In most cases, there is little difference between synthetic and natural vitamins. Vitamins do not exist alone or apart from food unless they are synthesized in the laboratory or are extracted from food. In the latter case, they are exposed to chemical solvents during both their removal from the original food source and their concentration into tablets, capsules, or pills. What began as natural ends up as a highly refined and processed product. In many cases, the word “natural” is used on a vitamin or mineral supplement to indicate that the product is free of preservatives and additives.
Little scientific evidence exists to justify the use of natural over synthetic for most vitamins. Studies show the synthetic forms to be as effective as natural forms in the treatment and prevention of disease and the maintenance of health.
There are exceptions to this rule. Limited research does suggest that the natural form of vitamin E might have greater biological activity than the synthetic form of the vitamin. The natural yeast forms of selenium and chromium might have greater activity and safety than the inorganic forms.