Energy metabolism Flashcards
1
Q
Name two things failure of energy metabolism can lead to?
A
- obesity
2. protein-energy malnutrition and cachexia (anorexia, cancer, infections).
2
Q
What is the first law of thermodynamics?
A
Energy cannot be created or destroyed, but it can be only transformed from one form to another.
3
Q
How do plants depend on energy?
A
From the sun to synthesise proteins, carbohydrates and fats.
4
Q
What are 3 different forms of energy?
A
- Chemical (synthesis of new macromolecules)
- Mechanical (muscular contraction)
- Electrical (maintenance of ionic gradients across membranes)
5
Q
What is the basic concept of energy balance?
A
Energy intake+Energy stores-Energy expenditure
6
Q
What do we call the heat energy that is no longer available for work?
A
Entrophy
7
Q
What is a colorie?
A
The amount of heat required to raise the temperature of 1g of water by 1 degree.
8
Q
What are the 3 forms of energy storage in our body?
A
- Fat (major energy storage)
- Glycogen (short-term energy/carbohydrate reserve)
- Protein (rarely used for energy except in severe cases of starvation and wasting conditions)
9
Q
What is the ‘494’ rule used to calculate energy from food?
A
1g of carb - 4 kcal
1g fat - 9kcal
1g protein - 4 kcal
10
Q
What is the Basal Metabolic Rate (BMR)?
A
The energy to maintain basic physiological functions (heartbeat,respiration).
11
Q
How can the BMR be measured?
A
After a 12 hour fast with no stimulation.
12
Q
What is the difference between BMR and Resting Metabolic Rate (RMR)?
A
3% higher energy expenditure in RMR than BMR.
13
Q
What type of people have a higher RMR?
A
Physically active people.
14
Q
what is diet induced thermogenesis (DIT)?
A
The thermic effects of food.
15
Q
What percentage of DIT is burnt off as heat?
A
10%
16
Q
Which two types of macronutrients contain the highest DIT?
A
Protein and carbohydrate
17
Q
What is the most variable part of energy expenditure?
A
Physical activity
18
Q
Name two other types of energy expenditure?
A
- Drug induced thermogenesis (smoking, caffeine)
2. Psychological thermogenesis (stress/anxiety)
19
Q
Name three factors to take into account in energy requirements?
A
- Disease/injury (burns,cancer)
- Physical activity (impaired/reduced)
- Underfeeding/overfeeding critically ill patients
20
Q
What is the glucostatic theory about?
A
Food consumption is triggered by decreased glucose availability to the tissues.
21
Q
Describe the three factors regulating food intake?
A
- Appetitie (psychological desire to eat)
- Hunger (subjective feeling that determines when food consumption is initiated)
- Satiety (state of inhibition over eating that leads to the termination of a meal)
22
Q
How does the CNS regulate food intake?
A
Hypothalamus regulates feeding behaviour.
23
Q
Which hormone is released by the duodenum for feeling satiety?
A
Cholecystokinin (CCK)
24
Q
Which hormone suppresses appetite and carbohydrate cravings?
A
Serotonin
25
Which hormone might be involved in food cravings?
Dopamine
26
What hormone levels are elevated in obese people and what is it produced by?
Leptin
| Fat cells
27
Name the 4 external factors influencing appetite and hunger.
1. Meal pattern (composition, smell, sight)
2. Climate
3. Emotional factors stress)
4. Disease states (anorexia, trauma, infections)
28
Name 4 external factors influencing appetite?
1. Specific learned likes and dislikes
2. Taste, palatability of foods
3. Cultural practices
4. Drugs, hormones
29
Suggest 4 factors that can stimulate people to eat when they are not hungry.
1. Eating in front of TV
2. Eating with people
3. Stress
4. Depression
30
What is sensory-specific satiety?
Foods that are similar in taste or appearance to those recently consumed are rated less pleasant than newly presented foods.
31
What is one of the key factors controlling food intake?
Energy density - available energy per unit of weight.
32
List 3 types of food with highest energy density.
1. meats
2. most dairy products
3. processed foods
33
What do high energy foods contain lots of?
fat, sugar, starch
34
What do low energy foods contain lots of?
water, protein, fibre
35
Why are foods with lower energy density more satiating?
The high fibre and bulk in these foods stimulate mechanoreceptors without excessive calorie consumption.
36
Consumption of bulky, low energy-dense food can help with?
weight loss
37
Freedom from hunger is a regulatory issue in food policy. What does this mean?
1. Considered to be a basic human right.
2. Adequate nutrition and quality/safety of food supply critical for basic human dignity.
3. Also essential for productivity, health and quality of life.
38
Which organisations work together to address food safety issues along the entire food chain from production to consumption?
World Health organisation (WHO) & Food and Agricultural Organisation of the United Nations (FAO)
39
Why is it necessary to link food monitoring data to public health monitoring?
In order to determine the diet-food relationship to any of the major public health problems within a population.
40
According to therapists what is the main interest of food production and policy?
How the totality of food production can be altered to improve the balance of nutrients available to the population.
41
How can demand driven options alter population nutrient intake and involve nutrition promotion strategies?
label information
media campaigns
work-based programmes
42
What is the role of the Food Standard Agency (FSA)?
The policies outlining the food production from Farm to Fork and is responsible for food safety and hygiene, labelling and food law enforcement across the UK.
43
What does fortification involve?
The addition of nutrients to foods irrespective of whether or not the nutrients were originally present in the food.
44
Name two food sources that are fortified by UK law?
margarine and breakfast cereals
45
How can fortification help countries where intakes of certain nutrients are low?
