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Vitamin D even in the SUMMER? This message is OLAF approved.

Hello and Happy Summer to all my WELLNESS WARRIORS!

If ten clients walked into my office today, I know that nine of them would be deficient in vitamin D. So when a patient recently asked me if they needed to supplement with vitamin D3 in the summer, my answer was, “Yes.”

It may seem strange but most of us, even in summer, rarely get enough direct sunlight on a regular basis. Many of us work in offices and spend most of our days indoors year-round.

Even if we take a week vacation where we are exposed to more sun than usual, this is rarely enough to offset common deficiencies. And when we are deficient, our health suffers.

So because vitamin D is so important, I want to take you through the basics: what it is, how to test for your levels, and how much is beneficial for you to take, even during the summer.

What is vitamin D?

Vitamin D is a fat-soluble nutrient that is closer to a hormone, like cortisol or testosterone. This is important to note because it means vitamin D has a deeper functionality than a simple vitamin compound.

There are tons of studies showing the importance of vitamin D. Optimized vitamin D levels have been linked to:

  • Improved mood and mental cognition
  • Increased production of antimicrobials that reduce gut infections and skin pathogens
  • Reduction of inflammatory responses
  • Reduced risk of osteoporosis by helping with assimilation and absorption of calcium
  • Reduced rates of most cancers
  • Lowered rates of diabetes
  • Decreased risk of cardiovascular disease
  • Decreased risk of winter flu
  • Decreased levels of depression and seasonal affective disorder

Where do I get my vitamin D?

You can get vitamin D from three places: sun, food and supplements. Since we can’t get enough vitamin D from food alone, I’ll focus on sun and supplements.


Vitamin D is often called the “sunshine vitamin” and for good reason. Vitamin D3 or  “cholecalciferol” is produced photochemically when cholesterol in the skin is exposed to sunlight.

We spent most of our history as homo sapiens around the equator soaking up all the vitamin D we needed from the sun. Even when some of our ancestors traveled north, they increased their ability to absorb vitamin D by developing fair skin with less melanin.

Just twenty minutes of direct sunlight on bare skin can produce more than 10,000 IU of vitamin D.


When we don’t get enough direct sun exposure, we don’t produce enough vitamin D. Instead of sunlight being converted to cholecalciferol, we can supplement it directly.

There are two common types of supplemental vitamin D, D2 and D3.

Vitamin D2 supplements are called ergocalciferol and are grown from mushrooms.

Vitamin D3 supplements are made by exposing a certain type of cholesterol to ultraviolet light, and then purifying it. The cholesterol is produced from lanolin, a naturally-derived grease found in sheep wool.

We recommend supplemental vitamin D3 because it is more effective than D2 (reference).

How do I find out my vitamin D levels?

Blood work can reveal your current levels of vitamin D. You can find out your vitamin D levels in two simple ways:

1) Ask your doctor to test for it

2) Use a service like directlabs.com to order the test

Doctors run a test that looks for 25-hydroxy-vitamin-D or 25(0H)D for short. It’s both the name of the test and what they’re looking for.

Most doctors recommend lower levels of vitamin D than functional medicine doctors. This is often because they are basing their recommendations on antiquated research.

I recommend that you aim to get your ng/ml above 50, preferably between 70 and 80.

How do I optimize my vitamin D levels?

For people living in the northern United States and Canada, it is difficult to get enough sunlight exposure. But even those in the south can still become deficient.

Here is how you maintain your vitamin D levels or correct a deficiency:


The sun is the cheapest and healthiest way to get your vitamin D. The challenge is making sure you get enough sun exposure to reach optimal vitamin D levels.

A lot of people believe that getting 20 to 30 minutes of sun exposure on their face will give them all the vitamin D they need. The research out there shows us this isn’t true.

Almost daily full-body exposure without sunscreen is necessary to achieve optimal levels. Even during the summer, when many of us are frequently wearing swimsuits and sunbathing, we rarely get this type of exposure daily.

Some people also think that you can stock up on vitamin D by spending long amounts of time in the sun during a week-long vacation. This idea also seems not to be true.

Studies have shown that after 30 minutes your body reaches equilibrium and any more sun exposure does not increase your absorption of vitamin D3. So in this case, more is not better. It’s the regularity of exposure.

On top of that, if you have darker skin the recommendation for sun exposure is 3x more than people with lighter skin (3 x 30 minutes), so it can be even more challenging to reach your optimal levels.

The sun is the best source of vitamin D, but as you can see all these factors make supplementation, for most people, essential.


For maintenance: Take 2,000 to 4,000 IU per day depending on the time of year. More in the winter, less in the summer. This is one of the few supplements I recommend taking on an ongoing basis.

To correct a deficiency: Take 5,000 to 10,000 IU under a doctor’s supervision. Correcting a deficiency can take 6 to 12 months. That’s why it is important to work with your doctor to monitor your vitamin D levels.

Note: If you’re taking high dosages (10,000 IU), have your doctor also check your phosphorous, calcium and parathyroid hormone levels for potential issues.


Daily sun exposure is crucial for health. But modern life is organized in such a way that getting the amount of vitamin D we need without supplementation can be challenging.

That’s why, I recommend you get your vitamin D levels checked, supplement accordingly and spend some time in the sun.

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