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93% Of People Have A Vitamin D Deficit—Here's How To Supplement

Last updated on February 25, 2022

What essential nutrient deficit affects over 90% of the population1 and rarely gets diagnosed? If you answered vitamin D, you're correct.

Vitamin D is a hormone-like micronutrient produced from a photolytic reaction with ultraviolet (UV) light—which can be hard to come for those of us who spend a lot of time indoors.

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Here's why low vitamin D levels are so common (over 40% of U.S. adults meet clinical criteria for vitamin D insufficiency) and why I recommend using supplements to get enough of the sunshine hormone.*

Why it's so hard for most people to get enough vitamin D.

Many of us live in more northern latitudes (pretty much anywhere north of Florida), where ample sunlight is not available year-round.

Even for those who do have access to lots of sun, many folks spend the majority of time indoors or slather on UV-blocking sunscreen when they do go out.

As you get older, your body also naturally slows down its production of natural vitamin D (skin photosynthesis becomes much less efficient).

The average 70-year-old creates significantly less vitamin D2 than a younger person.

Skin color makes a difference, too, as people with darker skin (i.e., more melanin) produce less vitamin D.

All things considered, you probably need to look beyond the sun to get enough vitamin D, especially if you're older.

While there are some vitamin-D-rich foods, including fungi-yeast (D2), UV-treated mushrooms (D2), and liver (especially from oily fish like cod, herring, and sardines) providing D3, most don't have high enough levels of the hormone.

Unless you're eating 30 ounces of wild salmon a day (i.e., 7 plus servings of fish) or downing 5 plus tablespoons of cod liver oil with breakfast, you might need to start taking a supplement to make sure you're getting optimal levels.*

I put nearly every one of my clients on vitamin D supplements, which are inexpensive and easy to take via softgels or liquid drops.*

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What's the right amount of vitamin D?

Here are five ways to optimize your vitamin D levels to get all of the benefits from this workhorse hormone:*

The National Academies recommends3 the general population consume 400 to 800 IU of vitamin D a day. That's 400 IU for infants, 600 IU for those ages 1 to 70, and 800 IU for individuals older than 70. To be clear: That is the amount to prevent frank vitamin D deficiency and two serious clinical bone mineralization defects, rickets and osteomalacia, which are directly caused by vitamin D deficiency and require medical attention.

But the real question is: How much vitamin D do you need for optimal health? Probably more than you think—but thankfully, here's what you can do about it:

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1. Get tested.

Before starting to supplement with vitamin D, ask your doctor for a serum total 25-hydroxyvitamin blood test4. This will give you information about your baseline vitamin D status and your doctor an idea of how much you may need to supplement.*

2. Take the right form.

Use D3, not D2 (because D3 is significantly more efficacious than D2).* Vitamin D3 is typically derived from lanolin, so strict vegans should find an algal-derived D3, preferably ones that's sourced with sustainability in mind.

To improve absorption, take vitamin D with food that contains some fat since it is a fat-soluble nutrient.*

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3. Take the right amount.

If you have an insufficiency or deficiency, correct it with 5,000 to 10,000 IU of vitamin D3 a day for three months—preferably in partnership with your healthcare provider.*

For maintenance beyond 3 months, 5,000 IU a day of vitamin D3 is useful for most.* Some people may need higher doses, but please discuss this with your provider.*

4. Get rechecked every three months.

Since everyone is a unique individual, genes and all, vitamin D status and response to supplementation can vary, and obviously seasonal changes affect it too.

There are different "optimal ranges." Experts and organizations have different ranges. You want your 25(OH)D levels well over 30 ng/ml. This is the cutoff for clinical insufficiency. Rechecking your levels after three months (and periodically beyond that) is the clinical consensus.

The goal is to keep your vitamin D levels sufficient and steady for life.*

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5. Be patient.

It could take six to 10 months to "fill up the tank" for vitamin D if you're deficient.* Once this occurs, you can lower the dose to a maintenance dose.

As I mentioned earlier, please talk to your doctor about making any changes to your normal health routine, as every body has different needs.

If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.
Mark Hyman, M.D.
Mark Hyman, M.D.
Functional Medicine Doctor & NY Times bestseller

Dr. Mark Hyman is a practicing family physician and an internationally recognized leader, speaker, educator, and advocate in the field of Functional Medicine. He is the founder and director of The UltraWellness Center, the Head of Strategy and Innovation of the Cleveland Clinic Center for Functional Medicine, a 13-time New York Times best-selling author, and Board President for Clinical Affairs for The Institute for Functional Medicine. He is the host of one of the leading health podcasts, The Doctor’s Farmacy. Dr. Hyman is a regular medical contributor on several television shows and networks, including CBS This Morning, Today, Good Morning America, The View, and CNN. He is also an advisor and guest co-host on The Dr. Oz Show.