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What are normal vitamin D levels?

Medically reviewed by Rosanna Sutherby, PharmD on August 11, 2020. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.


Vitamin D is crucial for overall health (it’s vital for bone health, for starters), but what should vitamin D levels be to be considered in the normal range? From normal levels to symptoms and causes of deficiency, you’ll learn the important facts about the “sunshine vitamin” by reading this guide.

Vitamin D levels: what’s normal?

What should vitamin D levels be to avoid deficiency and support health? The National Institutes of Health (NIH) reports that a vitamin D level between 20-50 nanograms/milliliter (ng/mL) is typically within the adequate range for healthy individuals. It’s worth noting, however, that optimal vitamin D levels vary from person to person and can depend on various health-related factors (like whether someone has certain medical conditions).


Easily check your vitamin D levels with the at-home vitamin D blood test.


How much vitamin D do you need?

The Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine recommends the following general intakes for vitamin D. (However, based on a number of factors, your healthcare provider may suggest doses that are higher or lower than what’s listed—so consider asking your provider for their recommendation.) Note that the amount of vitamin D in foods and supplements is usually expressed in terms of International Units (IU), so “IU/day” refers to “International Units per day.”

Infants 0-6 months:

  • 400 IU/day for adequate intake
  • Upper level intake of 1,000 IU/day

Infants 6-12 months

  • 400 IU/day for adequate intake
  • Upper level intake of 1,500 IU/day

Children 1-3 years old

  • Recommended dietary allowance of 600 IU/day
  • Upper level intake of 2,500 IU/day

Children 4-8 years old

  • Recommended dietary allowance of 600 IU/day
  • Upper level intake of 3,000 IU/day

People 9-70 years old

  • Recommended dietary allowance of 600 IU/day
  • Upper level intake of 4,000 IU/day

People over 70 years old

  • Recommended dietary allowance of 800 IU/day
  • Upper level intake of 4,000 IU/day

Women 14-50 years old who are pregnant or lactating

  • Recommended dietary allowance of 600 IU/day
  • Upper level intake of 4,000 IU/day

Related: Why do we need vitamin D?

Signs and symptoms of vitamin D deficiency

Adults with a vitamin D deficiency may experience fatigue, thinning hair, aches or cramps, changes in mood, depression, or weakness.

In addition, a low vitamin D level may also be associated with an increased risk of certain health conditions like bone weakness (osteomalacia) and heart disease.

In children, a chronically low vitamin D level may lead to rickets. Rickets is a rare disorder that causes bone pain, joint deformities, and muscle weakness. Besides rickets, children who are deficient in vitamin D may experience sore, painful, or weak muscles.

If you’re wondering what your vitamin D levels should be like, you may also be curious to learn how a vitamin D deficiency can affect your overall health.

Current research suggests that low levels of vitamin D may be related to the following health conditions:

  • Cardiovascular disease
  • Diabetes
  • Dementia
  • Alzheimer’s
  • Depression
  • Multiple sclerosis
  • Osteoporosis
  • Osteoarthritis
  • Rheumatoid arthritis
  • Psoriasis

What can cause a vitamin D deficiency?

If you’re wondering what causes low vitamin D levels, here are a few factors that can contribute to a vitamin D deficiency.

Reduced sunlight exposure or inadequate dietary intake

Exposure of the skin to sunlight triggers vitamin D production in the body—making sunlight the main source of vitamin D (and giving this vitamin the “sunshine vitamin” moniker). Dietary supplements can also boost vitamin D levels—but if your dietary intake of vitamin D is inadequate and you aren’t getting enough sunlight, vitamin D levels can drop.

Cystic fibrosis, Crohn's disease, and Celiac disease

Cystic fibrosis, Crohn’s disease, and celiac disease can prevent your intestines from absorbing adequate amounts of various nutrients, including vitamin D.

