What knowledge is of most worth?

Today I shopped for a blood glucose metre with my mum at Unity pharmacy and we were glad to receive so much new info from a pharmacist, as if we had visited a doctor.

Besides demonstrating how to use the metre step-by-step and advising my mum on what types of food to avoid, the pharmacist also recommended a type of supplement Sugar Guard (made from bitter gourd - thus "bitter gourd tablets" in short) to help balance the glucose level in the body.

I feel that it is really cool that pharmacists have such vast knowledge on medicine, health supplements, health-related issues and even operating of health devices. The way that this lady pharmacist spoke, though a bit dramatic (for comic relief, I suppose), did provide us with not less info than if we had visited a doctor. Furthermore, she had recommended us with relevant, inexpensive health supplement which was not something that a doctor would normally do.

I gradually can comprehend what Herbert Spencer (English philosopher, 1820 - 1903) meant when he believed the knowledge that was of most worth was "the knowledge needed to pursue those activities which directly minister to self-preservation". Doesnt that simply mean knowledge on health issues? Of course! How can a soldier save himself and others injured in a war if he has no knowledge on first aid? How well can we keep ourselves from being infected by H1N1 virus if we do not know anything about hygiene practice? When our health is not there, how can we succeed in doing any other things?

Glad that I have always been reading health magazines. :)