thiamine deficiency occurs as thiamine needed to metabolise CHO
- Fluid retention is caused by regeneration of the sodium/potassium pump causing rapid shifts in fluid
- Blood volume is increased causing peripheral oedema
- fluid overload and electrolyte depletion can cause cardiac malfunction if affects vital organs.
Management of refeeding risk:
- Supplementation of B vitamins for CHO metabolism
- Gradual reintroduction of calories - quarter portions, half portions then full portions or use of continuous tube feeding.
- Controlled fluid intake - enough to prevent dehydration but prevent excess water retention and cardiac overload.
- Vitamin and mineral supplements, particularly high potassium and phosphate
How are ED’s managed nutritionally?
What are the stages and key goals of nutritional management of ED?
Requires a multidisciplinary approach and requires addressing the social, physiological and physical aspects of the disease.
A collaborative and motivational approach is necessary as denial of the seriousness of one’s condition is common and hostility toward recovery is therefore common.
- Restoring appetite regulation
- Restoring weight and nutritional status
- Management of compensatory behaviours
- Avoiding relapse
Stage 1: correction of hypoglycaemia, electrolyte disturbance and dehydration, and stabilisation of cardiovascular function.
Stage 2: correction of nutrient deficiency
Stage 3: correction of body composition
Key goals in nutritional therapy for anorexia nervosa include:
- Weight restoration and body-weight maintenance
- Development of neutrality toward food through re-developing intuitive understandings of hunger, fullness, and satiety.
These goals are reached through a gradual increase of food through an individualised program.
How is appetite regulated in nutritional management of ED’s?
Regular balanced meals promote healthy cycle of fullness and gastric emptying
Avoiding low calorie foods and fluids
Consume low GI foods to prevent blood sugar spikes
Have protein fat and CHO with every meal to stimulate gut hormones that regulate appetite
Being a healthy weight/having healthy amounts of adipose tissue & glycogen contributes to satiety.
How can relapse be avoided in ED recovery?
Relapse in AN is common so care should be taken to avoid the risk of relapse.
Food and nutrition education to correct distorted views on food and eating.
Management of compensatory behaviours:
- Education and psychotherapy needed to help abolish ED behaviours, understand triggers and form new healthy habits
- Supervised ‘post meal’ period of time
- Education about weight gain in recovery e.g., large fluctuations in weight = fluid retention not fat
- Reducing hunger and hyper-reward sensation of food can improve binging
Explain micronutrient complications associated with ED’s.
Vitamin deficiency is uncommon in AN:
- Adaptive mechanisms to conserve vitamin store
- Many people with AN take vitamin supplements to mask deficiency
Most common mineral deficiencies in AN are calcium, zinc and iron.
- Vitamin D deficiency can occur leading to osteoporosis as intakes of meat tend to decline as disease progresses.
- Low calcium intake from avoidance of dairy products can together with low vit D, lead to osteoporosis.
Low iron is typical due to high consumption of tea and coffee as an appetite suppressant and high fibre foods.
Iron deficiency is seen as low blood ferritin rather than low haemoglobin.
Explain energy, macronutrient and body composition complications associated with ED’s.
Changes in body composition occur:
Loss of adipose tissue and muscle mass and tone which causes the characteristic wasted appearance of AN.
Loss of adipose tissue causes:
- hypothermia and cold sensitivity
- discomfort when sitting and lying
- reduction in leptin and other endocrine abnormalities
Low CHO intake leads to:
- depleted glycogen store and water (flat muscle appearance)
- high carb binges cause rapid weight gain through water retention which reinforces the binge-restrict cycle
- reduced CHO metabolism causes metabolic shift to using ketones for energy and people with AN are unusually tolerant to low blood glucose
Protein intake:
- typically adequate due to consumption of low calorie lean meats in early disease as disease progresses these are likely removed from the diet (in chronic AN)
- low protein intake causes immunosuppression and slow wound healing
What are some of the challenges faced by dietitians in treatment of ED’s?
ED’s are associated with a host of medical complications - requires a multidisciplinary team to manage of which a dietitian is a crucial part.
however:
Systematic review (Yang et al., 2021):
- Found that dietetic input in ED treatment improved body mass index/weight and nutritional intake however dietetic input did not improve ED psychopathology
No behaviour change = relapse
Food and nutrition education is important in ED recovery to correct distorted views about food - dietitian can help with this.
however, ED’s are physcological illnesses that are driven by trauma/distress/painful emotion - needs addressing by psychiatrist.
Poor appetite regulation can lead to cycles of binge/restriction.
Dietitian in charge of weight gain - recommended 0.5-1kg week inpatient and 0.5kg/week in community.
Weight gain/large fluctuations in weight due to water retention can drive increase in compensatory behaviours e.g., excessive exercise, purging etc.
Refeeding syndrome
micronutrient deficiency uncommon except for:
iron, zinc, calcium
low bone mineral density
Hostility and resistance from patient to accept treatment/recovery.
