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Biology Option D > Human Nutrition > Flashcards

Human Nutrition Flashcards

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1
Q

What are essential nutrients?

A
  • Nutrients that are required for normal physiological function that cannot be synthesised by the body
  • Obtained from dietary source
  • Nutrients: chemical substance
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2
Q

Into what categories are essential nutrients divided into?

A
  • Minerals, Vitamins, Amino Acids, Fatty acids
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3
Q

What are non-essential nutrients and give examples?

A
  • Nutrients that can be produced by the body
  • E.g. fructose
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4
Q

What is Malnutrition?

A
  • A health conditions caused by a deficiency, an imbalance or an excess of nutrients
  • Due to overnutrition or undernutrition
  • Common signs: stunted growth, wasted (too thin), obesity
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5
Q

What are essential fatty acids? Give two examples and their role in the body.

A
  • Cannot be synthesised by the body
  • Omega-3 needed for controlling blood clotting and building cell membranes in the brain
  • Omega-6 lower LDL cholesterol and reduce inflammation, protect against heart disease
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6
Q

What are sources of fatty acids?

A
  • Omega-3 in fatty fish, vegetable oils, brussel sprouts, walnuts
  • Omega-6 in corn, soybean oils
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7
Q

What are essential amino acids? What can a lack of them effect?

A
  • 20 amino acids, 9 are essential to humans
  • A shortage of these amino acids will prevent the production of specific proteins
  • Protein deficiency, health effects will vary on the type lacking
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8
Q

What are conditionally essential amino acids? Give an example.

A
  • Amino acids that can be synthesised by the body but at rates lower than requirements (pregnancy) are essential
  • Tryosine: can be produced by human body when phenylalanine (amino acid) is present
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9
Q

In what processes are amino acids involved in?

A
  • Protein synthesis, pH balance, behaviour, stress response, reproduction, metabolic regulation, growth and development, etc.
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10
Q

What are vitamins? Into what categories are they put into?

A
  • Chemically diverse organic molecules that cannot be synthesised by the human body, essential
  • Divided into water-soluble and fat-soluble vitamins
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11
Q

What happens with excess vitamins?

A
  • Water soluble: excess lost in urine (B, C)
  • Fat soluble: stored within the body (A,D,E,K)
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12
Q

What are dietary minerals? Give examples.

A
  • They are essential chemical elements
  • Basically elements: Ca, Mg, Fe, P, Na, K, Cl
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13
Q

How are minerals important in human development? Give examples.

A
  • Ca, P, Mg needed in teeth and bones
  • Na, K, Cl transmission of never impulses
  • Iron important for haemoglobin
  • Iodine needed for thyroid hormones, increase metabolic rate, regulate bone growth
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14
Q

How is appetite controlled?

A
  • By hormones produced in the pancreas, stomach, intestines, adipose tissue
  • Hormones send messages to appetite control centre (ACC) of brain, hypothalamus
  • Ghrelin released in empty stomach, stimulate appetite
  • Peptide PYY3-36 in full stomach, inhibit appetite
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15
Q

What is the Body mass index (BMI)?

A
  • Indication whether a patient is within normal parameters of mass or weight
  • Also consider muscular proportion and adipose tissues
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16
Q

What is the formula of BMI? What are the boundaries?

A

= mass/ (height)^2 (kg/m^2)
- Overweight of 25.1-29.9
- Obese: <30.0

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17
Q

What causes obesity?

A
  • Clinical obesity, excess in body fat and caused by increased energy intake and decreased energy expenditure (exercise)
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18
Q

What are overweight people more prone to? 1.0

A
  • More likely to have hypertension (high blood pressure)
  • More strain on heart to pump blood, faster heart rate
  • May lead to atherosclerosis, narrow blood vessels
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19
Q

What are overweight people more prone to? 2.0

A
  • Type 2 diabetes, when fat, liver and muscle cells become unresponsive to insulin
  • Beta cells in the pancreas still produce insulin, develop insulin resistance
  • Insulin receptors on the cells are no longer stimulated by insulin
  • Occurs by progressive overstimulation of cells, high sugar intake, higher risk
20
Q

What are causes of type 2 diabetes?

A
  • Diet consisting of lots of fats, low fiber, lack or exercise or Genetic make up
21
Q

What are symptoms of diabetes?

A
  • Increased glucose levels in urine or blood
  • Frequent urination, excessive thirst, tiredness and fatigue, weight loss
22
Q

What is starvation?

A
  • Severe restriction of daily energy intake, significant loss of weight
  • First glycogen reserves used up
  • Body tissues such as muscle and fat broken down as an energy source, catabolysis
  • Muscle loss and organ damage, death
23
Q

What is anorexia?

