by Aliza Becker, BA, MPS
Physiologically, the effects of winter air on health have been well-established. For example, exposure to dryer air increases water evaporation from the bronchial mucus1 in the lungs and may cause epithelial lesions and local inflammation in the trachea.2 Rates of tracheal and nasal mucociliary clearance are reduced when breathing dry air, enabling pathogens and debris to remain in the respiratory tract for longer periods of time.3-5 Cold, dry air can also trigger the release of histamine and other inflammatory mediators, which can induce rhinorrhea (nasal discharge) and trigger airway restrictions in some individuals.6–10
The skin, a significant component of the innate immune system, can also be adversely affected by exposure to winter air. Here, too, histamine release from skin cells in response to cold temperatures can lead to redness, itching, edema, and skin lesions in susceptible individuals—a condition known as cold urticaria.11 Cold, dry weather can also increase the risk of developing atopic dermatitis, a type of eczema that makes your skin red and itchy, and frequency of eczematous flare-ups can increase in cold dry weather as well in affected individuals.12 Research has indicated that even nonallergic individuals can experience skin discomfort during the winter months, including skin roughness, dryness, irritation, itching, and inflammation, due to lower humidity.13–17
Interestingly, in a pediatric study, researchers noted that significant increases in skin pH (toward less acidity) was associated with drier skin.18 In healthy skin, the stratum corneum—the outermost layer of the epidermis—has a slightly acidic pH due to its different overlying components, including amino, polyhydroxy, and fatty acids, which help prevent overcolonization in the skin by micro-organisms, such as Staphylococcus aureus (S. aureus).19,20 Skin pH is also influenced by a variety of other factors, including sex, age, and Fitzpatrick skin type (a commonly used system to describe a person’s skin type in terms of response to ultraviolet radiation exposure), as well as the use of different topical products, such as body soaps, and exposure of skin to detergents used to wash clothing.20-23 Research suggests that the development of some skin conditions associated with an overabundance of certain bacteria or fungi, such as atopic dermatitis, may be facilitated by a decrease in skin acidity (i.e., increased pH).18,24,25 This variation in pH is apparent even in the uninvolved skin (without lesions) of people with atopic dermatitis compared to those with healthy skin.26 Research has also shown that people with drier, less acidic stratum corneum develop wrinkling faster and more persistently.27
Tips on Keeping Skin Healthy During Winter
Staying hydrated. There are a number of ways to maintain or increase skin hydration and prevent transepidermal water loss during the winter. Drinking plenty of water throughout the day helps to ensure the body is adequately hydrated, including the skin. Keeping indoor air moisture levels high (e.g., by using an air humidifier) also helps maintain hydration in the body during winter months. Wearing clothing that protects the skin from cold, dry air and using a daily topical skin moisturizer (e.g., lotion, emollient) can help prevent transepidermal water loss and subsequent dry skin.28-33
Maintaining a healthy skin pH. Using gentle cleansers and topical moisturizers that are appropriate to your skin type can help maintain a healthy skin pH. For example, if you are prone to acne, skin care products that are more acidic may help control outbreaks. Different parts of the body have different pH levels appropriate to their anatomical location, which means a soap you use on your legs and arms may not be ideal for use on your face—same goes for topical moisturizers. Consult with a dermatology healthcare professional to learn what cleansing and moisturizing regimens are right for your particular skin type and any existing skin conditions you might have.34
Nutrition. Consuming certain foods can also positively impact the skin’s innate immunity and healthy microbiome, which is particularly important during the winter months when the skin’s immune functioning can be weakened by drier air.35
Vitamin A. Research has linked vitamin A deficiency with increased susceptibility to skin infection and inflammation, including atopic dermatitis. Vitamin A deficiency has also been linked to S. aureus colonization and a less diverse skin microbiome, increasing the risk of bacteria-related skin conditions.36 The human body can produce vitamin A from the carotinoids beta-carotene and alpha-carotene, which are found in plants. Vegetables rich in these carotinoids include cooked sweet potatoes, winter squash, kale, collards, turnip greens, and carrots; and raw sweet red peppers, Swiss chard, spinach, and Romaine lettuce. Fruits considered good sources of these carotinoids include mangos, cantaloupes, grapefruits, watermelons, tangerines, and nectarines.37
Vitamin C. While the role vitamin C plays in skin health is not well understood, research has found an association between vitamin C deficiency and poor wound healing, thickening of the stratum corneum, skin fragility, and loss of connective tissue.38 Foods rich in vitamin C include cherries, rose hips, chili peppers, guavas, sweet yellow peppers, mustard spinach, kale, kiwis, strawberries, oranges, lemons, Brussel sprouts, and broccoli.37
Essential fatty acids. Research has shown that polyunsaturated fatty acids, including omega-3 and omega-6, play important roles in protein expression related to inflammation and lipid metabolism, and are critical to the formation of the skin’s epidermal barrier function, which regulates the body’s water loss through skin.39 Good sources of omega-3 fatty acids include cold-water fatty fish, such as salmon, mackerel, tuna, herring, and sardines; nuts and seeds; and plant-based oils, such as flaxseed, soy bean, and canola. Good sources of omega-6 fatty acids include safflower oil, sunflower oil, corn oil, soy bean oil, sunflower seeds, walnuts, and pumpkin seeds.37
Winter’s cold, dry air can lead to dry, irritated skin, which will reduce the skin’s barrier functioning and increase your risk of infection and developing skin conditions, such as eczema. Drinking plenty of water, using a daily topical moisturizer appropriate to your skin type, and using a humidifier to alleviate dry air in the home, especially during the winter months, will help your skin maintain healthy moisture and pH levels, which will in turn reduce transepidermal water loss and help prevent overcolonization by bacteria. Additionally, wearing clothing that protects the skin from cold, dry air when outdoors can prevent moisture loss in the skin. Consuming a variety of fresh fruits, vegetables, whole grains, nuts, and legumes, especially those rich in vitamin A, vitamin C, and essential fatty acids, will assist your skin’s innate ability to fight off infection and protect the body.
Editor’s note. Please consult with a licensed healthcare professional to address any questions or concerns you have regarding your health.
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About the Author
Ms. Becker is the managing editor of The Journal of Innovations in Cardiac Rhythm Management. She also works as a freelance editor and as a teaching assistant for the George Washington University’s Master of Professional Studies in Publishing program.