Nutrition And Energy Balance Flashcards
What is nutrition?
The science of food + its relationship to health
Why do we need food?
Food contains nutrients used for growth, maintenance + energy
Some nutrients can be synthesized from other compounds by the body but those that can’t are essential + need to be taken in the diet e.g. vitamins, minerals, AAs + FAs
What diseases can occur as a result of a nutrition deficiency?
Kwashiorkor (lack of protein)
Pellegra overnutrition (lack of vit B3) -> can lead to obesity
What is the ultimate energy substrate for the bodies metabolic reactions?
ATP
How is Adenosine Triphosphate (ATP) produced?
Food metabolism via the Krebs/Citric Acid cycle which is a series of chemical reactions used by all aerobic organisms to release stored energy = end-product is ATP
What happens to fats in food once they have been eaten?
- Fatty acid glycerols go to adipose tissue
- Lipolysis occurs
- Products feed into the Citric Acid cycle producing ATP
What happens to carbohydrates in food once they have been eaten?
- Monosaccharides are used for glycogen storage in liver + muscle
- Glycolysis
- Products feed into Citric Acid cycle producing ATP
What happens to proteins in food once they have been eaten?
- AAs go to muscles
- Proteolysis
- Products feed into Citric Acid cycle producing ATP
All components of food eventually end up going into the ___ ___.
Krebs cycle
What is energy from food used for? In order of least energy to most.
Thermic effect of food
Physical activities (variable)
Basal metabolism (variable):
- Maintaining body temperature
- Keeping autonomic systems e.g. lungs, heart, kidneys, blood cell production etc.
What factors affect Basal Metabolic Rate (BMR)?
Height, gender + size Age + body composition Growth rates + activity Fever Stresses + illness Environmental temp Fasting/starvation Malnutrition Nicotine + caffeine Sleep
What is the simplest way in which to maintain a healthy weight?
Energy input = Energy output
Explain the thermic effect of food.
Some calories from food drive the digestion process - ~10% of calories but variable depending on food e.g. proteins harder to digest so use more calories whilst carbohydrates are easier so use less calories
What constitutes a normal, healthy diet?
1/3 fruit + veg
1/3 carbohydrates
1/3 protein, fat + dairy
What are the 6 essential nutrients that we need to survive in our diet?
- Water
- Calories (CHO, fat)
- Protein (AAs)
- Essential FAs
- Vitamins
- Minerals
How much carbohydrate should made up a healthy diet?
3.7-4.1kcal/g (4kcal per g)
50-75% of energy
Can be simple or complex
What are the functions of carbohydrates?
Increase blood glucose levels
Supply energy
How much protein should make up a healthy diet?
4.7kcal/g (vary in biological value) (5kcal per g)
10-20% of energy
What are the functions of proteins?
Growth + repair
How much fat should make up a healthy diet?
9.4kcal/g (9kcal per g)
15-30% of energy
< 10% from saturated fat
What are the functions of fats?
Maintain healthy skin + hair
Insulate body organs against shock
Maintain body temp
Promote healthy cell function
Storage of vitamins
What are the vitamins needed as micronutrients in the diet?
A B1 (thiamine), B2 (riboflavin), B3 (niacin), B6, B7 (biotin), B9 (folate)+ B12 C D E K
What is the difference between micronutrients and macronutrients?
Micronutrients are needed in small amounts in comparison to macronutrients which are needed in larger amounts
What is the source of vitamin A? What is its function?
Source: fish oil, green veg
Function: eyesight, growth + infection
What are the sources of vitamin B? What is their function?
Source: peas, grain, dairy, meat, fish, liver, egg + green veg
Function: carbohydrate, FA, protein metabolism + nucleic acid synthesis
What are the sources of vitamin C? What is its function?
Source: peppers, spinach + citrus
Function: cartilage + bones
What are the sources of vitamin D? What is its function?
Source: sunlight, eggs + butter
Function: calcium + phosphorus metabolism
What are the sources of vitamin E? What is its function?
Source: vegetable oil
Function: antioxidant
What are the sources of vitamin K? What is its function?
Source: vegetables + fruit
Function: clotting
What are the minerals needed as micronutrients in the diet?
Iron Calcium Zinc Magnesium Potassium
What are the sources of iron? What is its function?
Source: red meat, fortified cereals + green leafy veg
Function: component of Hb for O2 transport
What are the sources of calcium? What is its function?
Source: milk + tinned sardines with bones
Function: bones & teeth + nerve & muscle function
What are the sources of zinc? What is its function?
Source: meat, seafood + wholegrains
Function: enzymes + immune system
What are the sources of magnesium? What is its function?
Source: meat, dairy, green veg + nuts
Function: metabolism, nerve + muscle function
What are the sources of potassium? What is its function?
Source: fruit + veg
Function: fluid balance, nerve + muscle function
What are the different nutritional states a body can be in?
- Fed (0-4hrs after food)
- Fasting (4-12hrs after food)
- Starved (12+hrs after food)
What is happening in the body when there is high dietary intake in the fed state?
- Carbohydrates -> glucose -> glycogen stores + body fat stores
- Fat -> FAs -> body fat stores
- Proteins -> AAs -> body fat stores + body proteins
What is happening in the body when there is low dietary intake in the fasting state?
- Glycogen stores -> glucose -> energy for brain, NS + blood cells & energy for other cells
- Body fat stores -> FAs -> energy for other cells
What is happening n the body when there is very low/nil dietary intake in the starved state?
- Body protein -> AAs -> glucose -> energy for brain, NS + blood cells & energy for other cells
- Body fat stores -> FAs -> energy for other cells
- AAs + FAs -> ketone bodies -> energy for brain, NS + blood cells
