AS Lecture 18 - Nutrition Flashcards
What is malnutrition?
Often refers to undernutrition resulting from inadequate consumption, poor absorption or excessive loss of nutrients -> but cn also encompass overnutrition from overeating or excessive intake of specific nutrients
Problems in malnutrition facts:
1 in 3 of global popn live below recommended nutritional needs. Half of western society is overweight and 25% obese -> accounts for most T2DM, 30-40% CVD and is the largest risk factor for cancer. Many chronic diseases common in west are related to nutrition
How is body mass assessed?
BMI is a clinically relevant method of estimating adiposity OR waist measurement
What are the values for BMI levels?
40 morbidly obese
How is undernutrition measured?
Monitor body weight BUT can be complicated by fluid balance OR arm circumference
What is body weight a reflection of?
Total cell mass
Why can, in some cases of malnutrition, body weight not be reflective of nutritional status?
Oedema confounds body weight
What are dietary reference values?
Reflect the nutritional needs of a popn -> they are a way of assessing nutritional adequacy
Why are dietary reference values needed?
Many different nutrients are needed to maintain health and reduce risk of diet-related diseases -> different requirements of nutrients are needed at different stages of life
What is Vitamin C used for?
Essential in man -> is an anti-oxidant (converts Fe3+ to Fe2+) and it’s important in formation of collagen
What is a deficiency of Vit C called?
Scurvy
What does EAR, RNI and LRNI mean?
EAR: Estimated average requirement (mean) RNI: Reference nutrient intake (2.5 s.d. above EAR) LRNI: Lower RNI (2.5 s.d. below EAR)
How can the nutrients in the body be used effectively?
Demand for energy needs to be met first -> basic survival
What does energy in equal in stable weight?
Energy in = energy out + energy stored
What does energy equal in weight gain and why?
Energy in exceeds energy out due to increase intake, decreased expenditure and decrease in metabolic rate
How is energy spent in the body?
x
What is RNI?
Level at which most nutritional recommendations are set
What 3 components make up your energy expenditure?
Basal metabolic rate, adaptive thermogenesis and exercise
What are the 5 fates of acetyl CoA?
Pyruvate, amino acid, fatty acid, TCA, ketone bodies
Where is glycogen stored?
In the liver and muscle
What does adipose tissue store?
Lipids and is a major store
What is stored in muscle and why?
Glycogen due to periods of prolonged starvation
Why are fat stores not very well autoregulated?
Due to oxidation hierarchy, fat sparing occurs, so there is no adjustment of oxidation to intake
What is the body composition of a 70 kg man?
How does growth occur in humans?
Humans increase in weight 20x from baby to adult and all material in weight gain enters body as food/drink
How does body composition change from foetus to adult man (w/obese man as well)?
What are some peripheral signals that regulate appetite?
What complications relative to loss of lean body mass can occur?
What does severe malnutrition in childhood cause?
Delays in chemical maturation and can effect IQ
What are the causes of undernutrition in the developing world?
Politics, climate, poor water, poor agricultural policy, demand of developed world, food security will become the biggest public health issue in the coming years
What are the causes of undernutrition in developed countries?
Age, change in social circumstances (isolation, death of a partner, poor housing), illness, 10% of free living elderly people are undernourished to a degree that their function is effected
What are some signs of undernutrition?
Weight loss, loss of subcutaneous fat, muscle wasting, peripheral oedema, glossitis (cracking on edges of mouth), hair loss, chronic infections, poor wound healing, chronic wounds, pressure sores, listless, apathetic, recurrent pulmonary infections
What are the 2 mechanisms for energy restriction/starvation?
x
How does the body function when it is nonstressed in terms of CHO, fat and protein metabolism?
How does the body function when it is stressed, due to a short fast, in terms of CHO, fat and protein metabolism?
What are the symptoms/effects of marasmus?
General energy deficit, growth failure, no oedema, uncommon to have mental changes and good appetite
What are the symptoms/effects of kwashiorkor?
Relative protein deficit, growth failure, oedema, mental changes, poor appetite
What is thiamine used for?
Free thiamine (in body) and as TMP, TTP, TPP. It is critical for release and utilisation of energy from food and nerve function
What is Beriberi?
NS ailment caused by deficiency of thiamine in the diet as thiamine helps breakdown energy molecules (glucose) and found in membranes of neurons
What are the symptoms of beriberi?
Severe lethargy and fatigue, complications affecting CVS, NS, muscular system and GIS
Why is beriberi important?
Thiamine occurs in unrefined cereals and fresh foods so people whose diet consist of white polished rice have low thiamine -> chronic alcoholics and gastric bypass surgery are important
What is niacin used for?
Nicotinamide is derivative of niacin and used by body to form coenzyme NAD and NADP
What is a deficiency of niacin?
Pellagra
