What do experts think about commercially marketed nutricosmetic products? Cosmetics & Toiletries posed this question and others to renowned dermatologists Zoe Diana Draelos, M.D., and Alan Dattner, M.D. Following are excerpts adapted from part III in our five-part podcast series, "How Nutrition Impacts Beauty." Hear more by clicking on the podcast at the bottom of the page.
Follow additional podcasts in this series on: "How Nutrition Translates to Beauty" (part I); "Measuring Nutricosmetic Efficacy" (part II); "Consumer/Client Interest in Nutricosmetics" (part IV); and "How Epigenetics and the Microbiome Factor In" (part V).
Cosmetics & Toiletries: Several commercial products on the market are touted as nutritional cosmetics. Do you feel they support their claims?
Draelos: I think the idea of nutricosmetics is basically eating for performance. And if you dissect apart these products, you will see that each of these provides necessary nutrients to the body. For example, drinkable collagen. Collagen that you consume does get broken down in the stomach by gastric acid just like if you consume chicken or salmon. So it does provide a protein source.
Antioxidants such as vitamins A and C are also very important and that’s where dark chocolate comes in since it is very rich in antioxidants. But is dark chocolate the best way to get your antioxidants? Well, it’s a very high-calorie food; chocolate has a high fat content. So it might be better to get them from eating fruits and vegetables. However, adequate supplies of fruits and vegetables are sometimes not available year-round, and that’s where antioxidant supplements come in.
There is some evidence that if you super-charge the skin with topical solutions of vitamin C, you can provide some antioxidant protection but that is protection on the skin surface. And because many vitamins (such as C) are highly unstable in oxygen-rich environments, they are actually oxidized very quickly when they’re applied topically. So, any of the vitamins that sit on top of the skin are not providing much protection because after time, they become oxidized.
Now, there may be some vitamin C that is water-soluble and can penetrate the skin where it may function in the non-viable epidermis; that’s where there’s a lot of controversy. When you look at a vitamin-containing topical, you really have to look at the formulation to sit down and assess which ingredient is providing what benefit.
Dattner: A lot of these products are combined with peptides, which have constrictive properties to smooth out the skin. These peptides are "sort of" natural and have been found to have some biologic activity.
Antioxidants and ferulic acid products certainly were some of the early ones out there. Then you have the bioflavonoids that are in citrus; and a different kind in purple plants and vegetables: the oligocyanthopyriadines. And in carrots and yellow and orange fruits and vegetables, you have carotenoids.
There’s definitely data showing that vitamin C has protective effects, topically. For example, some studies show that when plasma levels of vitamin C are low, you can get some penetration with topical vitamin C. But there are two problems: 1) you’ve got to get the stuff into the skin, and the more acid the preparation, the better it works; and 2) you have to keep the vitamin C from oxidizing. Product developers use different forms of vitamin C but each once, e.g., ascorbyl glucoside or palmitate, has issues.