Food, Nutrition and Health

• Protein- Needed for growth, repair and maintenance
• Protein examples- meat, fish, dairy, nut, seeds and beans
• Proteins- made up from amino acids- thought as the building blocks of the body (we have to eat the amino acids that our body cant eat- called essential amino acids)
• Proteins:

  • Growth- eg. childhood to adulthood, growth of nails, hair and muscle mass
  • Repair- repairing our muscles, tissues and organs after illness or injury
  • Maintenance- eg. to make enzymes for digestion and antibodies to stop us getting ill
• Proteins have different biological values:

  • High Biological Values (HBV)- contain all essential amino acids, mainly found in animal sources (meat, fishh) but also soya beans and quinoa
  • Low Biological Value (LBV)- missing one or more of the essential amino acids we need, only found in plant sources
• Protein complementations: (combine LBV protein foods):

  • If we don't get enough HBV protein, we have to combine different LBV proteins to get all the essential amino acids.
  • Eg. hummus and pitta are LBV protein foods as they are missing some essential amino acids, so when eaten together, they provide all the essential amino acids
• Protein amounts:

  • Average male- 55g (each day)
  • Average female- 45g (each day)
• Protein Deficiency:

  • Growth is slowed down as hair, nails and skin don't grow as fast
  • Immune system can't work properly, so wounds don't heal as quickly
  • Struggle to digest food properly, so some nutrients aren't taken into the body
  • Can lead to oedema (build up of fluid which can cause swelling)
• Protein Excess:

  • Puts lots of pressure on kidneys and liver and strains these organs, which can be dangerous
• Protein Alternatives:

  • Soya
  • TVP (Textured vegetable protein eg)
  • Mycroprotein (made from mushroom-like fungus and egg whites)
  • Tofu
• Fats- provide energy, nutrients and insulation
• Why do our bodies need fat?:

  • Provide concentrated source of energy
  • Source of fat-soluble vitamins- A,D,E,K
  • Forms insulating layer under skin, helps us keep warm, protect our bones and organs
  • Fat makes cholesterol, essential part of all cell membranes
• Fats contain:

  • Fatty Acids (saturated and unsaturated)- fatty acid chains are made of carbon and hydrogen. Saturated fatty acids only have C-C bonds, unsaturated fatty acids contain at least one C=C bonds
  • Glycerol in the form of triglycerides
• Saturated Fats:

  • Bad for health
  • Classed as unhealthy fats
  • Solid at room temperature
  • Tend to come from animal sources but also plant sources like coconut butter
  • Too much can increase cholesterol levels which can increase risk of coronary heart disease
• Unsaturated fats:

  • Better for health
  • Generally soft/liquid at room temperature
  • Come from vegetable sources
  • Can be monounsaturated and polyunsaturated
  • Monounsaturated- contain one C=C double bond in their carbon chain, found in foods like olive oil, almonds and peanut butter
  • Polyunsaturated- contain more than one C=C double bond, only found in foods such as seeds and oily fish
• Fats make up- less than 35% of our daily food energy
• Fat deficiency:

  • Less fat-soluble vitamins are absorbed into the body (A,D,E,K) which causes vitamin deficiency
  • Lack of carbohydrate which means the body will start to use its fat store for energy, so not eating enough fat can cause weight loss
  • Less insulation to keep body warm
• Fat excess:

  • lead to weight gain then obesity
  • lead to health issues like type 2 diabetes where the body struggles to control blood sugar levels
  • too much saturated fats can increase blood cholesterol levels, which then cholesterol levels build up in blood vessels such as arteries and restricts blood flow which increases risk of high blood pressure and stroke
• Carbohydrates- needed for energy
• Carbohydrates split into two main types; sugar and starch:

  • Sugar- eg. glucose and fructose can be found in food naturally or can be added to food during the manufacturing process- have no other nutritional benefit other than energy
  • Starch- found in lots of people like potatoes, bread, rice, cereals- contain lots of nutrients including B vitamins, iron and calcium, high fibre content
• When eating carbohydrate based food:

  • body breaks down the sugar and starch into glucose which is absorbed into our blood and used by our body for energy
• Glycogen stores get full very quickly so if we continue to consume too many carbs, they get converted into fatty acids and triglycerides which are stored in adipose tissue around the body
• If we eat more carbs than we need, any extra glucose that isn't immediately used for energy gets stored in our liver and muscles as glycogen.
• Simple carbohydrates such as sugar can be divided into:

  • Monosaccharides
  • Disaccharides
• Monosaccahrides:

  • Most basic sugar molecules
  • eg. glucose and frutose
  • body rapidly digests it, making blood sugar rise quickly, providing a short burst of energy
• Disaccharides:

  • Made up of two monosaccharides
  • Eg. sucrose (made up of glucose and frutose)
  • Body rapidly digests it, making blood sugar levels rise quickly, providing a short of burst of energy
• Complex carbohydrates such as starch are polysaccharides:

  • Made up of lots of monosaccharides joined together
  • Eg. starch is made out of lots of glucose molecules
  • Takes longer to digest so they gradually increase blood sugar levels, providing slow and steady release of energy
• Glycaemic Index:

  • Rates how carbohydrates on how quickly they affect blood sugar levels
  • High GI foods are digested quickly and cause rapid rise in blood sugar levels eg. white bread, pasta
  • Low GI foods are digested slowly and cause gradual rise in blood sugar levels eg. wholewheat bread, brown rice
• 50% of our energy comes from carbs
• Excess carbohydrates:

  • Extra carbohydrates will be converted into fat which causes obesity and other diet-related issues
  • As sugars are digested quickly, the energy they provide is ready to use almost immediately and then if it isn't used, its stored as fat
  • Too much sugary foods can lead to tooth decay
  • As simple carbohydrates are digested quickly which cause rapid surges in blood sugar levels which can lead to the development of type 2 diabetes
• Deficiency of Carbohydrates:

  • Blood sugar levels drop which can cause hunger, dizziness and tiredness
  • If we have a fat deficiency, bodies start to use up protein so we lose muscle which makes us weaker
• Micro nutrients-

  • vitamins
  • minerals
  • trace elements
• Fat soluble vitamins:

  • found in fatty foods eg. meat, fish, vegetable oils...
  • A, D, E, K
• Vitamin A:

  • needed for good eyesight
  • needed for growth
  • needed for healthy immune system and skin
  • main source is retinol (found in liver, butter, oily fish)
  • too much can weaken bones
  • too little can lead to night blindness, weaker immune system and stunted growth
• Vitamin D:

  • helps body absorb various minerals including calcium which is important for development of bones and teeth
  • found in oily fish, egg yolks and produces when skin is exposed to sunlight
  • too much makes you absorb too much calcium which can lead to kidney damage
  • too little can lead to bone disease
• Vitamin E:

  • keeps skin and eyes healthy as well as improving immune system
  • found in leafy greens (eg. kale and spinach), nuts, vegetable oils and wheat grain
  • too much can interfere with blood clotting, cause nausea and blurred vision
  • too little is rare but leads to weak muscles and problems with sight
• Vitamin K:

  • helps clot blood, heal wounds and maintain immune system and boes
  • found in leafy greens, vegetable oils, dairy
  • no excessive level
  • too little is rare but can cause uncontrolled bleeding (in newborns)
• Fat soluble vitamins:

  • Any that aren't used up are stored in fat tissue for future use
• Water-soluble vitamins:

  • aren't generally stored in body
  • dissolve in water
  • Examples- B1, B2, B3, B9, B12, C
• Water soluble vitamins:

  • All the Vitamin Bs
  • Vitamin C