Nutrition E-book

Question 1

Macronutrients

Answer 1

There are three groups of macronutrients – proteins, fats and carbohydrates.

Question 2

Protein

Answer 2

Protein is the only source of nitrogen for the human body and it is their constituent amino acids which are the important building blocks. Proteins form 10‐15% of the energy in the human diet and they are essential for structural and functional processes and for growth and repair. As proteins are macromolecules made from amino acid chains it is the supply of these amino acids that is vital for protein synthesis. The human body can synthesise many amino acids but there are certain essential amino acids that must be supplied by the diet as they cannot be synthesised by the body

Question 3

eight essential amino acids

Answer 3

lysine, methionine, valine, leucine, isoleucine, tryptophan, phenylalanine and threonine.

Question 4

additional essential amino acids in children

Answer 4

arginine, histidine, cysteine, glycine, tyrosine, glutamine and proline

Question 5

Proteins in the diet and synthesised by the body have several major functions:

Answer 5

• Replace protein lost through metabolism and wear and tear. The production of hair and nails uses up protein. Protein is also lost through shedding of skin cells and digestive tract cells, and digestive enzymes.
• Produce new tissue particularly during growth periods, following injury, pregnancy and lactation.
• Manufacture of specific larger proteins
– Haemoglobin
– Hormones
– Enzymes
• Energy source

Question 6

Essential fatty acids

Answer 6

linoleic and alpha‐linoleic acids

Question 7

Carbohydrates are classified according to how many molecules are used to form them:

Answer 7

 Monosaccharides (glucose, fructose, galactose)
 Disaccharides (sucrose, lactose, maltose)
 Oligosaccharides (3‐11 monosaccharide units e.g. raffinose, inulin)
 Polysaccharides (12 or more monosaccharide units)
o Starches (amylopectin, amylose, modified food starches)
o Non‐starch (cellulose, fructans, gums, mucilages) – also known as fibre

Question 8

Total Energy Expenditure (TEE)

Answer 8

• BMR (50‐75%)
• Physical activity (PA) (20‐40%)
• Dietary induced thermogenesis (DIT) (10%)

Question 9

Coeliac Disease

Answer 9

Gluten-sensitive enteropathy. Increased immunological response to gluten found in wheat, barley, or rye which causes villous atrophy. This leads to malabsorption of nutrients

Question 10

Blood tests for Coeliac Disease

Answer 10

• Test for total IgA and IgA tTG as the first choice

- Use IgA EMA if IgA tTG is weakly positive

Question 11

Coeliac Disease treatment

Answer 11

• Gluten free diet

- vitamin B12, iron and folate supplementation to avoid anaemia.

Question 12

According to NICE CG9 (June 2004), the target groups for screening for eating disorders
include:

Answer 12

Young women with a low BMI
 Weight concerns raised by patients who are not overweight
 Menstrual disturbance or amenorrhoea (in female patients of an appropriate age)
 GI symptoms
 Physical signs of starvation or repeated vomiting
 Children with poor growth

Question 13

Anorexia nervosa - diagnosis

Answer 13

The key diagnostic criteria of anorexia nervosa include the following:
 The active maintenance of very low body weight
o 15% less than ideal as indicated by BMI or a BMI of < 17
 Cognitive disturbance
o E.g. a fear of becoming fat or a determination to be thin

Question 14

The symptoms of anorexia nervosa include:

Answer 14

 Low bodyweight
 Poor growth (in young patients)
 Fear of weight gain
 Amenorrhoea (in female patients)
 Electrolyte disturbances
 Lanugo (soft, downy hair which grows all over the body)
 Sensitivity to cold
 Hyperactivity

Question 15

There are many possible triggers for anorexia which may be divided roughly into three groups:

Answer 15

• Psychological factors: parental divorce, alcoholism within the family, physical and sexual abuse, feelings of loneliness and shyness, adolescent anxieties about approaching adulthood, sexual maturity or leaving home.
• Family factors: overprotective family, dominant mother, passive father figure, parents with excessively high expectations of their children, children striving to fulfill parental expectations.
• Cultural factors: a distorted view of what a healthy weight should be, often based upon a perception of an “ideal” size and shape rather than a health BMI. There is much debate over the influence of role models – e.g “size zero” models, idealized and stylized images in magazines.

Question 16

Anorexia nervosa is primarily treated with psychological treatments which include:

Answer 16

 Cognitive analytic therapy (CAT)
 Cognitive behavior therapy (CBT)
 Interpersonal psychotherapy (IPT)
 Focal psychodynamic therapy
 Family interventions focused explicitly on eating disorders

Question 17

Bulimia Nervosa - Diagnosis

Answer 17

The key diagnostic criteria for bulimia nervosa include the following:
 Frequently bulimic episodes
o Binges of large quantities of calorific food (an average of 3000 kcal per binge) with a feeling of a loss of control
 Extreme measures to control body weight
o Purging either as self‐induced vomiting or by laxative or diuretic abuse
 Cognitive disturbance
o E.g. a fear of becoming fat or a determination to be thin

Question 18

The clinical features of bulimia nervosa include:

Answer 18

 Restrained eating between binges
 Overly complex food rules (the breaking of which usually triggers a binge)
 Not overtly thin in appearance
 Dental erosion on the front teeth (from stomach acid brought up during vomiting)
 A callus on the dorsal surface of the dominant hand (from inducing vomiting)
 Electrolyte disturbances following bingeing and/or purging

Question 19

Treatment of bulimia nervosa

Answer 19

According to NICE CG9, the first step in treatment of bulimia nervosa may be to encourage patients to follow an evidence‐based self‐help programme. An adapted form of CBT – CBT‐BN – should be offered to all adults diagnosed with bulimia nervosa. This should consist of 16 – 20 sessions over a period of 4 to 5 months. If CBT fails or is rejected as an option by the patient, other psychological treatments may be considered. IPT is an
alternative but patients should be informed that it takes 8 – 12 months to achieve the same outcomes as the shorter course of CBT.

Antidepressant therapy with an SSRI may be rapidly beneficial for some patients. Fluoxetine is the only SSRI licensed for the treatment of bulimia nervosa. The dose of 60 mg per day is much higher than the dose required for the treatment of depression.

Question 20

Binge Eating Disorder - Diagnosis

Answer 20

Patients will exhibit one or more of the following symptoms:
 Binge eating on an average of 2 days per week for 6 weeks or longer
 No attempt to compensate for binge eating (i.e. no purging)
 A feeling of a loss of control whilst bingeing

Episodes of binge eating will usually involve three or more of the following:
 Eating more quickly than normal
 Eating until uncomfortably full
 Eating large amounts when not physically hungry
 Eating large quantities of food alone (i.e. not eating in company)
 Feeling guilty, disgusted or depressed about their bingeing

Binge eating disorder is often associated with obesity, a history of alcohol or drug abuse, treatment for emotional problems, impaired social functioning and difficulties in
employment.

Question 21

Binge Eating Disorder treatment

Answer 21

NICE CG9 recommends that an evidence‐based self‐help programme is possibly the best first‐line treatment. CBT adapted for binge eating disorder should be offered to all patients, but if there is persistent binge eating, IPT may be offered as an alternative. However, patients should be counselled that psychological treatments will have a limited effect on body weight and so this must be treated concurrently (if the patient has issues with food that can be resolved at the same time) or consecutively (if the food issues take priority over weight management). Conventional weight management therapies (diet and exercise) should be offered.
SSRIs may be of benefit in binge eating disorder if a clear psychological cause can be identified