GCE AS Food GCE AS Food TechnologyTechnology

Fats Fats

(Lipids)(Lipids)

StructureStructure

Fatty acids are made up of three Fatty acids are made up of three elements:elements:

Carbon Carbon Hydrogen Hydrogen OxygenOxygen

What does the body use it What does the body use it for?for?

Excellent energy source, with more than Excellent energy source, with more than twice the energy as either carbohydrates twice the energy as either carbohydrates or protein.  or protein. 

Essential to the structure and function of Essential to the structure and function of body cellsbody cells

Fat soluble vitamins (A D E and K)Fat soluble vitamins (A D E and K) InsulationInsulation Fat is digested slowly by the body and Fat is digested slowly by the body and

therefore make you feel fuller (satiated) therefore make you feel fuller (satiated) for longerfor longer

Saturated and Saturated and UnsaturatedUnsaturated

Saturated fats and trans fats are Saturated fats and trans fats are "bad" fats as they can raise "bad" fats as they can raise cholesterol cholesterol

Unsaturated “good” fats are better Unsaturated “good” fats are better for you, as consuming foods for you, as consuming foods containing "polyunsaturated" and containing "polyunsaturated" and "monounsaturated" fats does not "monounsaturated" fats does not increase cholesterol.increase cholesterol.

Saturated fatSaturated fat If the fatty acid has all the hydrogen atoms it can If the fatty acid has all the hydrogen atoms it can

hold it is said to be saturatedhold it is said to be saturated

   

This type of fat is typically found in large amounts This type of fat is typically found in large amounts in foods from animals, e.g. meat, butter, cheese in foods from animals, e.g. meat, butter, cheese and cream. Many baked goods such as cakes, and cream. Many baked goods such as cakes, biscuits and pastries are also high in saturated biscuits and pastries are also high in saturated fat. Excessive intake of saturated fat can increase fat. Excessive intake of saturated fat can increase blood cholesterol levels.blood cholesterol levels.

Unsaturated FatUnsaturated Fat In unsaturated fats, some of the carbon In unsaturated fats, some of the carbon

atoms are joined to others by a double atoms are joined to others by a double bond and, therefore, could accept more bond and, therefore, could accept more hydrogen atoms. This means that they are hydrogen atoms. This means that they are not completely saturated with hydrogen, not completely saturated with hydrogen, so are called unsaturated fats.so are called unsaturated fats.

There are two main types of unsaturated There are two main types of unsaturated fats - monounsaturated (containing one fats - monounsaturated (containing one double bond) and polyunsaturated double bond) and polyunsaturated (containing more than one double bond).(containing more than one double bond).

Trans-fatty acidsTrans-fatty acids ““Bad” fats because they raise cholesterol.Bad” fats because they raise cholesterol.

Monounsaturated fatty Monounsaturated fatty acidsacids Significant amounts in most types of fats of plant origin, such as nuts, avocado pears, Significant amounts in most types of fats of plant origin, such as nuts, avocado pears,

rapeseed oil and olive oil. Monounsaturates do not raise blood cholesterol and evidence rapeseed oil and olive oil. Monounsaturates do not raise blood cholesterol and evidence shows that they reduce blood cholesterol levels if they replace saturated fat in the diet.shows that they reduce blood cholesterol levels if they replace saturated fat in the diet.

Polyunsaturated fatty Polyunsaturated fatty acidsacids From vegetable sources, such as sunflower oil or seeds, but are also found in, nuts, green leafy From vegetable sources, such as sunflower oil or seeds, but are also found in, nuts, green leafy

vegetables and oily fish such as mackerel and sardines. Reduce blood cholesterol levels.vegetables and oily fish such as mackerel and sardines. Reduce blood cholesterol levels.

Which Fats Are Best?Which Fats Are Best?

Saturated fats, monounsaturated fats Saturated fats, monounsaturated fats and polyunsaturated fats all have and polyunsaturated fats all have proven health benefits so  should be proven health benefits so  should be included as part of your diet.  included as part of your diet. 

Trans fats should be avoided where Trans fats should be avoided where possiblepossible

SourcesSources

When it comes to dietary fats When it comes to dietary fats natural, unprocessed sources are the natural, unprocessed sources are the best foods.  best foods.  - Almonds.- Almonds.- Avocado.- Avocado.- Beef.- Beef.- Coconut.- Coconut.- Eggs.- Eggs.- Salmon.- Salmon.

Omega 3 Fish OilOmega 3 Fish Oil Type of polyunsaturated fat. Type of polyunsaturated fat. Most important fat we need for cell Most important fat we need for cell

reproduction and repair and for making reproduction and repair and for making substances that fight inflammation. substances that fight inflammation.

Cant make omega 3, has to be taken in Cant make omega 3, has to be taken in through diet or supplement.through diet or supplement.

Naturally found in oily cold water fish like Naturally found in oily cold water fish like tuna, salmon, and sardines. tuna, salmon, and sardines.

Vegetable sources include pumpkin seeds, Vegetable sources include pumpkin seeds, flax seeds, and walnuts. flax seeds, and walnuts.

Some products, such as margarine, Some products, such as margarine, yoghurts and eggs, are now enriched with yoghurts and eggs, are now enriched with omega-3 fats. omega-3 fats.

Exam style QuestionsExam style Questions

Fatty acids are made up of which Fatty acids are made up of which three elements?three elements?

Which fats are said to raise Which fats are said to raise cholesterol?cholesterol?

What are the two main types of What are the two main types of unsaturated fats? unsaturated fats?

What type of fat is omega 3?What type of fat is omega 3?

Answers:Answers:

Carbon, Hydrogen, OxygenCarbon, Hydrogen, Oxygen Saturated and TransSaturated and Trans Monounsaturated (containing one Monounsaturated (containing one

double bond) and polyunsaturated double bond) and polyunsaturated (containing more than one double (containing more than one double bondbond

PolyunsaturatedPolyunsaturated