Our skin is the largest organ of the human body and is continuously influenced by both internal and external factors. The internal factors are part of the natural aging process within cells (The Nine Hallmarks of Aging), that can be accelerated by external factors— such as ultraviolet (UV) radiation, tobacco and inadequate nutrition— that cause the production of reactive oxygen species (ROS) and inflammation that fragment and degrade collagen and elastic fibers. Over time, both internal and external aging factors lead to increased skin roughness, wrinkling, pigmentation change, loss of elasticity and decreased firmness, giving skin its aged appearance.
In the first part of this blog I am going to talk about carotenoids, fatty acids, NAC, and minerals reviewed in this article of 2018 Nutraceuticals: A Review, in order to understand their mechanism of action and their possible efficacy (clinical benefits) as dermatologic nutraceuticals for skin anti-aging. Nutraceuticals is a broad umbrella term that is used to describe any product derived from food sources with extra health benefits in addition to the basic nutritional value found in foods.
β-Carotene carotenoid is a precursor of vitamin A and protects cells by:
- inhibiting ROS, and
- having photo-protective properties, which increase the minimal erythema dose (MED⛱) — defined as the threshold dose that may produce sunburn— therefore protect against sunburn development and photo suppression of the immune system.
In particular, in 2008 Kopckel and Krutmann — by utilizing a meta-analysis study —showed that β-carotene supplementation protected against sunburn. And in 2013 Meinke et al. performed a clinical study in 24 healthy volunteers and the results showed that carotenoids increased the radical scavenging activity of the skin and provided significant protection against stress-induced radical formation.
Moreover, in mice β-carotene has been shown to prevent wrinkle formation and decrease matrix metalloproteinase (MMP)-9 activity, protecting the extracellular matrix (ECM) from degradation.
Lutein and zeaxanthin, the two primary xanthophyll carotenoids that promote eye and skin health, when given as a daily oral supplement of 10 mg of lutein and 2 mg of zeaxanthin, researchers concluded that within 12 weeks they increased the mean MED and significantly improved skin tone, luminance and color. Other studies have shown that lutein and zeaxanthin protect keratinocytes from UV radiation-induced photo-aging, stop ECM degradation and decrease lipid peroxidation in the skin.
Finally, lycopene (that has no vitamin A activity) is considered the best singlet oxygen quencher in the carotenoid family. Studies have shown that consumption of tomato paste 🍅, which is high in lycopene, significantly lowers UV-induced erythema and decreases MMP-1 activity, an enzyme involved in the breakdown of collagen.
Tip: Foods rich in carotenoids include apricots, asparagus, beef liver, beets, broccoli, cantaloupe, carrots, corn, guava, kale, mangoes, mustard and collard greens, nectarines, peaches, pink grapefruit, pumpkin, squash (yellow and winter), sweet potato, tangerines, tomatoes, and watermelon.
The essential fatty acids (long-chain polyunsaturated fatty acids) can be divided into two groups: omega-3 and omega-6.
We know that within the epidermis omega-6 fatty acids have the highest fatty acid concentration and serve as an important structural component, while the omega-3 polyunsaturated fatty acids, play an important anti-inflammatory role preventing the formation of pro-inflammatory molecules.
In particular, studies have reported a significant reduction in UV-radiation-induced inflammation when taking fatty acid supplements, attributed to the potential decrease in prostaglandin-E2 (potent inflammatory mediator) levels during the inflammatory response. While, another study reported an increase in the MED when participants took eicosapentaenoic acid (omega-3 fatty acid) daily.
Tip: Foods very high in omega-3 are mackerel, salmon, cod liver oil, herring, oysters, sardines, anchovies, caviar, flax seeds, chia seeds, walnuts and soybeans.
NAC along with two other amino acids (glutamine and glycine) is needed to make and replenish glutathione, which is the most abundant endogenous intracellular antioxidant that plays a pivotal role in the body’s antioxidant defense. But the rate of glutathione synthesis decreases as we age, leading to glutathione deficiency, eventually increasing our body’s oxidative stress.
A study has found that elderly subjects after 2 weeks of cysteine (NAC is the supplement form of cysteine) and glycine supplementation had a significant increase in their red blood cell glycine, cysteine and glutathione concentrations, while they had a decline in both oxidative stress and plasma markers for oxidant damage.
A review of clinical studies to determine the effect of NAC in the treatment of skin disorders such as — excoriation disorder, onychophagia, trichotillomania, wound healing, acne vulgaris, ulcers in scleroderma, toxic epidermal necrolysis and dermatitis — suggested that NAC could potentially serve as a safe, tolerable and effective therapeutic option for a variety of dermatological disorders.
Tip: To synthesise the amino acid cysteine, you need adequate amounts of folate, vitamin B6 and vitamin B12, and these nutrients can be found in beans, lentils, spinach, bananas, salmon and tuna. While most protein-rich foods, such as chicken, turkey, yogurt, cheese, eggs, sunflower seeds and legumes, contain cysteine, some people choose to supplement with NAC to increase their cysteine intake.
Copper is a trace mineral found naturally in soil with many innate properties and serves as an important cofactor in enzymatic reactions during collagen crosslinking and skin pigmentation. Therefore, copper promotes keratinocyte and fibroblast proliferation leading to skin rejuvenation and wound repair through its collagen crosslinking properties. Copper has been used in topical treatments for wound healing to promote repair of damaged skin because of its anti-inflammatory and anti-bacterial effects.
Zinc is an essential mineral important cofactor for cellular activity and defense. It protects against lipid peroxidation, UV-induced cytotoxicity and oxidative stress. It protects against lipid peroxidation, UV-induced cytotoxicity and oxidative stress induced by ROS. Zinc plays a major role in wound healing and keratinocyte cell survival.
Tip: Oysters contain more zinc per serving than any other food, but red meat and poultry provide also zinc. Other good food sources include beans, nuts, crab, lobster, whole grains, fortified breakfast cereals and dairy products. Foods rich in copper are: liver, oysters, spirulina, shiitake mushrooms, nuts/seeds, lobster, leafy greens and dark chocolate 🍫.
In the second part of this blog 📝 I am going to talk about polyphenols, vitamins and Aloe sterols also important skin nutraceuticals.
“Don’t forget that healing takes time⌛️. Don’t expect to try meditation and a new skincare line and end up with perfect skin in a week. Give yourself the gift of time and patience. The body is a complicated, miraculous system and each body processes change in its own time.” ― Yancy Lael
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