What Dr. Timothy O’Shea, author of “Conventional Medicine Vs. Holistic: A World of Difference” says:
Taking synthetic vitamins does not provide the expected effects of the natural products that contain them and worse, it can have a harmful effect on the body. Indeed, the latter can take them for medicines and these purified synthetic molecules can be associated with harmful products (additives, residual products) resulting from their mode of manufacture.
Vitamins are not simple chemical molecules. Synthetic molecules cannot replace the effects of natural vitamins. In fact, vitamins are only active when they are linked to their biological complex, which includes cofactors and other essential components. The action of vitamins results from a succession of biological functions that are dependent on a large number of parameters, including their environment.
Vitamins cannot be isolated from their complex and are only effective in cells.
In other words, synthetic vitamins are anything but vitamins with expected benefits.