Vitamin D Deficiency: More Common Than You Think

Up to 42% of American adults are deficient in vitamin D, with even higher rates among women. This "sunshine vitamin" affects far more than just your bones.

Why Vitamin D Matters

Vitamin D is actually a hormone that affects nearly every cell in your body: - Immune function and autoimmunity - Mood and mental health - Bone health and calcium absorption - Muscle strength and pain - Fertility and pregnancy outcomes - Cancer prevention

Who's at Risk?

• People living in northern latitudes
• Those with darker skin
• People who spend most time indoors
• Those with digestive disorders
• Women over 50
• People taking certain medications

Optimal Vitamin D Levels

Most labs list 30 ng/mL as the minimum normal, but research suggests optimal levels are 40-60 ng/mL for most health benefits.

Testing

The test you need is 25-hydroxyvitamin D (also called 25(OH)D). This measures your body's vitamin D stores.

Symptoms of Deficiency

• Fatigue and weakness
• Bone and muscle pain
• Depression and mood changes
• Frequent illness
• Slow wound healing
• Hair loss

References

• Holick, M. F. (2007). Vitamin D deficiency. *New England Journal of Medicine*, 357(3), 266-281.
• Forrest, K. Y., & Stuhldreher, W. L. (2011). Prevalence and correlates of vitamin D deficiency in US adults. *Nutrition Research*, 31(1), 48-54.
• Aranow, C. (2011). Vitamin D and the immune system. *Journal of Investigative Medicine*, 59(6), 881-886.