GCSE AQA FOOD NUTRITION

Coeliac disease

Allergic to gluten

Nutrients

Chemical compounds found in foods which include proteins, fats, carbohydrates, vitamins and minerals

Malnutrition

Lack of food or particular nutrients in the diet or too much of the wrong kinds of foods, causing obesity

List the micronutrients

Vitamins and minerals

List the macronutrients

Proteins, fats, carbohydrates

Causes of malnutrition

Not being aware of dietary needs, poverty, overeating, anorexia, not liking certain foods, losing interest in food (elderly people particularly)

Consequences of under-nutrition

Depression, severe weight loss, deficiencies, weak bones and teeth

Why do we need a balanced diet?

To maintain healthy and obtain all of the right nutrients

Factors affecting nutritional requirements

Age, activity levels, gender, pregnancy or breastfeeding, illnesses

Nutritional requirements regarding age

Birth->adulthood; requires energy for growth (mostly from 5-teens). Once fully grown, metabolism slows down but still need to grow, repair and be protected from infection

Nutritional requirements in growth spurts

Protein for growth, calcium and vitamin D for bones/teeth formation, iron and vitamin C for red blood cells/preventing anemia in girls

Nutritional requirements of the elderly

Protein for repair, less energy (less active), calcium and vitamin D to prevent brittle bones, vitamin C to prevent infection

Which gender needs more nutrients?

Male due to a higher metabolic rate

Nutritional requirements of pregnant women

Need more protein, vitamin B(folic acid), vitamin D, vitamin C, calcium. Don't need more energy(less active, slower metabolic rate)

Nutritional requirements of breastfeeding women

Increase energy intake

Nutritional requirements when ill/recovering

If blood has been lost, requires more iron. Broken bones, requires more calcium and protein. If ill and have no appetite, have small portions rich in protein and vitamins and minerals (less fat+carbs)

How to find out if your diet is healthy

Food diary, computer analysis (food in focus): include all food and drinks including quantity

Dietary diary

A record of all the food and drink intake of a person over a given period of days

Why is dietary analysis useful?

Highlights deficiencies or excess of food eaten. Helpful for research into dietary needs and food related diseases

Proteins

Building blocks of all body cells

Amino acids

Chemicals which make up protein molecules

Indispensable amino acids

Essential amino acids that we cannot live without

Novel proteins

Grown from micro-organisms which produce mycoproteins

Functions of protein

Growth, maintenance, repair, secondary source of energy

Animal proteins

Red meat, chicken, fish, eggs, cheese, milk

Vegetable proteins

Cereals, nuts, pulses, beans, soya, quorn, tofu

What is a HBV protein?

High Biological Value, contain all indispensable amino acids (Animal Proteins

Vegetable proteins are..

LBV(low biological value), don't contain all indispensable amino acids

How many grams of protein do adult females need every day?

45g

How many grams of protein do adult males need every day?

55g

How many grams of protein do pregnant females need every day?

51g

How many grams of protein do breastfeeding females need every day?

56g

Consequences of protein deficiency

Retarded growth in children, wasting of muscles and internal organs

How many amino acids are there?

22

How many amino acids are essential for growth and repair in children?

10

How many amino acids are essential to growth and repair in adults?

8

Protein sparing

Eating carbohydrates with proteins allowing the proteins to be used for repair rather than for energy

Why do we need fats?

Most concentrated source of energy, provide vitamins ADEK, provide protective layer around organs

Composition of fats

Glycerol head, three fatty acid tails. It is made of hydrogen, carbon and oxygen

Why are unsaturated fats healthier than saturated fats?

Double bonds make it more difficult to break down into cholesterol and block arteries

Animal fats

Lard, sausages, visible fat, cream, butter, pate SOLID AT ROOM TEMPERATURE

Vegetable fats

Olive oil, avocado, nuts, seeds LIQUID AT ROOM TEMPERATURE

How to cut down on fat

Cut off visible fat, buy low fat foods, buy flora instead of butter, eat less fried foods, use less oil in cooking, eat more chicken and fish and less red meat, use an oil spray, by lean mince and sausages, reduce fat in baking recipes, eat less cakes, pastries, biscuits

Why do we need carbohydrates?

For energy (cheapest source)

How much of the total energy intake should carbohydrates provide?

50%

Main types of carbohydrates

Sugars, starches, dietary fibre/non-starch polysaccharide

Starches

Cereals, bread, take long time to digest

Dietary fibre

Found in pulses, wholemeal/grain foods. Controls blood sugar, feel full for longer, humans cannot digest it, helps with constipation

Water soluble vitamins

BC

Vitamin B functions

Healthy skin, mouth, energy, healthy nervous system, helps prevent anemia, releases energy.

