Vitamins: natural or synthetic?

Vitamins: natural or synthetic?
Vitamins: natural or synthetic?

Chemistry enables us to synthesize molecules that are similar to natural molecules. However, the chemical molecules are not always the exact copy of their natural counterparts, and some differences may have an impact on their biological activity.

Different chemical structures

Indeed, the chemical structure of a molecule can determine its absorption, transport, storage or even its deterioration and therefore determine its overall effect. The following table lists the structural differences frequently encountered between natural vitamins and minerals and synthetic vitamins and minerals (1-2).

Vitamins / Minerals Salts



Vitamin B1

Free or esterified thiamin. Unphosphorylated.

Thiamin mononitrate or

thiamin hydrochloride

Vitamin B2

Riboflavin linked to coenzymes

Isolated riboflavin

Vitamin B3

Nicotinamides linked to

coenzymes, nicotinic acid

Niacin, nicotinic acid, nicotinamides

Vitamin B5

Pantothenic acid linked to

coenzymes, pantothenate

Pantothenic acid, pantothenol, calcium pantothenate

Vitamin B6

Free or glycosylated pyridoxine

Pyridoxine hydrochloride or


Vitamin B9

Folates (polyglutamates)

Folic acid (monoglutamate)

Vitamin C

L-ascorbic acid, dehydro-L ascorbic acid

Ascorbic acid, sodium ascorbate

Vitamin E

RRR-α-tocopherol and the

beta, gamma and delta forms, tocotrienols

8 stereoisomers of α-tocopherol (racemic mixture), tocopheryl acetate


Organic salts
E.g.: Selenomethionine

Inorganic salts
E.g.: Selenate and sodium selenite

The two major categories for sources of trace elements and minerals are inorganic salts and organic sources.

Among the common inorganic salts are: sulphates, oxides, chlorides and then the carbonates of the elements involved. The other category, organic, often uses the denomination “chelates”, which refers to the form linked to amino acids, proteins, polysaccharide complexes or the complexes derived from yeasts.

| These forms generally allow an improvement in intestinal absorption and bioavailability because they stabilize and make the organic salts less reactive in the digestive tract.

A synergy of action with co-nutrients

Generally speaking, natural vitamins extracted from plants (fruits, aromatic herbs, etc.) are in forms that are not only compatible with human physiology, but are also combined with other natural compounds present in the original matrix, and resulting from the extraction: co-factors, minerals, polyphenols, etc.

This combination is like a food matrix, promoting the synergy of the active ingredients present in the extract in terms of bioavailability and in the expected physiological effects.

In a randomized, placebo-controlled clinical trial, eight non-smokers aged between 18 and 41 were given ascorbic acid, or a lemon extract enriched with vitamin C. Bioavailability was assessed by measurement of vitamin C plasma levels.

In this study, the scientists were able to note that ascorbic acid combined with lemon extract was 35% more bioavailable than ascorbic acid alone (3).

Richard COLL, Formulation expert

Bibliography :

(1) Thiel RJ. Natural vitamins may be superior to synthetic ones. Med Hypotheses 2000;55(6):461-9.
(2) Bourgeois C. Les vitamines dans les industries agro-alimentaires. Paris : Editions Tec&Doc, 2003.
(3) Vinson JA et al. Comparative bioavailability of humans to ascorbic acid alone or in a citrus extract. Am J Clin Nutr 1988;48:601-4.