Weight loss surgery

Weight loss surgeries are meant to reduce the size of the stomach so food bypasses part of the small intestines. This procedure can make it more difficult for the digestive system to absorb nutrients—such as the vitamin D in dietary supplements—which is why people who have undergone these surgeries typically receive careful monitoring by a healthcare provider.

Kidney disease

Kidney disease can reduce the body’s production of an enzyme that’s needed to change vitamin D into a usable, active form—ultimately leading to low levels of vitamin D.

How to get more vitamin D

How do you get more vitamin D? There are three main sources of vitamin D: sunshine, the food you eat, and supplements.

Sunshine

Vitamin D is produced when your skin is exposed to sunlight. There are a number of factors that can affect how much sunlight reaches your skin—including the season, the time of day, the amount of cloud coverage, and air pollution. The melanin content of your skin is also a relevant factor: the darker your skin is, the more sun exposure you need for the body to make enough vitamin D.

In many cases, you can get enough vitamin D just by being outside in the sun for short amounts of time throughout the week. When considering sun exposure as a source of vitamin D production, here’s a helpful rule of thumb to keep in mind: you want to get enough time in the sun without getting burned, as sunburns may increase your risk of skin cancer.

Diet

Unlike many other vitamins, vitamin D can’t be found naturally in too many foods. You can find it in fatty fish like salmon, tuna, and mackerel—with smaller amounts in beef liver, cheese, and egg yolks. Many people also get their vitamin D intake from fortified foods—like fortified milk, yogurt, breakfast cereal, and certain brands of orange juice.

If you’re vegan or lactose intolerant, you may want to be especially aware of how much vitamin D you’re getting from dietary sources (since many natural dietary sources of vitamin D come from meat or dairy products)—and consider taking supplements.

Supplements

Many people get an adequate vitamin D intake through supplements, but it’s important not to overdo it: too much vitamin D can lead to vitamin D toxicity. For this reason, it’s a great idea to talk with your healthcare provider first before beginning regular vitamin D supplementation.

Vitamin D toxicity

Too much vitamin D can result in vitamin D toxicity, which is the opposite of vitamin D deficiency. This occurs rarely, and is typically the result of oversupplementing with vitamin D. Exposure to sunlight will not lead to toxicity because sunlight breaks down any extra vitamin D in your skin. Given the possibility of toxicity due to supplementation, be sure to speak with your healthcare provider about recommended dosages.

Common symptoms of vitamin D toxicity include:

  • Kidney stones
  • Anorexia
  • Diarrhea, constipation, nausea, and vomiting
  • Bone pain
  • Frequent urination
  • Drowsiness
  • Constant headaches
  • Irregular heartbeat

At-home vitamin D test kit

There’s an easy way to find out whether your vitamin D levels are within a normal range —or if they are too low (or too high). Vitamin D deficiencies are common, but thankfully, they can often be easily reversed.

Our at-home vitamin D blood test is a simple but effective way to learn more about your vitamin D status. This vitamin D blood test measures the concentration of vitamin D in a sample of blood to help detect a deficiency. It may also tell you if you’re getting too much of the vitamin through oversupplementation.

Once you order your test kit, it’s shipped directly to you. You register the test online using the unique code that’s included in your kit, then collect your blood sample with a simple finger prick (the kit includes a lancet for pricking your finger along with clear instructions to guide you through the process). Next, you ship your sample to the lab using the prepaid shipping label included with the kit. In just days, your easy-to-understand results will be viewable on our secure, online platform. If you do not have a normal vitamin D status, your healthcare provider may recommend vitamin D supplementation to restore your levels.


Why do we need vitamin D?

3 easy ways to get vitamin D

8 possible causes of low vitamin D levels


References

1. Vitamin D. National Institutes of Health. URL. Accessed August 11, 2020.

2. Vitamin D Deficiency. Cleveland Clinic. URL. Accessed August 11, 2020.

3. Wang H, Chen W, Li D, et al. Vitamin D and Chronic Diseases. Aging Dis. 2017;8(3):346-353. Published 2017 May 2. doi:10.14336/AD.2016.1021