So, vitamin D is an important vitamin—technically, it’s a hormone—that is made by your skin after exposure to sunlight. Most people don’t get enough sunlight to support healthy vitamin D levels, which is why we recommend supplementing it if you have low levels. Have your levels checked if you have any concerns.
You probably already know that vitamin D is super important for your bone health. But, you probably did NOT know that it’s also important for your skin’s health. That’s our topic for today.
As a cream or ointment, vitamin D has been used for years to treat psoriasis. It’s commonly used together with or as an alternative to topical steroids, and in general, it works well without too many side effects.
Vitamin D is also important when it comes to skin cancer reduction. For one, having adequate levels of vitamin D appears to reduce your risk of getting melanoma. At least one study has shown that having low vitamin D levels is correlated with a greater risk of getting melanoma. Having adequate vitamin D levels correlated with less risk of melanoma occurrence as shown in another study (with RR of 0.62). Getting enough vitamin D could be achieved through your diet — eating a vitamin D-rich diet is associated with lower melanoma rates. Taking vitamin D supplements also help lower your risk. A study published earlier this year found that in 500 adults at risk of skin cancer, taking vitamin D supplements regularly correlated with lower rates of past or present melanoma—by more than half—or even any type of skin cancer. Interestingly, the same was found in patients that were immunosuppressed. This seems like really promising data. But, just be aware, that not all studies have as clearly shown that vitamin D status correlates with a lower risk of skin cancer.
So, now that we know that having adequate vitamin D can lower your skin cancer risk, let’s shift gears and talk about vitamin D and implications if you already have skin cancer or have had it. If you have had melanoma, optimizing your vitamin D level can lower your risk of dying from it. There’s a lot of science that has shown that in people who have had melanoma, having low vitamin D correlates with worse outcomes—as in higher rates of dying from it. A study looking at 104 patients with stage 2 melanoma who took either a vitamin D3 supplement (having 100,000 international units) every 50 days for three years outlived people who took a placebo, or sugar pill. After just 1 year, the people who took a placebo had lower survival rates compared to those who took vitamin D supplements.
Apart from helping with optimizing melanoma prevention and outcomes, some research has also shown that having adequate vitamin D levels can prevent basal cell carcinoma and squamous cell carcinoma.
While our focus is your skin skin health, I just want to briefly mention that having normal levels of vitamin D has been shown to help with other cancers also— like colon, pancreatic, and prostate cancers.
So, why does vitamin D help prevent cancer and possibly improve your outcome if you have cancer? There’s research that shows that vitamin D directly interacts with cancer cells and can prevent them from dividing and can even cause them to die off—a process called apoptosis. Also, vitamin D can reduce abnormal vessel growth that the cancer creates in an effort to continue to feed itself nutrients. Finally, the vitamin D receptor in the skin can function as a tumor suppressor.
Cool. Now that you are more aware of the benefits of vitamin D for your skin health, let’s talk about practical application of this information. Because the studies that we talked about used different vitamin D thresholds, it’s not exactly clear how much you should be taking. So, the first step is to have your vitamin D level checked. The standard vitamin D test is one called 25-hydroxyvitamin D. A level greater than 25 ng/dL is considered adequate. Higher levels may be more optimal. You can have this lab test drawn by your regular doctor, but nowadays you can even have this done online and arrange to have someone draw your blood at home. Once you know your vitamin D level, then you can decide if you need to supplement or just to maintain your adequate level.
Based on your test, If you need to start a supplement, understand there are two forms available, vitamin D2 (called ergocalciferol) and vitamin D3 (called cholecalciferol). Vitamin D2 is the form that is made by plants and mushrooms, whereas vitamin D3 is the form that our own body makes. Vitamin D3 is preferred because it’s what we normally make and it’s more bioavailable. It appears to be able to raise our levels more quickly and in a more sustained way. The dose of the supplement that you need really depends on your level. If you’re really deficient, you may need to take a higher dose than if you had a slight deficiency. For example, if your level is less than 12 ng/mL, you may need to supplement with 50,000 units weekly for 6 weeks. If your value is closer to 20 ng/mL, you’ll need something like 1000 units daily. Again, this is not medical advice, just some information for educational purposes, so consult with your doctor before you start any supplements. Because vitamin D is one of the fat-soluble vitamins, it’s best taken with a fatty meal—we recommend taking it with an avocado or with some olive oil because these are super healthy fats.
