D1 Human Nutrition Flashcards
what is an essential nutrient?
chemical substance which cannot be synthesised by the body and must be ingested in diet
what is a non-essential nutrient?
nutrients which can be made by the body (eg.carbs)
what is malnutrition?
health condition caused by deficiency, imbalance or excess of nutrients in diet
how can you estimate the energy content of food?
using a calorimetry
how does calorimetry work? (2)
- combustion of food source causes stored energy to be released as heat which raises temperature of water
- amount of energy to raise 1g of water by 1 degrees is 4.18J (SHC)
what is the calorimetry equation?
energy(J) = mass of water (g) x 4.2 (J/goC) x temp increase (oC)
source of error for calorimetry?
energy lost to the environment
what should be done to avoid error in a calorimetry experiment? (2)
- food should be burnt at constant distance from water
- initial temp and volume should be kept constant
what are the 3 sources for energy?
carb - easier to transport and digest
lipids - stores more energy per gram, harder to digest and transport
proteins - produces nitrogenous waste which must be removed
how many different types of amino acids are there?
20
what 3 kinds of things can amino acids be?
- essentail
- non essential
- conditionally non-essential
what are essential amino acids?
cannot be produced by body so must be in diet
what are non-essential amino acids?
can be produced by body and are not required in diet
what are conditionally non-essential amino acids?
produced by body at lower rates than certain conditional requirements
what is PKU?
autosomal recessive disease caused by mutation to gene encoding phenylalanine hydroxylase
what is the function of phenylalanine hydroxylase (PAH) and what happens to bepope with PKU? (3)
- converts excess phenylalanine into tyrosine
- peeps w/ PKU convert excess phenylalanine into phenylpyruvate (phenylketone)
- results in a toxic build up of phenylketone in blood and urine
what occurs if you have untreated PKU? (3)
- brain damage, mental retardation
how is PKU treated?
- low protein diet
- medical formula that contains precise quantities of essential amino acids
what are 2 essential (cis)-polyunsaturated fatty acids?
- alpha-linolenic acids
- linoleic acids
(humans lack enzyme required to introduce double bonds at required positions of carbon chain)
What are vitamins?
Organic molecules with complex chemical substances
What is absorbed acid?
Form of vitamin C
- potent antioxidant and immune function
- synthesis of collagen and lipoproteins
What occurs if one has a deficiency in vit c? (2)
Scurvy
Weak immune system
What are the symptoms if of scurvy? (6)
Skin discoloration
Hemorrhaging
Anemia
Dental issues
Exhaustion
Swelling joints
What is vit D used for?
Absorption of calcium and phosphorus
What occurs if you do not have enough vit D?
(Calcium and phosphorus are excreted by body)
- rickets
- osteamalacia
Where is vitamin D stored?
In liver
What are the symptoms of vitamin D deficiency?
Bone fragility
Atrophy (bone weaken)
Dental problems
Growth retardation
Enlargement of liver
Skeletal deformities
Why are minerals important for in humans? (3)
- major constituents of teeth and bones
- important of body fluids
- cofactors for specific enzymes or components of proteins/hormones
How are minerals important in plant development? (3)
- magnesium in chlorophyll
- potassium inorganic salt in sap
- calcium for plant root and shoot elongation
What is the process of appetite? 4
From hypothalamus
- stretch receptors in stomach and intestines are activated
- adipose tissue release hormone in response to fat storage
- pancreases will release hormones in response to change in blood sugar concentrations
What are the hormones that trigger hunger response?
Ghrelin (stomach)
Glucagon (pancreas)
What are the hormones that tigger satiety response? (2)
- lepton (adipose tissue)
- CCK (intestine)
How does hypertension develop in obese people? (4)
Suffer from hypertension (high blood pressure)
- excess weight more strain on hear to pump blood -> faster heart rate and high blood pressure
- high cholesterol lead to arthesclerosis (narrow blood veins) which raises blood pressure
- can develop CHD
How does type II diabetes develop in obese people? (3)
- occurs when fat, liver and muscle cells become unresponsive to insulin (insulin insensitivity)
- result of diet rich in sugar -> causes over0stimulation of cells by insulin
- overweight individuals who have high sugar intake develop type II diabetes
What is obesity?
Significant excess in body fat caused by increased energy intakes and decreased energy expenditure
What is starvation?
Severe restriction of daily energy intake leading to signifiant loss of weight
What is anorexia nervosa? (4)
Eating disorder which individuals severely limit food intake
- body breaks down heart muscle
- blood flow is reduced and blood pressure decreases
- heart may develop dangerous arrhythmias (get smaller)
What is the recommended daily intake for adults?
8400 kJ (2000kcal)
