Low Vitamin D: What It Means and What to Do Next
Low vitamin D (below 30 ng/mL) affects an estimated 42% of US adults and causes fatigue, bone pain, muscle weakness, depression, and impaired immunity. It is one of the easiest deficiencies to correct — most people respond well to vitamin D supplementation within 8-12 weeks.
What Causes Low Vitamin D?
Limited Sun Exposure
Your skin produces vitamin D from UVB sunlight. Indoor lifestyles, northern latitudes, and sunscreen use reduce production significantly.
Darker Skin Pigmentation
Melanin reduces the skin's ability to produce vitamin D from sunlight. People with darker skin need more sun exposure to produce adequate levels.
Age
The skin's ability to synthesize vitamin D declines with age. Adults over 65 produce about 25% as much as younger adults.
Obesity
Vitamin D is fat-soluble and gets sequestered in fat tissue, reducing the amount available in the bloodstream.
Malabsorption
Conditions like celiac disease, Crohn's disease, and gastric bypass surgery impair vitamin D absorption from food and supplements.
Associated Symptoms
What to Do Next
1. Retest to confirm
A single abnormal result should be confirmed with a repeat test. Temporary factors like stress, illness, or medications can affect results.
2. Related tests to consider
3. When to see a doctor
If your Vitamin D is significantly abnormal, if you have severe symptoms, or if repeated results confirm the abnormality, consult a healthcare professional for appropriate evaluation and treatment.
Related Conditions
Frequently Asked Questions
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This page is for informational purposes only and does not constitute medical advice. Consult a healthcare provider for interpretation of your results.
Content reviewed for accuracy by the JustLabs editorial team.