Vitamin D is actually a hormone synthesized in the skin from sun exposure and activated in the liver and kidneys. It’s different than other vitamins because the body makes most of it on its own (with the help of sunlight), rather than exclusively relying on food sources to get enough. When your skin is exposed to sunlight, it makes Vitamin D from cholesterol. Spending time in the sun, without sunscreen, is one of the surest and easiest ways to get enough. How much sun you need depends on the time of year, how far from the equator you live, how much skin is exposed and the amount of pigmentation (melanin) in your skin.
Melanin is a substance that affects how light or dark your skin color is, and the more melanin you have in your body, the darker your skin color will be. Melanin gets released when we are exposed to the ultraviolet rays of sunshine.
The more sunshine we receive, the more melanin is released in our skin. The amount of melanin you have in your skin affects the amount of Vitamin D you can produce, so the fairer your skin, the more easily you can make it.
I take my daily walk when the sun is high (when I look at my shadow and it’s shorter than I am) or around noon to 2 pm here in my state. I use sunblock on my face but leave my arms exposed. In the colder months of the year, I jump rope for about ten minutes outside (arms exposed) and then get additional Vitamin D from supplementation. I realize that with increasing cases of skin cancer, some people may opt to use sunscreen regularly and reduce time in the sun and for those folks, they want to get their Vitamin D from supplementation and/or eating foods rich in the vitamin.
Why Do We Need Vitamin D?
Vitamin D deficiency is common and so if you fall into this category make sure you increase the amount of this important hormone to reap its benefits.
Here are some of the benefits associated with this vitamin:
- It contributes to bone health by helping with absorption of calcium into our bones. It works in concert with magnesium, Vitamin K2 and phosphorus to strengthen bones.
- It supports the immune system and may help prevent extended or extreme inflammatory responses.
- It serves as a cancer inhibitor by reducing cellular growth (which promotes cancer) and improving cell differentiation (which puts cells into an anti-cancer state). This can explain why there’s a correlation with Vitamin D deficiency and colon, prostate, breast, and ovarian cancer.
- It helps maintain the structural integrity of your gut lining (helping to prevent leaky gut and food sensitivities).
- It supports cardiovascular health and helps regulates blood pressure, cholesterol levels and inflammation.
- It helps manage blood sugar levels and works with calcium to regulate insulin secretion.
- It may help depression and mood disorders. Getting adequate amounts of Vitamin D can help treat seasonal affective disorder (a type of “winter depression”).
Vitamin D Supplementation
Vitamin D supplements come in two forms: D2 and D3. D3 from animal products (specifically from the cholesterol within these products) is closest to what sunlight naturally produces in humans when the skin works to convert UV light. Therefore, Vitamin D3 is the most bioavailable form of Vitamin D. Please note that it is fat-soluble, so it’s helpful to take it with some form of fat to aid in absorption.
Food Sources of Vitamin D
Many of the best food sources of Vitamin D are animal-based—specifically fish sources.
- Fish liver oils, such as cod liver oil: one tablespoon = 1,360 IU of
- Cooked wild salmon, 3.5 ounces = 360 IU
- Cooked mackerel, 3.5 ounces = 345 IU
- Sardines, canned in oil, drained, 1.75 ounces = 250 IU
- Tuna Fish — 3 ounces: 154 IU (39 percent DV)
Other types of Vitamin D-rich foods can be found here.
How Much Do You Need
The only way to know if you are deficient is to have your doctor perform a test, called a 25-hydroxy Vitamin D test. This will tell you if, and how severely, you are deficient.
The current ranges for “normal” are between 20 and 50 ng/mL. These might be fine if you want to prevent rickets—but not for optimal health. In that case, the range should be 40 to 70 ng/ml.
How much Vitamin D supplementation does it take for optimal levels? That depends as we’re all unique physiologically (differences in Vitamin D receptors) and where we live, the amount of time we spend outdoors, and the amount of skin pigmentation we have. I would start with a baseline and see how you’re doing based on your current lifestyle measures.
If you have a deficiency, you should correct it by increasing your Vitamin D3 supplementation—but only under a doctor’s supervision. Monitor your Vitamin D levels until they are optimal. Keep in mind that the amount of sunshine we get in the late fall and winter is vastly different than that of summer so get your levels checked twice a year as your levels will likely be different between these seasons and adjust your supplementation accordingly under consultation with your doctor.
