Vitamin D Deficiency: Symptoms, Causes And Treatments (2024)

Vitamin D plays a crucial role in maintaining our overall health in several ways.

Bone health. Vitamin D helps manage the body’s levels of calcium, the mineral that strengthens our bones and contributes to the proper functioning of muscles, blood vessels, hormones and nervous system.

Immunity against viral infections. Vitamin D has been shown to help prevent viral infections, such as pneumonia, and protect against such infections with its anti-inflammatory and immune support properties, according to one 2020 study in the Journal of Infection and Public Health^[1]Ali N. Role of vitamin D in preventing of COVID-19 infection, progression and severity. J Infect Public Health. 2020;13(10):1373-1380. .

Lung health. Due to vitamin D’s anti-inflammatory, anti-infective and immuno-modulatory properties, the vitamin has been shown to have a beneficial effect on the lungs in people with certain lung issues, such as acute respiratory failure and asthma, according to an article in The European Journal of Clinical Nutrition^[2]Amrein K, Scherkl M, Hoffmann M et al. Vitamin D deficiency 2.0: an update on the current status worldwide. Eur J Clin Nutr 74, 1498–1513 (2020). .

Heart health. Sufficient vitamin D levels are necessary for healthy blood pressure. While some studies have found that vitamin D supplementation can reduce blood cholesterol levels and high blood pressure, other studies show no benefits, so research is ongoing in this area.

Liver health. Vitamin D deficiency has been linked to the progression of fibrosis in chronic liver disease according to some studies^[3]Pop TL, Sîrbe C, Benţa G, Mititelu A, Grama A. The Role of Vitamin D and Vitamin D Binding Protein in Chronic Liver Diseases. Int J Mol Sci. 2022;23(18):10705. .

Diabetes. Vitamin D may also play a role in keeping blood sugar and insulin levels balanced. Several studies have found that vitamin D supplementation reduced the risk of developing type 1 diabetes in infants, especially those aged between 7 and 12 months compared to younger infants. Still, researchers recognize the need for more research around vitamin D and its relationship with diabetes.

Vitamin D deficiency occurs when there are insufficient levels of vitamin D in the body.

A vitamin D deficiency is typically diagnosed via a blood test (a 25-hydroxy vitamin D or 25(OH)D test) and are expressed based on blood volume either as nanograms of vitamin D per milliliter of blood (ng/mL) or nanomoles of vitamin D per liter of blood (nmol/L).

A vitamin D deficiency is when your levels fall below 12 nanograms of vitamin D per milliliter of blood, or 30 nanomoles of vitamin D per liter of blood, per the NIH.

The National Institutes of Health (NIH) Office of Dietary Supplements recommends the amount of vitamin D certain age groups should get each day, in micrograms (mcg) and International Units (IU):

• Birth-to-12 months: 10 micrograms/400 International Units
• Ages 1-to-70: 15 micrograms/600 International Units
• Ages 71 and older: 20 micrograms/800 International Units

FEATURED PARTNER OFFER

Partner Offers feature brands who paid Forbes Health to appear at the top of our list. While this may influence where their products or services appear on our site, it in no way affects our ratings, which are based on thorough research, solid methodologies and expert advice. Our partners cannot pay us to guarantee favorable reviews of their products or services

NativePath Vitamin D3 + K2

• Vitamin D3 + K2 liquid drops absorb rapidly to support strong bones as well as healthy heart, brain, immune function, and more
• Essential for rapid vitamin D3 absorption
• Vitamin D3 helps promote heart function and healthy blood pressure
• Improves mood, energy levels, cognition and reduces risk of depression

Shop Now

On NativePath's Website

See Also

Vitamin-D-Mangel: Anzeichen, Risiken

Deficiency vs. Insufficiency

Mild-to-moderate vitamin D deficiency may also be called vitamin D insufficiency, which is common and categorized as 12-to-20 nanograms of vitamin D per milliliter of blood (30-to-50 nanomoles of vitamin D per liter of blood).

