Macronutrients Flashcards
Carbohydrates (CHO)
Substances which produce energy and are made up of different mixtures of carbon, hydrogen and oxygen
Hydrated carbons
What are carbohydrates usually?
Plant products
Contain stored energy which the plant obtains from the sunlight with the help of chlorophyll
Non-milk extrinsic sugars (NMES)
Sucrose
Intrinsic sugars (IS)
Contained within cellular structure of food
Extrinsic sugars (ES)
Sugar added to the diet
E.g beverages
Milk extrinsic sugars (MES)
Lactose
What process is glucose produced by?
Photosynthesis
Why do we need carbohydrates?
Provides energy 1g provides 4kcal for:
Bodily function- breathing, digestion
Everyday activity- walking, eating
Physical activity- running, swimming
what are the types of carbohydrates?
simple
Complex
What are simple carbohydrates?
Contain one or two molecules
Sugars
Monosaccharides/ disaccharides
What are complex carbohydrates?
Contain hundreds/thousands of molecules
Starch and fibre
Polysaccharides
Monosaccharides
Contain 6c rings/ 5c rings
1 sugar unit
Glucose, fructose, galactose
Known as reducing sugars
How do you identify a reducing sugar?
Benedict’s solution
Oxidation reaction occurs
Why are monosaccharides known as reducing sugars?
The sugar is oxidised at the carbonyl group
Oxidising agents such as ferricyanide, hydrogen peroxide and Cu2+ are reduced
In which food source would you find glucose?
Honey
Sugar cane
Ripe fruits
Vegetables
In which food source would you find fructose?
Plant juices
Honey
Fruit
In which food source would you find galactose?
Produced when body digests lactose
Sugar found in milk
Disaccharides
C12H22O11
Two monosaccharides joined together with the removal of one water molecule
Maltose
Glucose + Glucose
Reducing sugar
Maltase
In plants (starch)
Animals (glycogen)
Lactose
Galactose + Glucose
Reducing sugar
Lactase
In milk
Sucrose
Glucose + Fructose
Non-reducing sugar
Sucrase
In fruit seeds, roots and honey
In which food sources would you find sucrose
Sugar cane
Sugar beet
Dates
Root veg
In which food sources would you find maltose
Barley (brewing of beer)
Forms of sugar commonly used in foods
Brown suagr
Fructose (natural fruit sugar)
Glucose
Granulate sugar
Honey
Lactose
Mannitol (sugar alcohol )
Molasses (thick brown syrup)
Sorbitol (sugar alcohol)
Xylitol (sugar alcohol)
Non-sugars (sweeteners)
If aldehyde/ ketone group replaced with OH group, sugar alcohols produced
Not absorbed into bloodstream via small intestine
Examples of sugar alcohols
Sorbitol
Mannitol
Ribitol
Examples of sweeteners
Saccharine
Aspartame
Acesulfame K
Oligosaccharides
Intermediate group 3-10 monosaccharides
Consist of long chains of glucose molecules
E.g fibre
Polysaccharides
Made of many monosaccharides joined together
E.g starch, glycogen, cellulose, beta glucan, pectin
Starch in the form of being structural
Cellulose
Forms part of dietary fibre (NSP)
Gives rigidity to structure
Insoluble
Not easily broken down
Digestibility of starch depends on cooking procedures
Starch in the form of storage
Glycogen
Serves as body’s quick energy source
Do no ingest glycogen broken down into glucose
Stored in liver and muscles for 24hrs
Starch
Two form = Amylose + Amylopectin
Amylose- straight chains of glucose
Amylopectin- branched chains of glucose
Dietary sources of starch
Grains ( wheat, rice, corn)
Legumes (peas, beans, lentils)
Tubers (potatoes)
Products (bread, pasta)
Fibre (NSP)
Dietary fibre (soluble)- adds bulk
Insoluble (NSP)
Structural element to pants
Difficult to digest in human body
NSP
Delay gastric emptying, but reduces overall GI transit time
Some NSP broken down by fermentation in the large intestine to produce short chain fatty acids
Some fibre bind to cholesterol in bile, reducing overall cholesterol levels
Dietary sources of cellulose
Skins of fruit
Veg
Cereals
Dietary source of dextrin
Crust on toast
How many molecules of glucose needed via aerobic respiration
1
How many molecules of ATP needed to yield glycolysis and Krebs cycle
33-35
Glycogenesis
Formation of glycogen from glucose
Glycogenolysis
Formation of glucose from glycogen
Glyconeogenesis
Formation of glucose from amino acids
Glycolysis
Takes place in anaerobic conditions in the cytosol
Glucose breaks down into 2 pyruvate molecules (3C) and ATP produced
Equation for respiration
Glucose + Oxygen —-> Carbon dioxide + Water + Energy
How much energy do most people obtain from carbs in UK?
40-44%
Equal to 280g per day - men
240g per day- women
How much energy do most people obtain from carbs in Africa/ Asia?
70-80%
Approx 400g
How much carbs does WHO recommend?
50-75% dietary energy as complex carbs
Less than 10% dietary energy from refined sugars
Deficiency of carbs
Makes the body work harder to breakdown stored fat to release energy
Breakdown of fatty acids to produce glucose is not an energy efficient process
Excess of carbs
Dental caries
Coronary Heart Disease
Diabetes
Obesity
Lactose intolerance
Diabetes
Body either does not produce enough insulin or insulin produced is not effective
Glucose levels in blood closely monitored
Kept in limits by action of the hormone insulin
Type 1 diabetes
Pancreas can’t produce insulin
Insulin producing cells destroyed by immune system
Most common in children and young people
Type 2 diabetes
Commonly diagnosed in adults over 40
Restrict energy intake
Hypoglycaemia- low blood sugar
Lactose intolerance
Inability to breakdown the carbohydrate lactose
Insufficient amounts of the enzyme lactase
Symptoms- abdominal discomfort, cramps, diarrhoea
Treatment- lactose free products
why do we need proteins
body composition
enzymes
hormones
blood clotting
source of energy
transport
what protein used for transport
haemoglobin
what protein is structural
collagen
keratin
forms of protein
globular
fibrous
globular proteins
cellular
enzymes
soluble in water
e.g myoglobin
fibrous proteins
connective tissue
extended
not soluble in water
sources of protein from animals
meat
milk
eggs
cheese
fish
sources of protein from plants
nuts, seeds
pulses, soya products
wheat, oats, rice
Protein requirements
1g protein provides 4kcal
Protein is a secondary source of energy
Daily recommend value is 0.8kg/d
Structure of proteins
Amino acids bonded together by peptide bonds to form proteins
Central carbon with amine group and acid group attached
Each amino acid has a distinctive side chain
