Ask the experts
Which vitamin supplements are "natural"?
The answer is: "Nearly NONE."
With the exception of vitamin B12 supplement, ALL vitamin supplements are chemically synthesized. This means that they are produced by combining separate chemical elements in a factory.
Vitamin B12 is biosynthesized. This means that it is made by using bacterial enzymes.
The chemical design of a vitamin can be in one of two forms, similar to a right hand and a left hand. The left hand form (the levo or "l" form) is produced naturally in plants and is much more vitamin-active than the right hand form (the dextro or "d" form).
Synthesized vitamins contain BOTH forms (right and left).
To represent that vitamin supplements are "natural" (except vitamin B12) is therefore doubly misleading. It is misleading because they are manufactured by combining separate chemical elements in a factory. And it is misleading because they contain the right-hand form which does not exist in nature.
Reference: Mayo Clinic Proceedings 74:531-532, 1999.