First isolated in the 1930s, vitamin B6 is a highly water soluble vitamin of vital importance to human health An adequate dietary supply is essential because the vitamin cannot be manufactured by the body, and is required for the proper action of more than 100 enzymes involved in vital biochemical reactions

Back in the 1930s, thiamine, also known as vitamin B1, was one of the first compounds to be isolated and recognised as a vitamin, that’s to say a compound essential to health which the body cannot manufacture for itself, and which must therefore be obtained from the diet The functions of thiamine within the body are highly complex biochemically, but what’s important to know is that thiamine and its associated enzymes are essential for the body’s production of energy from food

Green tea became well known in China during the period of the Tang dynasty (AD 618–907) and was quickly prized as a promoter of health and vitality There’s good evidence, however, that its many benefits had already been known to the elite for thousands of years by then

Tryptophan is one of the “essential” amino acids; “essential” in this context meaning that it cannot be produced by the body, and must therefore be obtained from dietary sources The best dietary sources of tryptophan are the animal proteins known as first class proteins because they contain all ten essential amino acids; principally meat, including poultry, fish and dairy produce

Glutamine is one of the amino acids which are described as “non-essential”, but this should not in any way be taken as implying that it is unimportant In this context the term “non-essential” simply means that the amino acid in question can be synthesized within the body and therefore need not necessarily be obtained from food sources