It can help reduce nutrient deficiency diseases.
46
Give an example of a food source which has to undergo restoration (nutrients lost during food processing)?
White and Brown flour
47
What is added to margarine as a substitution?
Vitamin A and D to compare levels to butter.
48
What are some of the potential effects of fortification?
1. High intakes of folic acid from fortified foods or supplements may mask vit B12 deficiency.
2. It can interfere with the absorption of other micronutrients.
3. It may change the taste, colour and texture of some foods.
49
What is one of the largest public health problems regarding food safety?
Foodbourne illnesses caused by microorganisms.
50
Which are vulnerable groups of people to catch foodbourne illnesses?
1. Elderly
2. Children
3. Pregnant/lactating women
4. Immunocompromised individuals (HIV/AIDS, cancer)
51
How did beef become contaminated by the BSE virus?
Cattle feed prepared from the bovine tissues such as brain and spinal cord was contaminated by the BSE agent.
52
Which bacteria is the major cause of diarrhoeal illness in humans and what is it caused by?
Campylobacters responsible for E-Coli, listeria and salmonella caused by contaminated chicken.
53
What are the most common symptoms of campylobacter infections?
diarrhoea (frequently with blood in the faeces), abdominal pain, fever, headache, nausea and/or vomiting.
54
Name some complications with campylobacter infections?
bacteraemia, hepatitis, pancreatitis
55
How can we prevent campylobacter infections?
Control measures at all stages of the food chain.
56
What four precaution measures can we use to prevent campylobacter infections?
1. Cook food properly and serve hot.
2. Avoid ice unless you are sure it is made from safe water.
3. Wash hands thoroughly and frequently using soap.
4. Wash fruits and vegetables
57
What is shingella?
Genus of bacteria that is a major cause of diarrhoea and dysentery (blood and mucus in stool).
58
How can you differentiate the symptoms caused by shingella?
Rectal pain
59
How is the shingela bacteria transmitted?
By ingestion of contaminated food or water or through person to person contact.
60
What is escherichia coli (E.Coli)?
A bacterium commonly found in the gut of humans and warm blooded animals.
61
How is E.Coli transmitted to humans?
Through consumption of contaminated foods such as raw or under cooked ground meat products and raw milk.
62
What are the symptoms that can progress in E. Coli?
Bloody diarrhoea (haemorrhagic colitis)
63
What is the incubation period for E.Coli?
It can range from 3-8 days with a median of 3-4 days.
64
What life threatening disease can E.Coli lead to in elderly and young children?
Haemolytic Uraemic Syndrome (HUS)
65
What are the characteristics of salmonella symptoms?
Acute onset of fever, abdomincal pain, diarrhoea, nausea and sometime vomiting. In some cases, particularly the very young and in the elderly, the associated dehydration can become life threatening.
66
Which group of people are most at risk with listeria?
Pregnant women which can lead to miscarriage.
67
Which foods are most at risk of being infected by listeria?
Pate, soft and ripened cheeses, smoked salmon, pre-packed sandwiches and deli meats
68
What is the most common cause of a stomach bug?
Norovirus
69
Why do antibiotics not help with the norovirus?
Because it is a viral illness and highly contagious.
70
What are Persistent Organic Pollutants (POPs?)
Organic compounds that are resistant to environmental degradation through chemical, biological and photolytic processes.
71
How do POPs accumulate?
POPs have high lipid solubility passing through the phospholipid structure of biological membranes and accumulate in fat.
72
How are POPs categorised?
They must be extreme of persistence, mobility and toxicity in order to rank them as POPs.
73
Why is human milk a preferred matrix for assessment of body burdens for POPs?
Biomonitoring of human milk data can provide information on the exposure of the mother as well as the infants.
74
Where is the greatest long term exposure of POPs?
In developing countries where the use of POPs in tropical agriculture has resulted in a large number of deaths and injuries.
75
What is DDT solubility?
Highly insoluble in water and soluble in most organic solvents.
76
When was DDT widely used?
In the Second World War to protect people from spread of malaria, typhus and other vector bourne-disease. Thereafter in agricultural crops.
77
What does DDT produce?
Oestrogen like alterations of reproductive development.
78
What is DDT best known for it's adverse effects?
On reproduction in birds, especially due to the eggshell thinning in birds impacting reproductive success.
79
How are dioxins released into the environment?
Through the production of pesticides and other chlorinated substances.
80
What are furans?
A major contaminant of PCBs.
81
What are the 4 heath effects of exposure to dioxins?
Peripheral neuropathies
Fatigue
Depression
Hepatitis
82
What food sources contain the highest levels of acrylamide?
starchy foods like potato and cereal products.
83
What are the harmful effects of acylaminde to animals and humans?
Can cause cancer in animals and toxic to the nervous system to both animals and humans.
84
How is acrylamide formed in food?
Excessive cooking i.e too long or too high a temperature
85
How can nutrients be lost during food preparation?
High levels of heat, and/or oxygen cause the greatest nutrient loss. They can also be 'washed out'.
86
Which vitamins are lost boiling a potato? How can we avoid loss of nutrients?
B and C vitamins.
| By consuming the liquid i.e turn into soup
87
What are the 2 types of carcinogenic compounds that are by-products of BBQing?
1. Heterocyclic amines (HCAs)
| Polycyclic Aromatic Hydrocarbons (PAHs)
88
Why is microwaving food a potential health risk?
Microwave radiation interacts with molecules in food. Microwaved food contains both molecules and energy not present in food cooked conventionally.
