Synthetic or Food-Derived Vitamin C—Are They Equally Bioavailable?

Abstract

Vitamin C (ascorbate) is an essential water-soluble micronutrient in humans and is obtained through the diet, primarily from fruits and vegetables. In vivo, vitamin C acts as a cofactor for numerous biosynthetic enzymes required for the synthesis of amino acid-derived macromolecules, neurotransmitters, and neuropeptide hormones, and is also a cofactor for various hydroxylases involved in the regulation of gene transcription and epigenetics. Vitamin C was first chemically synthesized in the early 1930s and since then researchers have been investigating the comparative bioavailability of synthetic versus natural, food-derived vitamin C. Although synthetic and food-derived vitamin C is chemically identical, fruit and vegetables are rich in numerous nutrients and phytochemicals which may influence its bioavailability. The physiological interactions of vitamin C with various bioflavonoids have been the most intensively studied to date. Here, we review animal and human studies, comprising both pharmacokinetic and steady-state designs, which have been carried out to investigate the comparative bioavailability of synthetic and food-derived vitamin C, or vitamin C in the presence of isolated bioflavonoids. Overall, a majority of animal studies have shown differences in the comparative bioavailability of synthetic versus natural vitamin C, although the results varied depending on the animal model, study design and body compartments measured. In contrast, all steady state comparative bioavailability studies in humans have shown no differences between synthetic and natural vitamin C, regardless of the subject population, study design or intervention used. Some pharmacokinetic studies in humans have shown transient and small comparative differences between synthetic and natural vitamin C, although these differences are likely to have minimal physiological impact. Study design issues and future research directions are discussed.

Urinary metabolomics of complete Freund's adjuvant‐induced hyperalgesia in rats

“…In vivo, ascorbic acid plays an important role as a cofactor for different enzymes required for the synthesis of amino acids, neurotransmitters, and neuropeptide hormones (Carr & Vissers, 2013 (Chiang et al, 2005). In vivo, ascorbic acid plays an important role as a cofactor for different enzymes required for the synthesis of amino acids, neurotransmitters, and neuropeptide hormones (Carr & Vissers, 2013 (Chiang et al, 2005).…”

Enriched Milk Drinks for Vitamin Deficiency Correction in Toddlers and Preschoolers

“…В ряде клинических исследований дока-зано, что синтетические витамины хорошо усваиваются человеком [15,28]. В последние годы в специально спланированных исследованиях получены новые убе-дительные подтверждения этому [29][30][31]. Наконец, при оценке биологической доступности витамина из пищево-го продукта за 100% принимают усвоение из препарата химически синтезированного вещества.…”

The behavioural effects of supplementing diets with synthetic and naturally sourced astaxanthin in an ornamental fish ( Puntius titteya )

“…Whether natural or synthetic additives exhibit different effects due to bioavailability is contested. For instance, vitamin C as an additive is synthetically produced with an identical chemical structure to its naturally occurring counterpart (Carr & Vissers, 2013). In human experiments natural and synthetic vitamin C are equally bioavailable, however in animal studies there is greater variation in natural versus synthetic bioavailability dependent upon the animal model used (Vissers et al, 2011;Carr & Vissers, 2013).…”

“…For instance, vitamin C as an additive is synthetically produced with an identical chemical structure to its naturally occurring counterpart (Carr & Vissers, 2013). In human experiments natural and synthetic vitamin C are equally bioavailable, however in animal studies there is greater variation in natural versus synthetic bioavailability dependent upon the animal model used (Vissers et al, 2011;Carr & Vissers, 2013). Naturally produced supplements are often synthesised in conjunction with other compounds which are thought to influence bioavailability, an example being the interaction between flavonoids and vitamin C affecting uptake (Song et al, 2002;Vissers et al, 2011).…”