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How to Properly Supplement Vitamin D

A hand holding up a vitamin D capsule to the sun.

Compared to other essential nutrients, supplementing vitamin D is pretty tricky. Here’s what you need to know about adding some to your diet to maximize the benefits.

Spending too much time indoors can negatively affect your vitamin D levels. This is because it’s one of the rare micronutrients that’s almost impossible to get through food. The main source of vitamin D is sunlight. When your skin doesn’t get the exposure it needs, smart supplementation is key.

But what’s the right dose and type of supplement you should take? Is there a specific amount for everyone, or does it vary from person to person? Here’s how to properly supplement your vitamin D levels.

What Is Vitamin D?

Although classified as a vitamin, Vitamin D is also a hormone, as its effects on your body mimic those of other hormones. Believe it or not, scientists are still discovering new ways in which vitamin D interacts with our body and influences everything from our physical to mental health. What they do know is many of our organs and tissues have vitamin D receptors, and that proper supplementation ensures their optimal function.

Vitamin D is fat-soluble, meaning it needs fat to be absorbed properly. One of its main functions is allowing the intestines to efficiently absorb calcium and phosphorus to build strong bones and joints.

It’s also thought to be a great immune modulator, to help reduce inflammation, and it’s even been connected to cancer prevention. With all the current research being done, it’s only a matter of time before we find out more information on this incredible vitamin/hormone.

Where Can You Get Vitamin D?

Foods that naturally contain vitamin D.
Ekaterina Markelova/Shutterstock

Since only a few foods naturally contain vitamin D, getting your daily intake through your diet is hard, if not impossible. Foods that contain it include fatty fish, like tuna, salmon, herring, sardines, and mackerel, as well as cheese, egg yolk, beef liver, and mushrooms. Some other foods fortified with vitamin D, include dairy products, cereal, orange juice, and soy milk.

Even if your diet consisted only of the foods mentioned above, you would have to eat seriously large amounts each day to come close to the recommended daily vitamin D intake. We’re talking six cups of milk, eight cups of mushrooms, and five ounces of fatty fish every single day. Even then, you couldn’t be certain your body was actually absorbing all the vitamin D available in those foods.

The greatest source of vitamin D is sunlight. The UVB rays cause a chemical reaction in your skin, which triggers cholesterol to produce vitamin D instantly. That’s why some studies suggest that even 13 minutes of sunlight at noon (when it’s at its peak) a few times a week can be enough. That, of course, differs based on your location, and which season it is.

Woman sunbathing at the beach.
Olesia Bilkei/Shutterstock

Naturally, you’ll get the greatest exposure during the summer, when the sun is at its strongest and the weather is nicer. Although vitamin D is fat-soluble, our body fat doesn’t store enough of it to last through the winter. Almost all the vitamin D our body produces from summer sun exposure is used right then.

Additionally, SPF and protective clothing lower the absorption of vitamin D, making daily tanning sessions not so efficient, after all. Due to the threat of skin cancer and worldwide encouragement from health officials to protect our skin, it’s unlikely most people will place vitamin D absorption at the top of their priority list.

If we can’t get enough vitamin D from food or basking in the sun, supplements are the only other option.

Vitamin D Supplements

The current recommended dosage is 600 IU (international units) for children and adults, 400 IU for babies up to 12 months old, and 800 IU for people over 70 years of age. However, most health professionals agree that dosage is still too low, considering more than 40 percent of Americans are vitamin D deficient.

That’s why ordering a test at your local lab is probably your best bet. You’ll then know how much your body actually absorbs, and whether you’re deficient.

When it comes to supplements, there are two forms of vitamin D you can find in any pharmacy or health food store:

  • Vitamin D2: Ergocalciferol or pre-vitamin D. It’s produced in plants and fungi.
  • Vitamin D3: Cholecalciferol is produced in humans and animals.

There’s an ongoing debate about whether D3 is better than D2, or vice versa. However, a meta-analysis of randomized D2 and D3 trials showed that vitamin D3 tends to raise the blood concentrations of the vitamin much more. It also keeps it sustainable longer, making it the preferred form of supplementation.

Deficiency and Overdose

Since vitamin D is a hormone, it’s really important to know exactly how deficient you are before you take that 10,000 IU pill your friend swears by. As most of us are deficient, overdosing on vitamin D is rare, but possible. The consequences range from mild to severe, including confusion, vomiting, abdominal pain, and even the formation of calcium kidney stones.

The only treatment is to immediately stop taking vitamin D and calcium, even via food. You can then potentially flush the excess levels from your system with specific medications.

This is why it’s important to check your levels before you decide on a dosage.

Vitamin D is an important micronutrient we all need to stay vital and healthy. How deficient you are depends on a variety of factors, including where you live and what you eat. Still, smart supplementation is key, so find out what your real numbers are to help you choose the right dose.

Karla Tafra Karla Tafra
Karla is a certified yoga teacher, nutritionist, content creator and an overall wellness coach with over 10 years of international experience in teaching, writing, coaching, and helping others transform their lives. From Croatia to Spain and now, the US, she calls Seattle her new home where she lives and works with her husband. Read Full Bio »
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