Protein

Macronutrients are needed by the body in large amounts. Protein, fat and carbohydrates are macronutrients.

Protein:

• Protein is present throughout the human body
• Protein is a secondary energy source
• One gram of protein provides 4 kcals of energy 

There are four functions of protein in the body:

Growth, Energy, Repair and Maintain ( Germ)

Enery is second in the list as protein is a secondary source of energy; most energy comes from fats and carbohydrates 

Functions of protein in the body: Growth, repair, maintain tissue and is a secondary source of energy

Sources of protein: 

  -High biological value sources: Meat, fish, eggs, milk, cheese, mycoprotein (quorn)

  -Low biological value sources: Cereals ( rice, oats), wheat, peas, beans and lentils, nuts and seeds 

If you dont get enough protein you experience poor growth, thinning hair/ hair loss, catching infections easily, fluid under the skin (oedema) 

If you get too much protein it puts strain on kindneys and livers and you gain weight as extra protein is converted into fat 

• Proteins are made up of builiding blocks called amino acids 
• The body can make amino acids but some can only be obtained from food- these are called essential amino acids. There are eight essential amino acids needed by adults and children, and at least two more needed just by children becuase they are growing 
• Foods that contain all the essential amino acids are described as high biological value (HBV). These include soya beans and soya producst, and quinoa 
• Foods that lack one or more of the essentail amino acids are described as low biological value (LBV)

• Combining LBV protein foods to form an HBV protein meal is known as protein complementation
• Protein complementation is needed to make sure that vegetarians get all the essential amino acids 
• The essential amino acids lacking in one of the LBV foods will be provided by the other LBV food 
• An example of this is beans on toast. Beans on toast seperately are both LBV foods, but together they become HBV protein as, when combined, all of the essential amino acids are present 
• Protein complementation can save money because LBV foods tend to be cheaper than HBV foods

• Protein alternatives provide protein from plant or vegetable sources
• They are important for people who don't eat meat or animal products 
• There are three main protein alternative: Soya ( textured vegetable protein (TVP)  tofu); mycoprotein (quorn); and quinoa ( a bead- shaped seed). All of these are HBV

Soya:

• Fresh soya beans are known as edamame beans and are eaten in salads 
• Dried soya bens can be made into TVP, tofu, soya milk, tempeh and miso

Mycoprotein:

• Quorn is made from mycoprotein, a type of fungus grown under special conditions

Quinoa:

• Quinoa are tiny seeds used in many dishes ( curries, soups, salads)

• Boys aged 11-14 require 42.1g of protein each day
• Girls aged 11-14 require 41.2g of protein each day 
• Men require more protein than women as they are generally bigger
• Babies and children require lots of proetin because they are growing
• Teenagers needs more protein to support their rapid growth spurt 

Deficiency and excess of protein:

• Protein deficiency is very rare in the developed world 
• Kwashiorkor is a deficiency of proetin and energy. Children suffering from kwashiorkor have poor growth rates and persistent infections