Vitamin D Deficiency Signs and Symptoms

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Vitamin D is an essential fat-soluble vitamin that helps your body better absorb calcium. That makes it an important supplement for bone strength. It also strengthens the immune system and assists the body with turning glucose into energy.

Some consider vitamin D deficiency a "global health problem," reporting that it affects roughly one billion people worldwide. Since it is so common, it's important to know the symptoms of vitamin D deficiency, helping you better identify whether you may need to get your levels checked.

Symptoms of Vitamin D Deficiency

Vitamin D deficiency often has no noticeable symptoms at all. Still, there are four main things to watch for that could indicate a deficiency: muscle weakness or pain, bone weakness and pain, fatigue, and depression.

Note that each of these symptoms is nonspecific and could be present in many other health conditions, so work with your doctor to figure out what the cause could be in your case.

Muscle Weakness or Pain

People with vitamin D deficiency may experience muscle weakness, aches, or cramps, although the symptoms may be very mild at first.

Some studies suggest that low vitamin D levels can also trigger or worsen chronic pain conditions. This is because vitamin D helps regulate the nervous system, so people may become more sensitive to the pain they experience when it isn't available in the needed amounts.

Bone Weakness and Pain

Vitamin D deficiency can also reduce bone strength. Children diagnosed with rickets often have soft bones and skeletal deformities, whereas deficiency in adults can lead to osteomalacia, which is a condition that makes your bones weak.

If you have bone pain, this could also signal vitamin D deficiency. One way to tell bone pain apart from muscle pain is that, with bone pain, the achiness is there when you're still as well as when you are moving around. Usually, muscle pain only flares up when you move.

Fatigue

While fatigue can be a sign that you are training too hard or not getting enough sleep, it could also be a symptom of vitamin D deficiency. That makes this factor one to pay attention to, especially if reducing your workouts and increasing sleep doesn't seem to help.

Research suggests that low vitamin D levels can lead to excessive sleepiness by affecting substances in the human body that are known to help regulate sleep. If there isn't enough of this vitamin to get these substances to react appropriately, sleep is disrupted and fatigue results.

Depression and Other Mood Changes

Another common symptom of vitamin D deficiency is feeling depressed. Like with fatigue, this symptom is associated with a lot of other conditions. Therefore, this is only one potential cause that can easily be verified with a blood test.

One explanation for the connection between vitamin D deficiency and feelings of depression is that the vitamin is involved in a variety of brain processes. When there isn't enough of this vitamin to fully support all of the brain's actions, it's possible for depression to result.

Your healthcare provider can order tests that measure your levels of 25-hydroxyvitamin D, which is the form of vitamin D that circulates in your blood.

Causes and Risk Factors of Vitamin D Deficiency

Not eating foods that contain vitamin D and not getting enough sun exposure may lead to vitamin D deficiency. Certain individuals may be at higher risk for a deficiency.

  • Exclusively breastfed infants do not typically receive enough vitamin D through breast milk to prevent deficiency. It is also recommended that they are not exposed to direct sunlight for long periods of time.
  • Older adults have an increased risk of vitamin D deficiency because their skin's ability to synthesize vitamin D decreases with age.
  • Housebound individuals have little to no sun exposure and are unable to obtain adequate vitamin D from sunlight.
  • Darker-skinned people have more melanin in their skin, which acts as a filter to sunlight and reduces the ability to produce vitamin D from sun exposure. Darker-skinned people need more time in sunlight than lighter-skinned people.
  • People with certain medical conditions that limit fat absorption are at higher risk of deficiency since vitamin D is a fat-soluble vitamin or those that take specific medications.
  • People with obesity or those that have undergone gastric bypass surgery are also at higher risk.

The Endocrine Society and the United States Preventative Services Task Force (USPSTF) does not recommend screening asymptomatic low-risk individuals. However, if you fall into one of the higher risk categories of vitamin D deficiency, they do recommend routine testing. Speak to your doctor if you think screening may be a good idea for you.

How to Prevent Vitamin D Deficiency

There are few actions you can take to help ensure that your body gets enough vitamin D. These include eating more vitamin D-rich foods, spending time regularly in the sun, and taking a vitamin D supplement.

Dietary Sources of Vitamin D

The recommended daily allowance (RDA) of vitamin D is 600 to 800 international units (IU). You can help your body meet this amount by eating foods that contain a good dose of vitamin D, such as:

  • Cod liver oil, 1 tablespoon: 1360 IU
  • Trout, 3 ounces cooked: 645 IU
  • Salmon, 3 ounces cooked: 570 IU
  • Mushrooms, 1/2 cup: 366 IU
  • Milk (2%, vitamin D fortified), 1 cup: 120 IU
  • Breakfast cereal (vitamin D fortified), 1 serving: 80 IU

Your body stores fat-soluble vitamins such as vitamin D, but it would be tough to get too much vitamin D from foods—even fortified foods—unless you consume large amounts of cod liver oil.

Exposure to Sunlight

You need sun exposure to make vitamin D, but it only takes five to 30 minutes of sun exposure on your face, arms, legs, or back twice each week without sunscreen to stimulate sufficient vitamin D production.

Excessive sun exposure will not cause vitamin D toxicity. However, it does increase your risk of skin cancer, so the American Academy of Dermatology does not recommend getting your vitamin D from the sun.

Vitamin D Supplements

Vitamin D is available as an over-the-counter supplement. Before taking this or any other type of supplement, it is always recommended that you speak with your doctor first. This helps ensure that the supplement is safe for you to take.

Speaking with your doctor also helps you decide how much vitamin D you need in the supplement after considering how much you get in your foods and by way of the sun. This helps avoid any potential issues with taking too much, reducing your risk of vitamin D toxicity.

Insufficient levels of vitamin D in the blood have been associated with a variety of other health conditions such as diabetes, hypertension, multiple sclerosis, and some forms of cancer. However, more research is needed to determine if vitamin D can prevent or treat any of these disorders.

11 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Shereen Lehman, MS
Shereen Lehman, MS, is a former writer for Verywell Fit and Reuters Health. She's a healthcare journalist who writes about healthy eating and offers evidence-based advice for regular people.