Intro to nutrition Flashcards
what does a healthy diet supply
energy, building blocks for metabolism, essential nutrients
what are people eating too much of and too little of
to much saturated fat, salt and added sugar
too little fruit, veg, oily fish and fibre
what do these acronyms mean: EAR LRNI RNI safe intake
estimated average requirement - half need more than this value and half need less than this value - its is the middle of the values
lower reference nutrient intake - sufficient for few people but not meeting 97.5% of the pop - two SD lower than the EAR
RNI - sufficient for 97.5% of the population 2 SD above average
safe intake - sufficient for almost everyone but not so large it causes undesired affects
what does energy expenditure = and what does it depend on
energy intake
depends on basal metabolic rate (age, weight and sex)
and the amount of intensity of physical activity
what is the trend between men and women for EAR in adults
both slowly decreases as you get older but men is higher than women
what are our main sources of energy
fat stores (80-90%)
what happens to muscle during starvation
protein from muscle tissue is metabolised to provide amino acids for other reactions
what is the average daily requirement for protein compared to athletes
0.75 g/kg/day ie a 75kg male requires 50g protein per day
athletes recommend 12.-1.7 g/kg/day
how much are proteins synthesised and degraded per day
250 g per day
in a healthy adult what does nitrogen intake =
nitrogen excretion
what is the difference between a negative nitrogen balance vs a positive one
positive means you intake more than you excrete and vice versa
positie occurs during growth, pregnancy etc - when building new tissues
negative occurs during fasting or illness where the body is breaking down proteins for energy
what are the 9 essential amino acids
that can’t be synthesised by humans
methionine valine histidine leucine phenylalanine tryptophan isoleucine lysine threonine
what lipids do we need and why
triacylglycerols for energy as 1g fat provides 9kcal (39KJ) compared to carbs and protein that provide 4 kcal
cholesterol and fatty acids are precursors for hormones and prostaglandins
what are the 4 different types of fats and what are some examples
saturated - no double bonds - found in meat and dairy products
mono-unsaturated - one double bond found in olive and peanut oil
polyunsaturated - more than one double bond - corn and sunflower oil
trans(hydrogenated) - trans double bonds - cakes biscuits and pastry
what do double bonds do to the structure in fatty acids
produce a kink
what are the confounding factors in the saturated fat debate
variation in study designs
variation in effects of individual fatty acids on serum lipid profile
heterogeneity of LDL particles
for the 4 types of fats what are the recommended % of dietary intake
saturated fats - 11% cis-monounsaturated - 12% cis-polyunsaturated - 6% trans-fats - less than 2% total less than 35% around 30% desirable
why should we eat 2 portions of oily fish each week
good source of omega 3 polyunsaturated fatty acids to decreases risk of heart disease
what are the 4 types of crabs
polysaccharides - mainly starch
disaccharides - mainly sucrose
monosaccharides - mainly glucose and fructose
non-starch polysaccharide - dietary fibre
what is the recommended percentage intake of total carbohydrate
50%
what is the percentage of energy intake of free sugars
10%
what are the two types of micronutrients
vitamins - organic compounds for normal metabolic function which cannot be synthesised
minerals - inorganic elements which have a physiological function
which vitamins are water soluble vs fat soluble
fat soluble - vit E/K/A/D
water soluble - vit C, B1-3/5/6/7/9/12
what are the real names of the water soluble vitamins
thiamin - b1 riboflavin b2 niacin b3 pantothenic acid b5 pyridoxal phosphate B6 biotin b7 folic acid b9 cobalamin b12 vit c - ascorbic acid
what is the role and effect of deficiency of thiamin
cofactor in decarboxylation reactions such as link reaction and kerb cycle
beri-beri - müsle weakness, nerve damage and can affect heart
what is the role and effect of deficiency of riboflavin
constituents of co factors eg flavin adenine dinucleotide - involved in fays crabs and proteins
very rare ariboflavinosis - usually is is efficiently conserved in the body
what is the role and deficiency of niacin
constituent co factor eg NADH
