PROTEIN : Understanding Amino Acids

PROTEIN : Understanding Amino Acids

Protein is a vital part of our chemistry and is derived from dietary sources. They contain one vital compound which our bodies cannot integrate in it’s pure form – nitrogen. Proteins form a major part of lean body tissue and cells consist of about 15% protein in total mass (water being the other major component). Proteins are needed for regulation and repair of the body, visual processes, synthesis of enzymes & some hormones, blood components and is sometimes used for energy. Protein as an energy source provides about 4 Calories/gram and are only used as a last resort to glycogen and fatty acids (as in starvation situations.)

The basic unit of proteins are amino acids. When we eat proteins they are broken down to individual amino acids before being reconstructed into usable proteins for various functions. There are 20 standard amino acids normally found in the diet – most of these can be synthesized in the body with carbohydrates and lipids but 9 are essential. This means we MUST consume these in order for adequate amino acid intake and for complete protein synthesis, going without any one of these 9 essential amino acids for long periods can occur in protein deficiency.

  • Histidine
  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophane
  • Valine
  • (Arganine – essential only in growing children but not in fully grown adults)

How do we make sure we eat the 9 essential amino acids?


Protein sources in the modern diet can be derived from animal, plant and supplement forms. The following table can help you identify sources of complete and incomplete protein sources.



  • animal muscle tissue
  • animal organ tissue
  • eggs
  • milk products
  • soy bean products (tofu, soy milk)
  • goji berry
  • bee pollen
  • spirulina
  • AFA blue green algae
  • marine phytoplankton
  • hempseed
  • grains
  • cereals
  • legumes
  • nuts
  • seeds
  • vegetables


Include any animal meats, product derived from animals and the listed plant protein where eating from these sources ensures you will consume all 9 essential amino acids. Plant sources also provide additional benefits of a variety of vitamins, minerals and phytochemicals. All highly beneficial for your body.

Complete Protein Sources - Egg & Meat
Complete Protein Sources – Egg & Meat


Must be eaten in conjunction with each other (not necessarily at the same meal) so that complete amino acid levels in the body are reached.

Incomplete Protein Sources - Nuts & Fruit
Incomplete Protein Sources – Nuts & Fruit
This diagram can help you remember what plant sources complement each other to ensure you consume all 9 amino acids daily when eating from protein plant sources.  # - missing amino acid
This diagram can help you remember what plant sources complement each other to ensure you consume all 9 amino acids daily when eating from protein plant sources.
# – missing amino acid


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We need protein for

–       growth (especially before adulthood)

–       recovery from illness or injury

–       forming hormones and enzymes

–       immune functions (proteins form antibodies to help fight antigens)

–       forming glucose (when carbohydrates aren’t available the liver synthesizes glucose from proteins)

–       provide energy (only during prolonged exercise and calorie restriction)

–       maintenance of blood fluid pressure

–       regulation of acid/base balance

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If you’re aiming to gain lean muscle mass (bulk up, get buff, cut up or whatever you’d like to call it), are training hard for a marathon, or if your career choice has high physical involvement (dancer, sportsman or manual labourer) a good idea would be to increase your protein intake so your body can repair and build after your hard work.

The recommended protein intake for daily consumption under normal circumstances is 0.8g/kg of healthy body weight. For example

65kg person X .8 = 52g

For people undertaking a high level of physical activity some experts suggest increasing this to 1.7g/kg of healthy body weight. For example

65kg person X 1.7 = 110.5g


The modern diet and abundance of protein sources means we usually hit & exceed this amount.

If you’re aiming to lose weight protein leaves you feeling much more satisfied after a meal than carbohydrates or lipids making it a great choice if you’re finding it hard to feel satisfied after meals. Complete protein sources also don’t affect  blood sugar levels as much as carbohydrate sources so are great for people who need to keep their insulin levels in check.

When protein is used as an energy source it’s breakdown products are H2O, CO2 and nitrogen. The body can’t use this nitrogen so it’s converted into urea which is excreted in urine. This is a result of excessive protein intake (other factors are fluid and sodium intake) so if you find you’re going to the toilet more when increasing protein intake, don’t be alarmed!

I hope that helps you in understanding this important macronutrient more. You should be able to consider the amount of protein you need with this information to help you reach your health and fitness goals.


1 – Marieb, E. & Hoehn, K., ‘Human Anatomy and Physiology’ Pearson Education

2 – Byrd-Bredbenner C., Berning, J., Beshgetoor, D., and Moe, G, Contemporary Nutrition – A Functional Approach, McGraw Hill, New York

3 – H. Stephen Stoker, ‘General, Organic, and Biological Chemistry’, 2013

4 – Mary Dan Eades. “Protein Power: The High-Protein/Low-Carbohydrate Way to Lose Weight, Feel Fit, and Boost Your Health–In Just Weeks!”, 1996

I'm currently studying a Bachelor in Health Science - Nutritional Medicine with a background in dance and fitness. I believe sharing knowledge is the key. I hope my love for food, fitness and well-being along with my studies helps you in finding something useful. Enjoy!

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