All we have to be deficient in is one micronutrient and we cannot survive. It is silly that mainstream medicine provides little more than lip service to celllular biochemistry and the absolute necessity of micronutrients. Most of us don't realize that it only takes 6 weeks of no vitamin C intake to develop scurvy!
Yet major deficiencies exist in most of the US. The USDA has done at least three studies on tens of thousands of people documenting this. We should be eating food that is fresh, unadulterated with pesticides, additives, preservatives, and not processed. What we eat is just the opposite!