pellagra - diarrhoea, dementia, dermatitis and death
what is the role and deficiency of pantothenic acid
constituent co enzyme A, energy metabolism and fat metabolism
unknown - found almost in all foods so do deficiency
what is the role and deficiency of biotin
prothetic group - acts as a carrier for co2 in carboxylation reactions eg fat synthesis
very rare to have a deficiency
what is the role and deficiency of pyridoxal phosphate
cofactor for enzymes involved in protein metabolism, haem synthesis, neurotransmitter synthesis and modules steroid hormone action
deficiency leads to irritability, depression, confusion and inflammation of the tongue and mouth
what is the role an deficiency of folic acid
1-C transfers particularly in DNA synthesis
neural tube defects, spina bifida, anencephaly, macrolytic anaemia
what is the role and deficiency of cobalamin
required for methionine synthesis and odd-chain fatty acid metabolism - only found in animal products
deficiency causes macrolytic anaemia, irreversible neurological damage - commonly caused by autoimmune disease preventing absorption
what is the role and deficiency of vitamin C
collagen synthesis also role in antioxidant
deficiency causes scurvy - weakened collagen
what is the role and deficiency of vitamin A
vision (rod cell function)
transcriptional regulator
deficiency causes blindness
what is the role and deficiency of vitamin D
role of bone formation and maintenance - also roles in immune regulation, cell differentiation and muscle function
deficiency causes rickets in children and osteomalacia in adults
what is the role and deficiency of Vit E
acts as an antioxidant, its main role if to prevent lipid oxidation in membrane
deficiency in fatmalabsorbtion (eg CF) causes neurological problems
what is the role and deficiency of vit K
cofactor for enzymes which activate blood clotting proteins - may also be involve din bone maintenance
rare def in healthy adults but deficiency in new borns causes bleeding
what are the key minerals that we need
iron zinc iodine calcium magnesium fluoride phosphate sodium and potassium
trace elements of cobalt, copper, chromium, manganese and selenium
what is the recommended daily intake of sodium
what is the risk in high sodium
less than 6 g / day
increases risk of CVD
what are factors of inadequate diet
food availability (poverty / disability)
food choices
problems with eating (dysphagia)
what are the factors associated with inadequate absorption
problems with fat absorption affects fat soluble vitamins (cystic fibrosis, coeliac disease, crowns disease) pernicious anaemia ( B12 absorption)
what is iron deficiency anaemia caused by
often arises from persistent blood loss from gastric ulceration, colon cancer or excessive menstrual loss
when is folic acid deficiency common in women
during pregnancy
what is the definition of malnutrition
inadequate or excess intake of protein, energy and micronutrients such as vitamins and minerals
which deficiencies cause the greatest effect to the body
iron, vit a, iodine, zinc
what is scurvy
vitamin C deficiency - found mainly within Uk low income population (found more commonly in men)
what is vit D deficiency and which areas of the Uk are most at risk during which seasons
winter and mainly spring - northern regions of the UK
vit D is formed in the presence of UV light in the skin - causes osteomalacia in adults and rickets in kids
which community are most at risk to B12 deficiency
vegans who don’t take supplements
what is pernicious anaemia
caused by Vit 12 deficiency which can lead to irreversible neurological damage - common signs are tingling of toes and fingertips - can ultimately lead to death if untreated
why is folic acid needed during pregnancy
folic acid is vital for DNA synthesis
without enough folic acid it causes neural tube defects such as anaecphaly, spina bifida
what does deficiency in iodine do during pregnancy
can cause cognitive defects in children
what are the guidelines for macronutrients
starchy foods - 40% energy intake 5 portions of fruit / veg moderate amounts of protein moderate amounts of milk and dairy less saturated fats, salt and sugar
what are the guidelines for micronutrients
pregnant women should take 400 micro grams of folic acid until the 12th week of pregnancy
children under 5 may need vit ADC sups
all individuals are advised to take 10 micro grams per day of vit D
