1- Myth or truth: Darker skin has a built-in SPF protection ?
Darker skin does have some inherent protection from the damaging effects of Ultraviolet light. That said, this concept must be looked at critically, as the amount of protection can vary wildly among skin tones. Those skin skin types 6 that have the richest level of melanin may have an inherent SPF in the 11 range. Keep in mind that this SPF is not uniform throughout the body and should not be considered protection. Also an SPF of 11 is not sufficient to confer significant photoprotection. Some believe that darker skin does provide the same level of protection conferred by sunscreen. It's hard to say what the exact origins of this myth are, however it likely has something to do with the fact that the effects of the sun aren't as immediately evident on darker skin tones. In general, the pigment in dark skin can offer some protection from the immediate visible effects of the sun, such as redness and discomfort. However, UV rays from the sun can in fact lead to decreased collagen, textural changes, hyperpigmentation and even skin cancer over time.
SPF stands for sun protection factor, and it is a relative measurement for how long a sunscreen will protect against the ultraviolet B rays or the UVB rays, the rays most responsible for causing redness from sun exposure. The UVB rays also lead to certain forms of skin cancer and other unwanted skin changes. More specifically, if an individual is wearing an sunscreen that is SPF 30 and they typically burn after 20 minutes of sun exposure without sunscreen, they should be able to be in the sun 30 times longer without burning, or for 10 hours. Keep in mind that these numbers are developed in a very controlled lab setting and they are assuming that the sunscreen is applied correctly. Also, remember that in reality UVB rays vary in intensity at different times of day and can therefore affect the sunscreens ability to protect. Lastly, this number does not take into account the ultraviolet A, or UVA rays, that penetrate deeper into the skin and also contribute to skin cancer development as well as skin aging. It's important to find a sunscreen that is "broad spectrum," thereby protecting from both UVB and UVA rays. I recommend that patients stick to sunscreens that are at least SPF 30.
2- Should darker skin wear SPF the same way white skin does? What is the nuance there?
This is an interesting and challenging question, As stated above, darker skin does have some inherent photoprotection and therefore can offer some inherent protection. That said, protection with SPF is still important for all levels of skin pigmentation as even the darkest skin can still be negatively affected by chronic UV light when unprotected. Daily use of a moisturizer with SPF should still be part of the routine skincare regimen for all skin tones, particularly in the spring and months.
3- Does SPF block Vitamin D synthesis? how to find the balance
Vitamin D synthesis occurs through both sun exposure and from some dietary sources. UV light exposure assists the body in making Vitamin D., therefore both the use of sunscreen which blocks Ultraviolet light from the skin can somewhat impair innate production of vitamin D. This also occurs in those with darker skin tones, as the melanin acts to block some of the UV light as stated above. That said, people typically do not use sunscreen to such an extent that to block all ultraviolet light, or they use sunscreen irregularl, so the sunscreen's effect on vitamin D may not be that important. There are other ways to obtain vitamin D aside from getting natural UV rays. Most of these options include making smart dietary choices. Foods such as fatty fish are a good source of vitamin D. Some options include salmon, trout, mackerel, tuna and eel. Even canned fish options such as canned tuna and sardines can help. Fortified milk is an excellent source of vitamin D, as are some types of fortified orange juice. Egg yolks and certain fortified cereals can provide additional sources of vitamin D. Lastly, Vitamin D supplements can help women of color get their daily dose. Of course, as with many things, too much vitamin D can also lead to other problems, so moderation is key particularly when taking supplements.
4- How should dark skin use SPF? how often? how long? when?
As mentioned above, the use of a daily moisturizer with an SPF of at least 30 should be part of the skincare regimen. Of course if you are planning to spend extended time outdoors, it is also important to use a broad spectrum sunscreen on sun exposed skin of at least 30. Also, it is key to reapply sunscreen every 2 hours particularly with sweating or swimming.
5- Why does mainstream SPF have a white cast on darker skin?
Unfortunately, a lot of sunscreen products are not at all sheer when applied to darker skin tones. This is particularly true for sunscreens containing physical block ingredients such as Zinc Oxide and Titanium Dioxide. Understandably, this makes it difficult to use sunscreen on a daily basis, and even more challenging for darker skin as the white cast left on the skin can be significant and cosmetically unappealing. Some sunscreens are formulated by using small particle physical protection which can provide a more shear application. Also sunscreens that combine both physical and the so called chemical blocking agents can result in more elegant application By choosing sunscreens that are formulated.
6 - Explain the sun’s impact on different skin tones.
The look and feel of sunburns in women of color will depend on their skin tones. Obviously, women of color come in all shades. For women with lighter (but pigmented) skin tones, sunburns will oftentimes present in a similar fashion as to what's seen in white women, with redness, blisters and eventual peeling. Additionally, they may experience various forms of hyperpigmentation in sun exposed areas. In women with darker complexions, sunburns may just lead to a darker overall tone. As far as how sunburns will feel, this is a pretty universal sensation of itching, discomfort and occasional pain. Unfortunately, reversing the damage is difficult once it has occurred. However, bland emollients such as Aveeno and even Aquaphor can help to soothe the skin. If the sunburn is severe then I would recommend a visit to the dermatologist. Some prescription strength creams and oral medications can assist with the discomfort.
7- Explain the difference between physical and chemical sunscreen. Which is better for darker skin tones?
Sunscreen, as the name implies, helps to protect the skin from sun's damaging ultraviolet rays. There are two main types of sunscreens, chemical and physical blockers, and they work by different mechanisms. The chemical blockers work by essentially absorbing the energy from the UV rays before it makes it to the skin. In contrast, the physical blocker sunscreens such as zinc oxide and titanium dioxide, work by blocking and dispersing the sun rays away from the skin. Both mechanisms are effective in terms of protection, however the physical blockers have some particular attributes that make them the sunscreens that I recommend the most. First, people with sensitive skin can oftentimes react poorly to the chemical blockers with allergic or irritant rashes. Also, the chemical blockers take a little longer to work once applied than the physical blockers.