'Trans' fats may cause bad side effects - worse the sat fats
recommended 11% of energy from fat
A food labelled low in fat must contain no more than 3g of fat per 100g
High sat fat = type 2 diabetes, some cancers, cardiovascular disease
Insoluble fibre and Soluble fibre
Energy
In a balanced diet only fat and carbohydrates should be used to provide energy
1g of fat contains 9kcal, 1g carbohydrate contains 3.75kcal, 1g of protein contains 4kcal
Uses
To maintain body functions (to breathe, to keep the heart beating, to keep the body warm etc.)
For growth and repair which require new tissues to be made
For active movement (muscle contractions)
Factors affecting how much energy a person needs:
Metablolic rate & level of activity
GENDER - men and women have different body structures, build, weight and activity levels
LIFE STAGE - During pregnancy a mother needs to consider the unborn babies needs to allow healthy growth and development as well as looking after herself.
AGE - periods of rapid growth and development cause the need for more energy. Older people need less energy
OCCUPATION - people who have different jobs use different amounts of energy. The more you move the more energy you use
Forms
HEAT - to maintain body temperatures
ELECTRICAL - transmission of nerve impulses
CHEMICAL - for metabolic reactions
MECHANICAL - muscle movement
Salt
Salt = sodium x 2.5
Hidden salt is in: baked beans, cereals, sausages, bacon, cheese, soy sauce
Maximum amount per day = 6g
If you reduce the amount of salt in your diet your blood pressure will reduce and you will notice a wider range of flavours
Reduce/replace - add fresh herbs instead, use black pepper, make fresh sauces, add spices to stir fries, buy reduced salt products
Babies should have less salt than adults because their kidneys are smaller and less developed
High is more than 1.5g per 100g. Low is 0.3 g or less per 100g
Carbohydrates
Carbohydrates
are a
macronutrient
made up of the
elements
carbon,
hydrogen and
oxygen
In the diet
carbohydrates
provide energy,
aid digestion,
sweeten and
add flavour to
food, bulk up
your diet and
help to lower
your blood
cholesterol level.
Cereals and Starch
Soluble fibre: is found in the flesh of fruit
and veg, oats, flesh and lentils, Digestion
partially breaks it down to form a gel-like
substance that can coat the digestive tract.
This helps to speed up digestion, helping to
lower blood cholesterol levels and prevent
cancer and other digestive problems.
Cereals are primary foods which can be processed into other ingredients and products. Cereal crops are known as staple foods: crops that are easy to grow, store, process, use, are cheap and high in carbohydrate
Starch is found in cereals, bread, pots, pasta and root veg. They are filling and provide you with many other nutrients.
Wheat is milled to make flour; the endosperm is separated from the rest of the grain. The resulting particles are used to make semolina, pasta and breakfast cereals. The extraction rate controls the nutritional content of the end product.
Insoluble fibre is found in the outer skins of fruit and
veg, cereals and wholegrain food products. The body
cannot digest insoluble fibre. Insoluble fibre acts as a
bulking agent, absorbing the end-products of digestion
allows the waste products to be removed from the
body.
Protein
Protein is a macro nutrient. Made from amino acids. Essential amino acids are amino acids that must be provided as we cannot make I=them in our bodies.
Adults need 8, children need 10.
High Biological Value foods are food containing all 8 EAAs. Eg meat, poultry, eggs, dairy. Only HBV food from plants is soya.
Soya can be used as whole beans, soya sprouts, soya milk, tofu, temmpen, sauce, miso or TVP
Low Biological value foods are foods that are missing one or more of the EAAs, eg. cereals, nuts, seeds...
Complimentary proteins are LBV food combined to contain all the EAAs, such as beans on toast, rice and peas...
Benefits = nutritional benefit, more varied diet, can save money
Functions
Growth, repair, promotes manufacture of enzymes, needed to regulate body functions (hormones), secondary source of energy
Deficiency
Slow growth in children, digestive problems, malfunction of liver, weak muscles, thin limbs, stomach distended, kwashiorkor
Kwashiorkor = a protein energy malnutrition disease that occurs in children more frequently in less developed countries.
Meat
Meat and poultry are primary foods that can be processed into secondary foods. Meat is more expensive due to production costs.
Meat is composed of different proteins. Muscles are held together by connective tissues. The more connective tissue the tougher the meat. Collagen is a soluble protein that can be softened by long moist cooking methods. Myoglobin gives meat its colour, carries oxygen to the muscles. Fat may be found in the adipose tissue around the vital organs and marbled between the muscle fibres. Meat is rich in vit A,B and D and
iron.
When cooking you need to choose the appropriate cut of meat. Some cuts are suited to dry, quick cooking and others require slow, moist methods to ensure tenderness.
The muscle fibres increase in size as the animal gets older; the older the animal, the tougher the meat is
Stewing meat tenderizes it because the adipose tissue becomes soft and tender when cooked and the fat melts into the meat allowing texture to
develop further
Poultry is more tender than beef or lamb because it has less connective tissue and so the meat is more tender.
Supermarkets are more reliable and all the hygiene issues will have been checked. If you buy from an individual supplier you don't know if it will be free from disease.
It contains protein but very little connective tissue making it easier to tenderize and cook. If overcooked it becomes tough and dry. Mainly EFA. Oily fish is high in vit A & D. If fish bones are eaten then calcium may be provided. Fluoride may be found in all fish and sodium in seawater fish.
The size and type of fish will determine the choice of cooking method. Some fish can be coated or dipped in a batter to add variety and help maintain the structure.
Fish should be checked for freshness, smell should be mild. Fish deteriorate quickly so it is important to process or eat it asap.