Vitamin B sources

Fortified cereals, cheese, eggs, milk, meat, cabbage

Vitamin B deficiency symptoms

Fatigue, slow growth, beriberi, anemia, skin problems

Folic acid function

Sources of folic acid

Folic acid deficiency

Prevents premature birth, needed to form red blood cells, prevents neural tube defects in babies

Cabbage, spinach, cress, nuts, seeds

Tiredness, anemia, birth defects

Vitamin C functions

Sources of vitamin C

Vitamin C deficiencies

Formation of bones, helps absorb iron into blood, needed to heal wounds/fractures, antioxidant; prevents cancer risks

Citrus fruits, blackcurrants, green vegetables

Mouth infections, slow wound/fracture healing, scurvy

Vitamin A functions

Vitamin A sources

Vitamin A deficiencies

Healthy mucous membranes, eye formation, antioxidant

Milk, cheese, eggs, fish, carrots, spinach, tomatoes, fortified margarine

Poor eyesight, excess in pregnancy=birth defects

Vitamin D functions

Sources of vitamin D

Vitamin D deficiencies

Absorption of calcium for healthy bones

Fish oils, fortified margarine's, sunlight

Rickets and brittle bones

Vitamin E functions

Sources of vitamin E

Vitamin E deficiencies

Healthy skin, antioxidant

Plant foods, vegetable oils, cereals

Very rare

Vitamin K functions

Sources of vitamin K

For normal blood clotting

Spinach, cabbage, meat, liver

Antioxidant vitamins

ACE Protect body cells from damage and help reduce the risk of cancer

Function of calcium

Calcium sources

Calcium deficiency

Strong bones and teeth, healthy nervous system, blood clotting, muscle contraction

Milk, cheese, butter, yogurt, eggs, white bread

Weak bones and teeth, rickets

Functions of iron

Sources of iron

Iron deficiency

Formation of haemoglobin in red blood cells to carry oxygen

Red meat, breakfast cereals, spinach

Tiredness, anaemia, particularly in menstruating women

Fluoride functions

Fluoride sources

Strengthens teeth making them resistant to acid

Drinking water, seafood, tea

Sodium function

Sodium sources

Maintains correct concentration of body fluids

Table salt, cooked meats, bacon, ready meals

Iodine function

Sources of iodine

Iodine deficiency

Makes the hormone thyroxine and controls body's metabolism

Seafood, milk, green veg, tap water

Slow metabolism and enlarged thyroid gland

Which vitamin aids iron absorption?

Vitamin C

Where do we get nutritional advice from?

Government reports, government departments, food standards agency, NHS, British nutrition foundation, schools food trust

Healthy eating guidelines

Eat less fat, sugar and salt. Eat more dietary fibre and starch. 5 a day

Eight tips for eating well

Base meals on starchy food

Eat lots of fruit and vegetables

Eat more fish

Cut down on saturated fats and sugar

Eat less salt

Do exercise

Drink water

Eat breakfast

How many grams of salt should you eat per day?

6g

What percentage of total food energy should be made up of fat?

35%

How many calories should men aged 11-14 have per day?

2220

How many calories should men aged 15-18 have per day?

2755

How many calories should women aged 11-14 have per day?

1845

How many calories should women aged 15-18 have per day?

2110

DRV iron males

DRV iron females

8.7mg

14.8mg

DRV calcium males

DRV calcium females

1000mg

800mg

DRV sodium males

DRV sodium females

1600mg

1600mg

Why should we follow dietary guidelines?

Avoid obesity, heart disease, diabetes, tooth decay, high blood pressure, strokes, constipation, diverticulitis

DRV

Daily reference value

EAR

Estimated average requirement- for different groups of people

RNI

Reference nutrient intake- amount of nutrient needed for 97% of country

LRNI

Lower reference nutrient intake- enough to meet low needs of some of the population

Safe intake

Amount of food to satisfy needs without being harmful to the body

BMR

Basal metabolic rate- the rate at which the body uses energy when it is warm and resting

Energy dense

Containing high amounts of fat and sugar

What are the main nutrient groups that provide energy?

Carbohydrates, fats and proteins

Which nutrient is most energy dense?

Fats

Glycaemic index

The rate at which carbohydrates are converted into glucose during digestion

What kind of food are converted rapidly and give an immediate burst of energy?

Foods with high glycaemic index

High glycaemic index examples

Cakes, biscuits, sweets, fizzy drinks

What kind of food are converted into glucose more slowly and slowly releasing carbohydrates

Low glycaemic index

Examples of low glycaemic index

Wholegrain products, nuts, seeds, fruit

Which kind of foods contain more dietary fibre

Low glycaemic index

Why are foods with a low glycaemic index healthier than foods with a high glycemic index

They help you stay fuller for longer

What percentage of energy should come from carbohydrates?

50%

What percentage of total energy should come from protein

15%

Digestive process

Food enters the mouth and is chewed

Saliva breaks down cooked starch into sugars

Passes down oesophagus

Pepsin in the stomach breaks down proteins into amino acids

Liver produces bile to emulsify fats

Food is churned in stomach and mixed with gastric juices

Passes through duodenum where proteinase breaks protein into amino acids

Fat is broken down by lipase into fatty acids and glycerol

Carbohydrates broken down into glucose by amylase

Nutrients absorbed into the bloodstream in the ileum

Undigested food and fibre pass into large intestine and excreted through the anus

Importance of water in the diet

Prevents dehydration, regulates body temperature, aids body process such as digestion, makes up blood sweat and urine

How is water lost in the body?

Through urine, faeces, sweat, respiration

Foods with high water content

Cucumbers onions melon cabbage strawberries