“The majority of patients with [mild-to-moderate] vitamin D deficiency have no symptoms,” says Allyson Ocean, M.D., a gastrointestinal oncologist at Weill Cornell Medicine based in New York City.

The NIH’s vitamin D guidelines also set:

• 20 nanograms of vitamin D per milliliter of blood (50 nanomoles of vitamin D per liter of blood) and higher as adequate for bone and overall health
• Above 50 nanograms of vitamin D per milliliter of blood (125 nanomoles of vitamin D per liter of blood) as too high and potential cause for concern

“Patients with vitamin D severe deficiency are at increased risk for having accelerated bone loss, bone pain and fractures,” adds Dr. Ocean. “Although diseases like rickets (a type of bone disease) or osteomalacia (weak bones) due to severe vitamin D deficiency are now uncommon, except in populations with unusually low sun exposure, lack of vitamin D in fortified foods and malabsorptive syndromes.”

“I would make a strong pitch that at least once a year you ought to do a vitamin D level [blood test],” recommends Ron Hunninghake, M.D., chief medical officer at Riordan Clinic in Wichita, Kansas.

“The clinical manifestations of vitamin D deficiency depend upon the severity and duration of the deficiency,” says Dr. Ocean. “Most people with [mild-to-moderate] vitamin D deficiency (between 15 to <20 nanograms of vitamin D per milliliter of blood [37.5 to 50 nanomoles of vitamin D per liter of blood]) are asymptomatic.”

A common sign of severe vitamin D deficiency in children is rickets, which results in bowed legs, weak bones and other bone deformities. Other noticeable symptoms of rickets include drowsiness, muscle weakness and seizures.

In adults, Dr. Ocean, Dr. Hunninghake and Tanya Mezher, certified dietitian nutritionist and lead functional practitioner at Malla, a functional medicine company, say that vitamin D deficiency can cause:

• Accelerated bone loss
• Increased risk of bone fractures
• Fatigue
• Decreased sleep quality
• Muscle pain, sensitivity or weakness
• Mood disturbances
• Lowered immune response

Prolonged and severe vitamin D deficiency can lead to bone pain and tenderness, muscle weakness, fracture and difficulty walking, adds Dr. Ocean.

According to Dr. Ocean, Dr. Hunninghake and Mezher, vitamin D deficiency can be caused by:

• Reduced sun exposure (occurring in the winter and while wearing UV-protective clothing or sunscreens)
• Decreased vitamin D intake
• Darker skin color
• Aging
• Obesity and gastric bypass surgery
• Diabetes (type 1 and type 2)
• Conditions that limit nutrient absorption in the digestive system, such as inflammatory bowel disease (IBD) and celiac disease
• Certain medications, including weight loss drug Orlistat and steroids such as prednisone, that inhibit the body’s absorption and lower your blood levels of vitamin D

A lack of adequate vitamin D in breast milk may also lead to vitamin D deficiency in breastfed babies; the NIH recommends ​​supplementing babies’ diets with 10 micrograms, or 400 International Units, of vitamin D each day.

“Treatment for vitamin D deficiency typically revolves around diet and lifestyle changes as well as supplementation, depending on the severity of the deficiency,” explains Mezher.

Such changes include getting at least 15 minutes of sun exposure a day and eating more foods high in vitamin D, such as fatty fish (i.e. salmon, tuna and mackerel), cheese, mushrooms and egg yolks.

When it comes to supplementing, moderate doses may be between 2,000 to 5,000 International Units daily, while more severe deficiencies may require “prescription strength mega doses such as 50,000 International Units weekly,” according to Mezher.

Dr. Hunninghake recommends finding a vitamin D supplement that also contains vitamin K2, which helps get vitamin D and calcium to where they need to go, such as bones and teeth, instead of places like the arteries.

“Just like running on a 1/4 tank of gas vs. running on empty—the fuller the tank, the less likely for complications to happen,” says Mezher. “With that said, it is common and generally a positive outlook to get levels back to adequate or normal with proper diet, lifestyle and supplementation.”