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Monday 17 February 2014

Nutrition for Healthy Skin: Vitamin A, Zinc, Vitamin C



One of the biggest motivations to adopt a more nutritious diet is the desire to improve skin health. Many people of all ages struggle with skin conditions such as acne, rosacea, dry skin, wrinkles, and sun damage, among others. This can be very upsetting for those who have yet to find a solution to their problematic skin. While conventional medical professionals often discount the connection between skin health and nutrition, there is strong evidence to support the influence of our food choices on the health and vibrancy of our skin.
The consumption of certain vitamins, minerals, and other beneficial compounds in the diet is one of the most effective ways to treat skin conditions and improve the look and feel of one’s skin. There are several nutrients that are known to play a role in the proper growth and immunity of the skin, and many people have found that their skin health has dramatically improved after making purposeful changes to their daily diet. For example, Liz from the blog CaveGirlEats has a great post about how eating a traditional diet has improved her skin health. As her story suggests, making simple changes to your diet can have a significant impact on skin appearance in a short amount of time.
In this series, I will discuss how vitamins and minerals from a nutritious whole foods diet can treat acne, wrinkles, and other problem skin conditions.

Vitamin A

Vitamin A, or retinol, is one of the most widely acknowledged nutrients for healthy skin. Synthetic retinoids have been used as effective treatments for severe acne and psoriasis since the 1980s, demonstrating how useful vitamin A can be in treating problem skin. Vitamin A influences the physiology of the skin by promoting epidermal differentiation, modulating dermal growth factors, inhibiting sebaceous gland activity, and suppressing androgen formation. (1) As it promotes cell turnover in the skin, vitamin A is effective in preventing the formation of comedones that cause the most common forms of acne.
Lack of vitamin A causes the skin to become keratinized and scaly, and mucus secretion is suppressed. (2) Rough, dry skin is a common sign of vitamin A deficiency, which often first appears as rough, raised bumps on the back of the arms. (3) This condition is called hyperkeratosis pillaris, and is found in approximately 40% of adults. (4) Though dermatologists believe this is an inherited condition with no cure, I have successfully treated this condition in several patients by significantly increasing their consumption of vitamin A rich foods. While physicians prescribe synthetic retinoids to treat skin conditions including acne, eczema, psoriasis, cold sores, wounds, burns, sunburn, and ichthyosis, it is possible to obtain similar effects from consuming natural sources of pre-formed vitamin A. (5)
Preformed vitamin A, which is well absorbed by the body, can be found in a variety of traditional foods. The most vitamin A-rich foods are liver and cod liver oil, but other sources include kidney, cream and butter from pastured cows, and egg yolks from pastured chickens. I recommend using cod liver oil if you wish to supplement, as this provides a balance of vitamin A and vitamin D that will reduce the risk of overdosing on vitamin A. Eating liver once or twice per week is a great dietary strategy for those looking to reduce and even eliminate stubborn acne.

Zinc

Zinc is an essential mineral that is an imperative part of many physiological functions, including structure in certain proteins and enzymes, and regulation of gene expression. It plays a role in immune function, protein synthesis, wound healing, DNA synthesis, and cell division. (6) In skin, zinc assists in the proper structure of proteins and cell membranes, improves wound healing,  has anti-inflammatory effects, and protects against UV radiation. (7)
Several studies indicate that dietary zinc may reduce acne, even as effectively as antibiotics such as tetracyclines. (8) This may be because it interacts with vitamin A as a component of retinol-binding protein, which is necessary for transporting vitamin A in the blood. (9) Zinc supplementation has been shown to significantly increase the level of vitamin A in the blood, indicating an interaction between the two nutrients that may explain its positive effect on acne. (10) In fact, men and women with serious acne are found to have lower levels of serum zinc than healthy controls. (11)
Dietary sources of zinc are best absorbed from animal sources, where it is not bound to phytates as in plant sources. Organs such as kidney and liver, red meat such as beef and lamb, and seafood such as oysters, scallops, and other shellfish are the highest animal sources of zinc. Plant foods such as pumpkin seeds and other nuts can also be high in zinc as well, but are less bioavailable, as the zinc is bound to phytates if not properly prepared by soaking. To get the most zinc from your diet, include shellfish, organ meats, and red meat on a regular basis.

Vitamin C

Vitamin C has been known for decades to play a crucial role in the regulation of the structural protein collagen, which is necessary for the extracellular stability of the skin. A vitamin C deficiency causes scurvy, which is first manifested as rough dry skin and corkscrew hair growth. Inadequate vitamin C is also known to contribute to the development of the common problem of hyperkeratosis pillaris, as the follicles become damaged when collagen formation is impaired.
Increasing the amount of vitamin C in the diet can contribute to improved skin health and faster healing. Observational studies have shown that diets high in vitamin C are associated with better skin appearance and less skin wrinkling. (12, 13) Vitamin C may also help prevent and treat ultraviolet (UV)-induced photo damage by acting as an antioxidant. (14) Higher intakes of dietary vitamin C have been correlated with a decreased level of dry skin, and ascorbic acid may have effects on trans-epidermal water loss. (15) Vitamin C has an important role in wound healing and can improve the proper formation of strong scar tissue. (16)
While true deficiency in the United States is uncommon, it is possible to be consuming sub-optimal levels, particularly in a diet with limited fruits and vegetables. The highest sources of vitamin C include bell peppers, guava, dark leafy greens, broccoli, brussel sprouts, kiwi, citrus fruits, and strawberries. Certain fresh herbs such as cilantro, chives, thyme, basil and parsley are also high in vitamin C. Consuming a wide variety of colorful plant foods on a regular basis is the best way to get adequate vitamin C in your diet. It’s important to remember that vitamin C is sensitive to heat, so lightly cooking these plant foods or eating them raw (if possible) is ideal to maximize your intake of this vitamin.

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