Alternative sources
Quorn is made from edible fungus, its a mycoprotein bound together with egg. HBV. Processed into different shapes, replace or extend meat
Pulses & Nuts are a valuable sources of LBV protein. Pluses are sourced from seeds of legume plant family, includes beans, peas and lentils. Nuts are generally eaten in small quantities because they are expensive.
Soya is the only HBV food from plants. Primary product so can be processed into secondary products eg soya milk
Textured vegetable protein (TVP) is made from dehydrated soya beans that have had all their starch removed. Mixed with water to forma paste, can be shaped, dried, frozen. Turned into many products that resemble meat - very bland
Fats and Oils
Fats and oils are known as lipids. They are macronutrients made
from carbon, hydrogen and oxygen. These elements combine to make
fatty acids and glycerol. Different fatty acids are fond in different
fats and oils. The way in which the carbon and hydrogen atoms are
arranged produces either sat or unnsat fats.
Sat Fats are solid at room temp. They
are found in foods hat originate from
animals. Cholesterol is found in foods
that have high sat fat content.
Cholesterol is a natural fat
manufactured in the liver and
transported by the blood around the
body. Sat fats are unhealthy because
they can cause a build up of fatty
deposits in and around the major
organs. Leading to CHD, obesity and
high blood pressure
Hydrogenation is when hydrogen is added to vegetable oils to produce solid
margarine Trans fatty acids are produced, this is a problem because they
lead to high cholesterol.
Unsat fats largely derive from plant and fish oil. Two types: monounsaturated – soft at
room temp, healthier, may lower cholesterol and reduced the risk of diabetes and caner,
one double bond. Polyunsaturated – liquid at room temp, more than one double bond.
Essential fatty acids cannot be made in the body but are vital. Omega 3 –
found in oily fish, seeds, green leafy veg, protect the heart. Omega 6 – found
inn grains, seeds, veg & poultry. Helps to lower cholesterol.
Fats provide energy, form an insulating layer under skin,
protect and surround vital organs, provide texture and
flavour and promote a feeling of fullness.
Functions
Oils form emulsions with liquids
Add colour and 'shine' to food
Prevents lumps of flour forming in a sauce
Gives a shortening ability to a mixture and changes texture
Required to aerate foods
Helps to extend shelf life of baked products
Adds distinct flavours and odours to food
Act as a cooking medium for roasting foods
Add a flaky texture to pastry
Rancidity is when after you have kept fats in a fried for a long time the fate deteriorates and goes off
Hydrolytic rancidity occurs when
fat is attacked by enzymes that
alter their chemical structure
resulting in odours – useful in
cheese making
Oxidative rancidity occurs when unsat fats are
attacked by highly reactive particles called free
radicles resulting in odours, change in colour and
texture of fat or oil
Vitamins
Vitamin C (ascorbic acid).
Formation of connective tissue
and aids absorption of iron.
Found in citrus fruit and green
leafy veg. Deficiency = scurvy
and poor health of gums, teeth
and skin
Vitamin A (Retinol/Carotene) Maintenance and health
of the skin/produces a substance called 'visual purple'
which heps night vision and keeps healthy eyes. Retinol
is found in liver, oily fish, egg yolk, milk and cheese.
Carotene is found in carrots ad green leaft veg.
Deficiency = night blindness, skin infection. Excess =
may conntributeto liver and bone damage.
Vitamin D. Proper formation of teeth and bones,
aids absorption of calcium. From liver, oil fish, egg
yolk, milk, dairy foods, Marg and sunlight.
Deficiency =rickets and osteomaacia
Vitamin B1 (Thiamin).
Maintenance and
functions of nerves. Found
n wholegrain cereals, liver,
kidney. Deficiency =
beriberi and depression
Folate/Folic acid. Essential for all bodily functions.
Important during rapid periods of growth,
production of healthy red blood cells. Found in leafy
veg, seeds, beans, fruit, liver and fortified cereal
products. Deficiency = anaemia and neutral birth
defects
Vitamin B2 (riboflavin). Normal growth
and aids the release of energy from foods.
Found in meat, milk and green veg.
Deficiency = poor growth, skin disorders,
swollen toungue
Minerals
CALCIUM - combined with vit D and phosphorus, calcium helps the formation of strong teethe and bones. Found in milk yoghurt, cheese, green veg and sardines. Deficiency = stunted growth and rickets
IRON - Combined with protein, forms haemoglobin, to give blood its red colour, and helps transport oxygen around the body. Found in liver, kidney, red meant, bread, pots, egg yolk, green veg. Deficiency = anaemia
SODIUM - Maintains water balance in the body. Found in salt, cheese, bacon, fish and processed foods. Deficiency = ramps. Excess = high blood pressure, stroke, CHD
FLOURIDE - Strengthens teeth against tooth decay. Found in fish, tea and water. Deficiency = tooth decay
Dietary reference values
Estimates of nutrients and energy for specific groups of a population
Lower Reference Nutrient Intake (LRNI) is the amount of a nutrient that is enough for a small number of people who have low energy needs.
Estimated average requirements (EARs) give an average estimate of the requirement for energy, for a certain group of people.
Refence Nutrient Intakes (RNIs) show estimated amounts of protein, viatmins and minerals needed for 97% of the population. This will be too much for some people.
Sugars
We should
avoid
extrinsic
sugars
because high
amounts can
lead to tooth
decay, obesity
and diabetes
Extrinsic are
processed
sugars and
include
granulated,
syrup, icing etc.
added to foods
Intrinsic sugars are found naturally in cells of fruit and veg