Nutrition is the key to a healthy body and mind, it helps us stay fit, mentally ready and ... well, we all love food :)
Furthermore, the relationship between skin and nutrition cannot be neglected, it is well known, and we cannot deny it. however we aren't here today to talk about that, today we will be comparing topical application versus nutrients obtained by oral intake.
Food has most of the nutrients needed by the skin, including proteins, minerals, fatty acids and many more, however as previously discussed in previous blogs, because of the lack of blood vessels that normally deliver nutrients to cells, the epidermis is a challenging environment for nutrients delivery. Nutrients are delivered from the vascularized dermis by diffusion, a mechanism that limits the arrival of nutrients to the outermost layers of the epidermis(this is where we need them the most for a healthy-looking skin). In addition, in these outermost layers, there is a little movement because of the skin barrier resulting in a more limited diffusion. All of this lessens the number of nutrients arriving at the epidermis. Nonetheless, as seen in figure 1, topical application can be used to target epidermal nutrients delivery.
Figure1 Delivery of nutrients to the skin
However, in this case, the SC (stratum corneum) is an important aqueous barrier preventing the passage of many substances. Lipid soluble compounds are able to pass through the SC, but many other substances are unable to reach the lower layers of the dermis, therefore, in this case, nutrient delivery is preferred to be mediated through the bloodstream. (1)
(1) Pullar JM, Carr AC, Vissers MCM. The Roles of Vitamin C in Skin Health. Nutrients [Internet]. 2017 Aug 12 [cited 2019 Jul 13];9(8). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579659/