1.1-Macronutrients Flashcards
What are proteins?
Large molecules consisting of chains of amino acids made up of carbon, hydrogen, oxygen & nitrogen. (also has R group- this varies in each amino acid)
What are the nutritional functions of protein?
-make up the structure of the body e.g. cartilage, muscles, skin and hair are made of protein.
- required for growth and repair of body cells when they are damaged or old.
-Act as antibodies in the immune system, helping to prevent infection.
-Enzymes are proteins that help reactions occur in the body. They function as a catalysts, increasing the rate of chemical reactions.
-Some hormones are proteins. They are chemical messengers produced in one part of the body to function in a different part of the body.
(water-soluble hormones eg. growth hormones are made from amino acids.)
-Used for energy if other energy sources are running out
How are proteins formed?
Condensation reactions (water is byproduct)
(if 2 amino acds- dipeptide bonds, many amino acids- polypeptide)
What are non-essential amino acids?
Amino acids that the body can make for itself.
What are essential amino acids?
Can’t be synthesised by the body so must be provided in the diet.
What are the essential amino acids?
for adults: Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine,
Tryptophan
Valine
-potentially arginine as its non-essential but can only be synthesised slowly
(Children: histidine)
What is HBV?
High biological value proteins- contains essential amino acids in the necessary amounts
-Found in meat, poultry, eggs, dairy and fish.
What amounts of protein do chicken, fish, eggs and dairy provide?
chicken- 32g per 100g
fish- 20/25g per 100g
eggs- 14g per 100g
dairy- 3/27g per 100g
What is LBV?
-Low biological value proteins.
Contains a limiting amino acid- the amino acid in shortest supply relative to the amounts needed.
-normally plant proteins are LBV
Examples of Plant protein?
Beans, nuts, seeds, quinoa, leafy greens, whole grains
(soya beans & quinoa- HBV, Peas, nuts & seeds- LBV)
What amounts of protein do lentils, chickpeas & beans provide?
lentils- 8/9g per 100g
`chickpeas- 7g per 100g
Beans- 7/10g per 100g
name some examples of limiting amino acids
-Lysine in wheat protein
-Tryptophan in maize protein
-Methionine and Cysteine in beef protein.
What are Novel proteins?
Newer/ rarer forms of protein that have immune-enhancing properties.
Eg. whey and soy
Where can whey and soy (Novel proteins) be found?
whey- in milk, cheese and yoghurt
Soy- soybeans(contains all essential amino acids), miso, soy sauce, tofu
cheese- 19g per 100g
soybeans- 12.35g per 100g
tofu- 8g per 100g
Benefits of novel protein instead animal?
can reduce bad cholesterol & heart disease and cancer
What is protein complementation?
When 2 LBV proteins are eaten together to produce a HBV meal eg. beans on toast- the amino acids of 1 protein compensate for the lack in the others.
What are carbohydrates?
Sugar molecules that provide energy.
3 types-
starch(Complex carbs)
sugar(simple carbs)
fiber (complex carbs)
Describe what happens to carbohydrates during digestion?
-They are broken down into glucose.
-Glucose is also stored as glycogen and when glucose supply is low in the diet, glycogen is converted back to glucose.
-Glucose is then transported via the bloodstream to cells where energy is released.
What are the 3 different carbohydrate structures?
-Monosaccharides
-Disaccharides
-Polysaccharides
What are monosaccharides?
-single sugar molecules eg.Glucose, Fructose, Galactose.
What are disaccharides?
-are made up of different pairs of monosaccharides eg. Sucrose ( glucose + fructose)
Lactose (glucose + galactose)
Maltose (glucose + glucose)
What are polysacchariddes, give examples?
-Long chains of monosaccharides
eg. -Starch (chains of glucose), found as either amylose (long unbranched straight chains of glucose)or amylopectin (branched chains of glucose)
-Glycogen (glusoce polysaccharide), used to store glucose in liver and muscles, this is then used when extra glucose is required overnight, excercise or between meals.
-Pectin (non starch polypeptide NSP) found in cells of fruit and veg ( seed, pith and peel), helps create jam and gelling agents.
-Cellulose (NSP) although is a glucose polysacchraide it can’t be broken down in digestion
What are non starch polysaccharides (NSP)?
the structural parts of plants eg. cell walls -are insoluble fibre
-adds bulk to the stool and helps food pass more quickly through the stomach and intestines.
