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A1 Nutrition Flashcards

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1
Q

Nutrient

A

a chemical substance found in food that is used in the human body

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2
Q

Diet

A

total sum of all nutrients eaten

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3
Q

Essential nutrients

A 
cannot be synthesized by the body;
Fatty acids
Vitamins
Minerals
Amino acids (BUT non-essential amino acids can be sythesized by the body from other nutrients)
Water

Fat Velociraptor Markets Arty Water

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4
Q

Protein deficiency malnutrition

A

cause: inadequate supply of one or more ESSENTIAL AMINO ACIDS
key factor in the development of kwashiorkor
- swelling of the abdomen - one of the most visible consequences - caused by tissue fluid retention (oedema) due to a lack of plasma proteins in the blood
- skin flaking
- hair lacking pigmentation
- children: retardation of physical and mental development

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5
Q

Phenylketonuria (PKU) - cause

A

genetic disease
deficinecy / complete lack of enzyme TYROSINE HYDROXYLASE, because of a mutation of a gene coding for this enzyme
–> tyrosine hydroxylase catalyses the reaction of synthetizing PHENYLALANINE (an essential amino acid) into TYROSINE (non-essential)
—> as phenylalanine cannot be converted into tyrosine, it is converted into PHENYLPYRUVIC ACID, causing high leve;s of KETONES in blood

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6
Q

Phenylketonuria - consequences

A

retarded mental and physical development
skin rashes
eczema

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7
Q

Phenylketonuria - diagnosis

A

simple blood test for the levels of phenylalanine (soon after birth)

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8
Q

phenylketonuria - treatment

A

early diagnosis + special diet (low in phenylalanine, should include fruits, grains, vegetables, and special milk)
can prevent most harmful effects

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9
Q

Fatty acids

A
  • all have a carboxyl group (COOH) and a hydrocarbon chain

- vary in the bonding between the carbon atoms and the number of hydrogen atoms bonded to the carbon

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10
Q

Saturated Fatty Acids

A

all carbon atoms connected by a SINGLE covalent bond

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11
Q

Unsaturated fatty acids

A 
Monounsaturated = 1 double bond
Polyunsaturated = multiple double bonds

Cis-unsaturated - hydrogen atoms bonded to carbon atoms on the same side of a double bond
Trans unsaturated - hydrogen atoms bonded to carbon atoms on opposite sides of a double bond

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12
Q

Health consequences of a diet rich in saturated fatty acids

A

high levels = high Coronary Heart Disease mortality
BUT correlation =/= causation - it could be e.g. low fiber content of most diets high in saturated fatty acids that causes CHD

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13
Q

Health consequences of a diet rich in Cis-monounsaturated fatty acids

A

Mediterranean diet - rich in olive oil (Cis-monounsaturated fatty acids)
rates of CHD low
BUT apart from the amount of fats in diets, other factors vary between people, too

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14
Q

Omega-3 fatty acids

A

Much of the eye and brain tissue is made up of long-chain fatty acids, synthesized in body from essential fatty acids, including Omega-3 fatty acids

BUT no clear evidence that Omega-3 dietary supplements improve brain and eye development

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15
Q

trans fatty acids

A

high levels = high incidence of coronary heart disease;

  • analysis has shown that other factors cannot explain this correlation, leaving trans fats as the only risk factor (cause)
  • autopsies after death of CHD: most of fat in arterial plaque = trans fat
  • raised LDL and reduced HDL levels, associated with CHD
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16
Q

Minerals

A

usually INORGANIC elements

in ionic form (e.g. NA+)

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17
Q

Vitamins

A

ORGANIC compounds made by plants and animals

e.g. vit. A

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18
Q

Recommended daily intake

A

the amount of a nutrient that should be consumed per day to ensure health

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19
Q

Recommended daily intake of vitamin c

A

50 mg

  • probably sufficient
  • eliminates the risk of rebound malnutrition, associated with higher intakes (body adjusts to high rates of intake by excreting the excess, so that the intake drops to normal levels BUT when the intake is lowered such high excretion continues, causing SCURVY)

1000 mg

  • Linus Pauling, Nobel-winning chemist, argued to increase the RDI to such level
  • reason: it may give protection against cold (upper respiratory tract infection), although there’s little evidence for that
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20
Q

