2. Food Nutrition and Health

• What are the three macronutrients?

  Carbohydrates, proteins, fats
• Protein is made up of amino acids
• Essential amino acids - the eight amino acids that need to be provided by the diet. Children require an additional two.
• What is the function of protein in the diet?

  Growth, repair, maintenance.

  Also a secondary energy source.
• Sources of protein:

  • Animal sources - meat, fish, poultry, milk, eggs, cheese
  • Plant sources - soya, nuts, seeds, mycoprotein, TVP
• What is mycoprotein?

  Quorn - grown from a fungus called Fusarium which is fermented.

  Used as a vegetarian meat alternative.
• What is TVP?

  Texturized Vegetable Protein
• What is a biological value?

  The amount of essential amino acids present in a protein.
• Examples of HBV (High Biological Value) Proteins:

  • Animal protein sources
  • Mycoprotein (Quorn)
  • TVP
  • Soya (which is a plant protein, the only exception)
• Examples of LBV (Low Biological Value) Proteins:

  • Plant protein sources
• What is protein complementation?

  Eating LBV proteins together to provide all the essential amino acids

  This is important for vegetarians and vegans

  Example: Beans on toast
• Protein excess:

  • Used as energy
• Protein deficiency:

  • Kwashiorkor - a severe form of protein malnutrition
  • More likely in developing/poor countries
• What groups of people need more protein and why?

  Babies & Children - for growth

  Adolescents - for growth spurts

  Pregnant women - for the growing baby

  Nursing mothers - for lactation (milk production)
• Fat can be solid or liquid, and is made up of fatty acids and glycerol.
• Fatty acids can be saturated fats, or unsaturated fats.
• Function of fat in the diet:

  • Is a source of fat-soluble vitamins (ADEK)
  • Provides protection for the major organs in the body
  • A component of hormones
  • The third energy source, that provides concentrated energy
• Saturated fats:

  • Increase the cholesterol level in the blood
  • Too much can cause health problems (CHD, CVD, high BP)
  • Examples are butter, ghee, lard, and coconut oil
• Unsaturated fats:

  • Help reduce cholesterol in the blood
  • Examples are nuts, seeds, avocados, vegetable oils, and oily fish
• Hydrogenation - turning a liquid oil into a solid fat.
• Fat Excess:

  • Leads to weight gain, obesity, and other medical conditions
  • Excess saturated fats increases cholesterol levels
  • Could cause coronary heart disease (CHD), cardiovascular disease (CVD) and high blood pressure, as well as some cancers
• Fat Deficiencies:

  • In babies and children, can affect normal growth
  • Could result in a poor supply of fat-soluble vitamins (ADEK)
• Three main types of carbohydrates:

  • Sugars
  • Starches
  • Fibre
• Carbohydrates are produced by plants during photosynthesis.
• Carbohydrates are classified as:

  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides:

  • Simplest form of a carbohydrate structure
  • Glucose - all carbs are converted into this in the body
  • Galactose - from the milk of mammals
  • Fructose - found in fruit
• Disaccharides:

  • More complex sugars that are formed when two monosaccharides join together
  • Sucrose
  • Maltose
  • Lactose
• Polysaccharides:

  • Many monosaccharides joined together
  • Starch - lots of glucose
  • Glycogen - formed after digestion
  • Dietary fibre
  • Dextrin - sugars that are formed in dextrinization, makes food turn golden brown
  • Cellulose - formed by plants from glucose
  • Pectin - found in fruit, forms a gel, used in jams
• Sugars are digested quickly in the body, providing instant energy.
• Eating starchy foods is better than eating sugary foods.
• Starches have to be digested into sugars before absorption - large, but slow energy release.
• Starch is found in bread, pasta, rice, breakfast cereals, and potatoes.
• Carbohydrate excess:

  • Converted to fat, stored under the skin, causes obesity
  • High sugar is linked to type 2 diabetes.
  • Excess sugar, causes tooth decay
• Carbohydrate deficiency:

  • Exhaustion & fatigue
  • Losing weight - the body starts to use protein and fat for energy
• Dietary fibre:

  • Also called Non-Starch Polysaccharide (NSP)
  • A type of carbohydrate that can't be digested to provide energy
  • Soluble NSP - absorbs water, forms a gel-like substance
  • Insoluble NSP - not absorbed, passes through body as waste, helps prevent bowel diseases
  • Dietary fibre can be found in wholemeal bread, wholegrain breakfast cereals, wholemeal flour, fruits & veg, nuts, and seeds
  • Adults should consume at least 18g of fibre a day
• Dietary fibre excess:

  • Constipation
  • Bloating
• Dietary fibre deficiency:

  • Constipation
  • Diverticular disease - pouches form in the intestines, which become infected with bacteria
  • Bowel cancer
• How many fat-soluble vitamins are there?

  Four - Vitamin A, Vitamin D, Vitamin E, and Vitamin K
• What is Vitamin A called?

  Retinol
• Function of Vitamin A:

  • Normal iron metabolism
  • Maintenance of normal vision
  • Maintenance of skin and mucus membranes
  • Maintenance of healthy immune system

  Sources of Vitamin A:

  • Carrots
  • Green leafy vegetables
  • Whole milk

  Deficiency:

  • Causes night blindness

  Excess:

  • Toxic, could cause liver and bone damage