Nutrition Myths

Essential Amino Acids

Amino acids are components of proteins and are used for such essential functions as protein synthesis, hormone, enzyme production and growth and repair of the tissues.

Amino acids are divided into three categories: (1)

  • Essential amino acids (our bodies cannot produce them and therefore they must come from our diet). There are 9 essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. We don’t need to eat essential amino acids with every meal, but should have the full range throughout the day.
  • Non-essential amino acids (our bodies produce them, so we don’t need them from the diet). They include: alanine, asparagine, aspartic acid and glutamic acid.
  • Conditional amino acids (only needed during illness or stress). They include: arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline and serine.

Limiting amino acids

If certain amino acids are not available in sufficient amounts from the diet, protein synthesis cannot proceed beyond the rate at which those amino acids are available and hence are referred to as limiting amino acids. In other words the proteins production in the body can be only done at a rage of the slowest supplied (limiting) amino acid.

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