Methods to determine the recommended daily intake of vit. C (2)

A

1) GUINEA PIGS fed with diets of different amounts of vit. C for a trial period
- level of vit. C in blood plasma and urine measured
- strengths of collagen in bone and skin measured to test for scurvy
- results used to estimate the amount of vit. C by humans per kilogram of body tissue

2) VOLUNTEERS
during WW2 experiments conducted in Britain on a group of conscientious objectors to military service
- 6 weeks: all volunteers given a diet lacking vit. C + a daily supplement of 70 mg
- 8 months: divided into 3 groups and given 70mg, 10mg, or 0mg vit. C per day
- tests: skin cuts to test wound healing
results:
- 70 mg, 10 mg - no scurvy
- 0 mg - developed scurvy
suggest that 10 mg vit. C is sufficient, but in most countries much higher daily intakes are recommended to give a safety margin so that the risk of scurvy is minimized + to consider variations between individuals in their general health and in their ability to absorb and use vit. C

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21
Q

Source of vit. D

A 
oily fish
eggs
milk 
butter 
cheese
liver
NOT IN PLANT PRODUCTS, but often added to soya milk or breakfast cereals
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22
Q

synthesis of vit. D

A
  • can be synthesized in skin, but only in presence of ultra-violet light (UV)
  • in winter: intensity of UV light too low in high latitudes to allow for vit. D synthesis, BUT the liver can usually store enough vit. D during summer to avoid winter deficiency
  • inhibited by:
    • avoiding exposure to sunlight
    • covering skin with thick clothing
    • applying sun creams to block UV light
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23
Q

Malignant melanoma

A
  • form of skin cancer
  • can be fatal
  • UV light can cause mutations, which turn cells into tumor cells

– one should always find a delicate balance between over-exposure and under-exposure to UV light

24
Q

Deficiency of vit. D

A

skeletal deformities, slower growth due to calcium deficiency (rickets) - vit. D is required to allow calcium uptake

25
Q

Artificial supplementation

A

can be used to ensure that a population has adequate access to essential nutrients, even if the supply of naturally-containing foods is limited

26
Q

Iodine

A

Iodine is essential in production of thyroxine, a hormone responsible for regulating metabolic rate in the body and therefore body temperature

27
Q

Iodine Deficiency Disorder (IDD)

A
  • swelling of the thyroid gland in the neck
  • during pregnancy: children born with permanent brain damage
  • mental development and intelligence impaired
  • 43 mln people worldwide had brain damage due to IDD; 11 mln of them suffer from a severe condition called CRETINISM (UNICEF, 1998)
28
Q

Examples of artificial dietary supplementation (2)

A

Worldwide supplementation of edible salt with iodine has greatly reduced incidence of iodine deficiency disorders, at a very low cost (5 cents per person per year) and with minimal objection

Genetic engineering is also being used to produce enhanced crops, such as beta-carotene rich golden rice, though there is more ethical debate concerning these methods

29
Q

Dietary fiber

A
  • components of foods that cannot be digested by the body
  • provides BULK, ensuring continuous and smooth passage of materials through intestines
  • stimulates peristaltic contractions to enable the digestive system to pass food
  • helps regulate blood sugar
  • reduces blood cholesterol
  • helps prevent constipation
30
Q

Energy content of carbohydrates, proteins, and fats

A

Protein: 1,720 kJ per 100g
Carbohydrate: 1,760 kJ per 100g
Fat: 4,000 kJ per 100g

31
Q

Main dietary sources of energy in different ethnic groups

A
  • Rice - tropical and temperate areas (China, Japan)
  • Wheat - temperate climate (Ukraine, Poland; slavic cultures)
  • Cassava - tropical areas with high rainfalls - Yoruba tribe in Nigeria
  • Fish - where crop growth is impossible (Inuits in the far north of America)
  • Meat - ethnic groups with nomadic lifestyle (Maasai in Kenya)
32
Q

Health consequences of diet rich in carbohydrates

A
  • increased risk of obesity, type II diabetes, tooth decay (sugar)
  • carbs that cannot be digested (cellulose) count as fiber, which has many health benefits
33
Q

