Holistic nutrition should consider the human being in its entirety as a holobiont, a complex mixture of various species of microbes and eukaryotic cells. Given this paradigm, only merging together the knowledge derived from state of the art science can allow us to integrate the needs of the holobiont with the data from nature . Accordingly, the decrease in micronutrient qualitative and quantitative composition in our soil force us to reconsider the need for supplementation as a means for obtaining the maximum benefit from foods: the supply of vital micronutrients (vitamins and minerals). Supplementation is now becoming a must. Reasons will be explained and solutions discussed. Certain fundamental vitamins and their daily amounts will be introduced briefly focusing on their support for the holobiont. Overall, the necessity to define practical quantities of micronutrients beyond those already specified by Health Authorities are briefly evaluated. Special importance is given to two key micronutrients which have peculiar properties of regulators of the delicate equilibrium within the holobiont: vitamin C and iodine. In conclusion, it is proposed that a safe and maximally beneficial range of micronutrients can be set at about 40 times the average daily allowance as identified by HA. The end-result is to allow the holobiont to regain the equilibrium sought by ancient medicine.