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CELL Yr 1 > Dietary components > Flashcards

Dietary components Flashcards

1
Q

Define diet

A

The sum of food consumed by a person

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2
Q

Name 4 macronutrients

A

Fat, carbohydrates, protein and alcohol

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3
Q

What are micronutrients?

A

Vitamins and trace minerals

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4
Q

Name the 2 water-soluble vitamins and their 3 properties

A

Vitamins B and C aren’t stored, they’re easily destroyed and leach out when cooking

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5
Q

Name the 4 fat-soluble vitamins

A

Vitamins A, D, E and K dissolve in fat before being absorbed into the bloodstream

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6
Q

What’s the importance of calcium?

A

Calcium plays a role in helping build strong bones and teeth, regulating muscle contractions and making sure blood clots normally

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7
Q

Give dietary sources of calcium

A

Milk, cheese, sardines, bread, soya beans, tofu, nuts, leafy greens

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8
Q

What is the main role of iron?

A

As an oxygen carrier in haemoglobin in blood and myoglobin in muscle

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9
Q

Where is haem iron from?

A

Animal muscle/blood. Haem iron is well absorbed and not affected by other dietary components

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10
Q

Where is non-haem iron from?

A

Beans, nuts, dried fruit, wholegrain, fortified cereals, soybean flour, and most dark leafy greens. Non-haem iron absorption is reduced by tannins and phytates but increased by vitamin C

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11
Q

What is potassium important for?

A

Potassium is an intracellular cation and plays a fundamental role in acid-base regulation, fluid balance, muscle contraction and nerve conduction

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12
Q

What are sources of potassium?

A

Fruits e.g. bananas, vegetables like broccoli, parsnips and sprouts, pulses, nuts and seeds, fish, beef, chicken and turkey

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13
Q

How is iron stored in the body?

A

As ferritin

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14
Q

What correlates to total body iron stores?

A

The concentration of plasma ferritin. Small amounts of ferritin are secreted into plasma

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15
Q

Why does ferritin concentration rise upon infection/ inflammation?

A

Endotoxins up regulate ferritin expression

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16
Q

What are acute phase proteins?

A

APPs are a class of proteins whose plasma concentrations increase or decrease in response to inflammation in the acute phase reaction. Their serum concentration rises by >25% in response to inflammatory cytokines

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17
Q

What systemic effects do APPs play a role in mediating?

A

Fever, leucocytosis, increased cortisol, decreased thyroxine, decreased serum iron and many others

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18
Q

Name 2 positive APPs

A

C-reactive protein and fibrinogen

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19
Q

Name 2 negative APPS

A

Albumin and transferase

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20
Q

Name causes of iron deficiency

A

Menorrhagia, pregnancy. Bleeding in the stomach caused by NSAIDs, stomach ulcers, colitis, oesophagitis, piles or cancers of the bowel or stomach

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21
Q

Name symptoms of iron deficiency anaemia

A

Lethargy, shortness of breath, heart palpitations and pale skin

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22
Q

How is IDA diagnosed?

A

FBC tests to check red blood cell population

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23
Q

How is IDA treated?

A

Iron tablets. Drinking orange juice after taking them can help absorption of the iron

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24
Q

What are some side effects of iron tablets?

A

Constipation or diarrhoea, abdominal pain, angina, nausea and black stools

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25
Q

What can untreated IDA mean?

A

Greater risk of illness and infection- a lack of iron affects the immune system. Increased risk of developing heart or lung complications (tachycardia or heart failure). Greater risk of complications before and after birth in pregnant women

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26
Q

What is TEE= BMR + DIT + activity

A

total energy expenditure= basal metabolic rate + diet-induced thermogenesis + activity (± stress)

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27
Q

What does direct calorimetry measure?

A

The heat produced by a person confined in a steel chamber

28
Q

What does indirect calorimetry measure?

A

It estimates heat production by measuring gas exchange during respiration

29
Q

What are the 4 types of DRV?

A

Estimated average requirement
Reference nutrient intake
Lower reference nutrient intake
Safe intake

30
Q

What are 4 reasons for developing deficiencies in nutrients?

A

Inadequate intake
Reduced absorption
Increased losses
Increased demand

31
Q

What’s vitamin A for?

A

Vitamin A is a fat-soluble vitamin important for proper vision, immune system strength, reproduction and good skin health

32
Q

What is preformed vitamin A commonly found in?

A

Meat, fish, eggs and dairy products

33
Q

Where is provitamin A found?

A

Carotenoids in plant foods like red, green, yellow and orange fruits and vegetables

34
Q

Who are at highest risk of vitamin A deficiency?

A

Pregnant women, breastfeeding mothers, infants and children

35
Q

What 2 conditions may increase vitamin A deficiency risk?

A

Chronic diarrhoea and cystic fibrosis

36
Q

Give 8 symptoms of vitamin A deficiency

A

Dry skin and eyes, night blindness, infertility, delayed growth, throat and chest infections, poor wound healing and acne

37
Q

What does hypervitaminosis A cause?

A

Toxicity and vision changes, swelling of the bones, dry and rough skin, mouth ulcers and confusion

38
Q

What is xerophthalmia?

