Vitamin D Deficiency: What You Need to Know

What is Vitamin D Deficiency?

Vitamin D deficiency means your body doesn’t have enough vitamin D, a fat-soluble vitamin that’s essential for normal bone development, muscle function, immune health, and calcium absorption. It’s more common than many people think — and often goes unnoticed until symptoms get worse. Vitamin D deficiency can affect anyone and has been increasingly recognized as a common health concern.

According to the National Institutes of Health, nearly 42% of U.S. adults have low vitamin D levels. Among African American adults, that rate jumps to 82%. This rising trend reflects the widespread impact of vitamin D deficiency.

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Causes of Vitamin D Deficiency

You can become vitamin D deficient for several reasons:

• Limited sun exposure — especially in winter, or if you wear sunscreen constantly

• Dark skin — more melanin reduces the skin’s ability to make vitamin D from sunlight

• Low dietary intake — not eating fatty fish, vitamin D fortified milk, breakfast cereals, or egg yolks can lead to vitamin D deficiency

• Health conditions that affect absorption:

  • Celiac disease

  • Cystic fibrosis

  • Inflammatory bowel disease (IBD) like Crohn’s

• Chronic kidney disease or liver disease — reduces your body’s ability to activate vitamin D, contributing to vitamin D deficiency

• Certain medications — like steroids, anticonvulsants, or cholesterol-lowering drugs can worsen vitamin D deficiency

• Obesity (high body mass index) — vitamin D gets trapped in fat cells, increasing the chance of vitamin D deficiency

• Breastfed infants — breast milk contains only small amounts of vitamin D, which may not be enough and can cause vitamin D deficiency

You’re also at increased risk if you’re over 65, have limited mobility, or live in northern climates with less sunlight — all contributing to vitamin D deficiency.

Symptoms of Vitamin D Deficiency

Many people with vitamin D insufficiency or even severe deficiency don’t notice symptoms at first. When symptoms do appear, they may include:

• Muscle weakness, cramps, or spasms — common with vitamin D deficiency

• Bone pain — often in the lower back, hips, or legs, a classic sign of vitamin D deficiency

• Fatigue and low energy

• Hair loss

• Mood changes, including depression or anxiety

• Slow wound healing

• Pins-and-needles sensation in hands or feet

• Frequent illness or respiratory infections, often tied to vitamin D deficiency

In older adults, low vitamin D can increase the risk of falls, fractures, osteoporosis, and severe bone loss — all consequences of chronic vitamin D deficiency.

In children, severe vitamin D deficiency may cause rickets, a condition where bones become soft and bowed. Recognizing these signs early can prevent long-term damage from vitamin D deficiency.

Diagnosis: How to Know If You’re Low

Your provider may order a blood test to measure your serum vitamin D levels (25-hydroxyvitamin D) to check for vitamin D deficiency.

• Normal/adequate vitamin D level: 30–50 ng/mL

• Mild deficiency: < 20 ng/mL

• Severe deficiency: < 10 ng/mL

• Toxicity risk: > 100 ng/mL (rare, usually from too much supplementation)

Other labs may also check calcium levels, parathyroid hormone, and phosphorus absorption to confirm and assess the severity of vitamin D deficiency.

Treatment: How to Fix Vitamin D Deficiency

Supplements

Most people will benefit from vitamin D supplements, especially cholecalciferol (D3). Taking vitamin D supplements is one of the most effective ways to correct vitamin D deficiency.

• Mild deficiency: 1,000–2,000 IU of vitamin D3 per day

• Severe vitamin D deficiency: 6,000 IU daily or 50,000 IU weekly for 8 weeks, followed by a maintenance dose of vitamin D supplements

• In some cases, calcidiol or calcitriol is prescribed if malabsorption or liver issues affect vitamin D metabolism

Always work with your provider to determine the right dosage. Too much vitamin D can cause high calcium levels, kidney damage, or other problems.

Want to know how much vitamin D is right for you? Your provider can help based on your age, medical history, and lab results. It’s crucial to treat vitamin D deficiency with accurate dosing of vitamin D supplements.

Dietary Sources

You can also increase your intake through a few foods, especially:

• Fatty fish like salmon, mackerel, tuna, and sardines

• Beef liver

• Egg yolks

• Fortified foods: milk, yogurt, orange juice, breakfast cereals — all helpful in addressing vitamin D deficiency

These support bone health and your body’s immune system. Vitamin D deficiency is less common in those who eat a balanced, fortified diet.

Sun Exposure

Aim for 5–30 minutes of sun exposure, 2–3 times a week, with arms and legs exposed. People with dark skin may require more time in the sun to produce enough vitamin D. Be cautious of skin cancer risk with prolonged exposure. Lack of sun is a leading cause of vitamin D deficiency.

Co-nutrients

Magnesium and calcium supplementation may improve your body’s ability to absorb vitamin D and maintain calcium homeostasis. Supporting these systems is vital for reversing vitamin D deficiency.

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When to See a Doctor

If you have symptoms like bone pain, fatigue, frequent illness, or are in a high-risk group, schedule a visit with your doctor to get your vitamin D status checked. Maintaining adequate levels is essential for bone health and overall well-being. Addressing vitamin D deficiency early helps prevent long-term complications.

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– Disclaimer –
This blog is for informational & educational purposes only, and does not intend to substitute any professional medical advice or consultation. For any health related concerns, please consult with your physician, or call 911.