As we start to slide into cool fall and frigid winter days, there is one thing the majority of us living in the northern states have in common – less sun exposure. This poses a major issue as direct sun exposure is the most simple and effective way to boost and maintain your vitamin D level (plus it’s free!).
Most are aware of vitamin D’s role in healthy bones, as your body needs adequate vitamin D levels to absorb calcium and phosphorus and therefore, maintain normal bone mineralization. However, as it also plays a role in cellular communication, this vitamin is involved in hundreds of other bodily functions including immune function, prevention of cognitive decline and mental impairment, and cardiovascular function. It has also been shown to provide anti-cancer effects, particularly regarding colon, breast and prostate cancers!
Who is at Risk?
People with limited sun exposure.
Our bodies are designed to obtain the vitamin D it needs when it is exposed to sunlight. This can happen very quickly, before your skin has a chance to burn or even tan. According to The National Institutes of Health, “5–30 minutes of sun exposure between 10 AM and 3 PM at least twice a week to the face, arms, legs, or back without sunscreen usually lead to sufficient vitamin D synthesis.” Most Americans do not obtain this even in the summer months, especially those that are homebound, work indoors, and must remain covered for religious reasons.
People with darker skin.
Melanin is a pigment in your skin that determines how dark your complexion is. The more melanin you have, the darker your skin will be. Melanin blocks ultraviolet B rays, the type needed to produce vitamin D. Therefore, a person with a darker complexion and more melanin will require more sun exposure to make adequate amounts of vitamin D compared to someone with fair skin.
The ability to efficiently make vitamin D decreases with age.
Excessive sunscreen use.
Because sunscreen blocks the sun’s UV rays from absorbing, it also inhibits vitamin D production.
Vitamin D and Our Health
As mentioned previously, vitamin D deficiency has been associated with an increased risk of several of the most common and deadly cancers, including breast and prostate cancer. According to the Center for Disease Control, in 2018 approximately 9,320 deaths are estimated due to melanoma skin cancer, compared to 40,920 women from breast cancer and 29,430 men from prostate cancer. Although the use of sunscreen may aid in the prevention of skin cancer, the benefits of moderate non-burning sun exposure (without sunscreen) seem to outweigh the risks. In fact, this 2016 meta-analysis found some interesting results:
“While sunburns have been associated with a doubling of melanoma risk, chronic non-burning sun exposure and outdoor occupations have been associated with reduced risk of melanoma.”
How Much Vitamin D is the Right Amount?
The table below outlines the recommended daily intakes from two different organizations.
|Vitamin D Council||Endocrine Society|
|Infant||1,000 IU||400-1,000 IU|
|Child||1,000 IU/day per 25lbs of body weight||600-1,000 IU|
|Adult||5,000 IU||1,500-2,000 IU|
Talk to your doctor about what dose is most appropriate for you. There are also natural foods sources of vitamin D which include (from highest to lowest amount):
- wild-caught Alaskan salmon
- shitake mushrooms
I also highly recommend getting your 25-hydroxy vitamin D levels tested at least yearly. This will give you a better idea of how you’re doing and if supplementation is necessary. I recently had mine tested for the first time this past summer. As someone who was outside almost daily and prides herself on being able to get a great tan without ever even needing to touch sunscreen, I was in absolute shock to see my level was only 20 ng/ml –
mid-summer! Needless to say, I have been on a supplement ever since. Although optimal ranges vary by organization, the Vitamin D Council’s and Endocrine Society’s guidelines are as follows:
|Vitamin D Council||Endocrine Society|
|Deficient||0-30 ng/ml||0-20 ng/ml|
|Insufficient||31-39 ng/ml||21-29 ng/ml|
|Sufficient||40-80 ng/ml||30-100 ng/ml|
Note: Always be sure to ask for a copy of your labs results as nutrient deficiencies are commonly overlooked, especially if your levels are considered “borderline”.
When choosing a vitamin D supplement, make sure it is in the D3 form, as this has been show to raise levels most efficiently. As vitamin D is a fat soluble vitamin, taking it with a meal containing healthy fats will help improve its absorption. If you are unsure which supplement to choose, labdoor.com is a great company and resource that test supplements for contaminants, label accuracy, etc. Premier Research Labs has a great clean product that I would recommend.