The skin is our largest organ and something that we take for granted when it is healthy. As an academic dermatologist I often hear misleading ‘facts’ that seem to remain stubborn. Here are some of the most commonly shared myths that can be immediately clarified, and some truths that you can trust.
Skin constantly renews itself
WHERE The skin forms a dynamic barrier between the internal environment of your body and the outside world. Cells called keratinocytes in the epidermis (the outer layer of the skin) are constantly dividing to produce a supply of cells that move up through this layer and are shaken off the surface. The skin is a rich source of stem cells with the capacity to share and renew themselves.
Drink two litres of water a day for healthy skin
FALSE The amount of water you drink does not directly affect your skin. Water is supplied to the skin by blood flowing through the dermis, the innermost layer of the skin; water is lost from the epidermis, especially in a dry environment.
Water is needed to hydrate the skin and when you get severely dehydrated, your skin looks dull and less elastic. In a healthy person, the internal organs – kidneys, heart and blood vessels – determine the amount of water that reaches the skin. There is no fixed volume of water that you have to drink, it just depends on the amounts you use and lose.
Stress can make skin unhealthy
TRUE There are many health problems in modern life that we blame, but different skin conditions have been shown in scientific studies, which are exacerbated by life events, possibly through stress hormones including cortisol (a steroid hormone made in the adrenal glands). Well-known examples are alopecia areata, an autoimmune disorder in which the immunity of the body begins to attack the hair follicles, causing the hair to fail; psoriasis, another autoimmune disorder that causes thickening of the skin, peeling and inflammation; and eczema, itchy red skin inflammation often occurring in addition to asthma, hay fever and other allergies. Unfortunately, a flare-up of these skin conditions is exactly what you do not need when you feel stressed or under pressure.
Eating chocolate causes acne
FALSE Acne vulgaris, the common “teen” acne that can persist in your 30s and 40s, occurs due to the interaction between hormonal effects on the skin’s sebaceous glands, plus the immune response of the skin to blocked pores and microbes that live. on the skin. skin.
Eating a high-fat diet is unhealthy for many reasons, but it does not cause acne. In fact, some tablets prescribed for severe acne, such as oral isotretinoin, are better absorbed when pills are swallowed with a fatty meal – and that may also include chocolate.
Washing powder causes eczema
FALSE Eczema is a condition where the skin is dry, itchy and red. It is caused by a combination of genetic factors (how your skin is made) and environmental effects, leading to inflammation. Soaps, detergents and washing powders can irritate the skin and contribute to dryness by removing oil from the skin (just as washing-up liquid removes fat from your dishes). Organic washing powders contain enzymes – proteins that break down fats and other proteins to remove stains – and can irritate sensitive skin, which can aggravate eczema. It is important that all washing power is thoroughly rinsed before being worn to prevent skin irritation.
White marks on nails = calcium deficiency
FALSE Nails are manufactured in the nail matrix, an area under the skin at the top of your nail. If the matrix is traumatized, bombed or bitten, an irregularity occurs in the developing nail and air can get caught in it. This appears as a white mark when the nail grows out. Calcium is important for healthy nails (as well as bones and teeth), but these white spots do not indicate a shortage.
Sunshine is good for you
TRUE AND FALSE Many people have experienced the feel-good factor of a sunny day, but there are good and bad effects of sunlight. Light from the sun includes a mixture of different wavelengths of light: some are visible to the human eye, some are longer than the colors we can see – these are called ultraviolet (UV) – and some are shorter, the infrared. Different wavelengths have different effects on the skin.
UVB is used by the skin to make vitamin D that is essential for the health of the bones. Without exposure to the sun, this vitamin must be removed from the diet. Dermatologists use specific wavelengths of UVA and UVB in carefully controlled doses to reduce skin inflammation, a valuable treatment for some skin conditions.
But when the skin is exposed to too much UV radiation it can damage the DNA of the skin cells, leading to uncontrolled growth, the basis of cancer. As a simple rule, unless you have a disease or treatment that suppresses your immune system, sunshine is good for you in moderation, but you always avoid being burnt.
Keep it simple
The basic principles for keeping the skin healthy are mainly common sense. You have to wash your skin regularly to remove dirt, but not so much that you remove essential moisture and water-resistant substances. Use a moisturizer if your skin feels tight or dry – a greasy ointment works best unless you have a skin that is prone to acne, in which case you should use a non-greasy water-based cream. Avoid stress if possible, eat a healthy diet and drink water if you are thirsty. And finally protect your skin from too much sun with a hat and clothing or sunscreen.
Sara J Brown is Professor of Molecular and Genetic Dermatology and Wellcome Trust Senior Research Fellow at the University of Dundee.