by David Djerassi
For years, consumers have turned to cosmetics, potions and lotions to maintain and enhance the beauty of their skin and hair. However, such products do not always provide the expected performance, because of inadequate levels of actives, improper delivery vehicles or low skin absorption. Also, there may be underlying nutritional issues that must be addressed for optimal results.
Fortunately, in the last few years, the trend of “beauty from within” and a category of “nutricosmetics” has emerged. As scientists have uncovered the role certain nutrients can play in skin health—slowing premature aging and enhancing skin matrix—formulators and marketers have entered a new stage of product development.
Dietary supplements, functional foods and beverages, and nutricosmetics have seen major growth and adoption on a global level. These products are incorporating a range of biologically active ingredients to address the degeneration of the skin matrix and to enhance the health of the skin.
Dietary antioxidants, such as carotenoids and polyphenols can provide protection against free radicals and UV-induced damage. Antioxidants can also improve skin texture in the form of smoothness, thickness and density. Combinations of such antioxidants can generate synergy and enhanced performance.
While there are more than 600 carotenoids present in fruits, vegetables and green plants, only 20 are found in human plasma and tissues. Of these, the principal ones are lycopene, lutein, alpha-carotene, beta-carotene, phytoene, phytofluene, astaxanthin and zeaxanthin.
Oral supplementation with various carotenoids appears to increase the photo-protective properties of the epidermis and dermis against environmental stress (e.g., UV radiation, pollution, smoke) and by quenching free radicals, generated by oxidative stress. Study results have shown the ability of carotenoids to reduce edema, reduce DNA damage and protect against depletion of Langerhans cells, a key component of immune function.
The activity of carotenoids increases with daily consumption, due to the cumulative effect in skin. In addition, oral supplementation has been shown to increase skin smoothness, elasticity and density in direct correlation to the levels of actives in the products and the length of consumption.
The polyphenols and flavonoids include more than 5,000 natural substances consisting of a phenolic acid group, attached to the ring of the benzene groups. Polyphenols are potent, water-soluble antioxidants present in many plants and include anthocyanins, anthocyanidins, flavonols, catechins, resveratrol, tannins, ellagic acid, carnosic acid and rosemarinic acid, among others. A number of beneficial health and beauty effects have been attributed to polyphenols including protection against free radicals, anti-aging via stabilization of collagen and elastin, reduction of inflammatory activity, regulation of the immune system and promotion of enzymatic activity.
Essential fatty acids (EFAs) are another common ingredient in nutricosmetic formulations. EFAs are categorized based on the position of the first unsaturated double bond from the methyl end of the molecule as omega-3 and omega-6 oils. The parent omega-3 and omega-6 EFAs—alpha linolenic acid (ALA) and linoleic acid (LA), respectively—cannot be synthesized by the body and must be consumed in the diet.
Omega-3s, commonly found in marine sources and some grains including flax and chia, include ALA and the longer-chain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Oral consumption of omega-3 EFAs appears to reduce inflammation, which is associated with skin redness and wrinkling.
In addition to LA, the omega-6s include gamma linolenic acid (GLA) and arachidonic acid. Low levels of omega-6s are usually followed by keratinization and roughening of the upper layers of the skin, slow wound healing and even discoloration of hair. They play an important role in keeping the skin moist and supple because they are directly incorporated into the structural lipids of the epidermis (ceramides)—the building blocks of the intercellular moisture barrier of the skin.