Nutraceutical: Vitamin C

Nutraceutical: Vitamin C

The term “nutraceutical” is a portmanteu derived from the words “nutrition” and “pharmaceutical” and was coined in 1989 by the Foundation for Innovation in Medicine (FIM). According to Stephen DeFelice, founder and chairman, nutraceutical can be defined as “a food (or a part of it) that provides medical or health benefits." In this series, I'll explore the most researched nutriceuticals for mind and body.

Vitamin C 🍋

Also known as ascorbic acid, vitamin C is a water-soluble compound first identified in the 1920s by Albert von Szent Györgyi, who discovered that it was able to prevent and cure scurvy. In fact, "A-scorbic" means "anti-scurvy." Us humans, along with our primate cousins, cannot synthesize vitamin C on our own. (But our pet dogs and cats can, so you don't need to give them lemon water). We need to get this essential "Vital Amine = Vitamin" from our diet. Vitamin C is a powerful antioxidant that protects our tissues, cells, and DNA from oxidative damage.

Getting Under the Skin

A primer on skin structure: The skin has two main layers, the outermost epidermis and the inner dermis. The epidermis lacks the blood vessels that normally deliver nutrients to cells, and thus nutrient delivery depends on diffusion from the vascularized dermis. It goes without saying that nutrients we eat do not actually end up in our outermost skin layer - the stratum corneum. Remember this when you decide to skimp on the skincare products.

But here's the rub - it's also unlikely for nutrients delivered topically (think: serums) to easily penetrate into the lower layers of the dermis (because NO, not👏🏻everything👏🏻you👏🏻put👏🏻on👏🏻the👏🏻skin👏🏻gets👏🏻absorbed). So to boost our dermal functions, we need internal nutrient support delivered through bloodstream. The image below shows nutrient deliver to skin from the inside and out.

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Let me explain. On the right are SVCT1 and 2 - these are specific sodium-dependent vitamin C transporters (SVCTs) that mediate Vitamin C uptake from plasma. Notice there are two in the upper layer, the epidermis. This shows that our outermost skin layer is highly dependent on vitamin c for proper functioning. In fact, more vitamin c is found in the epidermis than in the dermis! And guess what. Smoking, pollution and sun exposure all oxidize your precious skin vitamin C. However, even if depleted, vitamin c supplements have their limit.

Oral Supplements

Taking C supplements, chewable or not, will only elevate skin vitamin C in people who have below-saturation plasma levels. Basically, you can take all the vitamin C pills you want, but when your body has enough, you will just pee it out (it's water soluble).

Topical Delivery

When plasma levels are low, some vitamin C can be delivered to the epidermal layer by topical application, although the efficacy of this is dependent on the formulation of the cream or serum used on the skin. Vitamin C, being a water-soluble and charged molecule, is repelled by the physical barrier of epidermal cells. It is only when pH levels are below 4 and vitamin C is present as ascorbic acid that some penetration occurs. However, a great deal of effort has been put into the development of ascorbic acid derivatives specifically for topical application. This is to ensure stabilization of the molecule from oxidation and also to overcome the significant challenge of skin penetration. Again, when you're at an optimal health status, there is no absorption of vitamin C following topical application. In this case, “beauty from the inside”, via nutrition, may be more effective than topical application.

Benefits

Obviously there are many benefits to vitamin c, like preventing scurvy for starters. In terms of antioxidant efficacy, many studies show that combining topical vitamin C with vitamin E can be photoprotective. For example, a small study of 10 people taking 2 g of vitamin C and 1000 IU of vitamin E per day had reduced sunburn, skin damage and blood flow compared to placebo [2]. Similarly, eighteen volunteers supplementing with 2 g vitamin C and 1000 IU vitamin E per day for 3 months had significantly reduced sunburns to UVB [3].
Healthy levels of C have been associated with improved skin elasticity, facial wrinkling, roughness and color. There are even studies on its effect on dryness. It is also a necessary component of building collagen in the skin, which decreases with age and even more so with sun damage. You don't need to overdose on oranges to reap the benefits, here are some fruits and veggies that pack more C than an orange:

  • Papaya
  • Bell Peppers
  • Broccoli
  • Brussels Sprouts
  • Strawberries
  • Pineapple

Aging, smoke, pollution and UV can all deplete our skin's vitamin C. Now you know that maximal skin functioning requires getting enough C from the inside and out.

References:

  1. Pullar, JM., et al. "The roles of vitamin C in skin health." Nutrients 9.8 (2017): 866.
  2. Eberlein-König, B., et al."Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-α-tocopherol (vitamin E)." Journal of the American Academy of Dermatology 38.1 (1998): 45-48.
  3. Placzek, M., et al. "Ultraviolet B-induced DNA damage in human epidermis is modified by the antioxidants ascorbic acid and D-α-tocopherol." Journal of Investigative Dermatology 124.2 (2005): 304-307.
  4. Pérez-Sánchez, A., et al. "Nutraceuticals for skin care: A comprehensive review of human clinical studies." Nutrients 10.4 (2018): 403.