Week 2 : Types of studies, macronutrients and micronutrients Flashcards
What is the significance of cell line/animal studies, since scientists are mainly concerned with studying how the human body works in nutrition?
Cell line studies allow scientists to formulate hypothesison how biological systems work and animal studies confirm the hypothesis. Only then, verification of effects and observation of side effects can be done in human studies
What are the 3 kinds of observational studies?
- Case-control
- Cross-sectional
- Cohort
What kind of conclusions can we draw from observational studies?
Correlation
What are the 2 kinds of interventional studies?
1. Randomised, double-blinded, placebo controlled intervention studies
2. Clinical studies
What kind of conclusions can we draw from interventional studies?
Cause-effect
What is the difference between case-control, cross sectional and cohort studies?
Case-control (past) : checks the subject’s history
- “There is a correlation/association of vitamin X intake in people with hair loss compared to people without hair loss”
- Case : group with disease - Control : group with no disease
Cross sectional (present) : collecting information of a current population to make a conclusion
- “ 5% of the population has hair loss”
Cohort (future) : follow subjects in time to establish a correlation
-“5% if healthy subjects develop hair loss over time. The intake of vitamin X is a risk factor that correlates to hair loss”
What is a good placebo?
What is a potential limitation of placebos which are food items?
The placebo should have the same characteristics as the treatment given to participants
- e.g. for vitamin pills, placebo should be of the same : shape/colour/size/texture
Limitation : it is very hard to find a placebo for food products
In a good intervention study, there should not be any placebo effect. True or False?
True
For carbohydrates, what are the 3 kinds of carbohydrates?
How many calories does each kind of carbohydrate give?
Digestible sugars
1. Simple sugars (mono and disaccharides) : 4 cal/g
2. complex carbs (polysaccharides) : 4cal/g
non-digestible sugars
3. Complex carbs (aka dietary fibre) : 0-2cal/g
Which of the following are reducing sugars?
1. Sucrose
2. Fructose
3. Lactose
4. Galactose
5. Glucose
6. Maltose
Reducing sugars are aldehydes and ketones
- Only sucrose is not a reducing sugar as both anomeric carbons are used for bonding, carbonyl group not available
- Though ketones can’t be oxidised further and reduce others. as long as there is free avaiable ketone group, they can undergo isomerisation into aldehyde (e.g. fructose can isomerise into glucose)
___ is the storage form of glucose in muscles of animals.
Glycogen
How much energy do fats give us?
9cal/g
What are the 3 types of dietary fats?
- Triglycerides
- Free fatty acids (some are essential to body)
- Dietary cholesterol
what fraction of cholesterol is produced by liver, and what fraction of cholesterol is obtained through our diet/
2/3 produced by liver
1/3 obtained from diet
What is the difference between high density lipoproteins (HDL) and low density lipoproteins?
HDL : good cholesterol
- scavenges cholesterol, delivers it back to the liver
LDL : bad cholesterol
- delivers lipids around the body, and may deliver to arteries and block them
How can we try to reduce cholesterol intake (LDL and HDL)?
LDL : Reduce saturated fat intake
HDL : reduce dietary cholesterol intake but reduction may not be significant
How much energy do proteins give us?
4cal/g
Does animal or plant protein have higher protein quality?
Animal protein as it contains all essential AA
Micronutrients are not essential to us since they do not contain calorie and do not provide us with energy. True or False?
False, they are essential. Deficiency may lead to disease
What are the water-soluble vitamins, and the fat-soluble vtamins?
Water-soluble : B,C
Fat-soluble : A,D,E,K
Does deficiency in water-soluble vitamins or fat-soluble vitamins take a longer time to develop? Why?
Fat-soluble vitamins, since the body can still utilise the previously stored vitamins in fat cells before a person becomes deficient
Consuming excess water-soluble vitamins is detrimental for health. True or False?
False, they are excreted out
What is so special about Vitamin D? What is its function?
Our body can synthesise vitamin D, unlike other vitamins. Vitamin D can be synthesised through exposure to sun and body will stop synthesising it when it is present in sufficient amounts
Function : Helps in absorption of calcium and phosphorous, thus maintaining bone integrity.
What is the function of vitamin C?
- Fight infection and repair wounds