Health consequences of diet rich in fats

A
  • increased risk of obesity
  • positive correlation between fat intake and CHD (BUT causes of CHD are very complex, other genetic and dietary factors can also play a role + type of fat is very significant)
  • cis- fats promote reducing harmful cholesterol
34
Q

Health consequences of diet rich in proteins

A
  • increased risk of kidney stones, gout
  • reduced kidney function
  • osteoporosis (due to increased intake of animal proteins)
  • BUT no controlled trials done - no proof
  • high-protein diets advertised as slimming diets, but considered as harmful by WHO as other nutrient rich foods are avoided, leading to malnutrition (Dukan diet)
35
Q

Appetite control center

A
  • location: hypothalamus in brain
  • role: makes us feel satiated when we’ve eaten enough food
  • not functioning properly may lead to obesity

Hormonal stimuli:

  • insulin - secreted by the pancreas when blood glucose is high
  • PY 3-36 - secreted by the small intestine when there’s food inside
  • leptine - secreted by adipose tissue as the amount of stored fat increases
36
Q

Body Mass Index

A
  • used to assess whether one’s body mass is at a healthy level
  • mass in kg/(height in m)^2
  • limitations: race, gender, and age aren’t considered; no distinction on body fat/muscle composition

below 18.5 - underweight

  1. 5 - 24.9 - normal
  2. 9 - 29.9 - overweight
  3. 0+ - obese
37
Q

Clinical obesity - consequences

A

Clinical obesity = excess of body fat
caused by consuming more energy than is used in activity, with the excess stored as body fat

consequences:
reduced life expectancy
high risks of CHD, diabetes, heart attacks, andstrokes.

The obesity epidemic is on the increase globally, in developed nations in particular.

38
Q

Clinical obesity - reasons

A
  • foods with high content of fat and/or sugar are cheap and widely available
  • economic growth, cheaper foods = larger portions
  • automated means of transport
  • physically undemanding jobs
  • home duties mostly performed by machines
  • less active ways of spending leisure time
  • sedentary lifestyle
  • genetic factors strongly linked to addiction, compulsive eating, heart disease, diabetes or problems with appetite control mechanisms

in general: more food is being eaten, but less energy is being used up on a daily basis

39
Q

Anorexia nervosa - outline

A

eating disorder in which the patient severely limits food intake

It is a medical condition with mental and physiological causes.

It is closely associated with body image and meeting aesthetic standards imposed by culture.

It is most common in females, but does occur in males.

Usually starts in mid-teens

40
Q

Anorexia nervosa - consequences

A
  • not enough carbohydrate or fat for cell respiration -
    proteins are broken down;
  • general malnutrition due to a lack of one or more essential nutrients
  • hormone imbalance: no menstrual cycles, risk of infertility
  • mental health: emotional imbalance, phobias, poor concentration
  • slow heart rate and poor circulation
  • lowered blood pressure
  • loss of muscle mass
  • osteoporosis
  • dry skin
  • thin, brittle hair, even hair loss
  • growth of fine hair all over the body
  • death a result of prolonged, severe starvation
  • social consequences (family and friends): anxiety about the ill person, feeling of guilt about difficult relationships, powerlessness when the treatment seems to fail
41
Q

Human milk

A

Carbohydrate: lactose
Protein source: 65% human whey proteins, 35% casein
Fatty acids: human butterfat
Antibodies: present only in the first milk - colostrum

42
Q

Artificial milk

A

Carbohydrate: lactose or glucose polymers
Protein source: 18% bovine whey, 82% bovine casein or soya proteins
Fatty acids: palm, coconut, or soil oils
NO ANTIBODIES

43
Q

Benefits of breastfeeding (6)

A

+ colostrum and early milk have ANTIBODIES, protecting the newborn against infections
+ prevents the allergies to proteins in bovine milk or soya, which can develop when babies receive artificial milk
+ promotes bonding between mother and baby
+ acts as a natural birth-control method, reducing the chance of conception when the mother is lactating - more time between the birth of one child and the next
+ is naturally sterile = safer to use in areas where it’s impossible to sterilize water to prepare artificial milk
+ helps mother loose weight after pregnancy and avoid post-partum depression

