Nutrition - Paignton Online

Nutrition

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Energy The sun provides solar energy.

Plants convert solar energy into chemical energy through photosynthesis. The chemical energy is stored as glucose.

Animals eat plants and use them as an energy source.

Humans eat plants and animals. The nutrients they contain supply our energy needs.

Energy is needed by anything that does work. We measure energy in kilojoules (4.2 kJ = 1 Calorie). Our bodies do work when we breathe, move and grow and they need energy to do all these things. However, if we take in too much energy, our body stores it as fat.

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Energy in food

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Nutrients in food Foods contain nutrients – these are substances we need to help us live and grow. The main nutrients we need are: protein

fat carbohydrates. These provide our bodies with energy. Our bodies also need: vitamins minerals fibre

water. 4 of 29

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Protein Protein comes from meat and fish, eggs, dairy foods, cereals and pulses. Proteins are made from amino acids. Protein is needed to grow and repair body cells. It also provides energy. Babies, children and pregnant women need more protein than the average adult.

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Protein in food

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Carbohydrates Carbohydrates are made up of two main groups: starches and sugars.

About 60% of the carbohydrate in British diets comes from starch.

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Carbohydrates – sugars Sugars are found in cakes, biscuits, desserts, milk, fruit and vegetables. The most common sugars are glucose, fructose (fruit sugar) and galactose. Sugars, especially glucose, provide an instant burst of energy to the body. If the diet is low in glucose, the body will make it up using protein. Most of us eat too much sugar, which is bad for our teeth and can make us fat.

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Carbohydrate – starches Cereal, pulses, pasta and potatoes all contain starches. Starches are made from long chains of glucose molecules. These chains need to be broken down to produce glucose, from which energy is released. Starches release glucose more slowly than sugars and so energy is released over a longer period of time. How much we need depends on how active our bodies are. We need more energy for running than for sitting still. 9 of 29

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Carbohydrates in food

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Who needs what and why?

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Fat Fats are made up of glycerol and different types of fatty acids. Saturated fats tend to be solid at room temperature (like butter), unsaturated fats tend to be liquid at room temperature (like olive oil). Fat provides energy and we need it to absorb some fat-based vitamins. Milk and cheese, meat, eggs, nuts and seeds all contain fat.

Too much fat, particularly saturated fat, is bad for health, and no more than one third of our energy should come from fats. 12 of 29

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Fat in food

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Know your potatoes

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Vitamins Vitamins are a range of substances that our bodies need to stay healthy. Each vitamin has a different job to do. We only need small quantities of vitamins but it is important that we include all of them in our diet.

We should be able to get all the vitamins we need from the foods we eat, but vitamin supplements can be useful if our diet is missing important nutrients.

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Vitamin A You can always find me in carrots, eggs and cheese

You need me to form teeth and bones.

I also help you to grow!

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Vitamin B Pyridoxine (B6) is essential for the production of red blood cells. Vitamin B12 helps with growth.

Niacin (B3) is necessary for the digestion of food and a healthy nervous system.

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There are lots of different B vitamins.

Thiamin (B1) is good for your nervous system, and is found in wholemeal grain, green vegetables and pork. Riboflavin (B2) gives you healthy hair, skin and nails and is in liver and marmite. © Boardworks Ltd 2004

Vitamin C

I’m found in citrus fruit, strawberries, tomatoes and peppers.

I help your cells grow and stay healthy.

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Vitamin D

I’m special – I help you to absorb calcium to give you strong bones and teeth.

I’m found in oily fish and eggs and can be made by sunlight.

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Vitamin E I help build body cells, protect lungs from damage by pollution, slow the aging process and lower the risk of heart disease!

You’ll find me in vegetable oil, cereals and nuts.

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Minerals Minerals are substances required to keep our bodies healthy. The important ones are: calcium magnesium phosphorous potassium sodium. We also needs small amounts of copper, iron, zinc, iodine, fluoride and selenium. 21 of 29

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Major minerals Mineral

Main Function

Main Sources

Calcium

Makes bones and teeth strong. Milk, cheese, yogurt and Helps blood clotting and nerve canned fish are rich function. sources.

Sodium

Regulates our body’s water content. Helps nerve function.

Salt

Potassium

Helps functioning of cells.

All foods except sugars, fats and oils.

Magnesium

Involved in energy transfer and Wholegrain cereals, nuts in cell and muscle functioning. and spinach are good sources.

Phosphorus Makes bones and teeth strong. Milk, cheese, meat, fish Helps us get energy from food. and eggs are good sources.

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Trace minerals Mineral

Main Function

Main Sources

Iron

Makes red blood cells, which carry oxygen around the body.

Red meat and offal are rich sources.

Zinc

Essential for growth.

Milk, cheese, meat, eggs and fish, wholegrain cereals and pulses.

Iodine

Formation of thyroid hormones.

Milk, seafood, seaweed. Iodised foods such as salt.

Fluoride

Helps to make tooth enamel strong.

Fluoridated water, tea, fish and toothpaste.

Selenium Acts as an antioxidant. Protects cell membranes against oxidation.

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Cereals, meat, fish, offal, cheese and eggs.

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Fibre What is it? Fibre helps us to feel full and we need it to digest our food (prevents constipation and diseases of the bowel) but it provides no energy or nutrients. Where does it come from? Wholegrain breads, cereals, pulses, nuts and dried fruit. How much do we need? We should take in about 18g of fibre a day but the average intake in western countries is half that.

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Getting your daily fibre

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Drink lots of water! Water makes up three-quarters of our body weight and is essential to all forms of life.

To maintain a healthy body we should drink between six and eight glasses of water a day.

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But does it really matter? Our diet isn’t the only reason we become ill, but studies have proved that a poor diet can increase our chances of getting cancer or suffering from heart disease.

We should look at our diet as part of our lifestyle. Improving it, together with not smoking and taking exercise can make a real difference to whether we keep well. The rules are simple, as the next screen shows.

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Rules for healthy eating

Enjoy your food! Eat a variety of different foods. Eat the right amount to be a healthy weight. Eat plenty of foods rich in starch and fibre. Eat plenty of fruit and vegetables. Don’t eat too many foods that contain a lot of fat. Don’t have sugary foods and drinks too often.

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Summary To keep them fit and healthy, our bodies need the correct balance of: protein fat carbohydrates vitamins minerals

fibre water.

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