Thinking Kabbalistically, Jupiter as a higher octave of Venus on the tree of life is also concerned with the synthesis of nutrients, via the function of the Liver.  What is broken down by the Mars and Mercury (Pillar of Severity) digestive processes is further processed in the body’s main chemical factory, the liver.  This relationship between Jupiter and Venus has to do with the utilisation of Insulin (secreted by the pancreas in response to dietary glucose) for the transport and final breakdown of glucose to be used or stored by the liver as glycogen.   Jupiter therefore is also concerned with the production and storage of body fat as evidenced in those whose diets are rich in high calorie nutrients – such as sugar and fat. 

It may be that Jupiter correlates with the accumulation of acid in the body through the Jupiterian tendency of over-eating of rich food.  The accumulation of acidic residues creates a balancing response from Mars which attempts to cleanse the body through its action of inflammation.  The excesses of a modern western diet, fuelled by excessive alcohol consumption, often leads to an inflamed liver and general liver heat which requires the balancing of the excess condition through detoxification and cooling yin foods and remedies.  Hence the balancing act of Mars and Jupiter, one encouraging accumulation and the other corruption and reduction.  The liver is also influenced by Virgo and Mercury which discriminates and disseminates that which is useful from that which is waste. 

The activation of the master gland the pituitary, ruled by Jupiter and located at the Ajna chakra, creates a spiritual awakening that brings us awareness of our one-ness with the true Source.  The pituitary secretes growth and puberty hormones (as you would expect from a rulership of Jupiter) as well as thyroid stimulating hormone which encourages the thyroid to make and release thyroxin which is vital for a number of body processes from heart health to metabolism.  This is also why aggressive transits from Jupiter to Venus and/or Mercury are often implicated in hyper-thyroidism  which can cause goitre and thyroid eye disease.