-found in wheat bran, vegetables, and whole grains.
eg. Pectin, Cellulose, Gums, Hemicelluloses
Are carbohydrates staple foods/ explain what staple foods are?
-Yes
-staple foods are often eaten in most people’s daily diets.
Staple foods should be:
-Readily available to the population, this often means low cost,
-Provide a major source of energy, so are generally high in starch,
-provide an important contribution to protein sources
-Provide micronutrients
eg. rice, wheat, cassava, corn, plantains, potatoes and quinoa
What are intrinsic sugars?
-sugars that are naturally integrated into the cellular structure of food eg. whole fruits and vegetables
What are extrinsic sugars?
-are free in the food or added it.
Eg, Milk sugar (lactose)
Non milk extrinsic sugars (NMES) include fruit juice, honey and sugar added during manufacture or during cooking.
What are the nutritional functions of fat?
-rich source of energy (1g provides 9kcal)
-act as insulating layer under skin
-protect vital internal organs
-act as a carrier for fat soluble vitamins A, D, E and K.
-prevent hair and skin becoming too dry,
What is the structure of fats?
-trigylcerides.
-made up of 3 fatty acids and glycerol
What is the difference between unsaturated and saturated fats?
Saturated- no double bonds present between the carbons of the fatty acid chains. -normally solid at room temp and from animal sources
Unsaturated- contains double bonds, normally liquid at room temp and from plant sources (healthier-lower cholesterol)
Role of cholesterol in the body?
-Makes bile acids which help to digest fats
-Absorbs and uses the fats from food
-Makes some hormones
Where does cholesterol come from?
-Can be made by body in liver
-found in animal foods because animals also have the capacity to make cholesterol.
Effects of eating a diet high in saturated fats?
-means the body will decrease the amount of cholesterol it produces.
-it increases the amount of cholesterol in the bloodstream/arteries which can be linked to heart disease and stroke.(raise LDL cholesterol)
Animal sources of fat?
Meat - visible and invisible fat
Fish - fatty fish, fish liver oils
Dairy foods - butter cream cheese
Plant sources of fat?
Fruits and vegetables - avocado, olives
Nuts - brazil, walnuts,
Seeds - sesame, sunflower
Other - palm, coconut
What are the 3 essential fatty acids & where are they found?
Linolenic acid
Linoleic acid
Arachidonic acid
(contain omega-3 and omega-6)
Found in Fish, Nuts and seeds, Green vegetables
When does malnutrition occur and what are the 2 types?
-occurs when there is an imbalance in the supply of one or more nutrients to the body
-Overnutrition and Undernutrition
What is over nutrition?
-eating a diet containing too much of one or more nutrients.
-can result in energy imbalance which causes weight gain because energy intake is higher than activity
-This causes adipose tissue to get stored up in the body causing weight gain
-can cause obesity, coronary heart disease, dental decay and diabetes
What is under nutrition?
-when a diet contains too little of one or more nutrients.
-causes an inadequate intake of energy can result in anorexia, stunted growth and wasting (too thin for their height)
Sources of NSP/ fibre
-nuts, beans, lentils, avocado, broccoli, whole grains, fruits and veg.
Describe some diseases cause by under nutrition?
kwashiorkor- caused by lack of protein, causes too much fluid in tissues, causing swelling under skin
marasmus- deficiency of all micronutrients, causes severe underweight, skeleton visible, loose skin etc
pellagra- lack of niacin or tryptophan, can cause diarrhea, dermatitis, and dementia.
beri-beri- lack of vitamin b1- causes low muscle strength or muscle paralysis even heart disease
scurvy- lack of vitamin C-bleeding gums, loosened teeth and bleeding under your skin.
rickets-vitiman D deficiency in children causes softening/ weakening of bones.
What is the recommended daily intake of each macronutrient in the diet?
Carbs- 45–65%
Fats- 20–35%
Protein-10–35%
Function/ examples of soluble fibre?
-found in barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables.
-helps reduce blood cholesterol levels and coronary heart disease risk
Function of monounsaturated/polyunsaturated fats?
-help protect your heart by maintaining levels of “good” HDL cholesterol while reducing levels of “bad” LDL cholesterol in your blood.
-olive oil, rapeseed oil and spreads made from these oils. and avocados
Difference between HDL and LDL
-high/low density lipoproteins
-HDL-good-carries cholesterol to your liver, where it can be removed from your bloodstream before it builds up in your arteries.
LDL-bad- takes cholesterol directly to your arteries
