Vitamin D is not a cure, wit. C does not cure, iodine is not a cure.
Life verify the hypothesis. The human body jast so complex that it is difficult to predict all the variables in the study. Practice (force) gives a true and harsh assessment of the effectiveness of the substance. Clinical trials can remove a large part of the question. Spin theory, dywagować on paper, you can always .... Fu** with the theory, practice counts. Practice = effectiveness or not