In Robert Sapolsky's talk in the post below, he describes how the chemical messenger dopamine operates when humans and other primates engage in goal orientated activity (work). It seems that when the brain gets the signal that activity is to be performed with the promise of reward dopamine levels go up - until the work is finished and in fact the levels of dopamine can back to the original levels by the time the reward arrives. It's seems that it's the anticipation that triggers the rise of dopamine rather than the reward itself.
Dopamine is quite a euphoriant - the effects of cocaine for example are based on it. So we can see how it is possible to get such a kick out of work and goal orientated tasks. Dopamine improves motivation and satisfaction, helps us pay attention, improves memory and cognition, enjoyment of activity and movement. It is deficient in cases of attention deficit disorder.
An interesting piece of research that Robert Sapolsky draws attention to is that the dopamine levels rise highest when there is a 50% chance of reward - there is even more euphoria from goal orientated activity when there is an element of risk it seems. It seems that the uncertainties and need to perform well to get the reward boost levels of this brain enhancing chemical. This gives us a biochemical explanation of the enjoyment of engaging in some kind of self-directed enterprise over a wage paid job!
Of course there are many implications of all this but the one that really strikes me is the intense satisfaction of working hard towards a inspiring visionary goal for the future and being able to forego some instant pleasures in lieu of this. And as well as short term goals to have a magnificent long term goal that includes them and yet stretches out into a time when we transcend all this seems to me to be key to the greatest life satisfaction right now. With our cerebral hemispheres restored, we don't yet know quite how our brain biochemistry would operate and we don't know whether this perception of goals in the future would be part of the picture, but for now it seems essential for our mental well-being.
On the food front, in order to have the raw materials to make dopamine we need enough of the amino acid tyrosine in our diet. Animal derived sources (such as raw dairy in the vegetarian sphere) are much richer in tyrosine than plant sources. Unfermented soy can inhibit conversion of tyrosine into dopamine. Also watch out for caffeine which boosts dopamine levels for a while after which they crash - as with some other stimulants. Caffeine also lowers serotonin levels.
Thyroid hormones are needed to convert tyrosine to dopamine and it is important that the the thyroid gets enough iodine, a mineral which so often lacking in our diets because of depleted soils - we can include sea vegetables, unrefined sea salt, kelp or a more concentrated iodine supplement. Chlorine and fluoride in tap water interfere with uptake of iodine so stick to spring water or purified water and avoid fluoride toothpastes.
Omega 3 fish oils (try fermented fish oil - also rich in fat soluble vitamins) are helpful especially if you also avoid heated and processed vegetable oils which compete with the omega 3's. Vitamin D is a hormone that directs the conversion of tyrosine into dopamine and the related neurotransmitters adrenaline and norepinephrine. It orchestrates much of this action through its relationship with calcium which is involved in controlling brain cells. So now we are getting to this time of year in the northern latitudes get to a sunshower/sunbed or eat vitamin D rich foods like raw butter. For these darker months the sun does not rise high enough in northern latitudes to give the UVB light necessary for us to manufacture vitamin D from sun exposure.
There is a list of raw dairy suppliers including raw butter here.