Symptoms of Vitamin D Deficiency: How Do You Tell?

Vitamin D deficiency is the most common nutritional deficiency in the world. You might become deficient if you don't get enough vitamin D through diet or exposure to sunlight. There are also a few health conditions and medicines that make it harder for your body to produce vitamin D.

Low vitamin D levels can cause muscle weakness, fatigue, hair loss, and other symptoms. Vitamin D affects most body systems and is important to overall health. Even so, you may not notice symptoms.

This article discusses vitamin D deficiency symptoms, how to find out if you're deficient, and why some people are asymptomatic (have no symptoms).

Who Gets Low Vitamin D Levels?

Among those most likely to have a vitamin D deficiency are:

• Babies who are exclusively fed human milk
  
• People with limited exposure to sunlight, such as those who can't go outside or those who cover all their skin
• Older adults because as you age, your skin doesn't synthesize vitamin D from sunlight exposure as well
• People with dark skin, which makes it harder to make vitamin D from sunlight exposure
• People with obesity or those who have had gastric bypass surgery

Vitamin D is a fat-soluble vitamin. If your gut doesn't absorb fat well, this interferes with absorbing vitamin D dissolved in fat in the diet. Conditions that can interfere with this process include:

• Celiac disease
• Crohn's disease
• Cystic fibrosis
• Ulcerative colitis
• Some liver and kidney diseases

Certain drugs that may affect vitamin D levels include:

• Some cholesterol medications, including Altoprev (lovastatin), Lipitor (atorvastatin), and Zocor (simvastatin) 
  
• Steroids, including prednisone
• Weight-loss medicines Xenical and alli (orlistat)
• Some anti-seizure medications, including Dilantin (phenytoin), phenobarbital, and Tegretol (carbamazepine)
  

Being Asymptomatic With Vitamin D Deficiency 

Most people with vitamin D deficiency are asymptomatic. However, it's easy to overlook nonspecific symptoms or attribute mild symptoms to something else. Symptoms may not be apparent until there are complications. For example, you may not know you have fragile bones until you experience a fracture.

Vitamin D Deficiency Symptoms 

Your body needs vitamin D to absorb calcium, and calcium is crucial to bone health. Vitamin D is also important to muscles, the nervous system, and the immune system.

Symptoms of vitamin D deficiency can include:

• Sleep problems
• Exhaustion, fatigue
• Bone pain or achiness
• Muscle pain
• Muscle weakness
• Muscle twitches, tremors, or spasms
• Sadness, depression
• Mood changes
• Hair loss
• Lack of appetite
• Pale skin
• Tingling in the hands and feet
• Getting sick easily

Vitamin D may not have a direct effect on weight changes. However, related contributing factors may play a role in weight loss or gain, including:

• Symptoms such as loss of appetite and fatigue
• Certain medical conditions and medications
  
• Obesity, weight loss medications, and weight loss surgery

Health Effects of Low Vitamin D

You might be deficient in vitamin D due to diet, lack of sun exposure, or because of certain health conditions or medicines. It's important to get a diagnosis and initiate treatment because severe vitamin D deficiency in children can cause rickets, a condition that leads to:

• Bone deformities
• Stunted growth
• Fragile bones that are easily fractured

In adults, severe vitamin D deficiency can lead to:

• Osteomalacia: Softening of the bones, which is the adult version of rickets
• Osteopenia: Low bone density, a precursor to osteoporosis
• Osteoporosis: A condition characterized by weak, brittle bones that are easily fractured

Vitamin D deficiency is also associated with chronic diseases that may include:

• Cancer
• Heart disease
• Diabetes
• Immune system diseases
• Neuropsychiatric disorders
  

How to Test for Low Vitamin D 

You can determine vitamin D levels with a blood test called 25-hydroxyvitamin D. It's not a routine test, but a healthcare provider might recommend it if you're at high risk of vitamin D deficiency or have symptoms.

Test results report vitamin D as measured by the 25-hydroxy level in nanomoles per liter (nmol/L) or nanograms per milliliter (ng/mL) as follows:

• Deficiency: less than 30 nmol/L (12 ng/mL)
• Inadequate: between 30 nmol/L (12 ng/mL) and 50 nmol/L (20 ng/mL)
• Adequate: between 50 nmol/L (20 ng/mL) and 125 nmol/L (50 ng/mL)
• High that can be associated with adverse effects: higher than 125 nmol/L (50 ng/mL)
  

Ruling Out Other Causes

The symptoms of vitamin D deficiency overlap with those of many other conditions. For example, symptoms such as muscle weakness, fatigue, and sleep problems can look like chronic conditions, including multiple sclerosis (MS) and fibromyalgia. Symptoms such as poor appetite, sadness, and mood changes might mimic a mood disorder like depression.

It's important to report all symptoms to a healthcare provider so they can determine the next steps to rule out or confirm the diagnosis.

Initiating Treatment for Symptoms of Vitamin D Deficiency 

Your vitamin D needs change with age. The recommended amounts in international units (IU) are:

• Birth to 1 year: 400 IU
• Age 1 to 70, including those who are pregnant or lactating: 600 IU
• Age 71 and older: 800 IU

You can get vitamin D fairly quickly by taking dietary supplements. Most multivitamins provide 400 IUs. Other supplements have just vitamin D or vitamin D with calcium. Be sure to take the amount your healthcare provider recommends.

You can also increase vitamin D through diet or by increasing sun exposure. However, your provider may not recommend extra sunlight because of the long-term risk of skin cancer.

When it comes to diet, not many foods contain vitamin D, though many are fortified with it. Some good food sources are:

• Cod liver oil
• Fatty fish such as trout, salmon, tuna, and mackerel or sardines
• Raw, white mushrooms exposed to ultraviolet (UV) light
• Eggs
• Beef liver

Foods fortified with vitamin D include:

• Most milk, including cow, almond, and soy
• Breakfast cereals
• Orange and other juices

A healthcare provider may recommend other therapies, depending on your diagnosis and overall health.

You are unlikely to get too much vitamin D through diet or sunlight. However, when taking supplements, keep in mind that the tolerable upper limit (UL) per day is:

• Birth to 6 months: 1,000 IU
• Age 7 months to 1 year: 1,500 IU
• Age 1 to 3: 2,500 IU
• Age 4 to 8: 3,000 IU
• Age 9 and up: 4,000 IU

Taking more increases the risk of toxic effects. Too much vitamin D can cause high calcium blood levels (hypercalcemia), which can damage the kidneys, soft tissues, and bones. Symptoms include:

• Poor appetite
• Excessive thirst
• Passing more frequent and larger amounts of urine than normal
• Dehydration
• Constipation
• Irritability, confusion
• Fatigue
• Muscle weakness
• Vomiting
• High blood pressure
  

Summary

Vitamin D deficiency is a common problem worldwide. Symptoms include fatigue, muscle aches, and getting sick easily. Severe vitamin D deficiency can lead to serious health issues, such as rickets and osteoporosis. Lack of vitamin D may also play a role in immune system disorders, heart disease, and cancer.

You can find out if you're vitamin D deficient with a blood test. If you are deficient, it's very treatable. Dietary supplements can get your vitamin D level up fairly quickly, but don't take more than your healthcare provider recommends.

Any further treatment will depend on your overall health and if you have related conditions.