With today’s increasing life expectations, the desire to look youthful plays a more important role than ever; thus the appearance of skin and hair becomes even more relevant. Even-toned, supple skin with a healthy glow and silky, shiny hair establish an individual’s image and self-perception. In humans, the association of nutrition with changes in skin and hair was first made by James Lind in 1747 with the confirmation of an empirical link between scurvy and vitamin C.
Nutritionals for the body and mind have been marketed for decades, first as medicines and later as food supplements. Skin and hair traditionally have been treated topically since they are located on the outermost areas of the body. However, since the penetration of ingredients into and through the skin is limited, research has attempted to reach the skin and its appendages through systemic means. Thus, the concept of “beauty from within” developed, and in turn, supplements for both dermocosmetic and dermatologic applications.
Yet, uncertainty remains among caregivers and consumers regarding the capabilities of such preparations. While not exhaustive, this review examines select data on nutritional supplements in relation to skin and hair benefits, to examine the potential for nutritionals to treat skin and hair aging.
Aging in Skin and Hair
Aging is the accumulation of genetically programmed changes in an organism over time. In humans, this refers to a multidimensional process of physical, psychological and social changes. Hair aging comprises weathering of the hair shaft and aging of the hair follicle. The first, weathering of the hair shaft, involves the progressive degeneration of the hair fiber from the root to the tip; for example, the tip of a long hair may be three years older than the root. The second, aging of the follicle, manifests as a decrease in melanocyte function, or graying, and a decrease in hair production, especially in the case of androgenetic and senescent alopecia.
Skin aging, which also includes the scalp, is induced by two processes that are well-characterized: intrinsic and extrinsic aging. Intrinsic aging, also known as natural aging or chronological aging, is inevitable and genetically controlled. In hair, it leads to cutaneous alterations and familial premature greying or androgenetic alopecia.