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%