Even after your vitamin D level is normalized, you may need to continue taking a supplement. The standard dose for adults is 600 to 800 international units daily.
Apart from supplements, having a balanced diet can help with your vitamin D levels. Plus, it’s good for your health otherwise, including your bones and your immune system too. For those of you that eat fish and animal-based products, you can get vitamin D by eating sardines, salmon, tuna, swordfish, and egg yolks. Cow’s milk is supplemented with vitamin D, so it’s a good source—but in general, we don’t endorse drinking cow’s milk. For you vegans out there, you can have some fortified plant-based milks, orange juice, or fortified cereals. Mushrooms are also a good source of vitamin D. Here’s a fun fact for you—depending on the type of mushroom and how it was grown, the vitamin D level will vary. Most mushrooms sold at the grocery store (like button mushrooms, shiitake and oyster mushrooms) tend to be grown in the dark and have very low levels of vitamin D—in the form of vitamin D2, or ergocalciferol. Fresh wild mushrooms like chanterelles and morels can contain up to 1200 IU of vitamin D per 3.5 ounce serving—a significantly higher level. Dried mushrooms are also a reasonable source and can last up to 6 months in your pantry. Please note that cooking your mushrooms WILL affect the vitamin D levels — specifically, if you cook them in oils, it can cause the vitamin D to leach out (because it dissolves in the fat/oil). If you cook them in water or steam them though, the vitamin D content will not be affected.
Some of you may be thinking, well, what about just going out in the sun? We briefly mentioned at the start of this episode that your skin makes vitamin D in response to sunlight. This is something that can help, but please understand that in general I don’t endorse this either. There’s too many variables and very clear harm from too much sun exposure on your skin. You’re clearly increasing your odds of getting skin cancer, which is the opposite of our goal, and your skin is going to look older more quickly if you get a lot of sunlight regularly. Plus, there is no consensus regarding how much sun exposure you actually need in order to get the vitamin D that you need and no guarantee that sun exposure will get you that amount as studies, at least in children, showed that they were unable to (MG et al p 3-4). Use a mineral sunscreen based on zinc or titanium or both when you spend time outside.
By the way, you DEFINITELY should not be using tanning beds thinking that will increase your vitamin D — these tends to be UVA based, which is NOT the type of UV light that helps us make vitamin D. We need UVB for this.
Also, if you’re really strict with sun protection or sun avoidance, don’t stress about lowering your vitamin D levels or increasing your risk of having brittle bones. There are really high quality studies that show that daily sunscreen, with at least SPF15, did not impact vitamin D levels. And, another study found that sun protection does NOT cause osteoporosis. Rather, people that used sun protection had LOWER risk of osteoporosis and spine fracture. As such, rest assured, using sun protection IS a good idea.
So, there you have it. Go get your vitamin D levels checked and enjoy healthy skin.
References
- Gracia-Darder Ines et al. Vitamin D deficiency in melanoma patients is associated with worse overall survival: a retrospective cohort study.
- Johansson H et al. Vitamin D supplementation and disease-free survival in stage II melanoma: A randomized placebo-controlled trial. Nutrients 2021; 13: 1931.
- Kanasuo E et al. Regular use of vitamin D supplement is associated with fewer melanoma cases compared to non-use: a cross-sectional study in 498 adult subjects at risk of skin cancers. Melanoma Res 2023; 33 (2): 126-235.
- Martin-Gorgojo A et al. Vitamin D and Skin Cancer: an epidemiological, patient-centered updated and review. Nutrients 2021 13: 4292.
- Moro R et al. Prognostic value of vitamin D serum levels in cutaneous melanoma. Actas Dermosilifilogr 2022. 113 (4): 347-353.
- Neale RE et al. The effect of sunscreen on vitamin D: A review. Br J Dermatol 2019; 181 (5): 907-915.
- Passeron et al. Sunscreen photoprotection and vitamin D status. Br J Dermatol 2019; 181: 916-931.