INTRODUCTION
With the expanding aging population and societal focus on youthful appearance, the market for anti-aging skin care products continues to grow. While there are currently numerous over-the-counter aesthetic anti-aging therapies on the shelves, research into the development of novel agents that are both safe and effective continues. In particular, topical cosmeceuticals and ingestible nutraceuticals labeled “natural†are becoming increasingly popular.1
Probiotics have been defined as “live microorganisms which when administered in adequate amounts confer a health benefit on the host.†They have received attention as of late for their ability to positively impact digestive health as well as regulate the immune system. Only recently has their potential to play a role in aging, beauty, photodamage, and skin health been revealed.2,3 The most frequently used oral probiotics are enterococci, lactobacilli, and bifidobacteria, which are also natural inhabitants of the gastrointestinal tract; but encouraging results have been reported with other strains, especially as they relate to the skin.4-6 The first report on probiotic use, by Elie Metchnikoff in the early 1900s, described the possibility of improving health and delaying senility by modifying the intestinal microbiome.7,8 Many studies have emerged since then supporting the efficacy of probiotics in the management of numerous diseases, ranging from gastrointestinal to inflammatory and autoimmune.
As reviewed by Varankovich et al., probiotics can decrease harmful gut microbiota including H. pylori, which is implicated as the causative factor in most cases of gastritis.9 Probiotics also aid in the management of gastroenteritis, irritable bowel syndrome, inflammatory bowel disease, and necrotizing enterocolitis in newborns. They can also be used proactively to restore the balance of microbiota following antibiotic treatment and have been shown to be helpful in the prevention and treatment of pseudomembranous colitis. Bubnov et al. discuss the supporting evidence for use of probiotics in atopic, metabolic, and inflammatory conditions.10 Currently, probiotics can be present in yogurt, kefir, miso paste and fermented beverages. They have recently been added as supplements to children’s popsicles, prenatal vitamins and facial creams, among other products.
In this article, we discuss the role of probiotics in countering physiologic and pathologic effects related to aging.
Skin Aging Process - Physiologic Changes and Pathologic Changes
Intrinsic and extrinsic factors contribute to aging skin. Intrinsic or physiologic aging is due to genetic and hormonal effects, skin-associated microflora changes, skin pH increase, reduced stratum corneum lipid content, decreased absolution of reactive oxygen species (ROS), and greater metalloproteinase activity.11 Some clinical features of intrinsic aging are desiccation, laxity, fine wrinkles, and atrophy of the skin.12 Extrinsic aging is precipitated by environmental stress in the form of UV radiation (UVR), trauma, pollution, infection, and tobacco use. UV exposure is the most significant cause of extrinsic aging. Therefore, the American Academy of Dermatology’s primary recommendation to decrease premature skin aging is to emphasize sun protection when outdoors by reducing the amount of skin exposed to sun and applying sunscreen to visible skin.13
Over many years, repeated exposure to UV light results in photoaging, which is illustrated by signs of fine and coarse wrinkling, increased skin fragility, desiccation, laxity and solar lentigines. Photoaged skin is characterized by the loss of dermal extracellular matrix integrity due to multiple insults at the molecular level. UVR has a direct damaging effect on DNA, contributes to the formation of reactive oxygen species, controls