A

Abnormal dryness of the conjunctiva and cornea of the eye, with inflammation and ridge formation, typically associated with vitamin A deficiency

39
Q

Describe the overall process of digestion of food

A

Food is initially broken down by mastication and salivary amylases. At the stomach it’s acted on by gastric acid and pepsins. In the duodenum, bile salts emulsify fats and neutralise residual stomach acid. Chyme then passes the pancreatic ducts and is acted on by pancreatic enzymes. Most carbohydrate and protein is absorbed n the duodenum and jejunum. Fat-soluble vitamins are absorbed in the ileum. The terminal ileum is uniquely responsible for vitamin B12 absorption, as well as bile acids. Bacteria in the caecum ferment indigestible fibre. Most water and electrolytes are reabsorbed in the colon

40
Q

What is malnutrition?

A

An imbalance that can be undernutrition or overnutrition, or the 2 coexisting

41
Q

What are some consequences of malnutrition?

A 
Weakened immune system
Impaired wound healing
Hypotrophy
Hydration problems
Reduced fertility
Apathy and depression
Impaired temperature regulation
Micronutrient deficiencies
42
Q

Describe the metabolic response to starvation?

A

In prolonged starvation, basal metabolic rate falls around 30%. There’s a decrease in mass of metabolically active tissues. Protein losses are minimised

43
Q

What are the 3 stages to metabolic response to injury, trauma and sepsis?

A

The ebb phase, the flow phase and the anabolic (recovery) stage

44
Q

What happens in the ebb phase of metabolic response?

A

Energy reserves are mobilised, but the body struggles to use it. There’s decreased BMR and body temperature

45
Q

What happens in the flow phase of metabolic response?

A

This is the catabolism phase, where energy stores are broken down, BMR and body temperature are increased, there’s acute insulin resistance and visceral and SK muscle breakdown

46
Q

What happens in the recovery phase of metabolic response?

A

This is the anabolic phase, where energy stores are rebuilt. Nutritional therapy aims to increase protein synthesis and restore lean body mass

47
Q

How much energy does the brain use daily, and what for?

A

The brain uses 100-120g glucose a day. Over half the energy consumed is used for Na+ K+ ATPase activity to maintain membrane potential and for neurotransmitter synthesis

48
Q

How is glucose transported to the brain?

A

The brain lacks energy stores, so glucose is transported via GLUT3 proteins, which have low Km, so they’re saturated under most conditions

49
Q

What’s the main energy source for cardiac muscle?

A

Fatty acids, followed by lactate and ketone bodies

50
Q

How much triglyceride in kg would a 70kg man have?

A

15kg

51
Q

Where do we get most fatty acids?

A

From chylomicrons in our diet. The liver also makes FAs

52
Q

What glucose transporters are present in adipose?

A

GLUT4 (insulin-sensitive)

53
Q

What does the liver use as its main energy source?

A

Alpha-ketoacids

54
Q

Describe liver glucose metabolism

A

Glucose is transported into hepatocytes by GLUT2 and immediately phosphorylated by glucokinase. Glucose-6-phosphate from glycogenolysis is converted to glucose by the action of glucose-6-phosphatase and transported out of the cell and into the blood by GLUT2

55
Q

Describe muscle glucose metabolism

A

Glucose is taken up by GLUT4 (insulin-dependent). It’s then converted into G6P by hexokinase, so there’s low free glucose concentration in the cells. Glucose is mobilised from glycogen in exercise. Glycolysis of the G6P is a rapid source of ATP

56
Q

What’s the fuel for a sprint?

A

ATP directly powers myosin, converting chemical energy to movement, but muscle ATP stores are small. A 100m sprint is powered by ATP stores, glycolysis, glycogen and creatine phosphate. Muscle creatine phosphate is a small store of ATP

57
Q

How does creatine phosphate synthesise ATP?

A

Creatine phosphate + ADP -> creatine + ATP

58
Q

How long does creatine phosphate provide energy for in a sprint?

A

Around 5-6 seconds

59
Q

Approximately how much ATP is required for a marathon?

A

In the region of 150 moles

60
Q

How much ATP can body glycogen provide?

A

103 moles of ATP

61
Q

What’s used for energy for a marathon?

A

Glycogen stores and fat metabolism

62
Q

What is the Cori cycle?

A

A metabolic pathway via which lactate produced in anaerobic glycolysis in muscle is converted to glucose in the liver

63
Q

What happens in the post-absorptive phase several hours after a meal?

A

Blood glucose falls, insulin levels fall and glucagon levels rise. Phosphorylase a activity increases, as does glycogen breakdown. The drop in insulin reduces glucose uptake by muscle and adipose tissue

64
Q

What happens in early starvation (around 24 hours after the last meal)?

A

Glucose is released from the liver due to gluconeogenesis and glycogenolysis. Fatty acids are mobilised from adipose tissue. Glucose use falls as muscles switch to FA oxidation. Insulin drops, causing GLUT4 expression to fall, reducing glucose uptake

65
Q

What happens in intermediate starvation (3-20 days)

A

Glycogen stores are depleted. Increased lipolysis and ketogenesis- plasma ketone bodies rise significantly as glucose falls. There’s increased gluconeogenesis to maintain blood glucose. After 60 hours, FAs account for 75% of energy provision. After 8 days, ß hydroxybutyrate is raised 50-fold

66
Q

What happens in prolonged starvation (>3 weeks)?

A

ß hydroxybutyrate plateaus at 20 days. As the brain starts to move to using ketone bodies, the need for glucose falls from 100g a day to 40g a day. Other sources of gluconeogenic precursors are lactate and glycerol. Lactate is recycled by the Cori cycle. Glycerol and amino acids are oxidised. Proteins are broken down to amino acid precursors. Alanine is also formed by transamination of pyruvate and it’s released into the blood, where it’s uptaken by the liver and converted to glucose

CELL Yr 1 (13 decks)

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