Enhancing Skin Health: By Oral Administration of Natural Compounds and Minerals with Implications to the Dermal Microbiome

Abstract

The history of cosmetics goes back to early Egyptian times for hygiene and health benefits while the history of topical applications that provide a medicinal treatment to combat dermal aging is relatively new. For example, the term cosmeceutical was first coined by Albert Kligman in 1984 to describe topical products that afford both cosmetic and therapeutic benefits. However, beauty comes from the inside. Therefore, for some time scientists have considered how nutrition reflects healthy skin and the aging process. The more recent link between nutrition and skin aging began in earnest around the year 2000 with the demonstrated increase in peer-reviewed scientific journal reports on this topic that included biochemical and molecular mechanisms of action. Thus, the application of: (a) topical administration from outside into the skin and (b) inside by oral consumption of nutritionals to the outer skin layers is now common place and many journal reports exhibit significant improvement for both on a variety of dermal parameters. Therefore, this review covers, where applicable, the history, chemical structure, and sources such as biological and biomedical properties in the skin along with animal and clinical data on the oral applications of: (a) collagen, (b) ceramide, (c) β-carotene, (d) astaxanthin, (e) coenzyme Q₁₀, (f) colostrum, (g) zinc, and (h) selenium in their mode of action or function in improving dermal health by various quantified endpoints. Lastly, the importance of the human skin microbiome is briefly discussed in reference to the genomics, measurement, and factors influencing its expression and how it may alter the immune system, various dermal disorders, and potentially be involved in chemoprevention.

Keywords: astaxanthin; ceramide; coenzyme Q10; collagen; colostrum; human skin; microbiome; oral applications; selenium; zinc; β-carotene.

Figure 1

Collagen fiber structure, absorption/metabolism and deposition into skin cells and dermal layers. It is generally thought that collagen (derived products) are hydrolyzed into amino acids in the gastrointestinal tract (GI) prior to being absorbed into the blood circulation, which are then deposited into the skin cells and/or utilized as building block components for extracellular matrix proteins produced by fibroblasts [25,26,27,28]. ALA = Alanine, HYP = Hydroxyproline, GLY = Glycine, PRO = Proline, and Ser = Serine.

Figure 2

The chemical structure of ceramides. A typical ceramide molecule is composed of long-chain shingosine bases (usually 18 to 20 carbons long) with amide-linked fatty acids (usually 16 to 24 carbons long). The shingonid base contains a polar head and a non-polar tail. In some cases, the fatty acids can be 16 to 36 carbons long [45,46]. The sphinosine base may consist of dihydrosphingosine, sphingosine, phytosphingosine, or hydroxy sphingosine. The fatty acid may be a non-hydroxyl fatty acid, an α-hydroxyl fatty acid, or an esterified ώ-hydroxyl fatty acid. Re-drawn with permission [46].

Figure 3

(A) The chemical structure and chemical characteristics of β-carotene. β-carotene is a carotenoid found in many naturally occurring fat-soluble yellow, orange, red, and green leafy pigments synthesized in fruits and vegetable [62,63,64]. (B) The chemical structure and chemical characteristics of astaxanthin. It is a keto-carotenoid, which is similar in chemical structure to β-carotene and it is found in plants, animals, and algae [67,68,69]. (C) The chemical structure and chemical characteristics of coenzyme Q₁₀. It is a novel quinone in the lipid extracts of mitochondria and participates in the electron transport chain [70,71].

Figure 4

Colostrum or “first milk” is produced by mammals (including humans) immediately following parturition. There are 10 major categories of compounds derived from colostrum, which are shown in the figure above [147,148,149].