nutrition diet and body weight Flashcards
(23 cards)
define metabolism
the chemical processes that occur within a living organism in order to maintain life
functions of metabolism
oxidative pathways : convert food to energy
fuel storage and mobilisation pathways:allow fuel to be mobilised when we are not eating or need increased energy.
biosynthetic pathways: produce basic building blocks for cells
detoxification pathways: remove toxins
define energy
capacity to do work
Why do living cells require energy
biosynthetic work- synthesis of cellular components
transport work across cell membranes- maintenance of ion gradients, uptake of nutrients
mechanical work- muscle contraction
electrical work-nervous conduction
osmotic work- kidney
define exergonic and endergonic
exergonic- energy released is greater than energy input
endergonic- energy input is greater than energy released
describe the ATP-ADP cycle
ADP + Pi forms ATP : energy production by oxidation of : lipids, carbohydrates, proteins and alcohol
ATP is broken down by energy usage
what is the official SI unit for food energy
KJ (kilojoule)
1kcal= 4.2 kilojoules
what nutrients do we require and why
carbs- supplies energy protein-energy and essential AA fat- energy and essential fatty acids minerals-essential vitamins- essential minerals and vitamins are micronutrients water-hydration fibre-for normal GI function
what are the major dietary carbs
starch-polymer of glucose sucrose-glucose +fructose lactose - galactose +glucose fructose glucose maltose-glucose+glucose glycogen-polymer of glucose
what are the essentials amino acids
isoleucine lysine threonine histidine leucine methionine phenylalanine tryptophan valine
what AA do children and pregnant women require in their diet
arginine
tyrosine
cysteine
why are fats important to the diet
contain much less oxygen than carbs/proteins so more reduced and yield more energy when oxidised
required for absorption of fat soluble vitamins(A,D,E &K)
provide essential fatty acids: linoleic and linolenic acid
why are minerals important to the diet
electrolytes establish ion gradients across membranes and maintain water balance
calcium & phosphorus are essential for structure(bones +teeth)
act as enzyme co-factors
iron essential for haemoglobin
why can’t we digest cellulose
don’t have the enzyme required to break the β-1,4 linkages in cellulose
what does the daily energy expenditure consist of
basal metabolic rate
voluntary physical activity
diet-induced thermogenesis
define BMR and which hormone is it mainly controlled by
measure of basal energy required to maintain life-the functioning of the various tissues of the body at physical, digestive and emotional rest.
thyroid hormones
why is BMR lower for women
women have more adipose tissue that is less metabolically active than lean muscle tissue
what can increase BMR
hyperthyroidism
pregnancy
lactation
define obesity
excessive fat accumulation in adipose tissue which impairs health
BMI of over 30
State the different classes in BMI index
<18.5 underweight 18.5-24.9 desirable weight 25-29.9 overweight 30-34.9 obese >35 severely obese
what is marasmus and how does it present
type of protein-energy malnutrition most common in children under the age of 5 child looks emaciated signs of muscle wasting and loss of body fat no oedema hair is thin and dry diarrhoea is common anaemia may be present
what is kwashiorkor and how may it present
occurs in a young children who have been displaced from breastfeeding and are fed a diet with some carbohydrate and low protein content.
child is apathetic, lethargic and anorexic
pitting oedema
hepatomegaly and/or ascites (accumulation of fluid in peritoneal layer) cause abdomen to distend
serum albumin low
insufficient AA to make proteins decreasing oncotic (protein) pressure, increasing net flow of fluid from capillaries to the interstitium by Staling’s law of the capillary resulting in oedema
what is refeedinging syndrome
rapid refeeding of energy rich foods in starved or inadequately nourished patients will rapidly increase blood sugar and insulin resulting in glycogen, fat and protein synthesis.. these processes use phosphate, magnesium and potassium from body stores that are already depleted. this causes electrolyte abnormalities like hypophosphatemia.
