Avena sativa more commonly known as oat is rich in many micro and macronutrients such as calcium, fibers, and amino acids, vitamins such as vitamin B, C, K and E as well as anti-oxidants such as flavonoids, polyphenols and beta carotene.
It is a healthy substance for the skin as well as for the health of gut and general body for instance, it may improve the immune system and remove toxic and harmful substances from the body, and it may also promote a dietary loss of weight by breaking down the fat. It may also contribute in reducing the cholesterol levels, blood sugar levels and also suppress inflammation along with improving health of the skin. Many research studies even suggested that they may even prevent the development of cancer and also improve the life quality of post-menopausal women due to presence of lignin and phytoestrogen .
Oats are one of the most produced grain worldwide after corn, wheat, rice, sorghum and barley [2, 3]. They have a shape similar to barley, but are considered healthier due to abundance of protein, vitamins, fibers and minerals.
Oat are particularly considered as a high-value crop due to the presence of β-glucan and essential amino acid, Lysine [4, 5, 6, 7]. Other than amino acid, it is also rich in unsaturated fatty acids such as linoleic acid, palmitic acid and oleic acid which are associated with many beneficial effects such as lowering the blood cholesterol, preventing dementia and its anti-oxidant properties [7, 8, 9, 10, 11]. Many other biological molecules are also present in oats such as various types of alkaloids and polyphenols (hydroxybenzoic acid, gallic acid, coumaric acid and caffic acid) which are not only responsible for a healthy gut life but also have great roles in promoting healthy skin [12, 13].
BENEFICIAL SKIN EFFECTS
Oat derived ingredients particularly Oat protein is reported to function in skin care and cosmetics industry as an antioxidant, absorbent, bulking agents, abrasive and skin conditioner .
Some of the major properties of Oat protein are as under:
- MOISTURIZING THE SKIN:
Oat protein and colloidal oatmeal is available as moisturizing cream. Since oat protein is high in concentration of beta-glucans and starches which thus make it contribute as a water-holding agent and a protective agent for the skin. The moisturizing and hydrating properties thus help to preserve the integrity of stratum corneum barrier (responsible for preventing water loss from skin) .
Oat protein containing products are used to treat itchy skin by acting as a moisturizer, they yield promising effects in reducing itching in dryness particularly winter itch, insect bites, chicken pox, swimmer itch (cercarial dermatitis), allergic dermatitis, atopic dermatitis and ichthyosis and in contact with poison ivy. They may also be indicated in sunburns, hives, rashes and prickly heat [16-22].
- ANTI-INFLAMMATORY PROPERTIES:
Oat protein is not only rich in anti-pruritic properties but also in anti-inflammatory properties due to the presence of a biological molecule called avenanthramides, which have been shown to reduce hypersensitivity induced by oxazolone as well as reduce neurogenic inflammation and the itch mediated by an allergic reaction (histamine mediated) .
In one of the studies it was reported that colloidal oatmeal and oat protein extracts shows anti-oxidant and anti-inflammatory properties . It is possible due to the fact that oat protein results in reduction in the expression of certain biological inflammatory mediators such as NF-kappa B, ROS generation and IL-8. NF-kappa B is an essential nuclear receptor which results in over expression of many other inflammatory mediators thus inducing a cascade of inflammatory process.
On the other hand, IL-8 is also responsible for pruritus and itchy skin . Itching of the skin, thus provoke scratching of the skin in the patient which in turn may disrupt the integrity of skin barrier function which will thus induce a positive feedback cascade which increase much more itching. Composition of oat protein thus restrict the loop cycle of itching and scratching.
The above mentioned research also demonstrated that by reducing the inflammatory mediators, oat proteins result in eczema, inflammation, dryness and irritation. Lotions and skin care formulation with colloidal oatmeal may not only improve the itchy and dry skin but also sooth the itching. It also pointed out towards the finding that, dryness, roughness of skin and scaling was significantly improved from day 1 in the patients included in the study with further improvement with continued use of the lotion.
- REGULATING THE pH:
Oat protein has an excellent buffering properties which was demonstrated when the elevated pH of skin with disease such as eczema or pruritus and alkali treated skin when applied with oat protein product returned back to their normal pH range[36,37]. This fact was further supported by a previous study which postulated that oat protein can buffer skin pH in individuals with atopic dermatitis . The presence of water soluble oat proteins and carbohydrates in colloidal oatmeal demonstrated a high buffering activity which supports the point that colloidal oat may prevent skin irritation and revitalize the skin by conserving the skin barrier .
It was also observed that it provide a skin barrier related effect and is responsible in formation of a protective moisturizing barrier (reducing transepidermal water loss) thus acting as emollient, humectant and occlusive to the skin . One of the clinical research study postulated that individuals with moderate to severely dry skin when treated with colloidal oatmeal and oat protein resulted in significant moisturization and restoration of water barrier of the skin. On clinical evaluation of skin of patients, it was observed that the dryness of skin was significantly reduced during the treatment and even during the regression phase .
- PROTECTING AGAINST HARMFUL RADIATIONS:
Oat protein and colloidal oatmeal also functions by protecting the skin against the Ultraviolet A light which is also in regulation with the FDA (U.S. Food and Drug Administration) in accordance with the Over-The-Counter Final Monograph for Skin Protectant Drug Products issued in June 2003.
- STERLIZING AGENT:
Many reports have demonstrated that colloidal oatmeal and oat protein may also be used in sterilization of surgical gloves by acting as a dusting powder .
ROLE IN COMBATING VARIOUS SKIN DISEASES
- EFFECT ON PSORIASIS:
Psoriasis is a chronic, inflammatory condition which may be considered to be medically and psychosocially debilitating disorder affecting about 1-3% to total world population [25,26]. It is postulated that anti-inflammatory and anti-pruritic properties of oat protein may be effective in the treatment of psoriasis [27,28].
- EFFECT ON ATOPIC DERMATITIS:
In one of the clinical trial, a fragrance free oatmeal skin care body was and cream was applied to the skin of 21 patients suffering from mild or moderate degree of Atopic Dermatitis . Additionally, the product contain ceramides, glycerin and panthenol which further increased the efficacy of the product. On evaluating the results after 2 week interval, it was observed that there was a significant reduction in the flaring and severity of eczema 
- ANTI-VIRAL AGENT:
In a trial study, patients with molluscum contagiosum (infection caused by pox virus resulting in benign, mild skin disease with lesions affecting any part of the body) were treated successfully with a cream containing zinc oxide and colloidal oatmeal .
It is postulated that this anti-viral affect may due to inhibitory effect of arachidonic acid mobilization in the keratinocyte layer of the skin and expression of cytosolic phospholipase AS (PLA2) both of which result in inflammatory reaction in the body .
- ANTI-FUNGAL AGENT:
Oat protein and oat seed extract was found to demonstrate an anti-fungal properties. In one of the article, it was observed that when applied directly on rye bread, it helped to prevent development of Penicillium roqueforti colony .
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