Vitamin D Deficiency — The Silent Epidemic
Vitamin D is actually not a vitamin but a prohormone that affects more than 2000 genes in the body. It is estimated that 40–80% of the Lithuanian population has insufficient vitamin D levels, especially during the winter and early spring months. For athletes who experience a higher physical load, the need for vitamin D is even greater.
📊 Vitamin D Level Assessment
| 25(OH)D level (nmol/L) | 25(OH)D level (ng/mL) | Status | Recommendation |
|---|---|---|---|
| < 30 nmol/L | < 12 ng/mL | Severe deficiency | 5000–10000 IU/d + physician supervision |
| 30–50 nmol/L | 12–20 ng/mL | Insufficient | 3000–5000 IU/d |
| 50–75 nmol/L | 20–30 ng/mL | Sufficient | 2000–4000 IU/d for maintenance |
| 75–125 nmol/L | 30–50 ng/mL | Optimal | 2000 IU/d for maintenance |
| 125–250 nmol/L | 50–100 ng/mL | High-normal | Reduce dose, monitor |
| > 250 nmol/L | > 100 ng/mL | Toxic | Discontinue, consult a doctor |
Optimal Level for Athletes: 100–150 nmol/L (40–60 ng/mL). This level is associated with the best athletic performance, maximum strength and the lowest risk of injury.
💊 D2 vs D3: How Do They Differ?
Two forms of vitamin D are available on the market. It is important to know the difference because their effectiveness differs greatly.
| Property | Vitamin D2 (Ergocalciferol) | Vitamin D3 (Cholecalciferol) |
|---|---|---|
| Source | Plant-based (mushrooms, yeast) | Animal-based (wool lanolin, fish oil) |
| Effectiveness | 2–3 times less effective | Standard |
| Half-life | Shorter (15 hours) | Longer (15–25 days) |
| Recommendation | Suitable for vegans | Recommended for most |
| Price | Cheaper to produce | Slightly more expensive |
🎯 Dosage Recommendations
By Weight and Level:
- Prophylactic dose (without deficiency): 2000–4000 IU per day. For most of the Lithuanian population, this is the minimum from autumn to spring.
- In Case of Deficiency: 5000–10000 IU per day for 2–3 months, then maintenance 2000–4000 IU.
- For athletes: 4000–5000 IU per day all year round. Intensive training increases vitamin D metabolism.
- For obese individuals: The dose may be doubled because vitamin D accumulates in adipose tissue.
Vitamin D Synergy:
- Vitamin K2 (MK-7): 100–200 mcg per day. Directs calcium to the bones rather than the arteries. Must be taken together!
- Magnesium: 300–400 mg per day. All enzymes that activate vitamin D depend on magnesium. Without magnesium, vitamin D will not work at full capacity.
🏋️ Vitamin D's Impact on Athletic Performance
💪 Muscle Strength
Vitamin D directly affects muscle cell receptors. An optimal level (100+ nmol/L) increases strength compared with deficiency. This is especially important for sprinters and weightlifters.
🦴 Bone Density
Stress fractures — a common problem for athletes. Vitamin D together with calcium increases bone mineral density by 2–4% per year.
🛡️ Immunity
Athletes with vitamin D deficiency get sick 3–5 times more often. An optimal level reduces the risk of upper respiratory tract infections.
⚡ Speed and Power
There is evidence that vitamin D level correlates with sprint speed and vertical jump height. This is related to type II (fast-twitch) muscle fiber function.
🇱🇹 Lithuanian Climate and Vitamin D
In Lithuania, natural vitamin D synthesis in the skin occurs only from May to September, and only when the sun is sufficiently high (between 11 and 15 h). From October to April, UVB radiation is too weak — vitamin D synthesis almost does not occur, regardless of how much time you spend outdoors.