It's your body's largest organ. It protects your body from water, the sun and germs. It also protects your internal organs and vulnerable tissues that lie just beneath it. It's your skin.
Skin is a clue to your age, gender, health and ethnic background. Without it, your body temperature could fluctuate dangerously.
With all the purposes the skin has, it's no wonder that there are so many myths surrounding it. Here are 10 of the most common.
1. Find the right skin cream and you can keep your skin looking young.
There are hundreds of skin treatments that can help you look younger. But the topical treatment with best evidence for reducing wrinkles is retinoic acid (as in Retin-A). The prescription strength can irritate the skin, but it's the most effective form. Many over-the-counter products contain retinoic acid as well, but it's difficult to say if one is better than another.
2. Use antibacterial soap to keep your skin clean.
Skin normally has bacteria on it. It's impossible to keep your skin completely free of bacteria for any amount of time. Of course, you can prevent the spread of an infection with good hand-washing, especially if you're sick. But many experts are concerned that the widespread use of antibacterial soap could lead to more resistant bacteria. Antibacterial soap is not necessary for everyday use. Regular soap is fine.
3. Eating chocolate or oily foods causes oily skin and acne.
This one was debunked long ago. Yet, there is still the perception that oily foods lead to oily skin and acne. The truth is an oily substance called sebum causes acne. It's made and secreted by the skin. In fact, there's no evidence that any food causes acne.
4. Any sun exposure is bad for you.
The sun has good and bad effects on the skin. Skin cells produce more pigment when they are exposed to UVA or UVB light from the sun. The extra pigment is what creates a tan. Still, most people do not have to fear any and all sun exposure.
Excessive tanning (by spending time in the sun or in a tanning booth) can increase the risk of skin cancer, especially if sun screen is not used. For example, spending several hours each day in the sun for months or years (depending on individual factors, such as how fair the skin is) could increase skin cancer risk, especially if sunburns are frequent. Skin cancer risk is correlated with total lifetime sun exposure and frequency of sunburns. In addition, spending too much time in the sun or a tanning booth can damage skin, causing it to wrinkle and age prematurely.
5. Tanning is good for you.
People often associate a dark tan with good health. But there's no evidence that tan people are healthier than people who are pale. Perhaps the most important health benefit of the sun is the effect it has on vitamin D.
The sun converts inactive vitamin D in the skin to its active form. Vitamin D helps keep bones strong. And recent studies suggest that vitamin D may lower the risk of certain cancers and boost immune function, for example. Depending on how much vitamin D you're getting in your diet, getting no sun exposure could increase the risk of vitamin D deficiency.
The bottom line is that you need just 10 to 15 minutes of daily sun exposure to get adequate vitamin D. This is much less than you'd need to get a good tan. And if your diet has enough vitamin D or if you take supplements, you may not need to rely on sun exposure anyway.
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6. The higher the SPF the better.
Above a certain level, a higher sun protection factor (SPF) has little added benefit compared with a lower SPF. Experts generally recommend using sunscreen with an SPF of at least 15. This blocks out 95% of UVB radiation. SPF 30 blocks out 97%. It may be worth the higher SPF if you're planning to be outside for more than two to three hours, especially if it's during hours of peak sun exposure (10 a.m. and 2 p.m.). Since products with higher SPF ratings tend to cost more, knowing about this myth can help you save money. In most circumstances, the added benefit of SPF 30 may not be worth the cost.
7. A scar that is barely noticeable is the mark of a good surgeon.
The true skill of the surgeon is demonstrated by what he or she does in between making and closing the incision. In fact, many surgeons leave the "closing" to an assistant. While surgeons routinely pay more attention to wounds on the face (using thinner suture, making stitches closer together or avoiding the use of sutures altogether if possible), the appearance of a scar after surgery tells you little about the skill of your surgeon.
8. Vitamin E will make scars fade.
There's little evidence to support this claim. In general, the most important way to take care of a wound is to keep it clean and dry. But talk to your surgeon or dermatologist if you have concerns about the appearance of a scar. There are other options for treatment, including laser treatments.
9. Crossing your legs causes varicose veins.
There are a number of risk factors for varicose veins, but crossing your legs is not one of them. Heredity is one of the biggest risk factors — an estimated 80% of people with varicose veins have a parent with the same condition. Other risk factors include smoking, inactivity, high blood pressure, pregnancy, obesity and having a job that requires prolonged standing. If you already have varicose veins, elevating the legs and compression stockings may be helpful. But keeping your legs "uncrossed" won't prevent or improve the condition.
10. Scalp massage can prevent baldness.
My mother suggested this to me when I began to lose hair in my 30s. Turns out, she was wrong about the advice. There's simply no evidence that scalp massage prevents baldness, tempting as it is to believe.
There seems to be no shortage of misunderstanding and false information out there regarding skin. The reality is that skin is largely a low-maintenance organ. Most people just need a moisturizer for dry skin and sun screen when they go outdoors. Most other skin issues take care of themselves.
If you see something unusual on your skin or have concerns about how to keep your skin healthy, talk to your doctor or dermatologist. And if you hear someone repeating these skin myths, you can set them straight.
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Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.