Do you know what are the best ways to take these minerals for maximum absorption:
Zinc piccolinate- 25mg twice daily.
L-Selenomethionine- 200mcg 2 to 3 times daily.
Magnesium citrate- 300mg 2 to 3 times daily. It is best to start out with twice a day, then work up to 3 times daily if needed. This will help the body to become accustomed to the dose to help prevent developing diarrhea.
What is yours recommendations? With food or on an empty stomach with water or other way...?
Minerals should be taken with food in nearly all cases. Especially zinc, which can cause severe nausea if you do not have enough food in your stomach. And taking them with water or juice is best. I do not advise taking them with coffee or tea.
I take magnesium citrate with 1 gram vitamin C or fresh squeezed apple juice at the same time. Will this enhance the ability of absorbing the magnesium or I should take it obligatory with protein food?
The vitamin C and apple juice will really make no difference. The reason is that it is already in an absorbable salt form. If the magnesium was in the form of an oxide/hydroxide or as a carbonate then the vitamin C and apple juice would be beneficial as the acids would again convert the poorly absorbed forms of magnesium in to better absorbed salts (magnesium ascorbate, magnesium malate primarily).