Nutrition health and exercise 1 2.0 Flashcards
What is known about the causal effect of diet on hard outcomes?
Little
Issues with non-randomised data?
It can be biased
What is revesed causality?
Smthn ab a disease might cause someone to change their diet
Example of reverse causality?
Obese people drink diet soft drinks–> diet soft drinks dont cause obesity its just that obese people drink them bc they want to lose weight
What are confounding factors?
One factor directly causing the disease, and another cause
Example of confounding factors?
Smoking–> causes cardiovascular disease, and changes in diet which in turn also cause cardiovascular disease
How does randomisation minimise systemic bias?
It can minimise the effect of known and unknown confounding factors
Example of long term study on diet effect on outcomes?
Mediterranean diet (oil, fish, vegetables and no red and processed meats) vs low fat diet (low fat dairy products, bread, potatoes, pasta) for 5 yrs
Observations of Mediterranean diet vs low fat diet?
Mediterranean diet has a lower risk of getting a cardiovascular event compared to low fat diet
What is metabolic health?
The ability to maintain metabolic control
Maximal eating study?
Ate dominoes pizza until comfortably full vs eating until they physically couldnt eat anymore
Results of maximal eating study?
1500kcal for normal, 3000 for maximal. 57g fat vs 113g. 187g Cho vs 367g
What happens when double the amount of fat is eaten?
Fat levels in the blood don’t increase by 2* (triglyceride conc in blood increase was buffered)
Why do fat levels in blood not increase by 2* when 2* the amount of fat is consumed?
Metabolite conc in the blood is buffered
What is observed regarding insulin secretion in maximal eating group?
It is secreted more
What is the oral glucose tolerance test?
drink w/ 75g of glucose
What is an oral fat tolerance test?
Give people x amount of fat and observe the metabolism
What is measured in oral glucose tolerance test?
Blood glucose response
Association between metabolic control and cardiovascular mortality?
Better metabolic control = lower CVD mortality
Healthy blood glucose cond 2 hrs post OGTT?
<7.8 mmol/L
Prediabetic blood glucose cond 2 hrs post OGTT?
7.8-11 mmol/L
Diabetic blood glucose cond 2 hrs post OGTT?
> 11 mmol/L
Average triglyceride conc difference between sexes?
Women have a lower average triglyceride conc than men
Issue with measuring conc of glucose?
Metabolism is dynamic so conc might be 5mmol/L, but there could be 130mg per min going in and out
Where does glucose come from if we haven’t eaten a meal?
Liver–> breakdown of glycogen, and gluconeogenesis
What is the main glucose consumer from the bood when resting?
Brain
Causes of an abnormally high BGC?
Defective liver glycogen metabolism (too much) or defective glucose uptake in muscles (too little)
Glycemia?
Blood glucose conc
Effect of eating on BGC, lactate and FA conc in blood?
Rise in BCG and lactate conc that reduces over time, and a suppression of circulating FAs
Why does blood lactate conc increase after eating?
Glycolysis stimulated by insulin
Why are circulated FAs suppressed after eating?
If FA conc remained high there would be competition for the muscle fuel uptake–> want muscle to take up glucose instead to buffer BGC
Effect of insulin on FFAs?
Suppresses their availability-> inhibits adipose tissue lipolysis
Effect of insulin on liver?
Suppresses liver glucose output
Postprandial meaning?
After a meal
What is glycaemic index?
A way to classify carbs
How is glycaemic index calculated?
Give people 50g of available carbs, measure blood glucose conc over 2 hrs and calculate area under curve and compare this to a refernce
What is the reference for a glycaemic index?
Pure glucose, white bread
What if the area under the curve of a food is the same as glucose?
GI=100
What if the area under the curve of a food is half that of glucose?
GI=50
Min GI value for high GI foods?
> 55
GI value of low GI foods?
<55
What GI is spaghetti regardless of wholemeal or white?
Low GI
What GI is bread regardless of wholemeal or white?
High GI
Monosaccharides example?
Glucose, fructose, galactose
Difference between sucrose and isomaltulose?
Bond between glucose and fructose is stronger isomaltulose
Oligosaccharide example?
Maltodextrin
Polysaccharides?
Amylopectin (starch) and amylose (starch)
Benefits of isomaltulose over sucrose?
Lower GI (more slowly digested) and better for teeth as it isnt fermented in the mouth
What is maltodextrin used in?
Sports nutrition products
What is maltodextrin made up of?
8-12 glucose molecules
Differences between amylopectin and amylose?
Amylopectin is branched, amylose is straight & Amylose has a lower GI as it takes longer to digest–> enzymes can only work on ends and in branch there is more ends
How is area under curve counted for BGC?
Look at resting BGC, only count area that goes above it (incremental area under curve)