44
Q

Type II Diabetes - overall

A

Diabetes mellitus
adult-onset diabetes
target cells become insensitive to the insulin secreted by pancreas - mechanisms controlling blood glucose level are ineffective

45
Q

Type II diabetes - causes

A
  • diets rich in fat and low in fiber
  • obesity due to overeating and lack of physical activity
  • genetic factors affecting the metabolism of fat
    ( all these factors only increase the risk; causes of type II diabetes aren’t entirely understood)
  • genetics: rates of type II diabetes largely vary between ethnic groups (2% in China, 50% in Pima Indians)
46
Q

Type II diabetes - symptoms

A
  • usually mild, develop gradually over a period of years - not always diagnosed quickly
  • elevated levels of blood glucose
  • tiredness
  • increased appetite and body mass loss
  • production of large volumes of urine
  • dehydration and thirst
  • increased appetite (polyphagia) and urine production
  • blurred vision
  • slow wound healing
47
Q

Type II diabetes - dietary advice

A
  • reduce intake of saturated fats
  • reduce intake of sugar (sweets, snacks, soda)
  • more food that are high in fiber, including vegetables and fruits
  • regular small meals throughout the day, each meal with a moderate amount of carbohydrates to prevent high blood sugar levels after a large meal
  • eating carbohydrates with a low glycemic index (GI) - are digested and absorbed slowly, so glucose is also released slowly over a longer period of time
  • learn how to read and interpret food labels, to avoid unsuitable foods
48
Q

Eating animal products - overview

A

Animal products are a major component of the human diet, though they are not without their ethical concerns

populations grow - demand for food increases, including meat and animal products

Concerns arise with regard to ethical treatment of animals and environmental sustainability.

49
Q

Issues concerning eating meat

A

Advantage: source of proteins, some vitamins, and minerals
Ethical concerns:
- animal welfare issues, poor living conditions for farm animals, pain and suffering in slaughter
- overuse of medication = development of multiple antibiotic resistance in bacteria and new strains of viruses
- use of growth hormones: may affect human body (e.g. too early onset of puberty)
- no longer sustainable: deforestation, increased methane emission, pollution

50
Q

Issues concerning eating fish

A

Benefit: source of proteins and Omega-3 fatty acids
Ethical concerns:
- overfishing = many fish species endangered
- concerns about biomagnification of toxins in food chain and its harmful consequences to human health

51
Q

Issues concerning eating milk

A

Benefit: source of proteins, calcium, energy
Concerns:
- animal welfare
- not sustainable - huge demand for land and water to grow crops to feed livestock

52
Q

Issues concerning eating eggs

A

Benefit: source of proteins and fats
Concerns:
- animal welfare
- excessive egg yolk consumption = cholesterol health risks
- battery-farmed chicken fed with hormones
- small, dirty spaces with poor sanitation - disease can spread easily
- male chicks are routinely killed as they don’t produce eggs

53
Q

Issues concerning eating honey

A

Benefit: natural sweetener + bees pollinate flowers
Concerns:
- farmed bees compete with local insect and bee populations for nectar
- artificial selection of bees can lead to a genetic shift in bee populations

54
Q

Cholesterol

A
  • steroid
  • mainly found in animal products
  • essential component of membranes
55
Q

Reducing cholesterol in diet

A
  • 10% increase in blood cholesterol = 30% increase in risk of CHD
  • BUT other studies suggest that total blood cholesterol is less significant that levels of cholesterol in LDL (low density lipoprotein), which rise due to high intake of saturated fats
  • high cholesterol diet = atherosclerosis (deposition of fatty plaques and hardening of the arteries)
56
Q

Food miles

A
  • measure of how far food have been transported from where it was produced to where it is eaten
  • increased food miles = air pollution, traffic congestion, release of greenhouse gases
  • refusal to buy products with high food miles - some consumers hope that supermarkets will start selling locally produced foods
  • others are not concerned with food miles - they want continuity of supply throughout the year and maximum choice of world foods
  • environmentalists point out other energy costs of food production (like use of fertilizers, etc.) - overall energy cost of lamb produced in New Zealand using low energy input systems and transported around the world by sea to the UK may be lower than energy costs of locally produced lamb
  • during famines, food transport is justifiable on humanitarian grounds regardless of food miles

Biology (9 decks)

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