A
  • Anorexia nervosa: type of anorexia, eating disorder, irrational fear of weight gain
  • Food intake limited, do not lose appetite
  • Unrealistic body perception
  • Excessive weight loss
  • Reduced blood pressure, slower heart rate, absence of menstrual cycle
  • Breakdown of heart muscle
24
Q

What is Ascorbic acid and why is it needed? Is it essential for humans?

A
  • A form of vitamin C
  • Required for metabolic activities
  • Production of collagen (protein)
  • Skin, connective tissues, tendons, blood vessels
  • Can be made by most mammals, monosaccarides
  • However it is sssential for humans, need dietary supply
25
Q

What is the deficiency of Vitamin C called? What is a source?

A
  • Scurvy, general weakening of normal immune function
  • Sources: citrus fruits
26
Q

What are symptoms of scurvy?

A
  • Bleeding gums, loose teeth (lack of collagen)
  • Lack of energy (extreme fatigue)
  • Mood swings/depression
  • Chronic joint pain
  • Suppressed immune system
  • Slow wound healing
27
Q

What is the recommended daily amount (RDA) of Vitamin C?

A
  • 50mg per day for humans
28
Q

What is Phenylketonuria (PKU)?

A
  • Genetic disease, autosomal recessive (2) disease caused by a mutation to the gene encoding the enzyme phenylalanine hydroxylase (PAH)
  • PAH usually converts phenylalanine into tyrosine
  • PKU makes it unable to convert phenylalanine into tyrosine
  • PKU accumulates in the body
29
Q

What are causes of PKU?

A
  • Intillectual disability
  • Reduced growth of the head
  • Lack of skin and hair pigmentation
  • Seizures
30
Q

How and when must PKU be diagnosed?

A
  • Within 24 hours of birth with the Guthrie test (blood test)
31
Q

How is PKU treated?

A
  • A strict diet that restricts the intake of phenylalanine to prevent its build up
  • BAD: protein, meat, dairy, wheat, nuts
    GOOD: fruits, grains, vegetables, formula milk
  • Supplemented medical formula with essential amino acids
32
Q

For what is Vitamin D needed? What can a deficiency cause?

A
  • For absorption of calcium in the digestive system
  • Calcium needed to build health bones
  • Deficiency causes soft or malformed bones (osteomalacia) or rickets, bone mineralization
33
Q

What are the two most important roles of Vitamin D in humans?

A
  • To maintain skeletal calcium balance by promoting calcium absorption in the intestines
  • Maintaining calcium and phosphate levels for bone formation
34
Q

How is Vitamin D synthesised? What are dietary sources of it?

A
  • Naturally by the body when human skin is exposed to UV light
  • Found in oily fish, egg yolk, liver, dairy products, or supplements
  • It is not strictly a vitamin, since the body can synthesis it itself
35
Q

In what units is food measured in? Give the conversion between the two units.

A
  • Energy of food measured in kilojoule (kJ) or kcal
  • 1 kcal = 4.184 kJ
36
Q

How do you calculate the recommended daily allowance (RDA) for children?

A
  • Calories: 120-160 kcal/kg of weight (in kJ)
  • Protein: 10-15% of the total caloric value (TCV), 3g/kg of weight
  • Carbohydrates: 35-60% of the TCV
  • Fats: 35-50% of the TCV
  • Fiber: age in years + 5g
37
Q

What are the excepted values for daily intake for men and women between ages 31 and 50?

A
  • Men: 11,300 kJ
  • Women: 8,800 kJ
  • May vary depending on how active ones lifestyle is
38
Q

What might dietary requirements depend on?

A
  • Age, gender, activity levels and medical conditions
39
Q

How do you determine the energy content in food?

A
  • Burning a known mass of the food
  • The food is placed under a test tube with water
  • The heat generated is absorbed by a known volume of water
  • The rise in temperature is recorded
  • Next apply formula
40
Q

What is the formula for calculating the energy?

A
  • temperature rise x mass of water x (specific heat capacity of water (4.184) or 1 calorie/g°C)
41
Q

What does cholesterol do?

A
  • A compound involved in the production of bile acids, Vitamin D and hormones (progesterone and oestrogen)
  • Protects the membrane integrity of animal cells
  • Presence in cell membrane allows the cells to change shape
42
Q

What disease can cholesterol cause when found in blood?

A
  • An indicator of the risk of coronary heart disease
43
Q

What are the recommended levels of blood cholesterol?

A
  • <200 mg dm^-3 = lower risk of CHD
44
Q

What factors increase the risk of developing CHD?

A
  • High levels of LDL
  • Genetic factors or lack of mobility
45
Q

How can blood cholesterol be lowered?

A
  • Drugs such as statin
  • It inhibits HMG-CoA reductase which catalyses the second step in the pathway from Acetyl CoA to cholesterol

Biology Option D (6 decks)

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