Vitamin D Deficiency in Adults
Vitamin D deficiency is one of the most common nutrient deficiencies worldwide, affecting an estimated 40-60% of the adult population. Dr. Charles Kamen, MD, board-certified neurologist at LiveNow Longevity in Las Vegas, screens for and treats vitamin D deficiency as part of comprehensive longevity care.
Why Vitamin D Matters
Vitamin D functions as a hormone, affecting virtually every tissue in the body. It regulates calcium absorption, immune function, inflammatory response, and cellular growth. [1]
Optimal vitamin D status is associated with reduced risk of cardiovascular disease, certain cancers, autoimmune conditions, and all-cause mortality.
Vitamin D Deficiency Consequences
Inadequate vitamin D produces various symptoms and health concerns:
- Bone health: increased fracture risk, osteoporosis, osteomalacia
- Immune dysfunction: increased susceptibility to infections, autoimmune conditions
- Muscle weakness: impaired muscle function, increased fall risk in older adults
- Fatigue and mood: low vitamin D associated with depression and chronic fatigue
- Cardiovascular risk: deficiency linked to hypertension and cardiovascular disease
- Accelerated aging: low vitamin D associated with increased all-cause mortality
Testing and Diagnosis
Vitamin D status is assessed through serum 25-hydroxyvitamin D testing. Dr. Kamen generally targets levels above 40-60 ng/mL for optimal health, though conventional medicine often considers 30+ ng/mL as sufficient. [2]
Treatment Approaches
For significant deficiency, IV vitamin D supplementation may provide advantages over oral therapy for patients with absorption issues or very low levels. Dr. Kamen's approach includes:
- High-dose oral vitamin D for moderate deficiency
- IV vitamin D when absorption is compromised or levels are severely low
- Adjunctive IV therapies: magnesium supports vitamin D metabolism
- Sunlight exposure guidance for natural vitamin D production
- Regular monitoring to ensure optimal levels are achieved and maintained
Key Takeaways
- Vitamin D functions as a hormone affecting multiple body systems
- 40-60% of adults are estimated to be deficient
- Deficiency affects bone health, immune function, and longevity
- IV vitamin D offers advantages for patients with absorption issues
- Regular monitoring ensures optimal levels are maintained
- Dr. Kamen screens for vitamin D deficiency and treats based on individual needs
Common Questions
What is the optimal vitamin D level?
Dr. Kamen generally targets 40-60 ng/mL for optimal health, higher than the conventional "sufficient" threshold of 30 ng/mL.
Can I get enough vitamin D from sunlight alone?
Sunlight exposure can maintain vitamin D in some individuals, but many factors affect synthesis (latitude, skin color, age, sunscreen use). Most patients need supplementation.
Is vitamin D toxicity possible?
Yes, excessive supplementation can cause toxicity. Monitoring levels ensures safe dosing. Symptoms of toxicity include nausea, hypercalcemia, and kidney problems.
Should I take vitamin D with K2?
Vitamin K2 supports calcium utilization and is often recommended alongside vitamin D. Dr. Kamen may include K2 in your supplementation protocol.
What causes vitamin D deficiency besides lack of sun?
Malabsorption syndromes, obesity, kidney or liver disease, certain medications, and older age can all contribute to deficiency.
Can IV vitamin D help if oral supplementation isn't working?
IV bypasses digestive absorption for patients with GI issues or very low levels that oral cannot adequately address. Dr. Kamen determines the best approach.
Vitamin D optimization is fundamental to longevity-focused healthcare. Schedule a consultation with Dr. Kamen to assess your vitamin D status and develop an appropriate optimization strategy.
References
- Holick MF. N Engl J Med. 2024;390(6):535-546.
- Pludowski P, et al. J Steroid Biochem Mol Biol. 2023;231:106308.
- Chowdhury R, et al. BMJ. 2024;386:q1427.
- Bouillon R, et al. Endocr Rev. 2025;46(1):52-76.